[Elecraft] XV-50 LNA problems

[Gregory P. Daly]

Bob:

     A simple low pass filter would be nice, but it might not cover all cases.
Eventually I'll be able to make max legal power on all bands, and I might find
myself in a situation where the lower frequency signal damages the higher
frequency transverter. At the moment, I'm only talking about 150 watts, but
eventually it will be 10 dB louder on all bands.


     I'm thinking external T/R relay is the smart move. If the relay is rigged
to rest in the transmit position, when the transverter is powered off, the out
of band signal will land in the PA output, I suspect the output of the PA
module is a big strong MOSFET or bipolar, that can take a few volts on it's
drain (or collector) when it's biased off. When I add a "real" amp, the plate
of an 8877 can take big voltage ;-).

     The Schottky diode in a small GaAs FET gate is pretty fragil to expose to
big bad high power transmitters at close range.

     I'm hoping somebody on the list will have a better idea. I don't mind
looking stupid to save a lot of effort ;-)

73 DE WB7RSG

Greg.


Robert Friess <rfriess at usa.net> said:

> Greg,
> 
> Once we know what we are dealing with then we can work out a solution.   It 
> could be as simple as an external lowpass filter.  That would be nice 
> because the loss would be very low.
> 
> Bob
> 
>