Are these specs for hot switching? I would think that if you can figure out
a way to switch the relay THEN apply power, everything would be happy and
the contacts will last much longer.

Tom


"N2EY" wrote in message
...
In article , "nick"
writes:

If a (let's say 12v) relay is rated for 10 amps @ 110 volts,
it will take 1100 watts.

It will take 1100 watts at 110 volts. But if you lower the voltage to,
say, 50
volts, and the contacts are still rated at 10 amps, it can only handle 500
watts. Etc.

Will it take 1000 watts of RF?

I would think not, but I don't know why.

Depends entirely on the RF characteristics - impedance, SWR, etc.

The trick is to exceed neither the voltage nor current ratings of the
contacts.
In a 50 ohm RF application with low SWR (less than 2:1), that relay is
probably
limited by its contact voltage rating, not the current rating. Which works
out
to about 200 watts.

73 de Jim, N2EY

On Mon, 29 Mar 2004 08:17:57 -0600, Tom S wrote:

Are these specs for hot switching?

No, these would be for switching bands by selecting coil taps at
the base of a vertical.

I would think that if you can figure out
a way to switch the relay THEN apply power, everything would be happy and
the contacts will last much longer.

I agree, but I have a tendancy to destroy equipment :o


Tom


"N2EY" wrote in message
...
In article , "nick"
writes:

If a (let's say 12v) relay is rated for 10 amps @ 110 volts,
it will take 1100 watts.

It will take 1100 watts at 110 volts. But if you lower the voltage to,
say, 50
volts, and the contacts are still rated at 10 amps, it can only handle 500
watts. Etc.

Will it take 1000 watts of RF?

I would think not, but I don't know why.

Depends entirely on the RF characteristics - impedance, SWR, etc.

The trick is to exceed neither the voltage nor current ratings of the
contacts.
In a 50 ohm RF application with low SWR (less than 2:1), that relay is
probably
limited by its contact voltage rating, not the current rating. Which works
out
to about 200 watts.

73 de Jim, N2EY

On Mon, 29 Mar 2004 08:17:57 -0600, Tom S wrote:

Are these specs for hot switching?

No, these would be for switching bands by selecting coil taps at
the base of a vertical.

I would think that if you can figure out
a way to switch the relay THEN apply power, everything would be happy and
the contacts will last much longer.

I agree, but I have a tendancy to destroy equipment :o


Tom


"N2EY" wrote in message
...
In article , "nick"
writes:

If a (let's say 12v) relay is rated for 10 amps @ 110 volts,
it will take 1100 watts.

It will take 1100 watts at 110 volts. But if you lower the voltage to,
say, 50
volts, and the contacts are still rated at 10 amps, it can only handle 500
watts. Etc.

Will it take 1000 watts of RF?

I would think not, but I don't know why.

Depends entirely on the RF characteristics - impedance, SWR, etc.

The trick is to exceed neither the voltage nor current ratings of the
contacts.
In a 50 ohm RF application with low SWR (less than 2:1), that relay is
probably
limited by its contact voltage rating, not the current rating. Which works
out
to about 200 watts.

73 de Jim, N2EY

nick wrote:

On Mon, 29 Mar 2004 08:17:57 -0600, Tom S wrote:

Are these specs for hot switching?

No, these would be for switching bands by selecting coil taps at
the base of a vertical.



The relay contacts can handle it fine, provided you
don't hot switch. You will introduce an impedance
bump in the transmission line. (The relay contacts and
associated wiring become part of the transmission line.)
Don't know how large that will be.

nick wrote:

On Mon, 29 Mar 2004 08:17:57 -0600, Tom S wrote:

Are these specs for hot switching?

No, these would be for switching bands by selecting coil taps at
the base of a vertical.



The relay contacts can handle it fine, provided you
don't hot switch. You will introduce an impedance
bump in the transmission line. (The relay contacts and
associated wiring become part of the transmission line.)
Don't know how large that will be.