eHam

eHam Forums => Amplifiers => Topic started by: KB6DYA on April 07, 2019, 04:02:54 AM



Title: Flex power genious xl
Post by: KB6DYA on April 07, 2019, 04:02:54 AM
Why is flex taking so long to introduce the Power Genius? will the addition of a diplexex help the Imd3? in the palstar- 35 IMD-3 with a diplexer. then there is elecrafrt with no diplexex at only -30 IMD3. will you here the -5 db on the air?
Thank you for your thoughts- KB6DYA


Title: RE: Flex power genious xl
Post by: K6AER on April 07, 2019, 08:00:25 AM
Most very high power solid state amplifiers have a very strong third harmonic component. The Genius amplifier is using two 1500 watt pallets and even at legal output could see a third harmonic of 150 watts. In the case of a low pass filter system the power would be reflected back to the final transistors and have to be dissipated.  In a diplexer system the power above your primary output frequency is sent to a load. This helps lower the harmonic output and improves the IMD somewhat but still the harmonic power has to be dissipated.

Either application of a Diplexer or a Low pass filter will be required for a amplifier to meet FCC certification standards. Has the Power Geniuus been FCC certified yet?

With a average dipole under normal band conditions a IMD of -30 dB is marginal and you might hear the difference between -30 and  -35 dB. Throw in a tower with a 6 dB of antenna gain and your signal could be S9 +30 dB. Now that IMD of -35 is not very good and you will be producing S8 sidebands up and down 10 KHz of band width.

I can't imagine that production is held up of over a filter design. The folks at FLex are not dummies. What did the manufacture say about the hold up when you called them?


Title: RE: Flex power genious xl
Post by: K6BRN on April 07, 2019, 10:05:09 AM
The fellows at Flex Radio are not dummies when is comes to digital signal processing.  But I believe that the "Power Genius" was subcontracted out to a former eastern bloc supplier who pretty obviously sold the concept to Flex well before it was ready to be put into production.  And the Power Genius promises all sorts of things, like "Maximum Efficiency", predistortion, heat pipe cooling, diplexer based filters, direct Ethernet control,....etc.  And presumably an affordable price (for hams, which is prety difficult).  It sounds more like a "science project" than a profit oriented product development.  And profit is NOT optional - it's what keeps a firm alive.

So, what could possibly go wrong?  Risk is always multiplicative.  If each "advanced" feature has a 90% chance of success within the required cost/schedule constraints, and there were at least five of them (see short list above - and there are more claims, too), then the overall probability of success, just based on those items alone would be about 60%.  Not good odds for an established shallow-pockets business that was not in the speculative venture capital mode - because there is an existing customer base to dissapoint.

I've had similar problems with suppliers - the only real fix is to recognize the risk right from the beginning and have a simpler but adequate "Plan B" ready to go if they fail or are excessively delayed.  And to limit investment.  Seems like Flex Radio was a little naive about this one and bought a convincing story without a backup plan.  Hopefully they have not sunk too much or their own capital into it, or it could seriously impact them.

Otherwise, just buy a KPA-1500.  It works.

Maybe time to call the Power Genius a loss.  That "Final Mile" getting a new product into production, especially if it is well over its cost/price target, difficult to produce or otherwise unstable, could last forever and drain every drop of capital put into it.  A case-study mistake almost every business school teaches.

I'm sure the principals at Flex are debating this right now.  I genuinely wish them luck and feel their pain.

Brian - K6BRN


Title: RE: Flex power genious xl
Post by: K6AER on April 07, 2019, 10:41:34 AM
A lot of hams do not understand business economics. Technology, declining business base and social norms can make a thriving company out of business in two years. A large influx of hams passing has flooded the market with legel limit amplifiers.

In 2001 NEC was the largest maker of tube computer monitors with over 2 billion in sales. 5 years later they were out of business.

Remember compact florescents? They were going to save the planet. Find one now.

For under $2000 I can buy a very nice Alpha 99 or 91B. So it takes 15 seconds to set the Tune and Load. The extra $4000 save from the Genius is better spent on a tower and beam.

If you are jumping for a 2KW solid state amplifier then buy the RF Kits out of Germany.


Title: RE: Flex power genious xl
Post by: KD8MJR on April 07, 2019, 11:03:45 AM
If I was a new ham i don't know if I would want a tube amp but I do know that turning on the radio and hearing almost nothing would not make me very enthusiastic about spending several thousand dollars on an Amp.


73s
Rob


Title: RE: Flex power genious xl
Post by: K6BRN on April 07, 2019, 11:31:41 AM
Michael:

You're right, most hams do not understand business economics - because they've never had to deal with it, except as an employee, and/or have never had training in it.  Happens a lot in small businesses to.  Plenty of fields of study to explore in this wide world.

The cases you mention below are not really where Flex is.  Solid state amps are where the market is going, big time, for many reasons that have been debated endlessly, not the least of which is that that tube technology has already been "end-of-life'ed" and we are now running on reserve stock and specialty firms whose business base is rapidly eroding.  Not a good place to be for a growing business.

This case might be labeled "New Product Development:  How NOT to do it."

I've been there and taken some very painful lumps - nothing like actual experience as a teacher.  Thankfully I survived and leveraged just what I learned, from my mistakes, my vendor's mistakes and my Customer's mistakes.  This is a learning experience for Flex.

They are developing a new product in an evolving but established market, trying to find a real discriminator (price?  Features?  Performance?  Cachet?)  and have picked Features, Performance AND Cachet at a reasonable Price.  Problem is, that price point is very hard to hit when all of the really critical features are covered by other manufacturers and the new features offered are difficult (expensive/takes a long time/may not perform as promised) to develop and deliver.  And the market volume is limited.  And the promises are becoming stale, which tends to poison the market for the offered product.  Lots of challenges.

As I said above, hopefully Flex has insulated themselves enough against their supplier's issues to make this a "non-issue".

The Flex core (ham) business of developing and delivering top-notch DSP ("software defined", in ham-speak) radios DOES appear healthy, and the hope is that the Power Genius issue will be resolved shortly, with minimum impact to the company.  I'm sure that's the plan, anyway.  The Flex-6400 and -6600 appear to be winner products - a very good sign.  And these radios are designed from the get-go for low-cost manufacturability while maintaining excellent performance.  Very elegant, very smart.  Should provide at least a decent cash flow and profit to leverage to get "over the hump".

Best Regards,

Brian - K6BRN


Title: RE: Flex power genious xl
Post by: K6AER on April 07, 2019, 02:29:23 PM
Brian,

I wonder how many millennial hams who buy homes in the urban nightmare with a S9 noise level will ever spend money for that level of sophistication? There is so much equipment on the used market now day's.

It is obvious by the questions I read in this forum and others that the technical has been greatly dumbed down. I can see the attraction of new hams thinking they don't have to learn much by buying a SS amp but antenna physics are still the same and still much has to be learned to be successful in QSO's.

If the ARRL wanted to really help the hobby they could give a copy of the ARRL handbook to every new ham. Then we could have regional jeopardy technical games.

"Alex, I will take Triodes for 50"


Title: RE: Flex power genious xl
Post by: G3RZP on April 07, 2019, 02:49:06 PM
K6AER,

Do you not need both a diplexer and a low pass filter, so that the majority of the reflected harmonic power goes to the load but the remainder still gets filtered out?

Quote
It is obvious by the questions I read in this forum and others that the technical has been greatly dumbed down.

Very, very true.....


Title: RE: Flex power genious xl
Post by: M0HCN on April 07, 2019, 03:58:45 PM
This thing is for use with a SDR in a closed (modulation domain) loop feedback scenario, not so?

If so then the reflected third harmonic can actually be used to LOWER device dissipation, if the reflected phase can be worked correctly by a combination of filter design and line length.
Sure it hurts linearity, but if the thing has a bucketload of modulation feedback then it should still be better then most of the other stuff out there. This is more often seen in VHF and UHF amplifiers where the harmonic tuning can be done with printed lines, but you can do it at HF using suitable design of a third harmonic trap before the main LPF. Doing it gets you about a 10% improvement in efficiency.
See multiple discussions of class F amplifiers.

I would not be surprised if they are trying to do drain modulation as well, which is really good for efficiency in SSB or QAM modes with high crest factors, but introduces some nice traps when combined with RF feedback (Gate puncture if you get too far into saturation due to the modulator not keeping up has cost me a few expensive LDMOS parts). PIN diodes and actually monitoring the gate voltage and feeding it to the drain voltage controller is helpful here. 

All of this stuff works on my bench, but works on the bench is one thing, works 100% into some badly maintained aerial and when hooked up with cheap coax full of water is quite another, works and gets FCC and CE (Which is tricky as this is a intentional radiator, so self cert is out) approval is a very other sort of problem. Doing it at a price which actually makes money? Tough, very tough. 

73 Dan.


Title: RE: Flex power genious xl
Post by: K6BRN on April 07, 2019, 04:56:51 PM
Michael:

Quote
I wonder how many millennial hams who buy homes in the urban nightmare with a S9 noise level will ever spend money for that level of sophistication? There is so much equipment on the used market now day's.

Smartphones are the primary tool of the Millennial. Instant communications, instant data, instant processing, anywhere.  No legacy knowledge of love of tubes anywhere in their experience.  How do you think they'll react to a tube amplifier.  That they can't get parts for.  And have to adjust every time they use it.  IMHO its pretty much a foregone conclusion.

Quote
It is obvious by the questions I read in this forum and others that the technical has been greatly dumbed down. I can see the attraction of new hams thinking they don't have to learn much by buying a SS amp but antenna physics are still the same and still much has to be learned to be successful in QSO's.

To really BE technical, you HAVE to be trained, by school, by mentoring, or with a very, very few, by experimenting.  Part of the work I've been asked to do is mentoring of 1st level engineers with 0-5 years of experience.  I've had zero problems with capability - the same mix it always was - brilliance, motivated and competent and needs help.  Colleges in the USA are doing a very good job, in my experience.  The best engineers will hit six figures income not very long after graduating with a... BSEE, for example.  And they'll have lots of experience with digital signal processing.  No mysteries about FLEX Radio to them.

There are more than 270,000 Electrical and related Engineers in the USA, and many more with technical degrees of one kind or another that provides a decent foundational background.  Maybe we should attract THEM and let them do the "heavy lifting".  Because they have the knowledge, they have the income, and they WILL have children.  No doubt they will also live in an urban environment.

Others that wish to enjoy ham radio and do NOT have a technical background will need to start with an "Elmer", will need to be primarily "appliance operators" and willl have a long journey in front of them.  But... if that journey is part of the fun of this hobby, then it's all worthwhile and we probably should not hammer on them for how they take enjoyment.

How many hams today can code up a 64-point FFT in MatLab, or in VHDL or Verilog?  How many know it needs a windowing function to be really useful?  Or what potential windowing functions are?  A few, maybe.  Not many.  (This work pays REALLY well, though)  I'm pretty sure there are MANY, MANY more who are competent CW operators.  An interesting skill.  But not terribly relevant today.  So.... those simple facts make 95% of hams "appliance operators" on new radios.   And that's OK with me.  It's all about fun, not status.

Just some personal philosophy...

