I did this with my TS-520 back in the mid 90's when I started running PSK31 and
RTTY. A 9V battery connected to the outside connections on a 10K linear taper
pot built in an Altoids tin.
Tuner the 520 for maximum smoke on SSB with thee "DX" switch off and dial the
power down to 30-40W PEP output. The rig was happy, it produced spectacular IMD
numbers so the PSK neighbors either side of my signal were happy, I was happy.
I've been thinking about buillding the HB 250/300W SS amp. The instability it
experienced on 80m was due to it's marginal power supply that would current
limit at 300W on that band. Feed it wuth a stiff 50V 20 amp power supply and it
should be golden. The LPF in that amp is a work of art. -60dB HF and -70dB 6m
harmonics. The IM3 measured -38 dB.
On Sun, 24 May 2015 21:46:19 -0700
"Jim Thomson" <jim.thom@telus.net> wrote:
A method to get around the ALC induced imd, is to use external 0 to –7 vdc alc
volatge, then feed it to thre xcvrs rear alc input. That way you can dial up
any PO you desire, and not have to develop alc voltage..after the fact. A
simple setup with a 9 vdc battery feeding the outer ends of a 50-100k pot
works great. The wiper and one end is the V divider supplies the 0 to –9vdc
to the alc jack. If you want say 65 watts pep.... just set the PO control on
the xcvr to max.....then adj the alc voltage to 65 watts pep. Done deal.
Scream all you want, with mic gain cranked up..and wattmeter never goes higher
than 65 w pep.....or what ever you set it for.
--
R. Kevin Stover
AC0H
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|