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eHam Forums => Amplifiers => Topic started by: AE5X on March 15, 2011, 03:05:02 PM



Title: Elecraft KPA-500 amp info released by FCC
Post by: AE5X on March 15, 2011, 03:05:02 PM
Details and downloadable files on my site.

John AE5X
http://www.ae5x.com/blog




Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: KF6A on March 15, 2011, 09:32:11 PM
My friend used one in the last HF contest and thought it was pretty nice. He commented that it would make a nice DXpedition amp. If I remember correctly he said it was about the same size as a K3.


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: TANAKASAN on March 16, 2011, 04:40:58 AM
Interesting, it's a totally different design to the first Elecraft amplifier that we saw. That one used multiple PA transistors, this one has only two.

Tanakasan


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: KD8MJR on March 16, 2011, 10:07:11 PM
Any price info yet?


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: K6AER on March 19, 2011, 02:49:42 PM
Three questions come to mind.

Where is the FCC designator?

Also there is not case emmisssions testing.

And how did it pass emmisions for operation above 21.45 MHZ? The amplifier emmissions must pass TIA-603C. According to the spectrum analyzer shots it does not pass.

Level must be 43 + log of the power below dBC of peak for conducted and radiated emmisssions. About 70 dB.

24.9 MHz is 62 dBc
28.5 MHz is 63 dBc
50 MHz is 64 dBc


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: KF6QEX on March 19, 2011, 03:49:45 PM

Quote
The amplifier emmissions must pass TIA-603C.




Quote
TIA-603C (December 2004)

Land Mobile FM or PM Communications Equipment, Measurement and Performance Standards
Hide Summary
Summary

Committee:
TR-8.1
Published:
December 2004
Category:
Telecommunications
Description:
This document provides definition, method of measurement and performance standards for radio equipment used in the Private (Dispatch) Land Mobile Services that employ FM or PM modulation, for transmission of voice or data using analog or digital techniques, with a frequency of 1 GHz or less.
 

You must be talking about some other TIA603-C
Somehow the words private , dispatch and Land Mobile Services employing FM or PM modulation don't bring the KPA-500 to mind.



Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: K6AER on March 19, 2011, 10:18:54 PM
All amplifiers that amplify (positive gain) above 25 MHz must conform to commercial standards. When you look at FCC type certification for ham equipment, 90% of the amplifier used in the ham band stop at 21.45 MHz for their certification.

Below 21.45 MHz the amplifiers are certificated to part 97.313.

I do FCC certification for Ham amplifiers and believe me I wish we did not have to do this.


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: AE5X on March 20, 2011, 01:47:33 PM
"Three questions come to mind."

Nowhere is it indicated that these are final results.
Relax.



Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: K6AER on March 20, 2011, 04:15:52 PM
“Nowhere is it indicated that these are final results.
Relax.”

I’m just pointing out that there is no type certification and by the information listed so far there is much work to be done. Getting the conducted and radiated emission down 70 dBc to the tenth harmonic is a real gut buster. The case radiation including the DC line to the amplifier is going to be a huge problem.

This is why most amplifiers being manufactured for ham used are only certified for operation to 21.45 MHz. You are no longer allowed to cut the “GREEN WIRE” for 12 and ten meter operation. The new ALS-1300 went so far to leave out the 12/10 meter Low pass filter to pass the FCC certification process.

The FCC has clamped down on the certification of amplifiers and as a result many possible designs have not been brought to market for they could not pass radiation requirements.  In addition Elecraft has to convince the FCC that, as a kit, they can control the possible certification integrity with a kit.

In looking at the basic construction of the kit I don’t see a case capable of 80 dB of isolation.  It will be interesting to look at the final product at Visalia this year.

Tube amplifiers are much easier to shield. Their harmonic content is much lower due the Q of the Pi network. In addition, I did not see what power levels the harmonics were taken at. As you approach compression the harmonic content of a SS amplifier rises exponentially. Is the shown harmonics at 500 watts out? No mention of the tested power levels.

The FCC will not let you ship an amplifier until all the requirements have been met.