Brian - K6BRN




Title: RE: Flex power genious xl
Post by: KB6DYA on April 07, 2019, 05:12:18 PM
I am sorry if I dumbed down the hobby. I use this form to gain knowledge. I know I am not the sharpest pencil in the box. So I will not be using this site to gain more knowledge and information. Thank You KB6DYA


Title: RE: Flex power genious xl
Post by: N0YXB on April 07, 2019, 05:30:42 PM
I am sorry if I dumbed down the hobby. I use this form to gain knowledge. I know I am not the sharpest pencil in the box. So I will not be using this site to gain more knowledge and information. Thank You KB6DYA

You have nothing to apologize for, keep doing what you're doing. Some oldtimers seem to forget how long it took them to accumulate their vast knowledge. Brian sums it up pretty well, IMO.

To really BE technical, you HAVE to be trained, by school, by mentoring, or with a very, very few, by experimenting. 

Others that wish to enjoy ham radio and do NOT have a technical background will need to start with an "Elmer", will need to be primarily "appliance operators" and willl have a long journey in front of them.  But... if that journey is part of the fun of this hobby, then it's all worthwhile and we probably should not hammer on them for how they take enjoyment.

How many hams today can code up a 64-point FFT in MatLab, or in VHDL or Verilog?  How many know it needs a windowing function to be really useful?  Or what potential windowing functions are?  A few, maybe.  Not many.  (This work pays REALLY well, though)  I'm pretty sure there are MANY, MANY more who are competent CW operators.  An interesting skill.  But not terribly relevant today.  So.... those simple facts make 95% of hams "appliance operators" on new radios.   And that's OK with me.  It's all about fun, not status.



Title: RE: Flex power genious xl
Post by: K6BRN on April 07, 2019, 05:41:47 PM
Oren (KB6DYA):

Crimeny, irony and sarcasm is supposed to be MY tag-line!  Cut it out!  :)  Just kidding.  You do it well. (Sigh!)  Competition!

Nobody has to be the "sharpest pencil in the box..." to enjoy ham radio.  If you're having fun and learning, too, I'd say you're doing pretty well.  And you're probably selling yourself well short, too.

This is NOT the "Hobby of Geniuses", it's the hobby of "Anybody who wants to (as long as you follow a few simple rules that the FCC has kindly laid down and spelled out)"

ITS.  A.  HOBBY.

Big money?  Little money?  MIT Summa Cum Laude?  High school only? King?  Senator?  Nobel laureate?  Nobody at all to speak of?  That's OK.  The only guideline that I THINK is valuable is that if you are having fun, enjoy the hobby.  If you're not, or have more improtant things to do, drop it.

Many operators come and go, and sometimes come back (like me).

Be cool, dude!  (Am I dating myself?  Hmmm.)

Brian - K6BRN





Title: RE: Flex power genious xl
Post by: M0HCN on April 08, 2019, 05:11:44 AM
It is a multi faceted hobby, for me pushing the technical limits is the fun, but (for example) contests are a complete turn off, while others consider a contest using whatever is the latest box from Icom to be cool, and others like the DX hunting, it takes all sorts, and I would not argue that my thing is in some strange way 'better' then another.

My spare room having a pile of HP, Anritsu, and Lecroy kit does NOT make me a more serious ham then someone who has a room full of log books and contest certificates, it just means we have different interests. Same with the fact that I don't know CW, sure I could learn, but it is not a mode that interests me much.

Why would anyone code up the butterflys in matlab? It has a perfectly good built in function to do FFTs of almost any length?

And yes, I can write an FFT in VHDL (Not generally a lot of point the vendors have IP for this), the windowing is of course important and choice will depend on what matters to you, Blackman made a career out of publishing a mess of different windowing functions, but Hann, Bessel, Hamming, Chebyshev, Harris, Walsh and others all have window functions named for them.
Sometimes writing something a bit more specialist can save a useful number of LUTs, say Gortzels algorithm instead of using a full up FFT.
Windowed Sincs are useful for computing FIR coefficient sets, and essentially the same windows apply.   

I am (mostly) a self taught hacker dating from before all knowledge was in google, so it is possible to get reasonably technically competent without spending three years for a degree. 

73 Dan.


Title: RE: Flex power genious xl
Post by: K4QXX on April 08, 2019, 05:30:55 AM
Per the Flex community site, there have been several people that have received their amps recently.  Hopefully Flex can ramp up production now and get caught up with all the back orders.


Title: RE: Flex power genious xl
Post by: VK3BL on April 08, 2019, 06:06:01 AM
Most very high power solid state amplifiers have a very strong third harmonic component. The Genius amplifier is using two 1500 watt pallets and even at legal output could see a third harmonic of 150 watts.

Second harmonic component.

If it was third, then by definition IMD3 would be -10dB in the above scenario, and not filterable by any practical means.

Even Harmonics = Filterable

Odd Harmonics = Passband

I can't believe all the pompous talk and postulation below when the first comment made should have been immediately picked up on. We should be Elmering here not telling people they've got no chance unless they have a college degree.



Title: RE: Flex power genious xl
Post by: W9IQ on April 08, 2019, 06:20:59 AM
Jarrad,

I believe you will find that the diplexer filter design is primarily there to absorb, rather than reflect, the third harmonic of the fundamental RF frequency. That is the minus -10 dB point. It has nothing practical to do with IMD.

 - Glenn W9IQ


Title: RE: Flex power genious xl
Post by: VK3BL on April 08, 2019, 06:39:27 AM
Jarrad,

I believe you will find that the diplexer filter design is primarily there to absorb, rather than reflect, the third harmonic of the fundamental RF frequency. That is the minus -10 dB point. It has nothing practical to do with IMD.

 - Glenn W9IQ

I understand the principle purpose of a diplexer filter, nor dispute that the claimed levels are not right; what I'm not certain of is whether it makes any sense to speak of it as absorbing the 'third harmonic', when we could talk about it absorbing the second, fourth, 6th or whatever, and retain compatibility with common Ham convention.

I'm sure there is a good enough reason to refer to it as such as you suggest.

Certainly, it is worth exploring the different conventions when half the thread is about the 'third order' IMD performance of Diplexer based vs Traditional Filter based dual LDMOS designs. 

As you suggest, if the primary purpose of the filter is to absorb the third (6th?) harmonic of the fundamental, then one cannot directly draw any correlation with 3rd order IMD performance improvements.


Title: RE: Flex power genious xl
Post by: W9IQ on April 08, 2019, 07:37:19 AM
Jarrad,

You are quite right about the higher order harmonics. These will also go into the dump resistor since that part of a diplexer is simply a high pass filter. My comment about the 3rd harmonic was simply contextual to the thread.

There is probably a case to be made that the diplexer helps to stabilize the finals and thus improves linearity. I don't know if that is the causal to improved IMD performance. Perhaps someone can enlighten us.

- Glenn W9IQ


Title: RE: Flex power genious xl
Post by: K6AER on April 08, 2019, 07:41:51 AM
A diplexer is not just to channel harmonics into a termination load but keeps the power from heating the device when power would be reflected under a normal low pass filter design. The third harmonic has most of the harmonic power in a solid state design application.

IMD, that is the  reciprocal mixing of a two tone signal has nothing to do with primary signal harmonics.


Title: RE: Flex power genious xl
Post by: W9IQ on April 08, 2019, 07:51:39 AM
A diplexer is not just to channel harmonics into a termination load but keeps the power from heating the device when power would be reflected under a normal low pass filter design. The third harmonic has most of the harmonic power in a solid state design application.

IMD, that is the  reciprocal mixing of a two tone signal has nothing to do with primary signal harmonics.

Isn't that what I said in my two posts above? I am trying to determine if there is a subtle difference that I am missing...

- Glenn W9IQ


Title: RE: Flex power genious xl
Post by: M0HCN on April 08, 2019, 07:57:28 AM
Not sure I have ever seen the 3F component referred to as the second harmonic before, certainly it is not common RF usage.

In a push-pull stage (which almost all the high power HF solid state designs are), the harmonic at three times the carrier is usually both the biggest and the most difficult to filter sufficiently (Particularly if, as is common practise, you are trying to cover multiple bands with a single LPF).

While it is possible to view the harmonics as a degenerate case of IMD, it is not usually all that useful because the IMD components that we care about are those that cannot be filtered out, which are typically the difference terms where the difference falls in band, so 2F1-F2, 3F1-2F2 and such. The harmonic terms 2F1, 3F1, 4F1, 5F1 and such are easily filtered as they appear well above the band we are working...

Normal ham practise seems to be to consider the multiples of a single tone to be harmonics while the difference components that fall in band are considered to be IMD, which makes sense because the treatment of the two is different.

The reflected harmonics from a filter do NOT have to wind up as heat in the finals, and can actually be used to reduce heating by making the voltage (or current) waveform more closely approximate a square wave, which is arguably a better use for them then heating up a dump resistor.

73, Dan.


Title: RE: Flex power genious xl
Post by: W9IQ on April 08, 2019, 08:10:55 AM
Dan,

Can you elaborate on this last point?

Quote
The reflected harmonics from a filter do NOT have to wind up as heat in the finals, and can actually be used to reduce heating by making the voltage (or current) waveform more closely approximate a square wave, which is arguably a better use for them then heating up a dump resistor.

Thanks,

- Glenn W9IQ


Title: RE: Flex power genious xl
Post by: K6BRN on April 08, 2019, 08:23:55 AM
Hi Dan:

Hacking is nice, but generally does not pay well.  Businesses, like people, cast their real votes with their wallet.

Engineers emerging with a 4 or 5 year (not three, BTW).undergraduate degree in EE, plus FPGA/ASIC and/or Systems Engineering skills are VERY well paid, right out of the box and generally have no problem finding work.

There is no real substitute for training, in the professional world.  Only a very, very few can "make it" as a professional on their own.

BTW... the reason you'd want to "code up" your own FFT in Matlab is to perform clockwise/bitwise co-verification with a power optimized VHDL/Verlog simulation.  There are about a million ways to reduce complexity, power and cost in an FFT implementation, and the built in Matlab FFT function knows nothing about optimizations that yield simpler designs, perhaps at the expense of some small error terms.

Its all about training.  Which is why trained professionals are so valuable to a business that needs to develop a competitive product and be credible to investors and clients.

No such requirements in amateur radio... its all about fun... and learning.  Because its a hobby, not a paying profession.  The two are not equivalent in any way.

Brian - K6BRN


Title: RE: Flex power genious xl
Post by: K6BRN on April 08, 2019, 08:46:40 AM
Glenn:

Quote
Dan,

Can you elaborate on this last point?

Quote
The reflected harmonics from a filter do NOT have to wind up as heat in the finals, and can actually be used to reduce heating by making the voltage (or current) waveform more closely approximate a square wave, which is arguably a better use for them then heating up a dump resistor.

I presume that's a rhetorical question?  :)

Brian - K6BRN


Title: RE: Flex power genious xl
Post by: W9IQ on April 08, 2019, 08:49:31 AM
Not at all. He seemed to have an idea that I have not heard of before and I am interested in learning about it.

Diplex filters for linear amplifiers, on the other hand, were well described in the prior century.

- Glenn W9IQ


Title: RE: Flex power genious xl
Post by: K6BRN on April 08, 2019, 08:59:17 AM
Glenn:

I see.  Very appropriate.

