Re: LF: Re: Antenna change over relay question

[Andy Talbot <andy.g4jnt@gmail.com>]

Digressing slightly, but a parallel warning...

I once hot disconnected  a BNC plug carrying 700 Watts of RF (Low Z, transmitter output) .    As the contact broke it generated  a plasma arc that shot out of the BNC plug that I dropped in shock.  It continued to burn, vaporising the centre pin of the BNC, and burning a mark into the floor surface I'd dropped it onto.

'jnt

On 24 July 2017 at 15:58, Chris Wilson <dead.fets@gmail.com> wrote:

Hello Ian,

You  have me worried now, as does Andy with his last post, the thought
of  putting  a kilowatt into the RX antenna socket of my 590 is not a
pleasant or cheap one... Hmmm.



Monday, July 24, 2017, 3:40:38 PM, you wrote:

> Hi Chris/Stefan

> Loosely connected to your question, I wanted to switch my Inv L between
> LF/MF Variometer/loading coils and HF Auto remote tuner remotely, i.e 120'
> away from the shack.

> Every relay I tried had insulation break down and contact arc over. Only
> running 360 W at MF and 300 at LF.

> My solution was to fabricate a 3 position Knife type switch operated via a
> Servo motor to switch the antennae and a standard 20 Amp Rated relay for the
> RF inputs to the Tuner and Variometers.

> No more insulation break down or arc over. The contacts are mounted on Old
> Eddystone porcelain insulators.

> I would be interested to know how the relay holds up with 1 kW at 136 kHz.

> 73

> Ian G4GIR






--
Best regards,
 Chris                            mailto:dead.fets@gmail.com