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Re: [Amps] 200w fast relay >> amp relays/ant switches

To: <>, "W0UN -- John Brosnahan" <>
Subject: Re: [Amps] 200w fast relay >> amp relays/ant switches
From: "Tom W8JI" <>
Date: Tue, 10 Jul 2007 21:37:49 -0400
List-post: <>
> Just what relays are cost effective and reliable at the 
> amp output
> side of things.  Not necessarily thinking QSK, just 
> something that
> could be the antenna relay in the amp or an antenna 
> selection relay.

RJ1A relays are just fine up to several kW if you do not hot 
switch them.

Speeding them up also does not hurt. I use a constant curent 
source of about 50 volts on mine, using a FET as a current 
limiter. This way current never exceeds the rating, but they 
close just as fast as some of the sloppy unregulated 

> For instance, what relays are used in the DX Engineering 
> 5KW rated
> antenna switch versus what relays are used in their 10KW 
> rated
> switch?

The DXE 10kW switch uses very wide contact spacing and a 
double make double break (form X) relay. It is like the 
RCS-8V relay on steroids, about three times the physical 
size and enclosed. It is connector limited, not relay 

The 5kW uses some custom modified SPDT 16 amp rated relays. 
Leads inside are shorter and wider than normal, and 
insulation is improved.

Unfortunately neither are off the shelf relays. My antennas 
took several direct hits a week ago, and my DXE 10kW relay 
box is in perfect shape. I stood in the carport and watched 
the 300ft tower get whacked twice! The coax from the 160 
meter dipole at 300 feet connected to one port is junk, it 
melted. It was a christening for my new tower I guess. The 
first severe lightning storm in several months.

73 Tom

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