I'd like to learn,  too.  Other than step function testing, when is driving current or voltage to look like a square wave a good idea in a communications system?

Brian - K6BRN


Title: RE: Flex power genious xl
Post by: M0HCN on April 08, 2019, 09:02:50 AM
W9IQ Consider a saturated power stage (If the stage is not in saturation then there are likely other things you can do to improve the efficiency), then with a broadband termination, the voltage across the device and current thru it overlap, producing heat.

In the ideal case, by reflecting the harmonics with the correct phase relationships you can square one of these waveforms up producing far less overlap and hence less heat, this is class F, and is in the literature. In practise in a HF amplifier, I have not managed better then about a 10% improvement in DC->RF efficiency, but that is worth having as it makes the cooling easier. It is instructive to take a power amp and measure the efficiency with various lengths of line between the amp and the LPF. You can do much better in a microwave or UHF stage because stub lines are just more practical up there.

For an example in a current fed (Choke in the DC feed) 6M amplifier you could use a 1/4 wave coax line at 156MHz to provide a short circuit termination to the drains at third harmonic, as well as providing some of the capacitance needed to tune out the parasitic inductance at 6M, not tried that, but it is a simple example, and might work quite well.

K6BRN, The four year undergrad thing is a US perversion, ours get it done in three by not doing the Major/Minor thing.

I work designing the doings of equipment for the TV broadcast industry so yea, it can be done without the paper, I have product out at NAB this week in contention for an award, and while the training is nice, If you can design digital logic, VHDL and constraints files are not a big leap even for an amateur.

Personally, if writing a bit exact simulation model for a VHDL core, I would be reaching for C or C++ in all probability, Matlab is a wonderful tool but not in my view for this.

73 Dan.


Title: RE: Flex power genious xl
Post by: W9IQ on April 08, 2019, 09:27:29 AM
Thanks, Dan for the explanation. I was thinking class AB. Now I understand your intent.

- Glenn W9IQ


Title: RE: Flex power genious xl
Post by: K6BRN on April 08, 2019, 12:59:36 PM
Hi Dan:

Quote
K6BRN, The four year undergrad thing is a US perversion, ours get it done in three by not doing the Major/Minor thing.

I work designing the doings of equipment for the TV broadcast industry so yea, it can be done without the paper, I have product out at NAB this week in contention for an award, and while the training is nice, If you can design digital logic, VHDL and constraints files are not a big leap even for an amateur.

Nothing perverted at all about the U.S. higher educational system,  Seems to work pretty good.  As does the U.K.  system.  I was at the University of Edinburgh not to long ago and spent a week with students there:  Scottish, English, German, American....  I was impressed.

Once of my critical mentors was a Brit by the name of Jack Bryan.  Ex RAF.  Very smart, very capable, very trained.

Also did plenty of co-development work with GEC Plessy, back in the day and got to know their engineering staff very well over more than a few pints.  (pre-ITAR)  Also well trained.  Kind of like in the U.S.

So I know it works about the same over here as in your neck of the woods.  There are some differences, but training counts.  Always. 

Glad to hear you skipped all that and were able to make it on your own.  Very few do.  It's a real achivement.  Really.

Also glad to hear that you think engineering is simple and are not intimidated by it.  Of course its simple.  All of it.  Kids do it in High school with robotics.  Easy to blast through 4-5 years of university and come out with a degree, right?

But qualification in ham radio is not what's required to be professionally successful.  Some incredibly hard work in school and in engineering is the usual path, for those that can do it.  Again, the minority.  You see, for me, it took effort.  And still does.

But that is NOT what my replies above were about.  They were about the (non-existant) requirement that amateur radio operators have in-depth technical knowledge of radios, antennas, etc.  And the fact that a lot of pseudo-experts on the forums, who could not make a living at what they profess to be experts in if their lives depended on it, hammer on what they call "appliance users".

As I KEEP ON SAYING - ITS A HOBBY OPEN TO EVERYONE.  AND IF THE PERSON WHO JOINS THE HOBBY AND ENJOYS IT AND EVEN LEARNS, THEY ARE SUCCESSFUL.  NO NEED FOR IN DEPTH TECHNICAL EDUCATION OR WEALTH OR FAME.  JUST ENJOY IT.

Regarding criticism of education - my obsevation is that the detractors are invariably the ones who've not tried it.  Sounds a lot like some antenna arguments over wire antennas that are popular on the forums.  And just as silly,

Best Regards,

Brian - K6BRN





Title: RE: Flex power genious xl
Post by: M0HCN on April 08, 2019, 02:00:11 PM
All too true, but if you think radio and RF are bad for 'cargo cult' "engineering", you should take a look at audio, sigh.

I concur with the ragging on 'appliance' operators, totally unreasonable IMHO, there are folks running black box rigs, in SSB  who are better at the operational side of radio comms then I will ever be, and more power to 'em.

On aerials I do so wish a few more people had read (and understood) "Fields and waves in communications electronics" before pontificating on that subject, but it is the internet, trying to correct all the 'not even wrong' would drive you mad, better just to grin hit next.

Most engineering is simple most of the time, but that is not the same thing as easy....
I sweated my way thru line and surface integrals so I could understand Maxwell, and use it about once in a blue moon in reality.
For every properly hard problem you hit in design there are dozens of stupid little 'datasheet clone' power supplies, IO ports and memory interfaces.

For the avoidance of doubt I am all in favour of education, but I am just a little leery of the formal route being right for everyone.

Regards, Dan.


Title: RE: Flex power genious xl
Post by: K6AER on April 08, 2019, 02:38:32 PM
A diplexer is not just to channel harmonics into a termination load but keeps the power from heating the device when power would be reflected under a normal low pass filter design. The third harmonic has most of the harmonic power in a solid state design application.

IMD, that is the  reciprocal mixing of a two tone signal has nothing to do with primary signal harmonics.

Isn't that what I said in my two posts above? I am trying to determine if there is a subtle difference that I am missing...

- Glenn W9IQ

Glen,

You and I posted at about the same time.


Title: RE: Flex power genious xl
Post by: KB6DYA on April 08, 2019, 03:41:56 PM
To every one who submitted something Thank You. Just to remove any doubt I am a " appliance operator " I like rag chewing and that's about it. I just want the BEST sounding station I can get. I did all the experimenting and building 50 years ago and I do not care to do it any more. Mike thanks for comet about adding a beam would make things worse. Here is what I decided to do I have a Alpha 8410 with 4cx1500b tubes ( very clean ) I will sell my ic 7610 and buy a Anan 7000 or 8000 and add a 0 DB coupler to the output of the amp and feed that back as "pure signal " and keep the amp to 1k and watch the mic alc and I SHOULD have a clean signal.That is best I know how to do it.  Thank You KB6DYA Oren


Title: RE: Flex power genious xl
Post by: VK3BL on April 09, 2019, 03:10:56 AM
To every one who submitted something Thank You. Just to remove any doubt I am a " appliance operator " I like rag chewing and that's about it. I just want the BEST sounding station I can get. I did all the experimenting and building 50 years ago and I do not care to do it any more. Mike thanks for comet about adding a beam would make things worse. Here is what I decided to do I have a Alpha 8410 with 4cx1500b tubes ( very clean ) I will sell my ic 7610 and buy a Anan 7000 or 8000 and add a 0 DB coupler to the output of the amp and feed that back as "pure signal " and keep the amp to 1k and watch the mic alc and I SHOULD have a clean signal.That is best I know how to do it.  Thank You KB6DYA Oren

Firstly,
Apologies to those affected regarding my lack of understanding of the usage of '3rd harmonic' with reference to diplexer filters; I was conflating it with two tone IMD measurements as Glen picked up on.


Oren: Sounding the best and having the cleanest station are not the same objective, or even particularly compatible objectives.

IMHO <30dBm IMD3 & 5 is a reasonable standard; others will differ because they can achieve significantly better results into a dummy load (as have I) but achieving those levels in practice is another story.

Not everyone can do it, and if you set your heart on -50dBm (10,000x less energy) prepare to be disappointed when someone tells you you're only -20 on their built in band scope because they've left the NB on or whatever.

I suggest you take a look at some of your local AM BC stations on your scope, and see what IMD levels they're meeting.  Then consider the fact they were once fully engineered by the best and brightest, with antennas physically isolated from near field passive IMD producing structures etc etc. 

Be responsible in achieving a clean signal (don't overdrive everything), but recognise that achieving better than -30dBm IMD3,5 into anything other a closed loop system (aka a dummy load with a sampler and a receiver you control) is likely to be an exercise in diminishing rewards. 

Really, it can suck the absolute life out of the hobby trying to please both the 'golden ears' and the 'imd critics' at the same time.  I've been there, having purchased an ANAN myself and run pure signal etc.

Have fun, and realise that if you're on air, someone is going to complain sooner or later about something.  The amount of 'wide signal' FT8 reports I got working 80M DX from locals was amazing, I even got a screenshot from a guy accusing my station of being 40kHz wide!  40!!! 

I've recently setup a second station 10 miles away, and have never been able to reproduce the "issues" I've had people claim from time to time.  I wasn't able to using local monitoring, I wasn't able to using WebSDRs, and now I'm unable to detect any out of spec performance with another station 10 miles away.

The moral of the story?  Have fun and don't worry about the people who run PreAmp2 on 80M with the NB on and NR cranked up too (aka don't know how to setup their receiver), but feel the need to tell you how to set up your transmitter...

Oh, and don't tell the local DXers when you achieve DXCC on 160M or 80M.  Just my advice for what its worth ;)


Title: RE: Flex power genious xl
Post by: VK3BL on April 09, 2019, 03:51:23 AM
Also, it's worth noting the IC-7610 and most 12v radios are significantly cleaner below 50W, where IMD5 stops becoming the dominant product and IMD3 emerges (this is a good thing as it reduces the overall bandwidth of your signal).

I believe the Alpha 8410 is quite a low drive amplifier?  If so, your current combination can probably achieve a very clean signal if you aim for a PEP power of 1Kw.  That would be about 30w drive from what I can tell from alpha's website.

I'd imagine you could achieve -40dB IMD3 with an output of between 800w to 1000w PEP (read with something like a Telepost LP-100), into a dummy load.

Be it solid state or tube, the greater the headroom you have, the cleaner your signal will be.  If you push things harder, you'll get thru the noise better, most likely won't sound any worse, but will have a wider signal.

Really, the best thing to do is to run the radio at low output into the amp (tuned for full power of course), and only dial up the power as needed for the QSO.  That way you'll always have a great sounding clean signal, and be least likely to upset others. 

Below 25w output, the IC-7610 is as clean as anyone realistically needs; go down to 10W or lower and you'd essentially have to say its running in Class A when you look at a 2 tone test.  I think I have plots on youtube from memory.


Title: RE: Flex power genious xl
Post by: K6BRN on April 11, 2019, 08:45:24 AM
Oren:

I hope you're kidding.  The IC-7610 is a fine radio.  I understand that you may be bored, and that's a reason to move on, but the ANAN will probably not be more satisfying - in fact, it's probably going to be quite frustating, so my advice is:  Don't burn your bridges."

