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Author Topic: Flex 1500 Amplifier Recommendations ?  (Read 37826 times)
N4OI
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Posts: 210




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« Reply #75 on: March 01, 2013, 05:04:51 AM »

Here is what never has made sense to me and I wish someone would explain the reasoning to me. Why would any ham buy a QRP rig and then put a 50/100 watt amp behind it? Does it not make more sense to buy a 100 watt radio and turn it down to 5 watts for those QRP moments? And less IMD to boot.....

Stan K9IUQ

Now that is an excellent question!   Although the new little TenTec amp is pretty cool....

73 ES GOD BLESS U ES URS DE KEN N4OI  Grin
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W4HIJ
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Posts: 367




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« Reply #76 on: March 01, 2013, 10:20:51 AM »

I have Stan and his buddy Gene on ignore so I don't have to read their Flex bashing and constant barrage of name calling and personal insults towards me but since someone did me the unfortunate pleasure of quoting his  question, I'll  try and answer it. And I'll admit that it's a fair question.
 
Some of us have realities in life that don't allow us  to go out and drop a few thousand on a radio anytime we feel like it. If fact we are lucky if we can muster up the sixteen hundred that it cost to get one of the bottom line Japanese rigs or a nice Flex 3000. I had a Flex 5000 and  it was my dream radio but some unexpected expenses stemming from a medical situation in my family came up and I had to sell it to help cover those.  If I wanted a radio at all, and I didn't want used,  the Flex 1500 was my best option because I'll never operate with a conventional knob radio again. During the time of owning the first Flex 1500, I had the opportunity to order a parts and PCB kit for a small amplifier for about $90 so I did so and built it. Final cost was about $125 for the amp. I already had some stuff like my PC and an antenna tuner and power supply so at that point I had about $775 in my 50 watt station. I actually did sell the first Flex 1500 with the full intention upgrading to a  Flex 3000 but life and family issues intervened once again and I had to settle for just getting another 1500 so I'm back to the $775, 50 watt station.  There's a lot of difference in $775 for my station and $1600 for a new Flex 3000. At least for me there is. So now I guess I've given you and your buddy Gene more ammo to hurl insults at me with because I can't afford to just drop money on a radio anytime I feel like it but I tried to answer the question as best I could. Oh, and for the record, I think it's an obscene amount of money that is being asked for the Flex 6700 and 6500 and I feel the same way about all the top of the line rigs from all the manufacturers. My XYL about had a coronary when I first told her what I wanted to spend on the 5000
Michael, W4HIJ
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N4OI
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Posts: 210




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« Reply #77 on: March 01, 2013, 11:24:11 AM »

[...] someone did me the unfortunate pleasure of quoting his  question, [...]

Sorry about that!
 
Some of us have realities in life that don't allow us  to go out and drop a few thousand on a radio anytime we feel like it. If fact we are lucky if we can muster up the sixteen hundred that it cost to get one of the bottom line Japanese rigs or a nice Flex 3000.[...]
Michael, W4HIJ

I apologize if my comment implied anyone was illogical for making any personal decision, and especially if it is consistent with good financial stewardship!   When I read Stan's question, I actually was thinking about my old TenTec OMNI-D that I just purchased with a matching power supply for much less than 300 bucks.  It has a "Drive" pot that I can just dial back from 100 watts to QRP...   And I really like that old radio for its nice QSK and quiet receiver.


Obviously, that approach will not float your boat!  Again, I apologize for any misunderstanding.

73 ES GOD BLESS U ES URS DE KEN N4OI  Grin
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W4HIJ
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Posts: 367




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« Reply #78 on: March 01, 2013, 11:46:17 AM »

[...] someone did me the unfortunate pleasure of quoting his  question, [...]

Sorry about that!
 
Some of us have realities in life that don't allow us  to go out and drop a few thousand on a radio anytime we feel like it. If fact we are lucky if we can muster up the sixteen hundred that it cost to get one of the bottom line Japanese rigs or a nice Flex 3000.[...]
Michael, W4HIJ

I apologize if my comment implied anyone was illogical for making any personal decision, and especially if it is consistent with good financial stewardship!   When I read Stan's question, I actually was thinking about my old TenTec OMNI-D that I just purchased with a matching power supply for much less than 300 bucks.  It has a "Drive" pot that I can just dial back from 100 watts to QRP...   And I really like that old radio for its nice QSK and quiet receiver.


