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Author Topic: Suggestions for a 100 Watt Class amplifier for a FLEX-1500?  (Read 23857 times)
K6AER
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Posts: 3501




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« Reply #75 on: June 19, 2013, 02:29:24 PM »

Not to get pickey on scientific notation but that is 7.5 dollars per watt.
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WB2WIK
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Posts: 20574




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« Reply #76 on: June 19, 2013, 02:43:19 PM »

If it was really $75 a watt, I'd have to buy Monster's oxygen-free ultra low-noise, high-conductivity copper cables to go with it.

And I can't afford them. Cry
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KE3WD
Member

Posts: 5694




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« Reply #77 on: June 19, 2013, 03:09:22 PM »

Not to get pickey on scientific notation but that is 7.5 dollars per watt.

Whoops!

Stuff like that has been happening more and more in this old brain of late. 

But even at the correct $7.50 per Watt rate, that's likely a lot more money than the average ham is going to be willing or possibly able to pay to get to the 100W mark. 

Time will tell,


73
« Last Edit: June 19, 2013, 03:11:26 PM by KE3WD » Logged
ZENKI
Member

Posts: 916




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« Reply #78 on: June 21, 2013, 04:41:10 AM »

Elecraft seems to making the claim that high price is a reflection on the high IMD performance of the amplifier.
Who knows they might have included some advanced amplifier  circuitry that makes the amplifier more linear than can be expected from a 12 volt device amplifier.
If they have succeed in pulling off producing a clean amplifier that is a step above the CB junk, they should  be congratulated. I however dont expect the amplifier IMD specifications to consistent
across all the bands nor would I expect world class 3rd order IMD numbers. It seems Elecraft believes that their radios with IMD specifications as low is -30db pep 3rd order is clean. Its very easy
to shift the goal posts to make your equipment look good.

At the end of the day the only solution that is going to save ham bands from the poor IMD malaise is the adaptive pre-distortion solution.
The HP_SDR crowd will probably deliver technology  this by the years end. And as usual its skilled real hams who have been working on the solution
rather than ham radio shopping experts who can only boast about  the crap equipment that they buy and who to want to pass it off as technical superior equipment.
Its easy playing spot the dummy by  the equipment they procure and  promote. Its even more amusing watching the hackles getting raised when the dummies
dont like you describing their favorite  amplifiers as junk. I think this is the case of the fisherman hooking themselves with their verbal diarrhea..

Superior transmitter IMD specifications is coming, be patient,  the real hams are working on helping  the poor technically illiterate hams feel good about what they buy in the future.



Well Elecraft just announced their 5 watt to 100 watt amplifier the KXPA100.

http://www.elecraft.com/tmp/kxpa100.htm

Auto band switching, 160-6 meters with bar graph SWR and power  display. Optional ATU for $399.

Very nice unit that runs on 13.8 VDC.  Has FCC certification and RS-232 communication. It only cost $750.00
In looking at the specifications and reviewing the FCC certification I did not see an IMD specification.

Wonder what it might be…………………………………..



At seventy five dollars per watt, very likely not too many hams are going to care if the thing is cleaner than clean can be.  --And at 13.8, it probably isn't. 

I have found that if a spec is not listed, there is usually a reason that it got left out. 

For that kinda money, one couls simply pick up a used 100W YaeKenCom and pull the PA and filters out of the thing and still be ahead of the game. 

73

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WX7G
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Posts: 5977




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« Reply #79 on: June 21, 2013, 05:23:34 AM »

Zenki,

I'm trying to quantify what good and bad IMD is. What do you consider good 3rd order IMD?

You cite the NTIA standard for spectral purity as being good and have mentioned Icom Marine radios as an example of clean SSB.

The 150 watt Icom IC-M802 HF Marine Transceiver specifies "spurious emissions" of -62 dB and meets the formula.

NTIA uses this formula for spectral purity.     43+10LOG(pX)

I interpret this to mean we ratio all of the spurious power to the total power. If all of the spurious power were contained in the 3rd order IMD products the Icom IC-M802 would have 3rd order IMD of -59 dBc. If we account for the higher order distortion products and harmonics the 3rd order IMD might have to be -56 dBc. Is it really this clean?

References

http://www.icomamerica.com/en/products/marine/ssb/m802/specifications.aspx

https://comm.capnhq.gov/comm/equipment/NTIA_Standards.cfm
« Last Edit: June 21, 2013, 05:56:31 AM by WX7G » Logged
K6AER
Member

Posts: 3501




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« Reply #80 on: June 21, 2013, 12:51:49 PM »

This weekend starting at 18:00 Zulu Saturday you will hear signals 5 deep every KHz on the money bands of 40, 20 15 and 10 meters on both CW and SSB. This spectral anomaly is called Field Day. Some will be using amplifiers but most will be 5 watts or 100 watts maximum. The IMD as viewed on a spectrum analyzer will be amazing.

