> Lee K7TJR said:
> Pete, I have had very good luck switching between radios
> with rotary switches on 160. Switching between different RX
> antennas to a single radio can be a problem due to lack of
> isolation.
> I see somewhere around 30 to 40 dB isolation with the
> larger diameter (2 inch wafers) rotary switches and reasonable
> care with RF wiring. YMMV
To switch RX antennas I highly recommend the MCM (1-800-543-4330) push
button (p/n 33-1490) high isolation A/B/C/ three port switch with F
connectors. The cost for a single unit is $13.69 and the advertised
isolation is greater than 65 dbs port to port up to 500 Mhz.. Since they are
push button switches they also have less impact on those with CTS problems
where the constant rotary wrist motion on RX antennas may take their toll.
If more then 3 selections are required they can be easily stacked together
with the vertical mounting holes. If three are used two of the switches
would need to give up a port to connect with a jumper to the input of the
switch below. Three of these configured properly would allow the selection
of 7 different RX antennas. The only drawback is the snap sound made when
the switch is pushed which is loud enough to trip the VOX on SSB and after
hours of snapping during a contest is a bit annoying.
I also use a Ameritron RCS unit but the tiny rotary knob on the remote
selector box was replaced with a larger one due to wrist pain after a long
contest. Now if someone would only market a illuminated momentary P/B
replacement for the Ameritron control box I would be in line to buy one.
Also switching through 4,6, or 8 antennas with a rotary while looking for a
letter better signal during a contest or DX-pedition sometime causes loss of
valuable information. An instant selection with a momentary illuminated
push button switch would have some significant advantages. I base this on
the fact that one hand was always on the rotary knob when it should be one
the keyboard and the others on the paddle. Now if there is an interface
with contest logging to allow control from open keys this would be IMHO a
big seller for low banders and contesters.
Herb, KV4FZ
_______________________________________________
Topband mailing list
Topband@contesting.com
http://lists.contesting.com/mailman/listinfo/topband
|