Obviously, that approach will not float your boat!  Again, I apologize for any misunderstanding.

73 ES GOD BLESS U ES URS DE KEN N4OI  Grin
I wasn't taking offense to you Ken and I really don't take offense to Stan's question either but lets just say he and I don't see eye to eye on a lot of things. I just tried to answer the question the best, most honest and forthright way I could.  Different strokes for different folks. Some people are perfectly content with buying older used radios and I hope you enjoy the Ten Tec. I just enjoy operating Flex SDR so the 1500 is the best choice for me and my smaller budget. If my radio budget gets bigger anytime soon, I'm sure I would make the step up to a higher powered radio. That's just not in the cards at present.
Michael
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W4HIJ
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Posts: 367




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« Reply #79 on: March 01, 2013, 02:15:46 PM »

-22dB measured by ARRL!
That is -16dB as ARRL numbers are inflated by 6dB.

Jean-Claude PJ2BVU
If I'm not mistaken, that's being measured at full power output. It NEVER takes full power output of my 1500 to drive my amplifier, it's typically less than half depending on the band. But hey, let's not let more  real world application of how the XCVR is actually used get in the way of a good bashing session. What fun would that be? Roll Eyes Roll Eyes Roll Eyes
Michael, W4HIJ

I wonder why Flexers think they are always under attack.
We are taking about the Flex-1500 and someone stated that ARRL measured IMD at -22dB on 40m. I cannot attest of the veracity of this statement but as no one said anything to the contrary I assume it is true.
I also assume that whatever they measured -22dB is accurate.
I also assume that when they found -22dB they double, triple checked the result as -22dB is not that good.
It could be that the unit they tested was below the norm or that Flex improved the rig after the review.
It is not the point, I just used -22dB as it was what was posted.
Or may be you think that when I say "inflated by 6dB" it is a form of bashing.
You are free to Google "Transmit IMD". May be you will find a link to National Instruments for example:
Quote
If F1 and F2 are the frequencies of the two tones, then the third-order distortion products occur on both sides of these tones at 2F2 – F1 and 2F1 – F2. Assuming that the power levels of the two tones are equal, IMD3 is the difference between the power of the fundamental signals and the third-order products, as defined in the following equation:

IMD3 = Po -Po3

where o refers to the output of the UUT, Po3 is the power level of one of the output third-order products, and Po is the power level of one of the fundamental tones.
I placed the emphasis on one, it is not in the original text.
Wherever you look, only ARRL uses this 2 tone PEP stuff.
Yes, IMD is measured at full power, that's the way ARRL does and not specifically for Flex radios but for any radio. Do you think ARRL is bashing all the rig manufacturers? That is a way to compare different rigs, you compare bananas with bananas (2 tone PEP at full power is still a valid comparison).
You said that you never (need to) drive your amp with 5W, I never said you did and I never recommended to do so. You drive it at around 2W and it is a good thing, it will improve things but until someone measure the IMD at 2W you cannot tell by how much.
Now imagine the guy who want to drive an amp to get 100W and does not have an idea of what this IMD stuff is and buys a 100W amp. If it is FCC approved it cannot have more than 15dB gain if I am not mistaken. If it is 15dB gain he can drive it with a little more than 3W, if it has less than 15dB gain he will drive it at 5W.
What I was trying to do was to show the guy who think it is Chinese, it is not. It is not rocket science: if it is a linear scale - like I double my power or I halve my power - you use multiplication and division. If it is a log scale like when using dB you use addition and subtraction. You don't know what is 100dB? I don't, I just use a conversion table or a dB calculator. Just remember to use the correct table depending if it is relative to voltage or power. For the transmit IMD just do a little reading, nothing complicated. And when you read the review of the Flex-1500 and it says 3rd order products IMD -22dB on 40m you have an idea of what it means and what will happen when you drive your 1kW amp with the Flex at full power (the 6dB difference is just a factor of 2 difference and it won't make much of a difference for the station on the adjacent frequency).
You can even use the ARRL handbook as a reference, there is some valuable information in there.
Oh my Gosh!
ARRL Handbook 2002 page 17.5
Quote
IMD Ratio
If a pair of equal-amplitude signals create IMD products, the IMD ratios (IMR) are the difference, in dB, between each of of the two tones and each of the IMD products (see Fig 17.6).
Fig 17.6 - Top: IMD ratio (as displayed on a spectrum analyzer).
It looks like they had to call it IMR in order to use their 2 tone PEP magic formula.

