[Amps] Vacuum Relay

[Paul]

I agree that hot switching is most likely the cause of relay failure.

I observed a flakey with one of my radios: when transmitting a continuous 
carrier the amplifier put out 1500 watts on my p-p wattmeter, when 
transmitting a continuous string of dots with qsk the amplifier output was 
about 1400 watts.

Hot switching was the problem.

I use an oscilloscope waveform monitor and it was very obvious on the scope, 
but for some reason not many hams use a scope as a waveform monitor.

de Paul, W8AEF

ZF2JI/ZF2TA 8Q7AA FO8DX/FO0PLA XZ0A VU7RG/VU3PYM TX5A A52PP


-----Original Message----- 
From: Vic K2VCO
Sent: Friday, December 07, 2012 1:25 PM
To: amps at contesting.com
Subject: Re: [Amps] Vacuum Relay

I can't suggest a different relay, but I think you should check that there 
is enough time
between the key out circuit closing from your transceiver and the start of 
RF, as well as
making sure that the key out does not open before RF ends. The initial delay 
should be at
least 5 ms. in order to be safe.  Relays should last for years, unless they 
are being
damaged by hot switching.

On 12/6/2012 5:27 PM, Carol Richards wrote:
> It looks like I fried another vacuum relay in my Alpha 78 operating it in 
> qsk mode. It is either an HC or RJ type. Can anyone recommend a more 
> sturdy vacuum relay for this amp and where I might get one?
>
>
>
> Carol
>