On 7/26/2014 10:51 PM, Lostgallifreyan wrote:
amdx wrote in :

I've* calculated a 6 inch loop made with a #12 or #14 wire will
resonate the FM band with a cap between 6.5pf and 10pf. Roughly!
Now, I'll see if I can generate the gumption in the next couple
of days to build it to see if it has any positive effect.
I hope someone beats me to it.
With an AM loop and radio the signal couples to the internal loop very
well, I don't know how well you can couple a signal into an FM radio.
Mikek

* actually I used a couple of online calculators.

http://www.deephaven.co.uk/lc.html

http://www.daycounter.com/Calculator...lculator.phtml


This is nice because it beats the issue with two ways to be selective. Even
so, I have to have one last shot at the broadband notion: could a 6dB boost
with one of those MAR6-based antenna amps be worth a shot? Driving a local
diple, taped to a doorframe perhaps, in the centre of the flat? Given the
tiny size of those IC's I doubt the amount of power getting out of the flat
will be a nuisance, especially given its reluctance to allow RF in (except
through the celing, and a dipole taped vertically to a doorframe isn't going
to send a lot upwards either.. To some extent the business may be eased by
the fact that the two frequencies I'm most keen to get, 91.5MHz and 93.7MHz,
aren't far apart. If there is ANY chance this can be solved with no
modification or encumbrance to the tiny radio I intend to carry from room to
room, that's the way I want to do it.

I made a 6 inch loop with a 2pf to 10pf cap, I could see a peak in
the loop where I adjusted it to, but it was very low Q and when I
started dangling it around my radio I couldn't hear any change.
It may take a slightly smaller loop, I had my cap set at minimum
to get it to tune the low end of the band.
In my mind the experiment failed.
I have had loads of fun with AM band loops with high Q and obvious
effect on reception.
Mikek

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amdx wrote in :

I made a 6 inch loop with a 2pf to 10pf cap, I could see a peak in
the loop where I adjusted it to, but it was very low Q and when I
started dangling it around my radio I couldn't hear any change.
It may take a slightly smaller loop, I had my cap set at minimum
to get it to tune the low end of the band.
In my mind the experiment failed.
I have had loads of fun with AM band loops with high Q and obvious
effect on reception.


Thanks for trying though, it's good info. One reason I imagined staying with
a dipole is it's close to what already works as standard. A loop for VHF is a
niuce idea for the selectivity of tuning and of orientation, but most radios
couple VHF to what amounts to a wire, not a magnetic coupling, so my
suspicion is that aiming for magnetic coupling won't work so well as a
dipole.

On 7/27/2014 3:16 PM, amdx wrote:
On 7/26/2014 10:51 PM, Lostgallifreyan wrote:
amdx wrote in :

I've* calculated a 6 inch loop made with a #12 or #14 wire will
resonate the FM band with a cap between 6.5pf and 10pf. Roughly!
Now, I'll see if I can generate the gumption in the next couple
of days to build it to see if it has any positive effect.
I hope someone beats me to it.
With an AM loop and radio the signal couples to the internal loop
very
well, I don't know how well you can couple a signal into an FM radio.
Mikek

* actually I used a couple of online calculators.

http://www.deephaven.co.uk/lc.html

http://www.daycounter.com/Calculator...lculator.phtml


This is nice because it beats the issue with two ways to be selective.
Even
so, I have to have one last shot at the broadband notion: could a 6dB
boost
with one of those MAR6-based antenna amps be worth a shot? Driving a
local
diple, taped to a doorframe perhaps, in the centre of the flat? Given the
tiny size of those IC's I doubt the amount of power getting out of the
flat
will be a nuisance, especially given its reluctance to allow RF in
(except
through the celing, and a dipole taped vertically to a doorframe isn't
going
to send a lot upwards either.. To some extent the business may be
eased by
the fact that the two frequencies I'm most keen to get, 91.5MHz and
93.7MHz,
aren't far apart. If there is ANY chance this can be solved with no
modification or encumbrance to the tiny radio I intend to carry from
room to
room, that's the way I want to do it.

I made a 6 inch loop with a 2pf to 10pf cap, I could see a peak in
the loop where I adjusted it to, but it was very low Q and when I
started dangling it around my radio I couldn't hear any change.
It may take a slightly smaller loop, I had my cap set at minimum
to get it to tune the low end of the band.
In my mind the experiment failed.
I have had loads of fun with AM band loops with high Q and obvious
effect on reception.
Mikek

Hi, Mike - 6 inch circumference, 6 inch diameter, or 6 inch radius. Just
clarifying...

John

On 7/27/2014 4:35 PM, John S wrote:
On 7/27/2014 3:16 PM, amdx wrote:
On 7/26/2014 10:51 PM, Lostgallifreyan wrote:
amdx wrote in :

I've* calculated a 6 inch loop made with a #12 or #14 wire will
resonate the FM band with a cap between 6.5pf and 10pf. Roughly!
Now, I'll see if I can generate the gumption in the next couple
of days to build it to see if it has any positive effect.
I hope someone beats me to it.
With an AM loop and radio the signal couples to the internal loop
very
well, I don't know how well you can couple a signal into an FM radio.
Mikek

* actually I used a couple of online calculators.

http://www.deephaven.co.uk/lc.html

http://www.daycounter.com/Calculator...lculator.phtml



This is nice because it beats the issue with two ways to be selective.
Even
so, I have to have one last shot at the broadband notion: could a 6dB
boost
with one of those MAR6-based antenna amps be worth a shot? Driving a
local
diple, taped to a doorframe perhaps, in the centre of the flat? Given
the
tiny size of those IC's I doubt the amount of power getting out of the
flat
will be a nuisance, especially given its reluctance to allow RF in
(except
through the celing, and a dipole taped vertically to a doorframe isn't
going
to send a lot upwards either.. To some extent the business may be
eased by
the fact that the two frequencies I'm most keen to get, 91.5MHz and
93.7MHz,
aren't far apart. If there is ANY chance this can be solved with no
modification or encumbrance to the tiny radio I intend to carry from
room to
room, that's the way I want to do it.

I made a 6 inch loop with a 2pf to 10pf cap, I could see a peak in
the loop where I adjusted it to, but it was very low Q and when I
started dangling it around my radio I couldn't hear any change.
It may take a slightly smaller loop, I had my cap set at minimum
to get it to tune the low end of the band.
In my mind the experiment failed.
I have had loads of fun with AM band loops with high Q and obvious
effect on reception.
Mikek

Hi, Mike - 6 inch circumference, 6 inch diameter, or 6 inch radius. Just
clarifying...

John

Diameter.

Five minutes with these calculators and you can pick your own dimensions.


http://www.deephaven.co.uk/lc.html

http://www.daycounter.com/Calculator...lculator.phtml

Mikek

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