Return to KLUBNL.PL main page

[Top] [All Lists]

SV: LF: Loops - current measurements

To: [email protected]
Subject: SV: LF: Loops - current measurements
From: "Dave Sergeant" <[email protected]>
Date: Wed, 1 Sep 1999 01:29:50 -0400
Reply-to: [email protected]
Sender: <[email protected]>
From Dave G3YMC
<The loop design programs RJELOOP1 and RJELOOP2, written
<by Reg / G4FGQ, both include induced ground loss when they
<compute the total loss resistance.

Thanks for the information on these programs.  I have simulated my loop
with them and the results are astounding:

Using  RJELOOP1 with a square loop (not strictly true, mine is very dog
legged), and 4mm dia wire gives:

RF loss resistance   0.347 ohm
Ground loss resistance 0.247 ohm

Total loss resistance  0.6 ohms

This agrees almost exactly with the measured results on my loop (0.66
ohms)!  However the calculated bandwidth of 1.3kHz is far too high - I have
to retune if I QSY more than 100Hz!  Note that these programs assume loop
or transformer coupling rather than my capacitive matching network -
perhaps this accounts for the discrepancy.

My loop wire is actually 2 wires of 2mm dia in parallel.  I have taken the
diameter as 4mm to account for the fact that the skin resistance will be
lower than for a single conductor.

Thanks also for the replies on a formula for skin resistance, in particular
to Alan G3NYK.  His formula agrees well with the approximation I had, and
now with G4FGQs program.

73s Dave G3YMC
[email protected]

<Prev in Thread] Current Thread [Next in Thread>
  • SV: LF: Loops - current measurements, Dave Sergeant <=