(K3) KPA-250 (sort of)

[Edward R Cole]

Hey, all that were wondering about the HF amplifier kit I obtained
over a year ago - I finally built it!  It uses two MRF-422 for 300w
output with 20w drive.  Well, the K3/10 will not provide that.  I do
get 15w output (uncalibrated RF) with my K3/10.

The amp kit is distributed by Communications Concepts, Inc. and the
model is EB27A.  I am getting 270w out on 20/15m, 240w on
10m.  Output drops as frequency drops but getting 170-190w on
40/80m.  Full data on;
http://www.kl7uw.com/HF-300PA.htm

I'll have photos up in a day or so.

I'm wiring up a relay to provide TR bypass in receive so may be heard
soon on the Elecraft Net.


73, Ed - KL7UW, WD2XSH/45
======================================
BP40IQ   500 KHz - 10-GHz   www.kl7uw.com
EME: 50-1.1kw?, 144-1.4kw, 432-QRT, 1296-?, 3400-?
DUBUS Magazine USA Rep [hidden email]
"Kits made by KL7UW" http://www.kl7uw.com/kits.htm
======================================
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[Edward R Cole]

After quite a bit of modification&dickering with an open-frame dc
relay that I had hoped would work as TR relay, it appears it needs to
be inside a totally shielded enclosure.  I'm getting feedback into
amp thru the relay that is causing it to generate RF without drive
(oscillate).  I need a relay that can be included inside the
amplifier enclosure so probably will investigate some HD SPDT pcb
relays and separate the input relay from the output relay.  Amp is
running well with just input and output coax lines.

So I checked into the Elecraft SSB Net with the barefoot K3/10 today
(14w).  I did use the new coax lines that will serve the amp and the
QRO tuner (Drake MN2000).  Drake power meter is generous when
compared with my Bird43 (with 500H element).  New stations block diagram:
http://www.kl7uw.com/2012_Station.jpg
I will post more info on the amplifier here:
http://www.kl7uw.com/HF-300PA.htm

Got to run the snowblower so my wife can get thru the 2-foot snow
drift to the Sunday paper!


73, Ed - KL7UW, WD2XSH/45
======================================
BP40IQ   500 KHz - 10-GHz   www.kl7uw.com
EME: 50-1.1kw?, 144-1.4kw, 432-QRT, 1296-?, 3400-?
DUBUS Magazine USA Rep [hidden email]
"Kits made by KL7UW" http://www.kl7uw.com/kits.htm
======================================
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html