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: AD5X on March 20, 2011, 08:23:29 PM
FCC Part 97.317 details certification of ham amplifiers.  It states "To receive a grant of certification, the amplifier must: (1) Satisfy the spurious emission standards of § 97.307 (d) or (e)..."  

97.307(d) states "For transmitters installed after January 1, 2003, the mean power of any spurious emission from a station transmitter or external RF amplifier transmitting on a frequency below 30 MHz must be at least 43 dB below the mean power of the fundamental emission."

97.307(e) states "The mean power of any spurious emission from a station transmitter or external RF power amplifier transmitting on a frequency between 30-225 MHz must be at least 60 dB below the mean power of the fundamental."

So per FCC Part 97, the amplifier meets the requirements for certification.

I don't see anything about adding 10 log (power).

There is no DC cable on the amplifier.  It is AC powered.

The FCC designator is UTR-KPA500

Phil - AD5X


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: KF6QEX on March 21, 2011, 01:16:49 AM
Quote
All amplifiers that amplify (positive gain) above 25 MHz must conform to commercial standards.
Ok..I looked and looked and looked and I can't find that.

I'm finding no reference to a requirement for adherance to commercial standards for amateur amplifiers that "go" above 25 Mhz

The testng was done by in independent Lab and the data was submitted to the FCC. Magically, the amp got approval.
I don't want to point any fingers but either the Lab lied, or you are wrong or the FCC gave approval by mistake. :)








Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: G3RZP on March 21, 2011, 03:54:33 AM
The international radio regulations reference ITU-R Rec. SM329. That requires  all spurious to be 43 + 10logP dB down, but not more than 50dB for transmitters operating below 30MHz and not more than 70dB down for transmitters operating above 30MHz.

Despite the US delegation to the ITU having an amateur as the FCC mand, they managed not to communicate well enough between him and the amateur who wrote the new rules that they got it wrong! To sell in Europe, it will need to be 50dB down up to 30MHz.


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: AD4U on March 21, 2011, 05:21:23 AM
All amplifiers that amplify (positive gain) above 25 MHz must conform to commercial standards. When you look at FCC type certification for ham equipment, 90% of the amplifier used in the ham band stop at 21.45 MHz for their certification.

Below 21.45 MHz the amplifiers are certificated to part 97.313.

I do FCC certification for Ham amplifiers and believe me I wish we did not have to do this.

I understand the reasoning behind these specs, but does ANYBODY think this will stop (or even slow down) the proliferation of CB amps?  It is just another un-enforceable government regulation that hurts the "good guys" and has absolutely NO effect on the "bad guys".

Dick  AD4U


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: AD5X on March 21, 2011, 07:31:37 AM
The international radio regulations reference ITU-R Rec. SM329. That requires  all spurious to be 43 + 10logP dB down, but not more than 50dB for transmitters operating below 30MHz and not more than 70dB down for transmitters operating above 30MHz.

Despite the US delegation to the ITU having an amateur as the FCC mand, they managed not to communicate well enough between him and the amateur who wrote the new rules that they got it wrong! To sell in Europe, it will need to be 50dB down up to 30MHz.

From the data, the KPA500 easily meets the -50dBc ITU requirement below 30 MHz.  The only question is on 6-meters, where the noise floor of the display appears to be about -68dBc.  Seems clean to that level anyway.

Phil - AD5X


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: KD8MJR on March 21, 2011, 06:03:42 PM
I understand the reasoning behind these specs, but does ANYBODY think this will stop (or even slow down) the proliferation of CB amps?  It is just another un-enforceable government regulation that hurts the "good guys" and has absolutely NO effect on the "bad guys".

Dick  AD4U

You hear this a lot and the truth is YES it does stop a lot of people, I would say most of the people!   Most people are not Tech Savvy enough or know a friend who they trust enough to do the Mods so they are well and truly stuck until something like this comes along on eBay and then once again they have to take the chances we all take when dealing with EBay.  So yes, many people get stopped because of these inclusions.
It's just for people in the know like you and me it seems so easy to get around, but then again so does picking a lock and hot wiring a car to some other people.


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: K6AER on March 21, 2011, 09:21:10 PM
Let’s just cut to the chase. I looked and did not find the FCC approval number. Could someone please attach the URL to the FCC designator.


