[Elecraft] 600 meters

[Edward R. Cole]

Mike Morrow, KK5F, wrote: "It is damnably difficult to radiate *much* 
power on 600 meters unless
one has a lot of transmitter and real estate for antenna and ground."
"Most hams will be lucky to achieve a few milliwatts ERP from a few hundred
watts input power with small antennas not located over salt water."

Well I assume you are talking theory.  I have been QRV for over a 
year on 600m running 100w RF output to an inverted-L antenna (43ft 
high x 122ft long) with large loading coil at the base.  My 
calculated (EasyNEC2) ERP = 4.15w (not mw).  Granted that this is an 
antenna efficiency of 0.8% so little RF is effectively radiated (most 
is warming worms).  I consider my soil as poor and use four radials 
of 2-foot wide chicken wire laid on the ground surface.  MY signal 
has been detected 2800 miles away!  QRO and renting a WWV site is not 
needed!   Some of our participants are radiating 20w ERP using 500w 
amplifiers.  BTW my 600m radio is my K3 or alternate Rx: SDR-IQ.

BTW I regularly check into the Elecraft 20m-SSB Net with 16w from my 
K3/10, with little problem.  Again, QRO is overrated.  Maybe in a QRM 
loaded 20m contest but this does not exist on 600m.  Just a handful 
of experimenters and enthusiasts finding out what can be done with ERP<20w.

Actually more than you would guess.  Out to 300-km propagation is 
100% all the time using ground wave.  I made a series of GW tests in 
summer of 2010 running 4w ERP with +35 dB SNR ( S6-S7) at 100-miles 
at my two receiving partners.  I wish our station in North Pole (AK) 
had been active (300-mi) to gather info at that range.

In the winter 600m acts somewhat like 160m with lengthening DX over 
thousands of miles.  I have copied a station in Buffalo, NY at about 
4000 miles from me, and several instances of copying Vancouver, BC 
and Oregon (1300-2000 miles).  The biggest limitation is static noise 
in the lower-48.  It doesn't exist much up here in Alaska.

So, yes, full-size antennas are huge, but a typical 160m antenna, if 
loaded, will work pretty good!
BTW I've heard that theoretically bumblebees cannot fly! ;-)



73, Ed - KL7UW, WD2XSH/45
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