[Amps] RX protection scheme, is this sound?

[Steve]

I think I'd go for higher speed diodes. A professional VLF multicoupler 
I worked on decades ago used a string of 6 or 8 MUR120 diodes back to 
back. The number was needed because of extremely high signal handling 
capability, one or two would be plenty for a normal radio.

Another option is to add a sacrificial preamp in front of the 
receiver(s), using something cheap and readily replaceable. I've learned 
the hard way, test gear front ends come expensive.

Steve

> RX protection sought for either a Kenwood TS-590 or a Red Pitaya
> functioning as an SDR for the LF 136kHz band. Change over relay box
> for the antenna has a 60 Amp automotive relay grounding the RX line
> and changing to switching the antenna to the amp with a Russian high
> power co-axial relay 500mS before TX starts. In case of unforeseen
> whoopsie an automotive 5W festoon bulb would be in series with RX
> antenna input prior to two back to back 6A10 diodes? The festoon bulb
> is long enough not to sustain an arc over (I have tested on full power
> one side of the bulb to ground). I don't believe the inductance of the
> bulb is significant "down there" frequency wise. But I am unsure about
> the effect of the big diodes...
> 
> 
> Amp is a 1kW + Class D FET amp, is this a sound scheme? The TX has a
> separate exciter and the SDR or TS-590 function solely as a receiver
> but sharing the TX antenna. Thanks.
> 
> -- 
>        Best Regards,
>                    Chris Wilson.