Pin diodes are great for rf switching at the kW level. However, they
have a few shortcomings due to the circuitry you need around them to
make them work.
The biggest problem is the rf chokes which are needed to feed in the dc
and provide isolation from the rf. Sod's law predicts that no matter
which choke you use, somewhere there will be a spurious resonance - a
bit like the plate choke problem with shunt supplied tubes!!
However, with a bit of playing around with the circuit values and types
of chokes can get you around this problem - with some pretty
spectacular "fire-works" whilst you experiment!!
The other parameters you mentioned can probably be worked out with help
from the various handbooks.
Good luck with your design.
John ZS5JF
----------
> From: Tarrant David <vq9jt@cwnetdg.io>
> To: amps@contesting.com
> Subject: [AMPS] 4CX1500B
To: <amps@contesting.com>
> Date: 12 January 1999 01:25
>
>
> Hello,
>
> I am in the process of putting together a 4CX1500 amp. Any input to
the
> following would be greatly appreciated?
>
> 1. Antenna switching ... Vacuum relays Vs pin diodes
> 2. Full break-in keying
> 3. Meter and protection circuits
>
> Tks & 73,
>
> Joe VQ9JT/K5DIY
>
>
> --
> FAQ on WWW: http://www.contesting.com/ampfaq.html
> Submissions: amps@contesting.com
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--
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