Hello everyone,
I'm looking at putting together a binary proportioned tuneable coaxial
line electromechanically adjustable from about 100' down to 6' or (1/4
wave on 160-10 meters) for use in the output section of a transistorized
amp.
If I use transfer relays to switch the line sections, I'll have about
40 connectors in the assembly plus all the relay's themselves which will
certainly introduce a bit of loss... and cost!!!
So, I was thinking of making my own integral "relays" using some 1/4"
wide silver rod sliced up to make the fixed contacts and 1/4" wide bar
stock to make the moveable contacts"
The circuit looks something like this and will be the same in assembly
view looking down on the contacts.
___
___ | |
| | | | <-- Line sections 1&2 of 10
B C F G
-----A D----E H---- <-- Main line
I would position the main line at an appropriate distance above the
chassis to maintain a 50ohm impdeance. The moveable contacts may have
to tolerate a slight mismatch.
To switch the first line section in requires a connection across fixed
contacts AB and CD; to bypass it, a connection across AD.
My query to the group is what would be the most expedient methodology
to use (also something I can easily fabricate!) for the relay mechanism?
A rotating contact arrangement driven by small motors? with the
contacts carried on an insulating disk pushed by a spring against the
fixed contacts.
or horizontally sliding driven by small linear actuators? Again with
a spring to provide contact force
or vertically (as in a "standard" relay") with the acutating mechanism
providing the force.
or something else????
I'm more electrically than mechanically inclined so, all suggestions
are welcome!
73
Marv WC6W
*
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