"Haines Brown" wrote in message
...
I'm sure a FAQ, but a search on line did not resolve my question.

I need to feed my coax (QRP, 10 meters) out through a pane of glass, and
for that I need a through-glass coax coupler (this is not an automotive,
but a home window situation).

Most couplers are apparently capacitative. At 10 meters, for example,
would I gain much by going to a microstrip coupler instead (whatever
that is)?

How good a coupling can I expect with a through-glass coupler? It sounds
very lossy, but perhaps not.

What brands of couplers would you recommend, or what is a good source
for such couplers?

--

Haines Brown, KB1GRM


Haines,

Automotive couplers for two metres manage with a 2 inch by 2 inch plate
either side of the glass. It could be worth trying 6 inch by 6 inch plates
on the domestic window and see what signal level gets out. Reception
shouldn't be a problem if you can get 50% or more of your transmission power
out through the glass.

You need to get as much capacitance as possible, which means big plates as
closely spaced together as possible.

The plates can be formed from aluminum foil taped closely to the window for
experimental purposes. Adhesive coated copper sheet or foil can be used once
you have found a size and shape that works best for you.

Provided the window is single glazed, you have a chance of getting this to
work. If the window is double glazed or has any type of thermal barrier
coating, get out the power drill and fix a cable through the wall.

The only advantage that a commercial coupler might have is that the visual
asthetics might be a bit better than a home brewed effort.

If the window can be opened, use a bit of thin figure of eight twin cable to
bridge across the opening and just shut the window on it. Connect up the
coax inside and outside and you're up and running. The bridging cable can be
easily replaced if it gets broken by the window opening and shutting. A few
inches of twin cable won't mess the overall impedence of the antenna system
up too much.

Mike G0ULI