Yes, an RF probe would be a good/better, idea...
but even better would be a nice Tektronix 465B scope.
Picked one up (might as well have stolen it) in the flea market at Dayton.
So nice to have one of these things around the house.
I was also scouring the flea market for a FT-301 that I could use for
spare parts. Found only one, the second day, on the tailgate of a
guy who was about to close down his table and go home. He had found
it a few parking slots away and had purchased it for
himself. Couldn't talk him down, and he wanted too much for a unit
that he did not know if it worked or not. Lots of FT-101E's but only
one FT-301 in the whole place. I found that suprising. I thought
there were more of these things around.
Anyways, having a scope now, I can really start to see what is going on.
When we last emailed, I had expected that the problem was on the RF
board, but now I believe that I was wrong.
I have a signal on the P101 coax pigtail input to the board, but the
other input signal to the mixer, coming in on pin 1 (labeled TX IN)
is pretty much nonexistant.
This signal comes from PB1434B, the NB UNIT PCB.
I will be looking at getting access to and tracing the signal on the
NB card tomorrow, but I was wondering if you had ever experienced a
Also, while the signal on the P101 coax pigtail to the RF board is
present, it is probably 40% or so stronger in RX than it is in TX. I
did not take measurements because I had nothing to compare them to,
but I do not see any reason why that would be so. I will probably be
probing the 13.5 volt pin 14 of the premix unit to see if it is
stable in TX/RX.
I would love to hear if you have any thoughts.
Mark in W8 LAND USA
|FT301 a problem with low transmit (an analysis)
|I have a signal on the
P101 coax pigtail
input to the board,
other input signal to
the mixer, coming in
on pin 1 (labeled TX
is pretty much
This signal comes
from PB1434B, the
NB UNIT PCB.
|P101 coax line also
going into the mixer