RE: [linrad] WSE RX2500 Tx control?

[Leif Asbrink <leif.asbrink@xxxxxxxxxxxxxxxxxxxx]

Hi Stan,

> How do you control the WSE RX2500 during periods of transmit? Is simply 
> muting the audio enough?

I do not control it at all:-)

The "rf clipper" on the audio signal and also the AGC if you wish
make sure that the signal level is not too loud for my ears.
I just do not listen to what I do not want to hear using
head-phones. It is relevant to say that I use fast full break-in.
(=RADAR) so I actually listen during key-up for the echoes from
aurora and the moon. During the Leonids fire-ball storm some years 
ago I could use this to make sure I was always pointing to a 
reflection point continously for many hours. (Got some surprised
comments about that...)

I plan to add muting during the tx period because it makes 
listening much easier. Currently I have no antenna and I have been
100% busy with other aspects of this project.

I will be busy with other things for a while, next is processing 
the data collected this weekend from the spurious emissions
of modern transceivers. The ALC is a real problem that most
rigs suffer badly from, but it is not widely known yet;-)
http://antennspecialisten.se/~sm5bsz/dynrange/alc.htm
(the problem is actually much worse than you would think
from the material at this link, but the principles should 
be clear from it).

Some day the Linrad package will read the status of your transmit
side and mute your own signal very precisely so you can make
a good narrowband radar. It really makes operating much more 
fun:-)

(In the old days I used a couple of SBL-1 to mute the receive 
side after having used it without any muting for a long time.
It was not the WSE boxes, but my previous system was also
a series of 50 ohm boxes. Muting with PIN diodes or FET switches
can be done in the 50 ohm lines without affecting the 
dynamic range performance.

A simple "switch", padding zeroes into the A/D read area when 
some signal says tx is on, would be trivial. It will not give 
exact timing but it should be good enough for conventional
usage. It could be one of the parallel port pins. I have not 
given it much thought yet.....


73

Leif / SM5BSZ





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