Regarding (TD) IMD... there is just a little too much focus on that by just a few people in the ham community.  And some of them have really screwed up their own TX signals by trying to apply active feedback in ways they do not understand and can't measure.  Fixed and active equalization of TX signals is pretty much standard in my industry, and has been for decades.  Done wrong, it results in a lot of problems.  And I don't think the amateur radio community has a good, consistent and uniform (appliance operator friendly) approach to doing this.

Personally, my ham friends and I have had a lot more problems with IMD on the RX end, especially at repeater sites and special operations, like Field day and IOTA.  Passive intermod products (PIMs) and saturation of RX front ends in dense RF environments has long been a REAL issue in these cases.  But you don't really hear the IMD crowd chanting about this.  No "Torch to Carry" about equipment manufacturers gone wrong, I suppose.  PIMs will be a much bigger problem now that we're getting into use of weak signal modes, like FT8, in Field Day.  Dissimilar metals, some slight corrosion between key antenna components or support structures, bad connectors on coax... and who's EVER seen this on Field Day (Everyone who's looked), and PIM product will pop up on the waterfall all over the place.  Maybe 15-30 dB down - but, HEY, that's where weak signal modes look for contacts.

Have fun, always, and Best Regards,

Brian - K6BRN


Title: RE: Flex power genious xl
Post by: W3RSW on April 11, 2019, 11:51:42 AM
Regarding IMD levels on commercial AM stations, yes it would be interesting to have a station eliminate the normal audio programming and put two equal tones or the three tone test (at three levels) on their carrier, otherwise we might confuse normal fully processed audio spikes for IMD on our typical, uncalibrated of course, but approximately representative SDR panadaptors. ;D

So I wonder what shows on a calibrated spectral analyzer at the same station using only two tone, etc.  Then When normal fully processed audio is run, IM3, 5, 7... may be superimposed on equal freq. audio spikes with all the concomitant overtones if just a few Hertz off, etc. and same for all the rest of the multitudenous, well infinite probably,  frequencies. A real cacophony. But somehow if not overdriven, or over processed, etc. really nice audio comes out of a decent receiver using decent demodulation of that station’s signal.  ;D


Title: RE: Flex power genious xl
Post by: K6BRN on April 11, 2019, 12:43:45 PM
I used to live less than a mile from a commercial AM station.  IMD was the least of my worries.  It was the incredible amount of passively demodulated programming rubbish coming out of phones, unpowered speakers and (I kid you not) the decoupling caps on the power supply of an old Imsai 8080 computer I had that drove me nuts. (Hence the person who stands before you, today.)


Title: RE: Flex power genious xl
Post by: K6AER on April 11, 2019, 01:17:58 PM
Some interesting reading on Digital AM transmitters IMD.

http://www.measurement.sk/2004/S3/Horevajova.pdf

The White Paper is from:

Measurement of AM Transmitters for Digital Audio Broadcasting J. Horevajová, K. Ulovec

Department of Radio Electronics

Faculty of Electrical Engineering, Czech Technical University in Prague.


Looks like most transmitters are a bit better than -30 dB two tone.


Title: RE: Flex power genious xl
Post by: VK3BL on April 13, 2019, 02:42:53 AM
Regarding IMD levels on commercial AM stations, yes it would be interesting to have a station eliminate the normal audio programming and put two equal tones or the three tone test (at three levels) on their carrier, otherwise we might confuse normal fully processed audio spikes for IMD on our typical, uncalibrated of course, but approximately representative SDR panadaptors. ;D

So I wonder what shows on a calibrated spectral analyzer at the same station using only two tone, etc.  Then When normal fully processed audio is run, IM3, 5, 7... may be superimposed on equal freq. audio spikes with all the concomitant overtones if just a few Hertz off, etc. and same for all the rest of the multitudenous, well infinite probably,  frequencies. A real cacophony. But somehow if not overdriven, or over processed, etc. really nice audio comes out of a decent receiver using decent demodulation of that station’s signal.  ;D

It's not that hard at all to do.

Ignoring Ham Transceivers, one can use an SDR Play (accurate to ~1dB due to the design target of its ADC - demodulating QAM-256) and FFT averaging to get a good picture of the occupied spectrum.  Then just measure the power of the passband compared to the skirts.

Sure its not a '2 tone' measurement; its better!


Title: RE: Flex power genious xl
Post by: VK3BL on April 13, 2019, 02:44:57 AM
Oren:

I hope you're kidding.  The IC-7610 is a fine radio.  I understand that you may be bored, and that's a reason to move on, but the ANAN will probably not be more satisfying - in fact, it's probably going to be quite frustating, so my advice is:  Don't burn your bridges."

Regarding (TD) IMD... there is just a little too much focus on that by just a few people in the ham community.  And some of them have really screwed up their own TX signals by trying to apply active feedback in ways they do not understand and can't measure.  Fixed and active equalization of TX signals is pretty much standard in my industry, and has been for decades.  Done wrong, it results in a lot of problems.  And I don't think the amateur radio community has a good, consistent and uniform (appliance operator friendly) approach to doing this.

Personally, my ham friends and I have had a lot more problems with IMD on the RX end, especially at repeater sites and special operations, like Field day and IOTA.  Passive intermod products (PIMs) and saturation of RX front ends in dense RF environments has long been a REAL issue in these cases.  But you don't really hear the IMD crowd chanting about this.  No "Torch to Carry" about equipment manufacturers gone wrong, I suppose.  PIMs will be a much bigger problem now that we're getting into use of weak signal modes, like FT8, in Field Day.  Dissimilar metals, some slight corrosion between key antenna components or support structures, bad connectors on coax... and who's EVER seen this on Field Day (Everyone who's looked), and PIM product will pop up on the waterfall all over the place.  Maybe 15-30 dB down - but, HEY, that's where weak signal modes look for contacts.

Have fun, always, and Best Regards,

Brian - K6BRN

Well Brian,

Theres something we completely agree on, a refreshing change hihi :)


Title: RE: Flex power genious xl
Post by: K6BRN on April 13, 2019, 10:47:24 AM
Hi JD (VK3BL):

Quote
Well Brian,  Theres something we completely agree on, a refreshing change hihi Smiley

Yep.  Nothing wrong with that!

Have a good one,

Brian - K6BRN


Title: RE: Flex power genious xl
Post by: G3RZP on April 13, 2019, 04:02:52 PM
To my mind, the average Joe Q. Ham these days is more limited in what he can hear and communicate with is limited by local noise from digital crap than from receiver IMD, spurious responses  and even high order tx IMD. Not that we shouldn't look at getting high order tx IMD down since the advent of solid  state transceivers has seen it get generally very significantly worse than the last generation of amateur transmitters with tube PA stages, but regrettably, external crap that no administration wants to bother with is really now the limiting factor in terms of reception for many amateurs in urban areas - and in some cases, even rural ones, too.

Interestingly, I hear that the SARSAT/COSPAS people are getting worried about the amount of noise at 406 MHz and its possibilities to reduce the capability of the Search and Rescue Satellite service to function effectively...

Individual equipment radiation limits came from CISPR, but nobody there considered the cumulative effects of lots of equipment. Plus CISPR seems more intent on having minimum standards regardless of whether or not they actually protect radio communication - to my mind as a professional engineer, they are an organisation well past their 'sell by' date who wants to protect manufacturers and allow them to radiate crap.


Title: RE: Flex power genious xl
Post by: VK6HP on April 14, 2019, 12:14:01 AM
With quite a lot of professional life spent in radio astronomy and passive remote sensing, you'll perhaps forgive my chuckles at the mention of CISPR and other "standards" doing anyone much good. Yer on yer own, mate.

I do agree that there's a great lack of coherence in spectrum management and there is no doubt that in some cases users shamelessly exploit the cracks.  In other cases, technology uptake overtakes the byzantine nature of what coordinating bodies there are.  A case in point is the solar power industry, which is fast becoming the biggest contributor to the HF cesspit that characterizes Australian suburbs.  It is possible to implement fairly economical, radio quiet systems and, indeed, one of my current projects does that successfully for remote radio astronomy and HF communications installations.  Unfortunately, there's no incentive for such systems to be widely adopted in the consumer world.

I was impressed with the OP's wish to have a clean transmission, principally for reasons of personal pride if I'm reading his note correctly.  Far from dissuading him in that goal, I support his desire to have the best station he can put together.  While there are many inputs to the current cesspit, "everyone else is doing it" never has been a valid justification for contributing to any mess.  There are always choices to be made and taking the position of a passive consumer rather defeats the justification for having an amateur radio licence, in my view.

Of course, you're quite within your legal rights to team an FT991 (or similar splatterbox) with whatever dodgy, over-driven, solid state amplifier you can hunt up.  -20 dB, or worse, IM3 (etc) shows little concern for the spectrum environment or your neighbours, or much concern for your own signal quality, but you can do it - just as you can walk around smelly and dishevelled if you want. It's all about personal responsibility and standards.

This being ham radio, you get to largely set your own standards.  Perhaps you choose a middle path and choose to spend a little extra to get a very good exciter and conservatively rated amplifer - a reasonable thing to do.  Personally I aspire to do better as time and other factors permit.  I still enjoy operating my Collins 32S-3 and seeing distortion products below -40 dB and, conversely, I'm slightly pained by the knowledge that, in my "new" console, the heavily de-rated exciter/KPA-1500 combination (despite being a great integrated system) is no better than it ought to be in the IMD stakes. However, the path towards a viable pre-distortion system is emerging and I look forward to implementing it.

By the way, while passive IMD is a real effect and of great concern in many commercial systems (including cellular links), if it's worrying you in an HF/sub-2kW amateur station, you have some pathological issues with your installation that you need to address.  Fix those issues rather than using them as an excuse to pump more crap into the cesspit.

73, Peter.





Title: RE: Flex power genious xl
Post by: K6AER on April 14, 2019, 08:43:47 AM
VK6HP –“ A case in point is the solar power industry, which is fast becoming the biggest contributor to the HF cesspit that characterizes Australian suburbs. “

Boy howdy is that spot on. Here in New Mexico near La Luz, there is a 20 acre solar farm. When I drive within a mile of the facility my HF noise level on the radio in the truck starts to rise. Twenty over S9 on 40 meters when I am out front.

Earlier this year several solar companies came out to the property to sell me on the idea of going solar. Only Arizona has a higher sun index. When I explained the interference problem, they were clueless. One said he would bring out a demonstrator trailer. A week later they arrived and showed me that 12 ea. 240 watt panels could generate over 2 KW of AC which would sync. with the grid feed and with the local utility approval, I could reduce my AC bill about $3.00 a day. Investment would only be $12,000. When they turned on the system it was 200 feet from my dipole. The RF noise was 30 over S9. They said I could turn off the system when I was on the air. I ask what about others in the area who use Ham Radio.  Silence.


Title: RE: Flex power genious xl
Post by: N2SR on April 14, 2019, 04:30:52 PM
Boy howdy is that spot on. Here in New Mexico near La Luz, there is a 20 acre solar farm. When I drive within a mile of the facility my HF noise level on the radio in the truck starts to rise. Twenty over S9 on 40 meters when I am out front.

Earlier this year several solar companies came out to the property to sell me on the idea of going solar. Only Arizona has a higher sun index. When I explained the interference problem, they were clueless. One said he would bring out a demonstrator trailer. A week later they arrived and showed me that 12 ea. 240 watt panels could generate over 2 KW of AC which would sync. with the grid feed and with the local utility approval, I could reduce my AC bill about $3.00 a day. Investment would only be $12,000. When they turned on the system it was 200 feet from my dipole. The RF noise was 30 over S9. They said I could turn off the system when I was on the air. I ask what about others in the area who use Ham Radio.  Silence.