Now if you think that my previous post was a personal attack on you or Flex you have serious problems.
May be the Flexer syndrome  Grin

Jean-Claude PJ2BVU

Wow, just wow....all that blather because I said that I didn't drive my amp with the full output of the Flex. Contrary to what you may think, I understand all about IMD and harmonics. I do not need anything explained to me.  I've been doing this hobby for awhile now. Some 35 odd years. Perhaps you are like Stan and Gene and it makes you feel better about yourself to try to talk down to people? Anyway, I digress..... The whole point was that the measurement was made at full power output. The fact that I'm driving my amp with less than half power from the Flex means that the ARRL measurement is most likely if not completely invalid in my situation, yet I'm being accused of not being a considerate operator for putting an amp behind my 1500. As far as my reference to personal attacks and attacks on Flex, that's because I see the call signs of two individuals ( Stan and Gene) in this thread and although I have them on ignore, I know they are bashing Flex and all their users at every turn and hurling personal insults at me every other one. I know this because that's their modus operanda.  Pretty much end of story.  I'm getting ready to go operate in the contest this weekend. Have a nice life OK?
Michael, W4HIJ
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KE5JPP
Member

Posts: 0




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« Reply #80 on: March 01, 2013, 02:50:55 PM »


Wow, just wow....all that blather because I said that I didn't drive my amp with the full output of the Flex. Contrary to what you may think, I understand all about IMD and harmonics. I do not need anything explained to me.  I've been doing this hobby for awhile now. Some 35 odd years. Perhaps you are like Stan and Gene and it makes you feel better about yourself to try to talk down to people? Anyway, I digress..... The whole point was that the measurement was made at full power output. The fact that I'm driving my amp with less than half power from the Flex means that the ARRL measurement is most likely if not completely invalid in my situation, yet I'm being accused of not being a considerate operator for putting an amp behind my 1500. As far as my reference to personal attacks and attacks on Flex, that's because I see the call signs of two individuals ( Stan and Gene) in this thread and although I have them on ignore, I know they are bashing Flex and all their users at every turn and hurling personal insults at me every other one. I know this because that's their modus operanda.  Pretty much end of story.  I'm getting ready to go operate in the contest this weekend. Have a nice life OK?
Michael, W4HIJ

W4HIJ is not able to make valid arguments against many of our points, so that is why he cowardly claims to have us on ignore.  It is funny though, since putting us on ignore, he still picks and chooses certain things that we say to argue against here and brings up our names quite often on the forum.  If he were not lying about having us on ignore (or actually intending to ignore us) he would not be obsessed with mentioning us all the time.   Roll Eyes Roll Eyes Roll Eyes
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K3GM
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Posts: 1824




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« Reply #81 on: March 01, 2013, 03:05:24 PM »

Michael, what I'm suggesting is this.  If you enjoy your 1500, by all means do so.  The transceiver is type accepted.  But without a spectrum analyzer, you have no way of knowing what your signal looks like with the exciter at any output level.  My suggestion is to have fun with your 1500, but do so barefoot until you can verify your spectral purity running with reduced exciter power.
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K9IUQ
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Posts: 2053




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« Reply #82 on: March 01, 2013, 03:18:54 PM »

As far as my reference to personal attacks and attacks on Flex, that's because I see the call signs of two individuals ( Stan and Gene) in this thread and although I have them on ignore, I know they are bashing Flex and all their users at every turn and hurling personal insults at me every other one. I know this because that's their modus operanda. 

Ok I am calling you out on this, since you persist in this nonsense. Please give a quote from me at anytime where I have personally insulted you?

I can back up and prove anything I have said on this forum. Can You?

