Posted by
Edward R Cole on
Jan 03, 2019; 5:55pm
URL: http://elecraft.85.s1.nabble.com/Ideas-for-an-FT8-Radio-tp7647476p7647654.html
I've been using JT since its advent in early 2000's (I began with
JT44 in 2003 using my HB psk-31 computer interface).
I only had 110w on 2m using a MOT repeater PA so lucky to get 80w to
antennas. But I was using four 10-element yagis, which was
considered minimum for CW eme in 1998 if using 600w. JT modes
allowed me to make contacts with a 10-dB weaker signal.
I was at about the bare minimum of ERP for doing eme back
then. About 2007 I started running 600w with an 8877 powered by HVPS
of an old Swan HF amp that ran 2500v at 400ma. About 2011 I upgraded
to a 4kV 750ma PS to run 1500w, which produced a big signal using my
array on JT65. It took 55w drive to reach that.
Just finishing a new sspa from W6PQL that will run about 1200w that
requires 2w drive and using a 50v PS. I installed a 30w 10-dB
attenuator so my 20w 2m transverter could run full power.
But the main issue is that one uses the RF power needed to make the
contact. I understand that FT8 is less sensitive than JT65, about
-24 vs -28 dB.
I may try it on 6m where I have 1kW and two 7-element yagis (not
quite yet QRV - rotator issues).
73, Ed - KL7UW
http://www.kl7uw.comDubus-NA Business mail:
[hidden email]
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