April 2016 QST, pages 33-37, written by K1KP, a well known contester. 



Title: RE: Flex power genious xl
Post by: K6BRN on April 14, 2019, 09:54:09 PM
Quote
Of course, you're quite within your legal rights to team an FT991 (or similar splatterbox) with whatever dodgy, over-driven, solid state amplifier you can hunt up.  -20 dB, or worse, IM3 (etc) shows little concern for the spectrum environment or your neighbours, or much concern for your own signal quality, but you can do it - just as you can walk around smelly and dishevelled if you want. It's all about personal responsibility and standards.

A persistent problem I've seen with amp users is that many still seem to overdrive them, solid-state or tube, to the point that distortion sets in.  At that point, I'll TAKE the IMD performance of an exciter/amp backed off to 80%.  I'm afraid that some amp manufacturers seem to encourage this by advertising an AL-811A as having 600-800 watts output (and the OP wants to SEE that on his/her power meter as AVERAGE power) or the apparent over-spec of the SPE 1.2K-FA.

There is always "Low-hanging fruit" in this area that some consistent "Elmering" MIGHT be able to help with.

Brian - K6BRN


Title: RE: Flex power genious xl
Post by: VK6HP on April 15, 2019, 03:42:20 AM


There is always "Low-hanging fruit" in this area that some consistent "Elmering" MIGHT be able to help with.

Brian - K6BRN

Yes, there are certainly great gains to be had by helping people choose decent radios and drive their amplifiers moderately.   I guess all we can do is to keep assisting hams who are open to learning but, that said, they may not actually be the main problem group.  Giving the opportunity for hands-on experiment and demonstration helps a lot, and using even a basic spectrum measurement system really opens eyes.  Although it's always necessary to carefully check for instrumental effects (such as SDR overload), the reality is that the average ham can grasp a comparative bandscope picture pretty well, regardless of worrying about absolute calibration etc.  And at the really bad end of the scale, even the old style station monitors are useful: two-tone envelope imperfections of the order of -20 dB or a bit better are visible to the eye.  

More modern accessories such as the Telepost LP-700 monitor help as well.   It's not an RF spectrum analyser but it's very sobering to have the transfer function of your amplifier plotted in real time, and to use the "pseudo spectrum" mode with the inbuilt two-tone and noise sources.  It does not take a responsible ham very long to realize the importance of optimizing the exciter setup, and the amplifier drive levels.  As Brian rightly says, the resulting output may not bear much resemblance to the marketing brochure figures.

While I and many others enjoy closing the test and monitoring loop by involving professional instrumentation and techniques, I would certainly encourage more people to have a go at comparative characterizations whether they be done with properly setup spectrum scopes, external SDRs, station monitor units, or whatever.  It's a curious thing that hams have never been so well served by test equipment, yet test and monitoring seems foreign to many. There are traps, but working through those is an indispensable part of understanding your station.

As an aside on solar power RFI, it is certainly possible technically for ham radio and solar power to co-exist at some level, as the article cited by N2SR demonstrates.  The issue, as K6AER implies, is that there's no incentive for the average consumer (i.e., your neighbor) to take on the extra capital/installation burden.  In practice, there are very big variations in inverter RFI characteristics and installation techniques, as well as a "one size fits all" issue: places like Western Australia and New Mexico have a surfeit of sun and those of us living there can well afford to sacrifice ultimate system efficiency with, for example, quieter inverter topologies.  However, you're unlikely to actually get very far with the majority of solar PV suppliers if you make that trade-off request.  

73, Peter.


Title: RE: Flex power genious xl
Post by: K6BRN on April 15, 2019, 06:16:47 PM
One comment on the LP-700.  I have one and use it, but it's not a particularly good spectrum monitor.  Just more of a very gross test to see if anything is really "broken".  A relatively inexpensive spectrum analyzer, like the Rigol DSA 815-TG in combination with a decent coupler (need about 50 to 60 db of TOTAL attenuation) works MUCH better and is not THAT much more expensive.

Brian - K6BRN


Title: RE: Flex power genious xl
Post by: VK6HP on April 15, 2019, 07:04:13 PM
Brian,

Overall, I agree with that assessment and I have exactly the Rigol setup you mentioned, as well as the LP-700.  But, with careful setup, the convenient "always on" nature of the LP-700 counts for a lot in my situation.  It's certainly true, though, that having the RF spectrum analyser side-by-side for the initial setup, understanding the limitations of the envelope detectors and the envelope detection scheme used in the pseudo spectrum mode, and taking care with the injection of the test tones makes for a better use of the product.  I wouldn't be without mine, although I use it far more in the wattmeter and envelope monitoring modes than in the pseudo spectrum mode.

In fairness, I think quite a lot of the problems that are reported in the pseudo spectrum mode come from people having poor quality low-level test signal injection systems and/or inadequate low-frequency transmitter response, causing the 200 Hz sub-carrier to be attenuated.  But still, it'll never rival a half-way decent RF spectrum analyser and the product description is reasonably clear on that.  I'm quite happy if I can do a quick comparative check on low-order IMD products with the in-line monitor and, carefully used, it's useful.  I don't recall the exact pricing but if I were out to buy a respectable digital power meter I'd go the extra distance for the waveform and pseudo spectrum modes.  (I guess we both made that decision at some point). 

73, Peter.


One comment on the LP-700.  I have one and use it, but it's not a particularly good spectrum monitor.  Just more of a very gross test to see if anything is really "broken".  A relatively inexpensive spectrum analyzer, like the Rigol DSA 815-TG in combination with a decent coupler (need about 50 to 60 db of TOTAL attenuation) works MUCH better and is not THAT much more expensive.

Brian - K6BRN


Title: RE: Flex power genious xl
Post by: KB6DYA on April 16, 2019, 05:50:32 AM
One comment on the LP-700.  I have one and use it, but it's not a particularly good spectrum monitor.  Just more of a very gross test to see if anything is really "broken".  A relatively inexpensive spectrum analyzer, like the Rigol DSA 815-TG in combination with a decent coupler (need about 50 to 60 db of TOTAL attenuation) works MUCH better and is not THAT much more expensive.

Brian - K6BRN
Quote



I to have a LP-700 and agree with Brian K6BRN - I am learning very quickly you get what you pay for!
Thanks to everyone who wrote in I appropriate the time you took to respond.
73 Oren KB6DYA


Title: RE: Flex power genious xl
Post by: AD5X on April 16, 2019, 05:55:26 PM
Or look at the Rigol DSA705 spectrum analyzer. $700 and covers up to 500MHz. I did a review of this for QST. The unedited review is in the REVIEWS section of my website at www.ad5x.com.

Phil - AD5X


Title: RE: Flex power genious xl
Post by: K6BRN on April 17, 2019, 08:49:39 AM
Hi Phil:

Yes.... that unit is much less expensive.

But... aside from frequency limitations...

Isn't the Rigol DSA 705 missing the tracking generator?   Really nice to have for sweeping fiters and traps.

One reason I really like tbe the DSA 815TG and its Siglent counterpart.  Very handy.  I think you had the Rigol and switched to the Siglent, if I recall correctly.

Very nice unit.

Brian - K6BRN


Title: RE: Flex power genious xl
Post by: KA4WJA on April 17, 2019, 10:00:51 AM
Okay....I've been following this discussion over the past week or so....originally 'cuz it seemed that there was going to be some IMD discussion... :)    But, then I also found some other parts interesting as well...

Those of you that are interested in some learned discussions of transmit IMD, etc., please have a look at these two threads...

Tube vs. SS amp / IMD Tests
https://www.eham.net/ehamforum/smf/index.php/topic,100600.0.html

12vdc HF Maritime vs. HF Ham Transceivers
https://www.eham.net/ehamforum/smf/index.php/topic,100600.0.html

I don't wish to argue any of those points here (well, other than I'm still a proponent of a clean signal / low IMD, no matter what "everybody else" is doing on-the-air....ya' know that old saying from your mother, "two wrongs, don't make a right!"), but I would like to comment on a couple of other things...


The 2 that seem most pertinent / least controversial are:  Solar Power RFI (or lack there of), and modern analyzers...and some other ancillary comments....so, here goes:

1)  I'm on shore at the moment (working this week), but wanted to pass some personal, real-world experience using HF radio and solar power, right next to each other.  (been doing this on/off for decades....about a dozen years with this current set-up)

I have an Icom M-802 HF Marine (and Ham) transceiver and AT-140 (remote antenna tuner), feeding a base-fed HF vertical antenna (approx. 62' long), fed against a short-copper strap-connected sea-water ground....primary use is HF maritime comms (SSB and digital) on 4mhz thru 12mhz, with some on 16mhz, and HF ham comms on 75m, 40m, 20m, and 17m (and occasionally 15m, too)....although is designed and perfectly usable from 1.6mhz thru 30mhz, most use is from 3.6mhz thru 14.3mhz...

This HF antenna is an insulated portion of the 1/2" dia SS wire rigging that holds the mast of my sailboat up, and there are four 130 watts solar panels (520 watts total), within inches (yes within 1 to 2 inches) of this HF antenna....and there are two output power cables (one for each pair of panels) that run within a foot or so of this HF antenna (although not much directly parallel to it)....and I have two switch-mode (aka MPPT) solar charge controllers, mounted below, within inches (approx 5" to 6") of the HF radio itself...

The antenna is the wire going up between the two panels on the left-hand side of this pic...
http://www.c470.jerodisys.com/470pix/4700417.htm
http://www.c470.jerodisys.com/470pix/4711201.htm

And, here is a close-up of the bottom end of the antenna...
http://www.c470.jerodisys.com/470pix/4711205.htm

The rig is just behind its "face plate" and the solar controllers are just behind the panel, just to the left of the stereo and radar display...
http://www.c470.jerodisys.com/470pix/4714801.htm

The panels are Kyocera KC-130's, the charge controllers are Blue Sky Energy 2512ix's, the wiring from panels to charge controllers, is 8 ga (two runs)....and the 4' from the controllers to main battery switch is 2ga....and then 4' of 00ga to batteries (~900 A/H of deep-cycle golf-cart batteries in series-parallel)

And, with this set-up (originally installed by me in late 2006), with the HF antenna just inches away from the solar panels, I had virtually NO RFI from the solar array /controllers, at all!!  I originally had one or two low level birdies (very low level!) in the 16mhz and 22mhz maritime bands, and that's it!!

A few years back, after a lightning strike, I changed out the charge controllers (as well as radio, tuner, and a lot of other electronics, on board), and I've found a few more birdies throughout the HF region....one or two in the 12mhz, 14mhz, 16mhz, and 22mhz ranges...they are all low level birdies (never move the S-meter, and have never caused a significant problem with receiving), there is NO wide-band noise / hash, there is NO rise in HF noise level on-board, just a few narrow birdies!!  And, remember, this is within INCHES of the antenna, not feet/yards/meters, and not "down the road 1/2 mile", but everything is within 15' to 20', and the antenna is just inches away from the solar panels!!


