Re: Cleaning relay contacts
Hot switching a small DC current really does work in many cases.
You generate micro-arcs at the contact surface which disrupt the oxide layer and promote a lower contact resistance
Some system designs allow a few 10ms of mA DC to switch alongside the RF in service to whet the contact at each switching event
I used to use special very slightly abrasive paper pulled between contacts on old (large) PO relays It was routine maintenance but even that did damage the contact surface and it was a constant battle
Mechanical 'cleaning' of delicate contact surfaces as in most RF relays is a recipe for disaster.
On 28/03/2021 16:56, Mike GD6ICR wrote:
Been going through my sma relays and testing them on my primitive spectrum analyser has shown that I have quite a few lossy relay on TX as high as 4dB and quite a few showing around 1dB on RX side. I wonder if anyone can suggest a suitable contact cleaning method - one suggestion Ive had is connect 12v thru 500ohm resistors to NO and NC and leave them switching for about 5 minutes