Wimpie writes:

Why not using inductive coupling? You can get reasonable coupling as
wires are just mm away from eachother, so you don't need high Q factor
circuit.

Didn't occur to me. Are you suggesting a couple coils sharing an axis,
one just inside the window and the other outside? Would the two coils
simply be designed for a 50-ohm impedance at, say, 10 meters?

I can imagine wrapping a 50-ohm coil on pvc, and inserting it into a
larger diameter pvc that is capped and which has a coax connector passing
through it. and the whole attached to the glass with silicone
adhesive. One on either side of the glass.

Matching indoor only is possible (so you don't need matching outside
to interface to 50 Ohm coaxial cable).

Not sure of your point. It seems I need to match outside.

Another problem just occurred to me. I'll use a MFJ magnetic loop, and
its tuner, if I recall, depends on an uninterrupted electical connection
through the coax. If so, I'm stuck.
--

Haines Brown, KB1GRM

On 3 abr, 23:42, Haines Brown wrote:
Wimpie writes:
Why not using inductive coupling? You can get reasonable coupling as
wires are just mm away from eachother, so you don't need high Q factor
circuit.

Didn't occur to me. Are you suggesting a couple coils sharing an axis,
one just inside the window and the other outside? Would the two coils
simply be designed for a 50-ohm impedance at, say, 10 meters?

I can imagine wrapping a 50-ohm coil on pvc, and inserting it into a
larger diameter pvc that is capped and which has a coax connector passing
through it. and the whole attached to the glass with silicone
adhesive. One on either side of the glass.

Matching indoor only is possible (so you don't need matching outside
to interface to 50 Ohm coaxial cable).

Not sure of your point. It seems I need to match outside.

Another problem just occurred to me. I'll use a MFJ magnetic loop, and
its tuner, if I recall, depends on an uninterrupted electical connection
through the coax. If so, I'm stuck.
--

Haines Brown, KB1GRM

Hello,

I was thinking of just 1 turn windings glued on the window of about
D=10'' (correctly aligned), in combination with a two trimmer
capacitor match (from which one can probably be a fixed value after
experimenting).

When you would do matching both inside and outside you can get a
broader response. Window glass is just about 0.15'' thick, so I think
a single match (inside) would have sufficient bandwidth (especially
when you would use foil/strip material for the two single turn
windings).

Best regards,

Wim
PA3DJS
www.tetech.nl
please remove abc from the address.

"Haines Brown" wrote in message
...
Wimpie writes:

Why not using inductive coupling? You can get reasonable coupling as
wires are just mm away from eachother, so you don't need high Q factor
circuit.

Didn't occur to me. Are you suggesting a couple coils sharing an axis,
one just inside the window and the other outside? Would the two coils
simply be designed for a 50-ohm impedance at, say, 10 meters?

I can imagine wrapping a 50-ohm coil on pvc, and inserting it into a
larger diameter pvc that is capped and which has a coax connector passing
through it. and the whole attached to the glass with silicone
adhesive. One on either side of the glass.

Matching indoor only is possible (so you don't need matching outside
to interface to 50 Ohm coaxial cable).

Not sure of your point. It seems I need to match outside.

Another problem just occurred to me. I'll use a MFJ magnetic loop, and
its tuner, if I recall, depends on an uninterrupted electical connection
through the coax. If so, I'm stuck.
--

Haines Brown, KB1GRM

Haines,

Just read the other postings about inductive coupling and I think that would
be the best way to go with a standard wire antenna like a half wave dipole,
vertical, etc.

I can't see any way of getting a magnetic loop antenna to work because you
need a direct DC path for power and tuning commands from the tuning unit to
the loop.

Might be better to put your ingenuity to better use by finding somewhere
hidden to run a thin bit of coax through the wall. Behind a switch plate,
power socket, joint fillet, alongside a pipe. There must be somewhere to put
a 1/4 inch hole that can be concealed later? For QRP work, you might get
away with a short through wall length of really thin coax, the 1/8 inch
stuff used to connect signal assemblies inside equipment.

If you are really brave, a masonry drill at high speed will cut through
glass with a bit of soapy water acting as a lubricant. Take your time and
try and brace the other side with a wooden block or elses a big bullseye
chip will be thrown out when the drill breaks through. Fill the hole with
transparent quick set epoxy when it is no longer needed.

Mike G0ULI

"Mike Kaliski" writes:

I can't see any way of getting a magnetic loop antenna to work because
you need a direct DC path for power and tuning commands from the
tuning unit to the loop.

I must apologize for starting a thread that I realized would be for me a
dead end. I've not used a magnetic loop before and so easily forgot
about the need for a direct DC connection. However, the thread was
interesting and hopefully worthwhile.

Might be better to put your ingenuity to better use

Yes. Options are limited because I'm at the eighth story of a steel
high-rise, and the enamled metal outside surface material doesn't lend
itself to drilling. In any case, I don't own it and wouldn't feel right
about destroying property not mine. The window is a casement window, and
I'm now thinking of leaving it permanently ajar and gluing (silicone) on
the inside frame a piece of plexiglass with a coax feedthrough. That way
I can have light from the window, protection from the elements and not
destroy anything. Ultimately it can be removed when necessary.

--

Haines Brown, KB1GRM

The window is a casement window, and
I'm now thinking of leaving it permanently ajar and gluing (silicone) on
the inside frame a piece of plexiglass with a coax feedthrough. That way
I can have light from the window, protection from the elements and not
destroy anything. Ultimately it can be removed when necessary.


If you are going to do it this way, I might suggest you use weather
stripping ( for doors, etc. ) instead of Silicone sealer. It comes in a
variety of thicknesses.... should provide a good seal for your slightly
ajar window, easily allow some RG-8X type coax through, and be a lot
easier to remove than the silicone in the future. Also, will still allow
you to open your window if need be ... just a thought.

Ed K7AAT

Haines Brown wrote:
... Options are limited because I'm at the eighth story of a steel
high-rise, and the enamled metal outside surface material doesn't lend
itself to drilling. In any case, I don't own it and wouldn't feel
right about destroying property not mine...

Have the window replaced and leave a space at the bottom
of the pane for a plexiglas feed through panel.

When you move, have the window replaced again.

Couple hundred bucks, it's done right, nothing
is destroyed.


Craig 'Lumpy' Lemke

www.n0eq.com