HF radio communications is my sole means of long-range comms, and is my primary means of weather info/forecasts when at sea, and (except for short-range Maritime VHF comms) is in effect my primary communications on-board....this is primarily SSB Voice, with dedicated/predetermined HF Digital (repeated/redundant 100-baud FSK-FEC) as the primary means of Safety signaling...

And, while satellite beacon (406mhz EPIRB) is the primary means of signaling distress, HF radio is a two-way means of distress/safety comms....as well as being the primary means of weather info/forecasts for both myself (and other offshore pleasure boats) and 1000's of merchant vessels worldwide...still to this day....(although "routine" data and telephone comms are now mostly via satellite for merchant vessels)

So...
So, having a solar energy system that reduces the capability of HF comms would not be just inconvenient, but dangerous!!   Hence, having a "clean" solar energy system on-board is of great importance!!

Those of you asking, "how is this possible, with today's systems?".... the answer is two-fold....

a)  Don't buy crap made in China, where at best they "self-certify", and most often have no testing no certification, no real FCC certification, actually no concern at all for anyone, not even their own customers....not even a Part 15 cert... Rather...Buy, well-made / American-made, FCC Certified charge controllers (and for off-grid installs, the same goes for the DC-AC inverters)!!  {Blue Sky and Moringstar are the only ones I recommend....they only ones that actually have real FCC certs}

b)  Use ferrites (and/or torroids) on all wiring from solar panels, and especially to/from the charge controllers / batteries, and to/from inverter(s)....and of course the AC wiring directly as it leaves the inverters (where decent RF filters are fairly inexpensive, and if not used is an indication of the ineptness of the system engineer/installer)

BTW, my M-802's receiver is similar to the IC-756ProII /ProIII....(except has few "user selectable adjustments")....and whether at sea, at anchor, etc....I'm so far away from most man-made noise, it's as "RF Quiet" as you can find (S-zero noise levels, except for natural noise)....

And even at my own dock (100+ yards away from anyone, and ~ 1/4mile from residential noise), it's still pretty RF Quiet....even at the dock, I have an S-zero noise level on all bands of 12mhz-14mhz and above, and usually/typically S-Zero daytime on 7mhz / 8mhz, and S-1 or so daytime on 3.5mhz/4mhz...so, even when at the dock with commercial mains power (Air Cond in summertime Florida), etc. I still have the solar array connected and working 24/7/365 (of course solar doesn't work at night, but you know what I mean), and have no significant HF RFI from it (nor from anything else on-board, save my refrigeration/freezer compressor controller, which is a Danfoss 3-phase/switch-mode inverter that's not well shielded and only 8' - 10' away from my HF antenna)....

So, all this talk about solar power disrupting HF comms is interesting to me....as I've been using solar energy within a few feet (or less) of HF antennas for decades now, without issues!!  And if you all are having such significant issues, perhaps a call to the FCC, FTC, US CBP, etc., would be a good idea....'cuz none of these companies are licensed to transmit signals (beyond their Part 15 limit) on our HF bands....a cease and desist order from the US Gov't might just make 'em realize they must comply or be shut-down??

For those of you outside of the US?? I know the UK OFCOM is pretty strict, and I assume Australia's authority would also be interested??

In any case, I just wanted some here to know that modern solar energy and HF radio can coexist right next to each other, pretty darn well....it just takes a bit more $$$ and some fairly simple engineering!!


2)  Modern analyzers....

Well, somewhere in the back of my garage I still have an older Tek analyzer....and an old Avcom portable (PSA-65c) that I just loaned to a buddy....but a few years back I gave away my HP 141 / 8554 analyzer to an old friend (he agreed to carry it to his car!)....'cuz I bought a new Rigol TSA-815-TG (and I'm eyeing one of their RSA-5000's)....and I'm very happy!!  (since I'm semi-retired / mostly-retired, haven't pulled the trigger on an RSA-5000....it would be a fun toy...but, not sure I can "expense it off"...I have no "corporate funding", just my own bank account...hi, hi...)

So, with decades of experience and assortment of directional couplers, samplers, etc., I'm well-equipped to test / evaluate things, and have found the relatively inexpensive (and mediocre / average phase-noise) Rigol's to be good for transmitter testing....but for lab use, etc., I think the better / higher end Rigol's should be recommended...(don't forget that while HF transmitter testing might not need super low phase noise specs in an analyzer, a lot of other stuff does...:)

But...

But, to be honest, if a ham is well-versed enough to understand transmit IMD and desirous enough to test / improve his/her system, then (in my opinion) they are probably well-versed enough to use an old station monitor (and/or cheap analog o'scope), and even just their grid-current meter / ALC meter / RF power meter, etc. to regularly / constantly monitor their own transmit signal....

Once they've seen / understood what the various adjustments do, and how they effect their transmit signal / transmit IMD / spectral purity, by using a good analyzer on their bench or just by studying these matters (whether it's their mic gain, amp tuning, processor settings, ALC, cw keying shape / rise-time, and of course actual drive power vs. output power), then during their daily operating they can quite easily SEE what is happening by watching their shack metering!!  (everyone can easily watch their RF drive power into your amp vs. amp output....and if you're operating a tube amp, watch your amps grid current...if your rig has an ALC meter, you can watch that too....and if you skip lunch at a hamfest, you can buy an old analog o'scope and make your own "station monitor", or skip a nice dinner and buy an older Heath SB610, etc., and use that!)   You do not need a rig with a "spectrum scope", nor waterfall....nor do you need to have a $2000+ analyzer at the ready, just to keep your signal clean!

Of course, we all should know by now that even when operated as spec'd / recommended by the manufacturer, there are some of our modern rigs that are just crap (in regards to transmit IMD and spectral purity) and some of them aren't cheap, entry-level rigs!!  So, even if you have a nice analyzer (or set-up your station / rig / amp, as prescribed, and monitor things well), you can still have issues with some rigs...

And, further on-point here, when it comes to amps and their cleanliness....yep, the three biggest issues are:

a)  rig mic gain

b)  rig IMD

c)  amp over-drive

Although, for those who care to look and are interested in a clean signal, tube amps still rule in regards to IMD...versus solid-state amps...that's not to say that anyone that runs a SS amp splatters across the bands, hi. hi...just saying if you're running a Class A exciter or one with active pre-distortion, you're losing your advantage with a SS amp (unless of course you or your SS amp has a coupler and can use your exciter's pre-distortion)...

https://www.eham.net/ehamforum/smf/index.php/topic,100600.0.html


3)  And, I gotta' say that Brian makes a great point....hams buying amps "marketed" for higher power than they can easily make without being over-driven!!  Hence they are "forced" to overdrive the amp, just to see it attain the output they paid for!!

And, while I do see / hear it, it's not quite as prevalent as a couple years ago....those with mic gains cranked all-the-way up are less apparent today than a couple years ago...(I suspect that some have migrated to FT-8??)


Also, yep, I agree the guys at Flex are pretty smart!!  And, while their amp (whether it will ever be a mass-produced item or not) might have a coupler built-in for use with a DSP/SDR rig that has pre-distortion, Flex's rigs don't have that capability....(and while we'd all like think they will have it soon....it's just not a high priority for them....i.e. no demand from the market!)


So, while I'm not railing about IMD today, I do hope some find the above to be useful, or at least interesting?

Fair winds and 73,

John,  KA4WJA



Title: RE: Flex power genious xl
Post by: W9IQ on April 17, 2019, 11:09:47 AM
a)  Don't buy crap made in China, where at best they "self-certify", and most often have no testing no certification, no real FCC certification, actually no concern at all for anyone, not even their own customers....not even a Part 15 cert... Rather...Buy, well-made / American-made, FCC Certified charge controllers (and for off-grid installs, the same goes for the DC-AC inverters)!!  {Blue Sky and Moringstar are the only ones I recommend....they only ones that actually have real FCC certs}

I seriously doubt that either company has submitted to an independent lab and had an FCC ID issued to show certification. As an example, here is Blue Sky's self certification declaration. I really like the addition of the FCC logo on their part to make it look "official"...

https://sunforgellc.com/wp-content/themes/sunforge/img/Certification_docs/FCC_SB3024.pdf (https://sunforgellc.com/wp-content/themes/sunforge/img/Certification_docs/FCC_SB3024.pdf)

And here is the typical quote from a Morningstar manual:

"FCC Class B compliant"

It is interesting that Morningstar doesn't even include the FCC required language in their manual:

Quote
Note: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:

—Reorient or relocate the receiving antenna.

—Increase the separation between the equipment and receiver.

—Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.

—Consult the dealer or an experienced radio/TV technician for help.

So by definition, they are not compliant with part 15 regulations. Blue Sky includes a shortened version of the language which is also not compliant.

- Glenn W9IQ


Title: RE: Flex power genious xl
Post by: KA4WJA on April 17, 2019, 11:17:50 AM
Glenn,
To be honest I haven't looked at either of theirs' sites and cert info in years....

But, I have spoken to the principles / engineers at Blue Sky a number of times over the past decade (as recently as a few months ago), and have spoken with application engineers at Morningstar a few times in the past 3 or 4 years....and have been met with helpful info and what I thought was an honest portrait of their specs and tests??

But, more on-point....in addition to my own personal experience with both of them over the past dozen or more years, others on boats with HF radios and Blue Sky and/or Morningstar controllers have also had good results...

And, further, even more on-point.....if some of my fellow hams are have problems with solar farms / solar homes, etc. from many feet/yards/meters away, or even worse, miles away....then I want them to know that they do not have to accept this....they can fight it, and there are examples that do work..


Just wish I could go back now and edit / remove my reference to FFC cert??  :(
Oh well, live and learn, huh??  :(

But, I DO thank you for the info!!  :)



73,
John,  KA4WJA
  


Title: RE: Flex power genious xl
Post by: W9IQ on April 17, 2019, 11:24:40 AM
John,

I have heard good things about both of these as well but they are not FCC certified. They have declared their conformance - just like every other brand.

It sounds like you are the victim of marketing speak. If in doubt, ask them for their FCC ID number.

- Glenn W9IQ


Title: RE: Flex power genious xl
Post by: VK6HP on April 17, 2019, 07:37:23 PM
John

I agree there's no need to repeat the previous IMD discussions since we've all had our inputs and the threads are there to read. And, being a model of self-restraint, you'll notice I've only mentioned a 32S-3 once in this thread ;)

One of my messages is that we should encourage hams who are keen to clean up their IMD act, especially if they have indicated a willingness to put time and money into doing so.  It's not "too hard", they can buy better radios which are not necessarily more expensive, their efforts will not be defeated by passive IMD in any decently put together station, and there is a range of decent monitoring and test options available to help them.  None of those options is technically perfect, and all will involve some learning, but all are better than nothing.  As you say, even a simple time domain monitor will help and, in my experience, can pick gross over-driving and IMD at the -20dB (or so) level.  (Exemplar  FT991and crappy "linear", for instance). Along with a spectrum analyser and coupler setup like yours, I routinely use the LP700 and its test tones in this mode (as well as in the pseudo spectrum mode which, as we've said, takes a little effort to make work usefully).

Brian made the valid point that one of the missing ingredients in the recipe for success can be insufficient mentoring or elmering; I support that view and hope that even forum discussions contribute in a small way, to more hams better understanding the topic.