Almost all interference on the ham bands is caused by the operator s and not their equipment.  This is just a fact of life. Luckily the band will quiet down just after all those Harbor Freight generators run out of gas and oil.

Worrying about IMD of an amplifier is like worrying about speeding Porsches when you are stuck in traffic.
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TANAKASAN
Member

Posts: 933




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« Reply #81 on: June 21, 2013, 01:03:59 PM »

"This weekend starting at 18:00 Zulu Saturday you will hear signals 5 deep every KHz on the money bands of 40, 20 15 and 10 meters on both CW and SSB. This spectral anomaly is called Field Day."

I know, and I have five experimental receiver front ends to test and verify, this is going to be fun.

Tanakasan
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KW6LA
Member

Posts: 91




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« Reply #82 on: June 21, 2013, 03:22:17 PM »

<< Almost all interference on the ham bands is caused by the operator s and not their equipment.  This is just a fact of life. Luckily the band will quiet down just after all those Harbor Freight generators run out of gas and oil. >>

Mike-  How nice to read something so intellectually honest and not some pet peeve on SS amplifiers. It is a shame so many hams have trouble setting the ALC / Processor levels. When you tune into a crunchy sounding signal
you often find the IMD is there too. Now contest day, you increase the values by 20 percent………………..See no problem. There has been loads of information on this site for new hams to setup correctly, but you find the old
dogs can be some of the worst IMD offenders. Martha…………….where are my glasses .   Roll Eyes
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WX7G
Member

Posts: 5977




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« Reply #83 on: June 22, 2013, 08:03:17 AM »

The NTIA.GOV website is down.

Does anyone have a working link to the NTIA SSB transmitter test method?
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KE3WD
Member

Posts: 5694




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« Reply #84 on: June 22, 2013, 02:28:08 PM »

1)  Hire outside testing facility.

2)  Be sure to take 'em out to an expensive dinner, endless bar tab and a sporting event or a concert.

3)  Pay 'em real good now, heah?  

*Providing them with an actual piece of said equipment to be tested, optional.  


How's that?  



73
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ZENKI
Member

Posts: 916




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« Reply #85 on: June 24, 2013, 02:44:26 AM »

ITU standards require 3rd order products to be down -36Db

The emphasis should be on the higher order products greater than the 9th order.

A super clean transmitter using a real voice IMD test  would have its IMD products suppressed 50db at 5KHZ and something like 70db at 20khz.

The old FCC Part 80 Marine regulations used to specify that the transmitters needed the 3rd order IMD to be suppressed by -36db relative to pep or 30Dbc. However the mask  was very tight for products above 9th order.
It specified something 43db+10log(txpower). So for a 1500 watt transmitter the IMD products above 9th order should be suppressed 75db

The Icom M802 pass under the current  ITU standard which is the same standard that the FCC uses now. The old Icom Marine radios like the M710 and radios of that era passed under the old FCC Part80 marine regulations.
The old Icom marine transmitters and beautifully clean transmitters. If ham transmitters were this clean we would not be talking about this issue now!

NTIA standards are the same as ITU standards for IMD and spurious products. This is an international standard and would  be perfect for the amateur service.

For me a clean transmitter would have 3rd order IMD figures of -40dbc with all successive IMD products dropping 10DB. And all IMD products above the 11th order suppressed by 80db. A radio such as this would not cause any splatter assuming that it does not have a ALC design issue or driven by a LID. If you look at Mil Standards for HF transmitters in the 1980s, you would find that most had this specification. DRM transmitters have such high standards and you would hear any splatter from a 250KW DRM transmitter.

A radio like the K3 with 50 volt PA and the K3's inherent correctly designed ALC would meet the above requirements with ease. A Collins 32SS3 will also achieve this level of performance without trying. Many of the old hybrid radios like the TS830S can also achieve such a clean signal. Its really a design  choice not pie in the sky wishful thinking. if you do want to design a clean transmitter.

For the ham service  ITU compliance would be a good first step and would eliminate most of the faulty transmitter designs we are now seeing. Meeting FCC or NTIA  standards would be a easy design change for most new ham transmitters.

I dont want to confuse spurious and IMD products. Hams dont realise that  to meet FCC type acceptance ham transceiver do have to meet spurious  product suppression standards. They dont have to  meet IMD emission standards.
Adding IMD to the FCC type acceptance testing regime will just be a tick box on a sheet of paper. Hams who argue against these standards are  truly exaggerating the difficulty of the costs of adding one more test.


