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Author Topic: Elecraft KPA-500 amp info released by FCC  (Read 18397 times)
AE5X
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Posts: 1454




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« on: March 15, 2011, 03:05:02 PM »

Details and downloadable files on my site.

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


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KF6A
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Posts: 225




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« Reply #1 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.
« Last Edit: March 15, 2011, 09:35:01 PM by KF6A » Logged
TANAKASAN
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Posts: 933




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« Reply #2 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
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KD8MJR
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Posts: 5557




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« Reply #3 on: March 16, 2011, 10:07:11 PM »

Any price info yet?
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“A lie can travel half way around the world while the truth is putting on its shoes.”  (Mark Twain)
K6AER
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Posts: 5726




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« Reply #4 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
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KF6QEX
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Posts: 651




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« Reply #5 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.

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K6AER
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Posts: 5726




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« Reply #6 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.
« Last Edit: March 19, 2011, 10:21:44 PM by K6AER » Logged
AE5X
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Posts: 1454




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« Reply #7 on: March 20, 2011, 01:47:33 PM »

"Three questions come to mind."

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

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K6AER
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Posts: 5726




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« Reply #8 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.
« Last Edit: March 20, 2011, 04:17:42 PM by K6AER » Logged
AD5X
Member

Posts: 1623




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« Reply #9 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
« Last Edit: March 21, 2011, 06:06:51 AM by AD5X » Logged
KF6QEX
Member

Posts: 651




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« Reply #10 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. Smiley






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G3RZP
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Posts: 1280




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« Reply #11 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.
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AD4U
Member

Posts: 2541




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« Reply #12 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
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AD5X
Member

Posts: 1623




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« Reply #13 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
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KD8MJR
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Posts: 5557




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« Reply #14 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.
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“A lie can travel half way around the world while the truth is putting on its shoes.”  (Mark Twain)
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