On solar power systems, I think you've missed the original point.  There is no doubt that individual systems can be properly designed or selected, then well installed, to be good enough for typical HF radio applications.  Indeed, I could have mentioned that some of the bespoke and commercial systems with which I been involved are destined for the Murchison Radio Astronomy Observatory in Western Australia, officially one of the most radio quiet sites on the planet and the home of the low-frequency half of the Square Kilometre Array radio telescope, destined to be the world's most sensitive receiving instrument in its (wide) operating bands. So, no doubt solar can be quiet - as quiet as you like, almost.

The issue is that application of low-bar, one-unit, testing of isolated system parts is highly likely to produced a poor outcome across mass installations.  In places like WA, and no doubt in other high insolation areas, the consumer uptake of rooftop PV has been large and rapid.  You can hear the resultant RFI mess, produced via simple incoherent addition, anywhere you care to drive in the city of Perth, for example.  Of course, all the systems installed have small stickers with ticks on them, no doubt diligently placed in 2-minute certification processes of the type mentioned by Glenn.

I don't know how the FCC is traveling at present but it's a long time since I've heard of the ACMA helping a ham! The technical and field arms have been pruned relentlessly and I suspect that an installation would need to be causing widespread and sustained interference to a commercial service before they would bat an eyelid.

73, Peter.

 
 


Title: RE: Flex power genious xl
Post by: K6BRN on April 18, 2019, 10:07:34 AM
Hi, John, Glenn and Peter:

On the topic of solar power system noise... what I have noticed is that some large home installations do generate a great deal of broadband "hash", while others (the majority), I'v had no lroblem with.

Either way, it does not help if your station is rigbt next to the problem.  At one problematic installation on tbe east coast, I noticed that the issue SEEMED to be driven by 1st generation microconverters at each of the large solar panels.

Regarding the suitability of Rigol ( or Siglent) entry level equipment for IMD testing... yes its much better than a monitor scope of ANY pedigree.  Is it adequate for in depth IMD evaluation?  Given that thjs is amateur radio, probably.  For a commercial test lab?  They WOULD use a higber grade of equipment.  Not a big deal.  Let me put it this way...  as a Liveaboard, would you rather take a tiny little Rigol, or a half-rack HP surplus spectrum analyzer.  If you had room for either. 

Best Regards,

Brian - K6BRN


Title: RE: Flex power genious xl
Post by: K6AER on April 21, 2019, 07:13:04 PM
The Rigol ( or Siglent) have 10KHz phase noise only down -88 dBc. The readings will be suspect at that low a level. HP analyzers are about -140 dBc at 10 KHz. Even my old (2001) HP8953E was -131 dBc at 10 KHz.


Title: RE: Flex power genious xl
Post by: K6BRN on April 21, 2019, 07:49:56 PM
Quote
he Rigol ( or Siglent) have 10KHz phase noise only down -88 dBc. The readings will be suspect at that low a level. HP analyzers are about -140 dBc at 10 KHz. Even my old (2001) HP8952E was -131 dBc at 10 KHz.

Ummmm.  this is amateur radio.  I have no problem working routinely at DANLs better than -100dB at 10 Hz RBW/VB on the DAS-815TG, which is fine for characterizing filters, checking signal generators for gross phase noise characteristics, checking circulators. measuring return loss.  The list is endless.  I'm NOT looking for a great deal of accuracy, at home.  I'm looking for GOOD accuracy and capability.

"Adequate" does quite a lot.  "Excellent" costs quite a lot.  In dollars, size or weight.  Take your pick.

BTW, I also use the Siglent SSA3000 series and no end of HP/Agilent/Keysight/etc. analyzers, from the 9000 series (current) to the old half-rack 8000 series and its options.  I use whatever works for my needs at the time, professional or amateur.  For home and amateur use, the Rigols and Siglents work fine and are light-years ahead of the old guard in terms of utility - a few lbs, the size of a small digital scope amd work pretty well.  I trot 'em out, use 'em an put 'em away.  No big deal.  Try THAT with an 8000.  (OMYGOSH!  It just crashed into a Buick and crushed it!)

Ack!  They have higher phase noise!  No kidding.  Need to move to a cavity oscillator or similar to do a LOT, LOT better.  Have fun.  There is a REASON why these old clunkers weighed so much.  And the Keysight 9000's are very good too, using more modern technology.  Brief-case sized.  Some compromises, some advantages.

Keep in mind that (regardless of phase noise) the AVERAGE noise levels are proportional to RBW and that Siglen't initial claims of far superior DANL was based on a 100 Hz RBW (Rigol) vs. 10 Hz RBW (Siglent).  Now Siglent is down to 1 Hz RBW (Rigols is down to 10 Hz).  What this specsmanship does not mention is that sweep time is inversely proportional to the SQUARE of RBW.  How much tine ya got?  A sweep that takes 1000 seconds at 10 Hz RBW will usually take 100,000 seconds at 1 Hz, for best accuracy.  10 Hz is about the minimum I've ever used at work.  1 Hz?  OK.  I'll just "let it run".

BTW... to the spec watchers out there... both the Rigol and Siglent products work just fine.  I find that the Siglent has a bigger, nicer screen.  But is also... bigger than the Rigol.  Take you pick.  Neither is a mistake for a home "lab".

P.S.  YES.  I've seen the EEVBlog tests and teardowns.  A lot has changed with both SAs.  Better RBW with the Rigols (and some HWupgrades) and better FW with the Siglents (was VERY bad when it 1st came out - buggy as heck - "How the heck does THIS work!  What DID I just do?").

Brian - K6BRN



Title: RE: Flex power genious xl
Post by: K6AER on April 22, 2019, 08:16:44 AM
Brian,

I am going to buy one of the Rigols units for every day use. The HP gear is getting fragile and my shoulder muscles are not what they use to be. How their service here in North America?


Title: RE: Flex power genious xl
Post by: K6BRN on April 22, 2019, 08:52:45 AM
Hello, Michael:

Never had to send mine in. (have two 'scopes and one spectrum analuzer by them)  But on-line questions, firmware, etc. is pretty easy, and TEquipment can also help with service returns, where needed.

Rigol DSA815-TG

https://www.rigolna.com/products/spectrum-analyzers/dsa800/

https://www.tequipment.net/search/?F_Keyword=dsa815tg

Suggest you also look at the Siglent SSA3021X

https://www.siglentamerica.com/spectrum-analyzers/ssa3000x-series-spectrum-analyzers/

http://www.saelig.com/category/siglent-spectrum-analyzers.htm

The second link is for Saelig - may be the only North Amarican Siglent vendor.  I've been using both the Rigol and Siglent units.  The Siglent has a snazzier screen and is bigger.  VERY nice.  Both Rigol and Siglent units work just fine (just don't expect perfection).

Make sure you get the Tracking Generator built-in.

Note that if you join EEVBlog and request a discount code, Saelig will usually knock off 10% or so from the price for Siglent equipment.

Have fun!

Brian - K6BRN



Title: RE: Flex power genious xl
Post by: AD5X on April 22, 2019, 09:37:07 AM
I had the Rigol for several years. An excellent SA/TG. I sold it and bought the Siglent after I did the Siglent review for QST. I liked the bigger screen and I found the Siglent a tad more user friendly, though this may have changed with time as both are always updating their firmware - which is easy to do. And yes - definitely make sure you get the tracking generator.

Phil - AD5X


Title: RE: Flex power genious xl
Post by: N4UE on April 22, 2019, 02:06:41 PM
Hi Guys, I'm a true 'newbie' when it comes to SA/TGs.
I have the Rigol and enjoy using it.

Is the software upgradable? I thought it 'was what it was'. I believe mine is 2 years old....

Any thoughts to help this OT out?

thanks!

ron
N4UE


Title: RE: Flex power genious xl
Post by: VK6HP on April 22, 2019, 06:31:13 PM
Yes, the Rigol firmware is upgradable.  See: http://int.rigol.com/Support/SoftDownload/3

Looking at the release dates, you may already have the latest version.

I use a lot of very high-end test gear but in terms of bangs per buck, the Rigol SA/TG combination takes some beating. (I've not tried the Siglent). About the only thing I've occasionally missed is the ability to do tracking generator offsets, but that really is asking a lot for an entry level system.  All test equipment has limitations and part of the engineering approach is to be familiar with those.  I'm not *that* old but I'm still amazed at the capability of contemporary "low end" equipment, especially in the ham environment.

73, Peter.


Title: RE: Flex power genious xl
Post by: K6BRN on April 22, 2019, 10:05:25 PM
Peter (VK6HP):

Your QRZ page is an interesting read.  If you lived next door I'd be pestering you to look at your very extensive gear selection.  I'm sure we'd find some very interesting projects to work on.

Had to really laugh when I read this:

Quote
I've recently overhauled the Heathkit HR-10B that I built as a teenager (second shelf from the top in the picture). It is a terrible receiver in nearly all respects but great fun to use.

Awful IS the word for the HR-10B.  But... with its crystal calibrator and warm glow on a cold winter's night, it facinated me as I tuned the short wave broadcasts, ham bands and even CHU in Canada, on their old frequency from my then-QTH in Connecticut.  It was the first receiver I'd ever built.  Pure magic.  I finally gave it away a few years ago.  Just ran out of room and never used it.

Best Regards,

Brian - K6BRN


Title: RE: Flex power genious xl
Post by: VK6HP on April 23, 2019, 02:55:00 AM
Brian,

I lost sight of the HR-10B for 40 years or so but, when re-discovered in the recesses of a family home, I felt motivated to resurrect it. Having owned one yourself, you'll understand that I am not exaggerating when I tell people about the difficulty of copying CW while living at the end of a rural mains feeder, with the attendant rapid voltage swings.  But it was fun and, when I got my first "proper" radio (a well-used FTDX401B), it was a truly transformational experience.

Anyway, maybe starting with something like an HR-10B makes us grasp the importance of the human in coaxing the best out of equipment, not to mention giving us a near zero-point for receiver performance evaluation :)

73, Peter.


Title: RE: Flex power genious xl
Post by: K6BRN on April 23, 2019, 10:01:03 PM
Quote
maybe starting with something like an HR-10B makes us grasp the importance of the human in coaxing the best out of equipment,

Hmmm.  I wonder if the HR-10B in on "Sherwood's List"?  :)

My first decent transceiver was a broken HW-101.  I was in heaven once I got it working.  It was a great sounding radio and using the RF gain, preselector and (optional) crystal filter, I could pretty much pull out any signal worth copying.  But the VFO was almost as "drifty" as the HR-10B, which I did not mind much until I started working RTTY and AMTOR.  THEN I had to "ride the knob" on the VFO to track the QSO.  Used an AEA AMT-1 I found at a flea market (no manual and no internet to look up how it worked - had to figure it out)  and had to design and build a low-voltage keying interface into the radio to support it.  Used high voltage BIPOLAR transistors, and it worked just fine.  

By the time I was able to buy a used Kenwood TS-440SAT, I thought THAT radio was the greatest.  But then realized my ears would ache after listening to it for a few hours.  Vary harsh, noisey audio.  Still have it, in fact.  The audio problem cleans up nicely with a CLRdsp attached.

