>Discussing Pin Diodes in RF amplifiers
>
>The problem of obtaining in my earlier post was for the Alpha 89 for a
>friend. I own one and a friend WW4US owns the failed unit.
>We were researching the problem this weekend before Crosslink opened.
>Since then Crosslink is shipping the needed KS1001 pin diodes.
>
>Please do not address some of the below suggestions about how it may be
>absurd. Be constructive.
>The suggestions have been listed as hams this weekend offered them up.
>
>New questions:
>
>* What can one do to protect RF Amps using pin Diodes?
** To protect PIN diodes from lightning, when finished operating, unplug
the feedline from the amplifier and toss it out the window on the ground.
The feedline should not come within 10-ft of the house., [note -
"C"-type connectors are ideal for this because they are bayonet mount]
>
> Suggestions and Solutions to date from on the air hams:
> I. Addressing static discharge
> A . Install High value resistor across amp output i.e.
300K
** A 10M bleeder R on the antenna itself worked for me.
> B. Provide a antenna with DC ground path. i.e. loop
antennas, dipole
> with coaxial stub., and high impedance choke to antenna.
** lightning is not just DC.
> C. Alpha has a gas discharge arrestor right at the
>output connector. Is this adequate and
> what level of static discharge protection does this provide?
> D. Short coax to gnd after reconnecting to amp
>after being disconnected.
> 2. High SWR
** keep plenty of spare PIN diodes on hand.
>...
.Good luck, Victor.
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