Johnson TR Switch on 160 meters

[sndtubes]

I want to use a Johnson TR switch on 160 for full breakin CW.  I know they are not designed to work on 160.  Has anyone modified theirs to work on 160?  I guess the input / output circuit needs to be changed.  I don't want to lose 80 thru 10 either.  Any ideas?

[kb3rdt]

mine has a 110v relay!

what you useing it on if you have 110v on transmitt can mod it that way!

[sndtubes]

Thanks but I dont want to use a relay.  I want to use the Johnson tr switch on 160.  That's why I asked the question.

[VE3AJM]

I have the Johnson relay here too. I've haven't tried this myself, but have you tried to use it on 160m?

I know the unit will give quite a bit of receive amplification when tied into the station receiver to overcome the losses of having it in line. Perhaps the unit is optimal for 80-10m but will work on 160m, but not quite as well on receive on that band.

Al VE3AJM

[sndtubes]

It will work with lots of attenuation.  Not optimal

[WQ9E]

I have never tried mine on 160 either because I am using it with a Johnson transmitter that doesn't cover 160.

I expect T2 is the issue on 160.   L1 and L2 should be fine as will the .005 coupling capacitor values.  Try it, the worst that could happen is too much receiver attenuation on 160 and given the noise levels on the band it may be fine for you depending upon your antenna and local noise conditions.

Make sure that your antenna is reasonably matched if you are running high power.  The power rating is based upon near unity SWR.  If the filter caps haven't been replaced recently they will need it.  The T/R switch runs very warm so pay the small additional amount for 105C instead of standard 85C caps.

[K1ZJH]

If it would prove anything I could sweep mine on the 141T analyzer and TG combo.

Pete

[KM1H]

Sounds like a good idea to me Pete.

Carl

[VE3AJM]

I tried using it yesterday on 160m. The relay works fine on transmit, and for receive, I disconnected the barrel of the coax going to my receiver from the relay, and it then worked well on 160m for receive. No suck out/attentuation effects noted of received signals.

For me its better than trying to re-engineer the relay. Up to you of course.

Al VE3AJM

[WQ9E]

Al,

I am glad it is working out for you.  If noise into your receiver becomes a problem (due to the disconnected coax shield) try adding an additional coil of about 40 turns of #24 on a 3/4" form on the "cold" end of T2 (the end opposite the plate connection to V1B) and I expect this will allow normal gain on 160 with the coax connected without impacting the other bands.