So... dropping over after work for a lager, whisky or coffee?  I want a look at the KPA-1500 and HR-10B.  You DO have the DX-60B to go with it?  :)

Best Regards,

Brian - K6BRN


Title: RE: Flex power genious xl
Post by: VK6HP on April 25, 2019, 01:23:37 AM
Brian,

Heathkits were not that common in Australia in the 70s and early 80s as I recall, perhaps because of a long supply chain and the strange tariffs in place at the time.  But I was mightily impressed with a friend's HW-101, mainly because it sounded great on CW and had all sorts of knobs to tweak.  I can well understand that it would be a revelation after an HR-10B.  Not sure about the Sherwood list, though - could you get the HR-10B to stay put long enough for the test signals to stay in the (admittedly barn door width) passband?

No DX-60 on a high school budget I'm afraid - just a homebrew transmitter using a 6BM8 and other parts gleaned as part of a B&W TV cannibalization. With a handful of donated crystals, it approached 10W output on 80m (on a good day), but the pea lamp glowed a lot less on 20m! Still, with the solar cycle of the day, life was pretty easy.  You can imagine, though, what a change the FTDX-401B brought.  I'm almost ashamed to mention that rig in what started out as an IMD thread: even if I had run the sweep tubes at 120W output (which I'm not sure I did), IM3 would have been about -(20-25) dB wrt tone, almost as bad as a one or two contemporary radios. About all I can plead in mitigation is that I did build a basic monitor scope and there was no obvious clipping.

I like the KPA1500 because it's well engineered and fits my requirements, although I do look forward to getting it operational in a pre-distortion environment.  Just now, it runs ridiculously de-rated (and clean) to meet Australian regulations.   However, I have tested it into a dummy load at full output, in various modes  for extended periods, and the published allowable duty cycle figures are achievable.  The only complaint might be that it won't be particularly quiet in e.g. RTTY and digital modes.  Still, there are various location options, including remote positioning and operation.  On SSB, though, it doesn't really break a sweat.

73, Peter.


Title: RE: Flex power genious xl
Post by: VK3BL on April 25, 2019, 05:39:11 AM
An SDR Play makes a fine substitute for a cheap spectrum analyser; the dynamic range is greater than 60dB and the accuracy is comparable at around 1dB.

It is also significantly cheaper.

If one doubts my statement, it is easy enough to verify if you research the ADC used in the device and its application notes; decoding QAM256 REQUIRES 1dB of resolution.

The only reason (for a Ham) to buy a cheap spec an is if it has a tracking generator IMHO.

73, Jarrad VK3BL


Title: RE: Flex power genious xl
Post by: K6BRN on April 25, 2019, 09:35:56 PM
Quote
An SDR Play makes a fine substitute for a cheap spectrum analyser; the dynamic range is greater than 60dB and the accuracy is comparable at around 1dB

Ahhhh...  no.  Not even close.  I have and use both.  A spectrum analyzer with TG is a tool that allows fast and easy checkout of many metrics, with reasonable accuracy and repeatability.  Even if its an "inexpensive" one.

An SDRplay is a fun "Kludge" made largely out of what I think is a DVB chipset intended for embedded applications.

One is a tool, the other is a toy.

If you have the opportunity to learn to use and apply a real spectrum analyzer / TG, you will REALLY appreciate it.

Brian - K6BRN




Title: RE: Flex power genious xl
Post by: K6BRN on April 25, 2019, 10:13:03 PM
Hi Peter (VK6HP)"

Quote
Heathkits were not that common in Australia in the 70s and early 80s as I recal

I wondered about that.  Always thought Heathkit was a U.S. phenomenon.

Regarding IMD - Glad your "Homebrew Transmitter" didn't destroy the world.  As for active linearization, step into that one carefully.  Done wrong, its a mess - and this is AMATEUR radio.

I've used many TWTAs (feed-forward passively linearized travelling wave tubes) and SSPAs in my career, and active feedback active linearization/equalization.  Without it, we had to "back off" the amps a lot more to get a clean signal, making them more inefficient in terms of power use vs. power output and mass.  In the ComSat business TX power x bandwidth = revenue.

But when active linearization went wrong, the signal usually became FUBAR, whereas the passive feed-forward networks just drifted and degraded a little over time.  So the active approach has to be done well in order NOT to become a big "part of the problem" (it's NOT forgiving) and it has to be monitored to detect when it goes "off the rails".  A lot less critical in amateur radio, but still a "Gotcha" most hams do not think about.  I'm generally not too concerned about IMD and run my amps backed off quite a bit at home.  But I do have an imaginary nightmare of thousands of hams trying to hook up their active linearizers and splattering entire bands into obiivion.  After all, many can't even connect and adjust an amps ALC correctly.  My fears on this are no doubt way too exaggerated - we'll just have to see how this evolves.  And if it works out (maybe a standard for feedback linearization is adopted and baked into amps and rigs), excellent!

Good Night!  Time to hit the sack over here.

Brian - K6BRN


Title: RE: Flex power genious xl
Post by: KD8MJR on April 26, 2019, 07:41:37 PM
Brian,

I am going to buy one of the Rigols units for every day use. The HP gear is getting fragile and my shoulder muscles are not what they use to be. How their service here in North America?

You would be better off buying a Siglent SSA3000 series than a Rigol.
Much better value for the money with the SSA3021x running around $1395 and it goes from 9Khz to 2Ghz.  Better yet it's almost like Siglent encourages you to hack the 3021x into a 3032X which goes up to 3.2Ghz and it unlocks all the optional pay to use features.  It took me about 15 minutes to do the hack and is pretty straight forward.  The equivalent Rigol which would be the DSA832 will set you back $3400 and the extra locked features will cost you extra $$.

The support for Siglent is excellent and Saelig, their US dealer also has excellent customer support.  BTW Saelig will even give you a discount if you ask for one on the phone, just say your an eevblog forum member.


73s
Rob



Title: RE: Flex power genious xl
Post by: M0HCN on April 27, 2019, 10:31:33 AM
Done wrong, its a mess - and this is AMATEUR radio.
Yep, had Cartesian feedback go pearshaped (fortunately into a dummy load, and I was trying to provoke it), but is is fairly easy to detect the problem and kill the output as the EVM goes thru the roof.

Adding logic to measure EVM and shut things down if it becomes excessive is fairly basic engineering. Having the logic keep an eye on I'Q -Q'I (A reasonable proxy for loop phase error) is trivial as you are probably using something like that to drive the phase correction anyway.

The other saving grace of a DUC/DDC radio in this scenario is that you can use the ADC to actually do transmitted spectrum measurement in realtime, you know how wide you are.

73 Dan.


Title: RE: Flex power genious xl
Post by: VK6HP on April 28, 2019, 01:06:24 AM
Brian, Dan

I agree that a robust feedforward implementation requires care, particularly in a typical ham environment involving a variety of sources, loads and practices.   That, allied with the small number of commercial options in the ham world, has been the reason I've been holding off with the KPA1500 trials.  I must say, though, the ANAN approach is interesting but, to date, I've not been particularly drawn to the ANAN transceiver operating environment, despite recognizing that it's a good one for many radio communication experiments.

I'm lazy enough to hope for an Elecraft K4 or similar turnkey solution, on the assumption that such a radio is likely to suit me better.  I understand Brian's concerns about opening the flood-gate to systems that may have inherently large parameter sensitivity, or simply too much of a good thing.  But in true spirit of ham radio development, I'd like to see more pre-distortion implementation options available.    However, I certainly agree that increased distribution of mic gain stops and ALC meter interpretation guides is the first priority  :)

73, Peter.


Title: RE: Flex power genious xl
Post by: M0HCN on April 28, 2019, 06:41:08 AM
However, I certainly agree that increased distribution of mic gain stops and ALC meter interpretation guides is the first priority  :)
I have never quite understood why mic gain is even a  thing on a modern rig. I mean I can see a menu option somewhere for 'dynamic/electret' microphone switching, but typically a modern radio is stuffing the audio into a DSP chip just as soon as it can, and a 'VOGAD' implemented in the DSP can trivially deal with any real world dynamic range. Certainly my marine HF set does NOT have such a control and manages just fine.

An 'RF Power' knob, a set of controls for the dynamics and clipper drive, and MAYBE a tx filter bandwidth control should be quite sufficient IMHO. For AM, maybe an option to allow a **little** over 100% positive mod?

Regards, Dan.


Title: RE: Flex power genious xl
Post by: W1QJ on April 29, 2019, 01:45:31 PM
looks like this amp might be dead and removed from the Flex line.


Title: RE: Flex power genious xl
Post by: K6JH on April 29, 2019, 02:35:26 PM
looks like this amp might be dead and removed from the Flex line.

Why do you say that?

The product link is still good on their web site.

Per forum posts another batch of amps shipped and delivered around end of March.

Per another forum post Gerald claims another batch is inbound from the manufacturer and due next week (for Flex inspection test, not necessarily shipped to end customers).

Sound to me like they're just being cautious. They don't want to ship a bunch of junk they have to take back.


Title: RE: Flex power genious xl
Post by: VK3BL on May 08, 2019, 11:35:38 AM
Quote
An SDR Play makes a fine substitute for a cheap spectrum analyser; the dynamic range is greater than 60dB and the accuracy is comparable at around 1dB

Ahhhh...  no.  Not even close.  I have and use both.  A spectrum analyzer with TG is a tool that allows fast and easy checkout of many metrics, with reasonable accuracy and repeatability.  Even if its an "inexpensive" one.

An SDRplay is a fun "Kludge" made largely out of what I think is a DVB chipset intended for embedded applications.

One is a tool, the other is a toy.

If you have the opportunity to learn to use and apply a real spectrum analyzer / TG, you will REALLY appreciate it.

Brian - K6BRN


I did specifically state that the only reason to buy an entry level spec an is if you also buy the tracking generator.

As such, I agree that it is a great tool worth having. 

But in terms of performance you'd be surprised what that 'DVT-B Chipset' can do - because it has to - in order to decode QAM256 signals.

If a ham can have an accurate toy (this is Ham radio, you know, with MFJ and all) for peanuts, or have nothing at all, I'll promote the ownership of the toy every day.

Workshop tools are on the 'buy list' now actually; I'm moving to a QTH that has pretty average reception compared to the current one, but does offer a nice workshop.  So its a little bittersweet, but hopefully when the sunspots come back I'll be able to enjoy a bit of SSB Phone DX Again.

In the meantime, there are other aspects of the hobby!


Title: RE: Flex power genious xl
Post by: K6BRN on May 11, 2019, 07:08:02 PM
J.D. (VK3BL):

Glad you like the SDRplay units and find them useful.  So do I.  And, as you said, this is AMATEUR radio.  If that's what you've got, that's what you use.

But look forward to the day whan you have an oscilloscope (time domain measurements) AND a spectrum analyzer (frequency domain measurements).  You'll be surprised at what a nice device this is (with tracking generator) for all sorts of amateur radio work.

You will also need a suitable set of attenuators, coax stubs and directional couplers to have some"extended fun".

The good news is there is STILL some fun equipment to aspire to acquire and learn to use.  No need to be bored (I saw your other post - you do NOT get to run out of toys quite yet!), and you can even do some videos on how to characterize antenna traps, SWR/Return Loss, transmitter spurs and harmonics... and many other things.  Not time to close the "Fun" office just yet.  Keep on Truckin'!

Best Regards,

Brian - K6BRN