[Lowfer] MP in MA

[Mitch Powell]

HI BILL:
You must have heard us talking about loops - and getting it all wrong !

Here is the info I just sent to Scott - WITH CORRECTED MATH   ;-(

Now will you forgive me ?

Mitch

Quote:
Scott:
1 --- You're right of course - I just checked at - using 7200 pf @ 137780 gives me ~185 uH. So that's probably right, considering the slightly different shape and twist I have with my loop.

2 --- Caps are the exact same as yours - I am using 3 of the 0.002uF 10KV Cornell-Dubilier Mica Capacitors.
These are in parallel with a 1500 pf air variable - which is set at ~1200 pf right now - thus giving me a 7200 pf capacitance to series tune the loop.

The wire is two pieces of #10 PVC covered - in parallel: Like an old open wire feedline. I have taken a picture and will forward separately. There are spacers every 3-4 feet made of 3/4 inch pvc pice - drilled and tied. The squirrels have a great time.
I used a spud gun with bailing twine - and shot it up about 60 feet and then spent a couple of hours of heavy pulling to get the final result.  120 feet horizontal - 50 feet vertical - 6-8 feet off ground.

I have just rewired the rf ammeter circuit ( courtesy W1TAG article ) and calibrated - and it looks like I have 1.32 amps currently flowing through the loop.

The rf phase meter ( courtesy Jim M0MBU ) shows resonance - and matched to an impedance ( due to my present taps ) of 40 ohms. So I will be out later - changing the tap - getting closer to 50 ohms.

The DC input to the amplifier is exactly 10 watts - and I am not sure of the efficiency.
On 2010-09-13, at 7:53 PM, Bill Ashlock wrote:

> 
> Mitch,
> 
> Your loop inductance is certainly a lot more than that! Have you gone loopie? It can happen, you know :)
> 
> I usually figure a 200ft perimeter loop with #12 wire has an inductance of approx 100uh.