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: KF6QEX on March 21, 2011, 10:27:09 PM
Here you go:

https://fjallfoss.fcc.gov/oetcf/eas/reports/ViewExhibitReport.cfm?mode=Exhibits&RequestTimeout=500&calledFromFrame=N&application_id=290417&fcc_id=%27UTR-KPA500%27


https://fjallfoss.fcc.gov/oetcf/tcb/reports/Tcb731GrantForm.cfm?mode=COPY&RequestTimeout=500&tcb_code=&application_id=290417&fcc_id=UTR-KPA500


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: K6AER on March 22, 2011, 09:49:41 PM
That was interesting. None of the PDF's came through.


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: KF6QEX on March 23, 2011, 03:20:47 AM
Well...here it is the "long way"

This is the link for the Equipment Authorization Search:
https://fjallfoss.fcc.gov/oetcf/eas/reports/GenericSearch.cfm   

Use UTR in the Grantee Code
Don't type anything in the Product code.
Use  Elecraft in the Applicant Name.

Hit Start Search

Good luck :)


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: K7KBN on March 23, 2011, 07:19:19 AM
That was interesting. None of the PDF's came through.

They came through fine for me...


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: KF6QEX on March 28, 2011, 10:04:37 AM
That was interesting. None of the PDF's came through.

Any luck getting to the PDFs ?


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: KO4NX on March 28, 2011, 11:26:45 AM
I am glad to see this news as I have been waiting to buy the KPA 1500. I have passed on other amps in the hopes Elecraft would finally produce the Amplifiers I saw long ago at Dayton.

The only concern I have is; where is the SO2R circuitry which was advertised when Elecraft first announced these amplifiers to the public? If I recall correctly, it was going to be an option on both the KPA-500 and KPA 1500.

Has anyone heard any more on the SO2R compliance specification?

73

Rich, AJ3G


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: AD5X on March 29, 2011, 09:34:07 AM
I am glad to see this news as I have been waiting to buy the KPA 1500. I have passed on other amps in the hopes Elecraft would finally produce the Amplifiers I saw long ago at Dayton.

The only concern I have is; where is the SO2R circuitry which was advertised when Elecraft first announced these amplifiers to the public? If I recall correctly, it was going to be an option on both the KPA-500 and KPA 1500.

Has anyone heard any more on the SO2R compliance specification?

73

Rich, AJ3G


The original amps announced were the KPA800 and KPA1500.  Maybe they had SO2R circuitry/connectors?  In any case, the KPA500 does not have this capability.  But it IS a nice amplifier!

Phil - AD5X


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: KO4NX on March 29, 2011, 11:16:54 AM
Hi Phil:

You are correct, the original was a KPA800, and I distinctly recall a SO2R add on option. I have no doubt this will be a nice amplifier, as I have built a lot of Elecraft gear over the years, and absolutely love it.

Unfortunately, the lack of the SO2R switching will prevent me from purchasing this amplifier, as I was hoping to retire two Ten Tec 425's and a Puma 6K in place of one KPA1500 with SO2R.

Oh well, I guess it's time to revisit SPE and see when they are planning to release the legal limit version of their amplifier.

73

Rich, AJ3G


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: ZENKI on April 02, 2011, 06:02:46 PM
Looks like a nice amplifier.

If the IMD numbers are good I will buy one, 500 watts is enough most of the time. If you need more than 500 watts you need to start spending money on some better antennas and not  bigger  amplifiers.


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: KO4NX on April 14, 2011, 04:52:58 PM
Well it's official, Elecraft now has these listed for sale.  Looks like the kit will be around $2000.00. 

Zeni - In the contest environment, when in a High Power Category, 500W is doing yourself a disservice, even with great antennas. That being said, my primary interest was some of the SO2R switching, which I thought would be wonderful for the contest community!

73

Rich, AJ3G


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: W8JX on April 14, 2011, 05:12:43 PM
- In the contest environment, when in a High Power Category, 500W is doing yourself a disservice, even with great antennas.

