[600MRG] Resonant frequencies and loaded antennas

Tue Sep 15 09:23:34 CDT 2015

Frank,
 It all depends on how the application was worded.
If the applicant specified exact dimension and GPS location coordinates for
an antenna, then there might be a problem moving it more than a few degrees
from that location, but if it was worded with "less-than" or other
government-weasel-words and the antenna remained within the bounds
specified, then (IMHO) the purpose of part-5 experimentation would not be
violated.
Quadrupling the size of a microwave horn or dish might be a different
matter.

Changing the configuration of my inverted-L did not change the fact that it
was a Marconi on my property. The Marconi is usually shown with the top
loading run symmetrically, but attaching the top loading anywhere from the
end to the center of the flattop, it is still a shortened vertical Marconi.

But then believing a barracks-lawyer can just get you into trouble.....
73,
Pat

-----Original Message-----
From: 600MRG [mailto:600mrg-bounces at w7ekb.com] On Behalf Of Frank Lotito
Sent: Tuesday, September 15, 2015 9:01 AM
To: dick.bingham; 600 / 630 Meter Group
Subject: Re: [600MRG] Resonant frequencies and loaded antennas

To all - Maybe I missed it in a prior posting: I assume (at least for now
while transmitting with a Part 5 grant) the new antenna revisions for 630 /
600 meters planned by a number of present Part 5 licensees have been
included in a formal modification of the licensee's Part 5 grant?  I
definitely believe when push comes to shove, all the experts in the world
will have a tough time proving that a non-formally documented antenna
revision will upset the peace  - harmony and coexistence with other services
on or near the 630 / 630 meter bands.  At least for the 630 / 600 meter
antennas we "amateurs" can afford to construct and maintain.
However.....better safe than sorry.......

I assume the preapproval of 630 / 2200 meter band transmitting antenna
designs will become a moot point when US amateurs gain formal access to the
proposed new MF and LF bands.  Has anyone verified that?

73 Frank K3DZ / WH2XHA

________________________________________
From: 600MRG <600mrg-bounces at w7ekb.com> on behalf of dick.bingham
<dick.bingham at gmail.com>
Sent: Tuesday, September 15, 2015 12:20 AM
To: kgordon2006 at frontier.com; 600mrg at w7ekb.com group
Subject: Re: [600MRG] Resonant frequencies and loaded antennas

Hi Ken

Regarding your ===>
====================
"FYI, this is a 140 foot long, overall, sloper. Slope angle about 67 degrees
(Brunton compass). Height at the top end, about 110 feet give or take the
hawk's nest. Height at the bottom end, close to 12 feet above the ground.

I'll be using this antenna:

https://www.arrl.org/files/file/Technology/tis/info/pdf/9207035.pdf
Build a Space Efficient Dipole Antenna for 40, 80 and 160 ...
Fig 2-The improved coaxial-cable traps use two layered windings to provide
an unusually high inductance-to-capacitance ratio, higher Q, and twice the
breakdown ...
Read
more...<https://www.arrl.org/files/file/Technology/tis/info/pdf/9207035.pdf>

adding a trap for 160 meters at its end, then continuing with wire to a 3357
uH loading coil for 630 meters, then an addition 12 feet of wire.

Modeling the 630 meter antenna only shows resonance at 515 kHz.

I also intend to install a remotely tunable base-loading coil to enable
"tweaking" on 630 meters, switching it out for HF.

I'll add tuned counterpoises for HF, and an extensive ground system for 630
meters, then will attempt to feed the entire thing with LMR-400 and an
antenna coupler.

All this remains to be seen. It will certainly be very interesting if it
works.
Maybe I'll publish an article on it so folks will be more inclined to think
that
630 meter operation is possible from a normal small city lot.

Thanks for all the help, folks.

Ken W7EKB"
================
I examined the traps at the website you provided and am puzzled by the
description given in the July 1992 QST article AND the follow-up September
1992 article "making more clear" how to fabricate the trap !!!

The wiring connections are totally NOT clear to me. As I read both articles,
one is suppose to strip off the shield from the coax and discard it. Then,
one is instructed to insert one end of the center-wire wrapped in dielectric
into one end of the coil form (apparently this forms one connection to an
antenna wire.) Then one winds a coil along the outside of the form to a
second hole on the other end of the coil-form where the wire is then
inserted into that hole and feed back inside the coil-form and routed out of
another hole in the coil-form close to the beginning hole. Here a second
coil-winding is wound on top of the first winding and the far-end is routed
through a second hole at the far-end of the coil. I guess this is the other
end of the trap.

What I do not see is where/how an LC-trap is formed. It just looks like two
solenoid-wound inductor-windings are formed with some capacitance between
winding layers.

Maybe you or one of the group can help me see what is going on here . . .

Dick/w7wkr and XSH-26 CN98pi and  w7wkr/7 CN97uj

----------------------------------------------------------------------------
-----------------

> On Sep 13, 2015, at 8:04 PM, Kenneth G. Gordon <kgordon2006 at frontier.com>
wrote:
>
> FYI, this is a 140 foot long, overall, sloper. Slope angle about 67
degrees
> (Brunton compass). Height at the top end, about 110 feet give or take the
> hawk's nest. Height at the bottom end, close to 12 feet above the ground.
>
> I'll be using this antenna:
>
> https://www.arrl.org/files/file/Technology/tis/info/pdf/9207035.pdf
>
> adding a trap for 160 meters at its end, then continuing with wire to a
3357
> uH loading coil for 630 meters, then an addition 12 feet of wire.
>
> Modeling the 630 meter antenna only shows resonance at 515 kHz.
>
> I also intend to install a remotely tunable base-loading coil to enable
> "tweaking" on 630 meters, switching it out for HF.
>
> I'll add tuned counterpoises for HF, and an extensive ground system for
630
> meters, then will attempt to feed the entire thing with LMR-400 and an
> antenna coupler.
>
> All this remains to be seen. It will certainly be very interesting if it
works.
> Maybe I'll publish an article on it so folks will be more inclined to
think that
> 630 meter operation is possible from a normal small city lot.
>
> Thanks for all the help, folks.
>
> Ken W7EKB
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