I do have correlation now. The vswr meters and the mfj all read the same
resonant frequency now, Wes. See my post that shows the data for 0,2,4,8
radials. While a given absolute value might be in error (a certainty due to
inexpensive instruments), the trend is sound for bandwidth, but a bit
strange for feedpoint impedance. (BW is narrowing but input Z is going up,
with increasing numbers of radials.)

Ideas?

73,

....hasan, N0AN
"Wes Stewart" wrote in message
...
On Fri, 2 Sep 2005 23:29:17 -0500, "hasan schiers"
wrote:

45' high, 25.8 sloping wire at the top, 29 feet high at the far end. #12
THHN Insulated copper wire, stranded.

Predicted Radiation Resistance: 25.8 ohms, very good ground (rich
pastoral,
midwest).

With no radials, I get a flat 50 ohm match at 3595 khz. Obviously this
would
indicate ground losses of approximately 25 ohms, if I'm thinking about
this
right. Also, predicted efficiency would then be 50 % (25/(25+25),
indicating
a 3 dB loss. Forgetting about fresnel region losses, this seems to be
better
than I had expected. 2:1 vswr bandwidth is very broad....broader than what
I
get with EZnec 4.x with a 25 ohm load in the base.

This means one of two things to me:

Either my ground losses are much higher than the 25 ohms I'm indirectly
calculating, or I have made some sort of conceptual error in thinking
about
what the implications are of a 25 or 26 ohm feedpoint. All my references
point toward a 25 ohm radiation resistance for my 42' vertical x 25.8 ft
inverted L (with sloping top wire instead of flat top wire). What is wrong
with my logic here? If the R(rad) is 25 ohms, and I measure a flat VSWR
(on
two other meters) at 3600 khz, then isn't the remaining 25 ohms, ground
loss?

I also show about 37 ohms resistance and 0 ohms reactance at 3600 khz with
my MFJ-269, which is really confusing, in that if I have 25 ohms for Rrad,
then I have 13 ohms of ground losses. Further, 37 ohms is around 1.3 to 1.
So I have two other vswr meters showing 1:1 at 3600, and the MFJ showing
37
ohms. This is a pretty large percentage difference.

I would be inclined to believe the 25.8 ohms predicted by both EZnec 4 and
the Low Band DX'rs Handbook. In any case, I'll put out 4 radials tomorrow
morning and repeat all my measurements, looking for narrowing bandwidth
and
lowered input Z as my ground losses decrease.

Ultimately, I'm going to put down 16, 66' radials, in steps of four,
taking
measurements of input Z (mfj-269) and vswr bandwidth for 2:1, at 0,4,8 and
16 radials. I'll report what happens as I go along.

Anywho, without any radials at all there are quite a few distant signals
on
80m this evening, that are consistently louder on the newly installed
inverted L, than on my Carolina Windom at 45'. Most signals as one pans
the
band, are louder (at 2 hours after sunset) on the C. Windom than on the
radial-less inverted L, but ones from several states away are equal or
better on the radial-less inverted L. Both seem to make good sense at
this
point. I sure will be interested to see the effects of 4 and then 8 and on
up radials, but that is going to take a few days, because I don't want to
make radial changes unless I have access to low angle signals, which only
happens at night or just before sunrise.

Tomorrow is radial day. I will be laying out 4 radials 65' long to begin
with. I have resistance and reactance measurements every 50 khz as a
baseline, before installing radials. 4 in the early morning, 4 more just
before sunset, then 4 more the next morning, and the final 4 the next
evening. #14 THHN stranded insulated copper wire for the radials, btw.

Depending on what I end up seeing for "effect" I'll go to 24 or 32 radials
by winter....but only if the improvement is both measurable and
"observable
on the air"...radials are a pain in the rear (or more accurately, the
knees)
to put in.

What fun!

Indeed.

Unfortunately, I believe that you are at the mercy of your
instrumentation. I doubt that you can make meaningful measurements of
the differences resulting from the addition of a few radials at a
time.

The fact that you can't get correlation between measurements made on
the -same- antenna with different instruments is a problem. Until you
have two clocks that read the same, you don't know what time it is.