It would only be about 4 1/2 db less than "legal limit"


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: KO4NX on April 15, 2011, 04:57:06 PM
I'll take 2/3 of a  S-Unit anyday, during a contest. The other item I worry about is overhead. I like to RTTY Contest, and even with the legal limit amps, I typically limit myself to 1KW to keep everything cool.


73

Rich, AJ3G


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: KD8MJR on April 15, 2011, 05:06:57 PM

It would only be about 4 1/2 db less than "legal limit"

True but that 4.5db for some odd reason on hard to reach DX makes a huge difference!
It should not as it's less than an S unit but somehow it does. ???


Title: RE: Elecraft KPA-500 amp info released by FCC
Post by: N3OX on April 15, 2011, 05:33:39 PM
True but that 4.5db for some odd reason on hard to reach DX makes a huge difference!
It should not as it's less than an S unit but somehow it does. ???


There are a combination of effects.  4.5dB is a useful audible amount when things are REALLY tough.  I could have used an extra 4.5dB when I tried to work Clipperton TX5C on 160m.  They had me as N3MX and a very polite pileup was all standing by for me.  They could clearly tell that I was in there making a little bit of noise, because the timing of the exchanges was right, but they just couldn't get the INFORMATION that I was N3OX, not N3MX.

When you are in the clear and the DX can tell you're in there but not copy you, that's when small amounts matter.  I hate S-units (because they're meaningless in terms of radio meter readings) but let's say that half an S-unit out of the noise is a lot better than half an S-unit under the noise ;D

There's another issue I think too.

People put too much emphasis on amplifier power as a measure of success, and that attitude actually changes their willingness to try hard in pileups.  People spend money to get 1500W instead of 1200W.  Why would you do that?  Because it's POWER OUTPUT.  BIG WATTS.  It's very psychologically important to people so that they feel that they're as strong as they can be.

I really think people, especially small stations running barefoot, pull their punches in pileups because they imagine all these other people who are stronger than them.    IMO, this imaginary problem  has something to do with why all of these untuned verticals are popular even on the low bands.  It doesn't really matter what comes out in radiation if you can't run your amp full bore into the shack end of the coax.

A lot of people are giving up 2, 3, 5, or 10dB (depending on band) when they feed their 43 foot vertical with a UNUN and coax.   Someone with a 600W amp and a 43 foot vertical with coax+UNUN could be exactly on par with a 100W station with a loading coil wound from $5 of house wire, but how many times do you think the 100W station dives headfirst into a raging pileup on 80m expecting to win against the amp guys?

Well I can tell you... I did.  And I won.  Quite a bit.  Then I upgraded to a quarter wave vertical and 100W and still won a lot.  I've worked something like 150 countries on 80 and 120 on 160m with a barefoot rig.  You know, 80 and 160, the "amplifier mandatory" ham bands?  And my 160m antenna should be down about 5-6dB from a full size vertical based on a couple measurements of the ground loss.   Don't get me wrong.  An amplifier helps.  I went to 400W on Topband and things seemed to improve even though I didn't get as much confidence boost as I think others may get.  But I worked plenty of countries for Topband DXCC with about 25W ERP.  Despite this, even some of us East Coasters won't get on TB without cranking up the amp. 

---------

I think you really need to take a balanced view on this issue.  Sometimes a dB matters, sometimes it's foolish to try for it.

Humans can detect 1dB changes or even less under good conditions for testing that.  A decibel is actually chosen to be more or less a human-detectable change.  We're not much good at 0.1dB and 10dB is too much to be a useful smallest unit.  There's a lot that goes on on the ham bands that means sometimes 1dB or even 3, 4, or 6dB  is practically invisible or at least just doesn't make a practical difference (signals 30dB out of the noise and fading 15dB).  Then there are other times when 1dB is considered quite critical (VHF weak signal, like moonbounce).

I think it's silly to try too hard for 1dB unless you can find a lot of 'em lying around to add them up.  3dB is probably worth not being careless about but also probably shouldn't worry you too much.    Here's a simulation of 6dB differences, make your own decision about how much an "S-unit" matters:

http://n3ox.net/files/6dB/

The only difference between the three files is the overall signal to noise ratio.  I used audio editing software to make those using real band noise and my independently recorded voice.