[Amps] open frame relay rating

[jeremy-ca]

Many amps used open frame relays with 10-13A contacts and they worked well 
at 1500W. The one issue with them is high VSWR in the thru position on 10M 
which can fold back the power in a SS rig. The cure is simple, add a 
capacitor from the thru loop to ground to tune out the Xl.

You can use an adjustable mica trimmer and leave it or measure the value and 
replace with a 1KV disc ceramic or 500V mica. Typical values are 25-35 pf. 
Any one will handle 100W with ease.

Carl
KM1H



----- Original Message ----- 
From: "Steve Flood" <kk7uv at bresnan.net>
To: <amps at contesting.com>
Sent: Saturday, March 29, 2008 11:54 AM
Subject: [Amps] open frame relay rating


>I have several open-frame relays.  If I use one for the T/R relay, what 
>should the contact rating be for a 1500w amp?   Is it as simple as 1500w / 
>50 ohms = SQRT of 30A or 5.5 Amps?
>
> Tnx,
> Steve, KK7UV
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