[SixClub] Band monitoring question

[Dana Rawding]

John,

I agree with you on the use sequencers.  I use them on 50 thru 1296  
MHz.  The sequencers (some ARR, some LNA Tech) switch Relcomm coax  
relays.  I don't have the figures at my fingertips at the moment but  
the isolation between the ports is fairly high.  High enough to  
protect my GaAsFET preamps from damage.  A similar but less expensive  
relay (Tohtsu CX140S) has 55 dB isolation between ports at 250W on  
6m.  Since 100W is 40 dBm it should be no problem to use a coax  
relay.  The only caution would be to pause a second after keying the  
FT-847 before transmitting to make sure the relay settles.  Yes the  
sequencer is the way to go but a coax relay would be a much better  
solution than trying to remember to manually throw a coax switch.

Dana  N1OFZ


On May 17, 2007, at 1:18 PM, K2UBG at att.net wrote:

>      The only way to be sure is to use a 'sequencer' to ground the  
> input to the receiver(tranceiver, in this case) before the  
> transmitter is keyed. A spendy prevention that I haven't dove into  
> yet. There is no coax switch made that I would trust my receivers  
> to and probably not many coax relays that I know of. The cheapest  
> and only strategy in use @ K2UBG is a uhf quick disconnect. Works  
> but not as convenient as methods that do not work.
>   Not as convenient, granted but, mailing out radios and I mailed a  
> lot,  is a preventable and inevitable exercise. I do the same at  
> night when I shut down the 756pro3 at night or for lightning. More  
> sensitive means more susceptable.
> --
> 73,
> John/K2UBG
>
>