[Lowfer] Ribbon cable loop antenna for receiving

[Rick Kunath]

On Wednesday 24 February 2010 08:26:26 pm Mike.WE0H wrote:
> Less inter wire capacitance and a wider freq tuning range.
> 
> Full details on assembly:
> http://www.we0h.us/505kc/Simple-RX-Loop-Antenna/
> 
> Mike
> WE0H
> 
> Andy - KU4XR wrote:
> > Thanks John;
> > ...Mikes loop looks pretty nice, AND !! simple. Looks like a vertical
> > stacked winding. What benefit does that provide over the wires
> > being side by side ??
> > Andy - KU4XR - EM75xr - Friendsville, TN. USA
> 

I never cared for pancake style loop windings, this is what the spiral type 
loop winding that you are describing is called. 

I prefer a solenoid type winding, this is the winding type that has the turns 
side by side. I have had better balance using a solenoid winding, as well as 
better nulls.

I center-tap the loop primary winding and use a split-stator tuning capacitor, 
and you can imagine that trying to find the center-tap and get it right on a 
spiral loop is near impossible as the two portions of the loop primary cannot 
be balanced.

If you don't use a canter-tapped primary the winding style works well enough, 
though I never got nulls as deep as a solenoidally wound loop. Part of that is 
because of the much better loop primary balance that you get with a solenoidal 
winding.

So for me, I'd call a pancake winding a disadvantage. 

Additionally, in general a solenoidally would loop primary will have all of 
the winding turns exposed to the same wavefront. This does not always happen 
with a pancake loop, though at LW these effects are much less pronounced than 
at MF.

It is the winding spacing that decreases inter-turn capacitance. 

In addition to wide spacing the primary windings to reduce the inter-turn 
capacitance, I also weave tongue depressors between the turns of the winding. 
These go over and under every other turn. If you insert the depressor flat, 
then turn it 90 degrees, and place two in each quarter of the primary winding, 
with each inserted opposite, i.e. over and under and under and over, turning 
them 90 degrees places an even wider spread on the windings and tightens the 
loop up too. It makes a huge difference.

Rick Kunath, k9ao