[600MRG] Fwd: Re: 630 with a 68ft vertical?

Wed Sep 30 16:47:25 EDT 2020

I sent this off to Dr. DWD, VK5BUG the MF specialist from Down Under.

Here's his reply:

Hello David

Yes indeed, though have not seen one in the flesh over this way. My rooftop
160m Big Bore helical sports a 7-foot ex-CB ‘stinger’.

Another MF edition has 3 top loading wires forming part of the guy system,
as is also popular practice. On small allotments like ours, snagging with
mature, tall tree branches such as almond, prove to be a nuisance though,
and I recently lost one poly guy rope to that nemesis.

At 75 & with the ‘gift pack’ of mobility & vulnerability issues as standard
issue (!), I no longer venture up ladders or otherwise climb to roofing, so
all I could do was turn the 3-guy setup into a 2-guy one, based on the most
common prevailing wind direction. Only made the adjustment 4 days ago, so
it will be interesting to see how long it lasts.

I have nobody in my network able to be my saviour monkey up the pole!!

I hope you are going well. Kind regards, 73 Doc/VK5BUG

PS. Latest project additions have been a 3-element helical 40m VPA spaced
30ft, & 2-element Big Bore helical 80m VPA spaced 61ft (two halves of a
160m 4-inch PVC pipe wound version). Turns are wide-spaced @ 3cm (2 & ¼
inches).

The 40m version is 10m fg roach pole wound, ground mounted & operates from
PVC pipe ‘sockets’, being simply disconnected from ground & pulled out for
horizontal rack storage on a substantial wooden garden trellis (Reflector)
& boundary fence rail rack storage (Director). This minimises risk of storm
damage, though so far the 40m elements have survived 60mph winds here. Very
effective @ 10-12dB reception improvement in the East firing direction,
with approx. 70-deg arc & take-off angle in the low/mid 20s.

I am still in the process of completing the 80m VPA similar pull-out &
adjacent storage. Both great fun projects & one-person throughout!

73

DR

On Wed, Sep 30, 2020 at 2:31 PM Edward R Cole <kl7uw at acsalaska.net> wrote:

> typo:  spacing is 1/4-inch.
>
> At 10:26 AM 9/30/2020, Edward R Cole wrote:
>
> Date: Wed, 30 Sep 2020 10:25:33 -0800
> To: Jim Miller <jim at jtmiller.com>
> From: Edward R Cole <kl7uw at acsalaska.net>
> Subject: Re: [600MRG] 630 with a 68ft vertical?
>
> I put up a 43-foot inverted-L with 122-foot top wire.  Only four radials
> at 100-foot or less.  I built a coil 10-inch in diameter with 1.4-inch
> winding spacing about 11-inches long using No. 12 solid copper wire
> (stripped std house wire).  Antenna tuned using about 2/3 of the windings.
> Without top hat you would need more inductance in a loading coil.
>
> I made it using white plastic food cutting boards.
> http://www.kl7uw.com/630m.htm
>
> 73, Ed - KL7UW
>
> At 07:41 AM 9/30/2020, Jim Miller wrote:
>
> What sort of efficiency could I expect with just base loading a 68ft
> vertical on 630m? I have 32 radials with an average length of 100ft.
>
> For a long list of reasons I can't top load this antenna at all, nor do I
> have any other antenna possibilities.
>
> I can put effort into making the loading coil as efficient as possible.
>
> Thanks!
>
> jim ab3cv
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> 73, Ed - KL7UW
>   http://www.kl7uw.com
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>
> 73, Ed - KL7UW
>   http://www.kl7uw.com
> Dubus-NA Business mail:
>   dubususa at gmail.com
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> 73, Ed - KL7UW
>   http://www.kl7uw.com
> Dubus-NA Business mail:
>   dubususa at gmail.com
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