Topband: Blowing diodes on relay switches

[Tom W8JI]

>I think you raise a good point Tom. I know I have some RF in the shack 
>especially when running the amplifier on 10M which has been happening a lot 
>the past few months. The computer sometimes reboots and USB and audio 
>peripherals go wacky. With the switch diodes dying during a big RTTY test 
>on 10M maybe my transmit signal just in the shack could do in the diodes 
>etc.
>

Since we all have RF halfway around the world, we have RF in all of our 
shacks. Most systems have poor port designs, and are sensitive to RF. We 
aggrivate that by antennas too close to the shack, or by poor wiring methods 
or installation.

> The bypassing of control voltages is just some dinky 50V .01uF monolithic 
> ceramics, and the inductance in the isolation transformer windings.
>

.01 should make a good bypass, especially a monolythic cap. Things often 
depend less on component value and more on how we lay out grounding in our 
boxes and how we wire things.  A large groundplane in a box goes a long way 
toward RF immunity, while a thin ground trace or buss wire might even make 
bypassed things worse than no bypass at all.

> Right now I have a rats nest of coax, each cable way too long, daisy 
> chaining rig to switchbox to amp to switchbox to tuner to antenna. 
> Computer, USB, video, audio, and footswitch wiring is all tangled up too. 
> Maybe should just clean that!
>

My wire-hider box is my common point for everything in the radio room except 
the overhead lights. All control, power, and RF cables are common ground 
there. I don't worry at all about what is on the desk or how it is grounded, 
within reason.

73 Tom