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Author Topic: Flex power genious xl  (Read 4881 times)
N2SR
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« Reply #45 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. 

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K6BRN
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« Reply #46 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
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VK6HP
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« Reply #47 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.
« Last Edit: April 15, 2019, 03:48:46 AM by VK6HP » Logged
K6BRN
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« Reply #48 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
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VK6HP
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« Reply #49 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
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KB6DYA
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« Reply #50 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
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AD5X
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« Reply #51 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
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K6BRN
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« Reply #52 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
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KA4WJA
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« Reply #53 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... Smiley    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...Smiley

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

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W9IQ
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« Reply #54 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

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
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- Glenn W9IQ

I never make a mistake. I thought I did once but I was wrong.
KA4WJA
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« Reply #55 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??  Sad
Oh well, live and learn, huh??  Sad

But, I DO thank you for the info!!  Smiley



73,
John,  KA4WJA
  
« Last Edit: April 17, 2019, 11:29:48 AM by KA4WJA » Logged
W9IQ
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« Reply #56 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
« Last Edit: April 17, 2019, 11:31:46 AM by W9IQ » Logged

- Glenn W9IQ

I never make a mistake. I thought I did once but I was wrong.
VK6HP
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« Reply #57 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 Wink

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.

 
 
« Last Edit: April 17, 2019, 07:48:30 PM by VK6HP » Logged
K6BRN
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« Reply #58 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
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K6AER
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« Reply #59 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.
« Last Edit: April 21, 2019, 07:15:29 PM by K6AER » Logged
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