Stan K9IUQ
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PJ2BVU
Member

Posts: 115




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« Reply #83 on: March 01, 2013, 03:40:43 PM »

Hi Michael,
I think you get pumped up too easily and for no reason.
My first post did not quote anyone, was not directed to you or anyone in particular. A limited number of hams post on this thread but as of today there has been 16,453 views of this thread. I presume some readers wonder what is this IMD stuff all about and what it is important. This the reason I made the first post.
You made a post quoting me and saying:
Quote
But hey, let's not let more  real world application of how the XCVR is actually used get in the way of a good bashing session.
A bashing session!!!
My second post was trying to show you that there was no bashing on my part but it looks like you did not really bother to read it, a lot of the blah-blah-bah was not directed to you but
Quote
What I was trying to do was to show the guy who think it is Chinese, it is not.
whoever the guy is.
If I want to criticize someone I am not afraid to do so by mentioning his name and as you can see I do not hide under a pseudonym contrary to some who do.
What I noticed is that Flexers always think they are under attack for no reason, The Flexer Persecution Syndrome,  and also have absolutely no sense of humor.
A little humor before the contest:
I like fishing but the fish seems to always outsmart me. I use bait, small hooks, big hooks, golden hooks, magic hooks but nothing seems to work.
With Flexers you don't need bait, hooks. You don't even need a fishing rod, they just impale themselves on whatever stick is laying around. I am sure that if someone did some DNA sequencing on a Flexer he would find that they are closely related to lemmings.  Cheesy Cheesy Cheesy Cheesy Cheesy
Good luck in the contest, no bad feelings and no splatter  Grin

Jean-Claude PJ2BVU
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PJ2BVU
Member

Posts: 115




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« Reply #84 on: March 01, 2013, 03:57:54 PM »

Hi Ken,
I see a reason why someone would use a QRP rig and put a amp behind it:
His main activity is outdoors QRP where you don't want to carry a cement block, a brick is heavy enough, and neither does he want to carry a car battery (these 100W rig when run at 5W still use the same huge amount of power on RX).
And once in a while he wants to use a little more power at home like Michael doing a contest. This without having to invest in a 100W rig.

At the end of last year I decided to enter the 10m ARRL contest in the QRP category (using my 100W rig) just to see. I did it very casually but let me tell you: it's tough and I made a lot less contacts than expected.

Jean-Claude PJ2BVU
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W4HIJ
Member

Posts: 367




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« Reply #85 on: March 01, 2013, 04:00:22 PM »

Hi Michael,
I think you get pumped up too easily and for no reason.
My first post did not quote anyone, was not directed to you or anyone in particular. A limited number of hams post on this thread but as of today there has been 16,453 views of this thread. I presume some readers wonder what is this IMD stuff all about and what it is important. This the reason I made the first post.
You made a post quoting me and saying:
Quote
But hey, let's not let more  real world application of how the XCVR is actually used get in the way of a good bashing session.
A bashing session!!!
My second post was trying to show you that there was no bashing on my part but it looks like you did not really bother to read it, a lot of the blah-blah-bah was not directed to you but
Quote
What I was trying to do was to show the guy who think it is Chinese, it is not.
whoever the guy is.
If I want to criticize someone I am not afraid to do so by mentioning his name and as you can see I do not hide under a pseudonym contrary to some who do.
What I noticed is that Flexers always think they are under attack for no reason, The Flexer Persecution Syndrome,  and also have absolutely no sense of humor.
A little humor before the contest:
I like fishing but the fish seems to always outsmart me. I use bait, small hooks, big hooks, golden hooks, magic hooks but nothing seems to work.
With Flexers you don't need bait, hooks. You don't even need a fishing rod, they just impale themselves on whatever stick is laying around. I am sure that if someone did some DNA sequencing on a Flexer he would find that they are closely related to lemmings.  Cheesy Cheesy Cheesy Cheesy Cheesy
Good luck in the contest, no bad feelings and no splatter  Grin