Zenki,

I'm trying to quantify what good and bad IMD is. What do you consider good 3rd order IMD?

You cite the NTIA standard for spectral purity as being good and have mentioned Icom Marine radios as an example of clean SSB.

The 150 watt Icom IC-M802 HF Marine Transceiver specifies "spurious emissions" of -62 dB and meets the formula.

NTIA uses this formula for spectral purity.     43+10LOG(pX)

I interpret this to mean we ratio all of the spurious power to the total power. If all of the spurious power were contained in the 3rd order IMD products the Icom IC-M802 would have 3rd order IMD of -59 dBc. If we account for the higher order distortion products and harmonics the 3rd order IMD might have to be -56 dBc. Is it really this clean?

References

http://www.icomamerica.com/en/products/marine/ssb/m802/specifications.aspx

https://comm.capnhq.gov/comm/equipment/NTIA_Standards.cfm

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W5JON
Member

Posts: 163




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« Reply #86 on: June 24, 2013, 04:54:06 AM »

ZENKI,

I sold both my ICOM IC-706 and IC-756PRO because I could not cure the "ALC Overshoot" problem in both. The ALC Overshoot power spike was causing constant tripout of my QRO Amplifier. Since replacing the ICOM with my FT-1000MkV I have never had another tripout. Per the below questions, I would be very interested to hear how you cured this problem in your ICOM IC-706.

John W5JON




Quote from: W5JON on June 14, 2013, 06:31:47 AM
Hi,

Thanks Phil for the information.

 As Zenki has been praised as an IMD expert, and posted a lengthy post on HIS testing of a RM Italy Amplifier, being driven by an ICOM IC-706, I wanted to know what HIS resolution was for the ALC Overshoot problems of the IC-706.

Given his statment in his post of the RM Italy/IC-706 testing, when speaking of OTHERS, he wrote, ""They will not even consider, supply voltage, saturation, ALC overshoot etc etc'".  Therefore I can not imagine that special attention would not be given to the IC-706 ALC problem during his tests. However thusfar Zenki has not replyed to my questions regarding HIS testing.

My questions to Zenki remain:
1. What was your correction for this "spike" while testing the RM amplifier? 
2. What was the IMD data result of this "power spike" before and after any correction while testing the RM amplifier?
3. It has been stated on Eham that you are N2NEP, is this correct?

73,

John W5JON





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AD6KA
Member

Posts: 2237




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« Reply #87 on: June 25, 2013, 04:56:33 AM »

Quote
My questions to Zenki remain:
.............
3. It has been stated on Eham that you are N2NEP, is this correct?

How is this germain to a discussion about 12v PA IMD?
73, Ken AD6KA
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W5JON
Member

Posts: 163




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« Reply #88 on: June 25, 2013, 05:52:28 AM »

I prefer having a conversation with an someone that is not anonymous.  I am proud of my callsign, license and credentials, and wish others were of their's.

When asked to accept test results, it is important to know that credentials of the individual doing the testing, to help establish validity of the testing and results.  During my 30 years in the industry I learned not to blindly accept test results because someone said or wrote so, but to know their capabilities. When submitting results of testing, "because I say so" does not cut it in the real world.  

I would think, in an amateur radio forum, having an amateur radio license is a basic credential, and not to much to ask.  

73,

John



Quote
My questions to Zenki remain:
.............
3. It has been stated on Eham that you are N2NEP, is this correct?

How is this germain to a discussion about 12v PA IMD?
73, Ken AD6KA
« Last Edit: June 25, 2013, 06:41:31 AM by W5JON » Logged
SWL2002
Member

Posts: 254




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« Reply #89 on: June 25, 2013, 04:12:05 PM »

I prefer having a conversation with an someone that is not anonymous.  I am proud of my callsign, license and credentials, and wish others were of their's.

When asked to accept test results, it is important to know that credentials of the individual doing the testing, to help establish validity of the testing and results.  During my 30 years in the industry I learned not to blindly accept test results because someone said or wrote so, but to know their capabilities. When submitting results of testing, "because I say so" does not cut it in the real world.  

I would think, in an amateur radio forum, having an amateur radio license is a basic credential, and not to much to ask.  

73,

John



Quote
My questions to Zenki remain:
.............
3. It has been stated on Eham that you are N2NEP, is this correct?

How is this germain to a discussion about 12v PA IMD?
73, Ken AD6KA

Come on, the Ham Radio licenses have been dumbed down so much at this point and are such a joke, the FCC might as well just charge $25 for each license class.  A total of $75 would get you an Extra Class.  Having a Ham radio license means nothing as far as credentials.  It means you memorized enough the of the published answers that you passed.  Some guys can't pass the first time even though they have had the answers GIVEN to them!  Pitiful!

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