OK - I just bought a new in the box 1955 Heath GD-1B grid dipper
with the extra low band coil set. $25. The dipper works FB and I
used an old SO-239 chassis jack plus a bit of 22g wire and a cut
down pill bottle to make a 4t coupling loop big enough to "dip" -
that is I inserted the dipper's coil inside the pill bottle coil
attached
to my feedline.

Now here is where I make myself look stupid - My antenna's best
SWR is at 7185 with a 1.1:1 but the dipper showed max dip at
6990 (I tuned into the dipper with my K2). What's going on here?

Someone educate me.....lol

73's de Ken KG0WX

Resonance and VSWR are NOT related!

My 75 meter mobile antenna is resonant at 3.94 MHz. My VSWR is 5:1.

You are measuring two different things.

The dipper is a very nice tool. I owned the Heathkit unit in the olden
days. I now use the Military surplus AN/PRM 10.

KG0WX wrote:

OK - I just bought a new in the box 1955 Heath GD-1B grid dipper
with the extra low band coil set. $25. The dipper works FB and I
used an old SO-239 chassis jack plus a bit of 22g wire and a cut
down pill bottle to make a 4t coupling loop big enough to "dip" -
that is I inserted the dipper's coil inside the pill bottle coil
attached
to my feedline.

Now here is where I make myself look stupid - My antenna's best
SWR is at 7185 with a 1.1:1 but the dipper showed max dip at
6990 (I tuned into the dipper with my K2). What's going on here?

Someone educate me.....lol

73's de Ken KG0WX

KG0WX wrote:
OK - I just bought a new in the box 1955 Heath GD-1B grid dipper
with the extra low band coil set. $25. The dipper works FB and I
used an old SO-239 chassis jack plus a bit of 22g wire and a cut
down pill bottle to make a 4t coupling loop big enough to "dip" -
that is I inserted the dipper's coil inside the pill bottle coil
attached
to my feedline.

Now here is where I make myself look stupid - My antenna's best
SWR is at 7185 with a 1.1:1 but the dipper showed max dip at
6990 (I tuned into the dipper with my K2). What's going on here?

Someone educate me.....lol

73's de Ken KG0WX

1. Although it's usually close for simple antennas, the point of minimum
SWR isn't necessarily the resonant frequency. The dipper measures resonance.

2. The coupling loop adds inductance to the circuit, lowering its
resonant frequency.

Roy Lewallen, W7EL

Thanks to all you guys for enlightening me. I did an experiment
- I tuned the dipper to 146.520 (not easy to get it right there) and
took my HT out for a walk. I could hear the carrier out to about
400 yards! I'm in a wire mesh/stucco/aluminum siding structure
in the city so that kind of output from an instrument is surprising.

Imagine what it would have done if I inductively coupled to my GP-6
at 25' ? lol! Next I'll try it on HF with my K2....

Ken KG0WX

ORIGINAL MESSAGE:

KG0WX wrote:

Thanks to all you guys for enlightening me. I did an experiment
- I tuned the dipper to 146.520 (not easy to get it right there) and
took my HT out for a walk. I could hear the carrier out to about
400 yards! I'm in a wire mesh/stucco/aluminum siding structure
in the city so that kind of output from an instrument is surprising.

Imagine what it would have done if I inductively coupled to my GP-6
at 25' ? lol! Next I'll try it on HF with my K2....

Ken KG0WX


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Back in the '50s or '60s there was a book published wherein the hero
was trapped or something and called for help by sending CW with a grid
dip meter. Don't remember any details but it was a great read when I
was a teenager.

73, Bill W6WRT

Totally plausible as I have noticed when I tune a FM receiver
to my dipper's carrier, I can deviate the carrier with my voice
if I get close to the case of the dipper. Found that out the other
day when I turned up the volume on my HT and got a squeal
from the dipper!

Now when I'm searching for the carrier and my scanner stops
on a signal, I tap the dipper's case with a coin and not only do
I hear it quite clearly on the scanner but it sounds like a mic
in a coffee can. Helps to differentiate between birdies and my
target carrier.

Love it!

Ken KG0WX

Bill Turner wrote:
Back in the '50s or '60s there was a book published wherein the hero
was trapped or something and called for help by sending CW with a grid
dip meter. Don't remember any details but it was a great read when I
was a teenager.

One of the Hardy Boys books was about ham radio.
--
73, Cecil http://www.qsl.net/w5dxp

On 19 Feb 2006 18:38:17 -0800, "KG0WX" wrote:

Thanks to all you guys for enlightening me. I did an experiment
- I tuned the dipper to 146.520 (not easy to get it right there) and
took my HT out for a walk. I could hear the carrier out to about
400 yards! I'm in a wire mesh/stucco/aluminum siding structure
in the city so that kind of output from an instrument is surprising.

Imagine what it would have done if I inductively coupled to my GP-6
at 25' ? lol! Next I'll try it on HF with my K2....

Back in the sixties I was living on a postage stamp sized lot in the
city and working 2M EME.

Some W6 moved to the next street over and decided what Tucson needed
was his crappy 2M repeater on the air.

Shortly after he moved in, while I was on the air, the next door
neighbor calls and said that I was creaming her TV. I hadn't changed
anything in months, but nevertheless began a witch hunt for my
problem. After a fruitless search I decided that maybe it was the
repeater and not me. Not owning an FM rig, I needed another way to
bring it up and thought of the GDO.

Swish swish and up it came (but with no TVI). It took more detective
work to figure out that it took my signal being on the air when the
repeater transmitted to clobber the TV. I let my automatic keyer run
the transmitter while walked next door to the neighbor's with the GDO
and went swish swish and the TV choked. I guess his receiver wasn't up
to handling 100KW erp a couple of hundred of yards away. [g]