[600MRG] Resonant frequencies and loaded antennas

[Warren K2ORS]

Frank,

   The Part 5 application asks for the antenna height and whether or not 
it is directional. It also asks for an "FAA Antenna Sketch" - the 
purpose of that is to make sure the proposed antenna does not interfere 
with aviation. I never interpreted either question to mean I had to 
submit a modification for minor changes in the antenna configuration as 
long as I don't cause difficulty for air traffic and I don't exceed ERP 
limitations in a given direction (impossible to do in any event as my 
license allows for a kW of ERP).

73 Warren




On 9/15/2015 10:00 AM, Frank Lotito wrote:
> 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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