On Apr 4, 1:30*pm, wrote:
wrote:
On Apr 4, 12:15*am, wrote:
wrote:
On Apr 3, 10:30*pm, wrote:
wrote:
On Apr 3, 8:22*am, Cecil Moore wrote:
wrote:
Did you ever try to model a resonator where the coil required is
actually longer than the insulator, so that the vertical part of the
resonator is actually inside the coil , ...
Never modeled it but have seen its effects during
75m mobile shootouts. One fellow had a hamstick
with the stinger bottom extending down into the
hamstick loading coil. It was a very lossy
condition which improved when he hack-sawed the
excess stinger off.
Do you have EZNEC? If so, I can modify a helical
loading coil to extend the stinger into the middle
of the coil and send the file to you.
Conductors within the loading coil field lower
the effective coil Q. However, I have had good
luck with a 1.25" fiberglass pipe running through
the center of the coil providing mechanical
support. Perhaps you could consider swapping your
insulator for a piece of fiberglass pipe or rod.
--
73, Cecil, IEEE, OOTC, *http://www.w5dxp.com
I have the top portion of the antenna put togather, ready to go up in
the next couple of days depending on wx, after I got it put together I
realized that when I got the toroids I was only concerned about 40 &
80M, and then wanted 160M, should these be some what acceptable on
160M with 100watts *Their red on the inner, outer, and top, the bottom
is some color of a green or brown. It measures very close to 26mm
outside,15mm inside and 10mm high. No markings what soever. Any
thoughts on if it should work or not. thanks 73, brett
They aren't usually color coded on the "bottom".
If they are iron-powder, red is material #2, which is good for .5 Mhz
to 10 Mhz.
The size seems closest to T-106, which in inches is 1.060 *X 0.570 X 0.437.
You can find all the specs, charts, etc. at:
https://www.amidoncorp.com/
--
Jim Pennino
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Thanks for the link to the info on the color codes , I have the red
one in the antenna right now ,I was going to test soon, According to
the document on the link, the red toroid spec is 2-30mhz but blue
toroid spec is .5-5mhz.
The blue one I have is close to 25mmOD * 11mmID * 10mmHigh. I'll redo
the blue toroid for the inductance I need before I waste my time with
the red one Thanks again 73,brett
Yeah, the numbers I quoted are from some old data sheets I have for
some torroids I have.
For whatever reason, some of the numbers are different on their web
site.
I have no clue if that's because the product changed over the years
or the old sheets were wrong.
YMMV.
--
Jim Pennino
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I removed the red toroid from the vertical and replaced it with a blue
one, I'm hoping to get this thing up today to see how it performs.
I'll do some tests on it for a couple of weeks then maybe try the red
toroid anyway to see if it too will work.From the specs I found red
being 2-30mhz *and blue 0.5-5mhz it seems obvious that the blue one is
the better choice for 160 but not a good choice for 40M. And vice
versa the red one better for 40 but a good choice for 160. I will to
to find out more info on color code and material type, *I also have a
couple of type 43 binocular core very small black ones, that a fellow
ham gave me, they measure about 15mm long X 11mm wide X 7mm thick the
two holes are about 7mm center to center and 4mm in diameter. I used
these on rx antennas, one *wound 9:1 for an EWE and another 4:1 for
loop, would these possibly work for tx with 100w or less on 160-40M
They seem to work very well on rx for that freq range. *Thanks again,
73, brett
My gut feel is either core will "work" and that unless you have access
to some lab grade equipment, you won't see any performance difference
between the two.
--
Jim Pennino
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I tried the blue toroid after being made aware of the color code.I
seemed to be ok regards to swr and forward power levels, however I
tried it in the SPDX contest and it was a flop , 0 contacts on
vertical for 80M, where I made some contacts on a dipole at 25 feet. I
will try it for another week or so as I am busy with work and not able
to do much work on my antenna just yet.Maybe due to propagation, but
dipole at 25 feet better than vertical for dx on 80M, boggles me.
Thanks again, 73 brett