Jean-Claude PJ2BVU
I just enjoy my radio Jean-Claude. SDR and the digital modes has put the fun back into what was becoming a dull hobby for me. And if you think that my perception of any other Flex user being attacked is wrong, you haven't seen what usually happens when someone relates a positive experience with their radios. There are those that have the " Flexer Shunned Syndrome" and think that because they had problems that it's an automatic that everyone else should have them too. If you dare to try to challenge them on this, you get shouted down. I've even had the memory of my late Father insulted by one of these guys.  I guess it's all in the perspective you look at it from.
Michael, W4HIJ
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K9IUQ
Member

Posts: 2053




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« Reply #86 on: March 01, 2013, 05:32:43 PM »

What I noticed is that Flexers always think they are under attack for no reason, The Flexer Persecution Syndrome,  and also have absolutely no sense of humor.

I like fishing but the fish seems to always outsmart me. I use bait, small hooks, big hooks, golden hooks, magic hooks but nothing seems to work.
With Flexers you don't need bait, hooks. You don't even need a fishing rod, they just impale themselves on whatever stick is laying around. I am sure that if someone did some DNA sequencing on a Flexer he would find that they are closely related to lemmings.  Cheesy Cheesy Cheesy Cheesy Cheesy

Any intelligent ham has been on this SDR forum for a long time (like you Jean-Claude) has come to the same conclusion. For whatever reason the Flexers seem determined to make themselves look silly.

Like fishing in a barrel it is SO easy to get a Flexer sizzling in the frying pan....... Wink Cheesy Cheesy Cheesy

I think the biggest conclusion and the most important one that you described is: Flexers have absolutely no sense of humor. They take themselves and their radios way too seriously.

Stan K9IUQ
« Last Edit: March 01, 2013, 05:36:53 PM by K9IUQ » Logged
K9IUQ
Member

Posts: 2053




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« Reply #87 on: March 01, 2013, 05:36:09 PM »


I just enjoy my radio Jean-Claude.

you haven't seen what usually happens when someone relates a positive experience with their radios.

Jean-Claude has been contributing to this forum before you ever came here. He is quite aware of what happens here.

Stan K9IUQ
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N4OI
Member

Posts: 210




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« Reply #88 on: March 02, 2013, 03:47:51 AM »

Hi Ken,
I see a reason why someone would use a QRP rig and put a amp behind it:
His main activity is outdoors QRP where you don't want to carry a cement block, a brick is heavy enough, and neither does he want to carry a car battery (these 100W rig when run at 5W still use the same huge amount of power on RX).
And once in a while he wants to use a little more power at home like Michael doing a contest. This without having to invest in a 100W rig.

At the end of last year I decided to enter the 10m ARRL contest in the QRP category (using my 100W rig) just to see. I did it very casually but let me tell you: it's tough and I made a lot less contacts than expected.

Jean-Claude PJ2BVU

Hey Jean-Claude!  Yes -- you are singing to the choir here!  I view QRP NOT as "life is too short for QRP," but "life is too short for me to give all my QRP rigs the play they deserve."   I have a K1, a pair of Small Wonder Labs DSW-IIs and a Rockmite now, and am in the process of building the little Hendricks TwoFer transmitter.  Most fun is using the QRP rigs on a small gel cell battery with a lightweight dipole suspended from trees and fishing poles. 

I guess I never really thought of the Flex1500 in an outdoor QRP operation because of the need for a computer.  But then there are laptops...   QRP is a hoot, regardless!  Cheers and hope to see you on the CW sub-bands!d

73 ES GOD BLESS U ES URS DE KEN N4OI  Grin
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WD5GWY
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Posts: 406




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« Reply #89 on: March 02, 2013, 09:41:58 AM »

I have been doing a LOT of reading about IMD lately and I can clearly
see now why it is not a good idea to put any amplifier behind the Flex 1500.
 The numbers listed by the ARRL testing labs really do speak for themselves.
It is better to use the 1500 as-is, as a qrp radio instead of driving an amp with
it. Its IMD numbers even at 5 watts is not that good. But, will create less problems
than it being amplified.  W8JI gives a good explanation about what IMD is and is not.
 Thanks to everyone that keeps pounding on that here and elsewhere. Whether you
know it or not, some of us do get around to trying to learn more about IMD , including
the cause and the cure(s).
james
WD5GWY
 
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