[Yaesu] FT-990 spurs

Sun Jan 15 22:09:41 EST 2006

 > I borrowed a friends FT-990 while my FT-1000D is on the
 > bench. Top Band was very good this AM but spurious sigs
 > on the 990 made operation almost impossible! I'm not sure
 > if it's intermod or synthesizer spurs but using the 20db
 > attenuator didn't seem to have much effect. Is it just this
 > rig or is this a common problem??
 I have never experienced this, I do not operate on the top band,
but check for the second harmonic of .54 to 1.6 mHz and listen
for 1.6 to 1.8 mHz broadcast stations all of the time.
(part of my feeble propagation studies)
 To the best of my knowledge the Yaesu FT-990 has NO internal
spurious signals.
 Could it be coming from a switching power supply (the internal
AC supply is a switcher) or a nearby lamp fixture?
(from a RF driven fluorescent lamp, 23 Watts looks like 100W.)
I operate my FT-990 (DC version) from a car battery and a 12 Amp
linear charger!
 Try listening to a "spur" then switch to a nonexistent external
antenna. (press the [RX ANT] button) Let us know what you find.
-- 
 Ron KA4INM