[Elecraft] K3 power out - key down

[Edward R Cole]

Subject: Re: [Elecraft] K3 power out - key down
Message-ID: <011e01cfa426$5fba6f80$1f2f4e80$@wjschmidt.com>
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Have you ever listened to the interviews of the Indy car drivers after a
race?  Do they say: "I wish I had a less powerful engine to make it a more
challenging race."?

I'm on the DX end a lot these days, and I always find myself stopping a
pileup to ask if there are any 10 watt or less stations calling.  The
response I get is usually three QRP stations responding (which I eventually
work after 10 minutes of additional instruction to much louder stations)
buried by 100's of QRO stations with massive antenna arrays.

Tough to win!


Dr. William J. Schmidt - K9HZ / J68HZ/ 8P6HK/ ZF2HZ/ PJ4HZ/ VP5HZ
----------------
Wow has this topic morphed...I was only following it casually, but it 
"was" (I think) about what power level is "safe" to run on the K3 
with "key-down" modes like JT65.  RTTY is pretty hard on the 
transmitter, as well.  FM would be the hardest as  it is usually 
accompanied by marathon talk-a-thons (note most VHF-FM radios are 
equipped with time-out-timers set to a max of 3-minutes).  JT65 runs 
about 50-seconds in Tx and then rests for about 70-seconds in Rx 
(2-minute TX/RX cycle).  The K3/10 seems to be happy at 8w running 
JT65 on 6m (I have not run JT65 on HF).  Psk-31 runs well at 12w with 
my K3/10 with no apparent heating issue.  Note: I have a 300w sspa 
that runs 275w on HF with 12w drive when I need more for SSB.

I suspect all you have switched to talking about normal CW/SSB ham 
radio - they do not compare to JT65, JT9, etc.  These are superior 
"weak-signal" modes designed for when signals are too weak to copy 
using CW.  The software provides about 10-dB better SNR (making the 
10w JT65 signal equivalent to 100w CW).

On HF, SNR requirements are very much lower than the usual RF level 
used by hams.  Evidence:  look at the QRP-SSB check-in's that are 
quite satisfactory on the Sunday Elecraft Net.  I checked in this 
morning with 12w with my K3/10 "barefoot" and was heard on the first 
call by Phil.  Yes, I run an old triband beam at 50-feet which helps.

My s-meter report would be about 2-units higher if I ran 100w, but 
that was not necessary for the communications link.  Working 
contests/DX, is a different "animal" as you are dealing with QRM and 
not specifically weak signals. How many of you are using JT65 for 
contesting or Dx'ing?  You can, you know!  (probably too slow for you)

I just finished operating the Dubus Magazine 2-meter digital EME 
Contest where I ran JT65B with 1000w and four ten-element 
yagis.  Yes, it was weak-signal and I did run QRO.  I have run as 
little as 150w on 2m-eme successfully by using JT65, but it is more 
difficult to make contacts and not particularly a good idea in a 
contest.  Minimum time to complete a valid JT65 eme contact is 
5-minutes if you have a good to great signal.  Running 150w would 
probably extend the time required by a considerable amount - not 
desirable in a contest.

PS, Dr. Schmidt:  I am not picking on you, just happened to decide to 
comment at your post! ;-)
Oh and how many folks drive an indy car to the market?  Different 
needs require different means.

Note: I began 2m digital-eme in 2003 using JT44 precursor to JT65, so 
have a few years experience in its use.


73, Ed - KL7UW
http://www.kl7uw.com
     "Kits made by KL7UW"
Dubus Mag business:
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