> Theory 2: My gut tells me that a robust design would include a self
> cleaning wiping action on the contacts, like on a band switch. I will not
> get reliable switching using traditional relays.
A properly adjusted relay will have 'follow' or wiping action on the
contacts. If there is no follow then the relay is not adjusted properly.
> So how does Ameritron get reliable connections? And Com-Tek with their
> phased arrays? Are relays unsuitable for this application? Should the
> contacts be gold? What am I missing here?
They don't. I finally had to replace two of the relays in my Ameritron
switch box because it was not possible to adjust them with follow, and still
have them operate. I have one relay (don't know which one) in my Com-Tek
switch box that the N.C. contacts oxidize during the summer months when I
don't use it. I just clean all of the N.C. contacts every fall and it's
good for the winter 40m season (10 years). No problems with the 80m relay
box (7 years).
Starting with surplus relays will guarantee oxidized contacts. I have a
contact burnishing tool from my days as a spring bender at the telephone
company that I use for contact cleaning, so it's not a problem here.
I suggest you start with new relays and check the contacts for a slight
wiping action on both the make and break side before installation.
Also, I use DPDT 15A rated contacts in my main relay switch box and parallel
the contacts. I run 1500 watts out of my Alpha 76A and all of my antennas
are resonant. I did blow one of the relays but that was because the
insulator on the stinger on my HT18 arced. That one also blew the 160m
loading coil in the 76A.
de Paul, W8AEF
not an engineer, but a moderately decent technician.
> Any help the engineer types can provide would be appreciated.
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