Marco !
The 100nF is just to remove DC from the pad (6V)....
I wonder if static cracks will induce enough voltage to clamp the diodes
but I will find out as Roelof said in his post.
Roelof !
It's not only about the costs it's also to avoid the work one has to
repair the antenna.
73 es gl
OE3GHB
Gerhard
Am Mittwoch, den 22.09.2010, 22:34 +0200 schrieb Marco IK1ODO:
> Hello Gerhard,
>
> the 100n capacitor will do nothing, it is in series with the input
> pad capacitance (a few pF).
> The diodes will clamp at 0.6 V, that is too low (every static "crack"
> will send the diodes in conduction) and limits the dynamic range.
> More, they will add capacity (2 pF each?) at the very critical point
> of the amplifier input, decreasing the gain.
> I think I will leave the gate alone, as in the original design.
>
> Possibly the idea of a small reed relay to be closed in TX may be
> better; those have very low C. But I will do that only after the
> ninth burnt J310 - they are so cheap from Roelof :-) (just jocking,
> of course, I could not resist)
>
> 73 - Marco IK1ODO
>
>
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