[Elecraft] Failing K3 at 3C0L

[Jim Brown]

This is far too conservative, and a far too limited approach.  I can 
offer several examples.

At home, I have two 3-el 20M Yagis spaced about 130 ft, and regularly 
use two K3s to drive two 1,500W amps. If I aim those two Yagis so that 
their driven elements are approximately colinear with each other, I can 
operate CW on the same band within 60 kHz of each other and not know the 
other is there! I first experienced this about four years ago with the 
original K3.

Successful multi-transmitter operations require both very good radios 
and very good SYSTEMS ENGINEERING. I regularly operate from W6GJB's 
contesting trailer on county expeditions for CQP and 7QP. From the 
trailer, we regularly run two stations, each equipped with a K3, 
P3/SVGA, KPA500, KAT500, and W3NQN bandpass filter sets. We mostly work 
CW, and usually have the two stations on adjacent harmonically related 
bands. The 80M and 40M antennas each have double stubs inline to 
suppress amplifier harmonics, and there is a serious common mode choke 
on each antenna at its feedpoint. Antennas for all three bands are 
within about five feet of each other on a 46 ft pneumatic mast.  The K3s 
have the new synth boards installed.  There are photos of the trailer at 
k9yc.com/7QP.pdf  Since these photos were taken in May 2016, Glen 
(W6GJB) has rigged the tri-bander to be at the top of the mast above the 
40M dipole.

For CQP, we run at least one SSB station in addition to the two CW 
stations, and we regularly operate CW and SSB on the same band. This 
does, of course, require good separation of antennas, and, when 
possible, colinear alignment. Operating from the same site for several 
years with colinear alignment of the antennas, we found that 200 ft was 
sufficient running tribanders on 20, 15, and 10, and 300-400 ft was 
enough on 40 and 80 with dipoles. The SSB station(s) have the same 
equipment as the CW stations.

As to failures at 3C0L -- the generator regulation failures could easily 
fry power supplies, which could include frying their regulators, which 
could fry the K3s. But the failures could also have been the result of 
poor system engineering, or operator errors, or both. Every human being 
I've ever run into screws up now and then, especially when we are tired.

As the examples cited above clearly show, there is far more to a 
DXpedition or contest than hooking up a bunch of radios to a bunch of 
antennas! The most successful of these operations have team members who 
are good operators and are worker bees, and at least some who are good 
engineers. I've seen drawings for the setups for DXpeditions that 
demonstrated careful planning and great engineering. The 2008 VP6DX 
expedition is a great example. It used some of the very first K3s to 
come off the production line, and the systems engineering was 
spectacularly good. Be sure to look at the site map and click on it to 
blow it up to see the antenna layout.

http://ducie2008.dl1mgb.com/index.php

This pdf describes the receive antennas for the low bands.

http://ncjweb.com/bonus-content/200807NCJVP6DXreceiveantenna1.pdf

73, Jim K9YC

On 10/27/2017 11:33 AM, Ron D'Eau Claire wrote:
> Successful multi-transmitter operation begins with a rational antenna layout
> considering the power levels involved. IMX, we've always used at least one
> wavelength between transmitters running 100 watts or so (250 feet on 80, 120
> feet on 40, and so on) and we orient the antennas to minimize coupling.