[CQ-Contest] [Bulk] Re: [TowerTalk] Reverse Fed Towers

[Peter Voelpel]

I do qro and have no problem at all.
All coax at the tower is bond with its screen to the tower near the antenna,
half way down and where it leaves the tower, from there it runs underground
to the entrance panel in the cellar where everything is connected to the
main ground system.
All cables are Cellflex or RG218. VDRs are across control cabling.
Nothing else in the shack, no filters no tuner and I can do SO2R without
band pass filters on the high bands with 100W.
Not on the low bands, there the phase noise is too high.

The 160m dipole is hung from the same tower as well and was not detuned when
the vertical feed was connected, not even one kHz.

73
Peter





 

-----Original Message-----
From: Grant Saviers [mailto:grants2 at pacbell.net] 
Sent: Dienstag, 15. Dezember 2015 22:26
To: Peter Voelpel; wosborne44 at gmail.com; towertalk at contesting.com
Subject: Re: [Bulk] Re: [TowerTalk] Reverse Fed Towers

Curious as to how one manages all the rf induced into yagis, rotators, 
coax, control cables, etc when an antenna loaded tower is QRO excited.

Also, how the same cables are decoupled from the tower at whatever 
levels are appropriate and what is done at the shack end if anything.

Grant KZ1W

On 12/15/2015 12:55 PM, Peter Voelpel wrote:
> I use a system like that.
> My tower is loaded with some yagis and 46m high at the top.
> I feed it at the 25m level against a single sloping radial.
> The inner conductor is connected to the radial, the shield to the tower.
> The connection point was simulated with EZNEC before and was right at less
> then 1m difference.
> The antenna works perfectly well for me, SWR2 band width is about 200kHz
and
> fine tuning can be done at the radial.
> It is also very good on receive, picks up much less noise then the
> previously used ground fed T-vertical.
> >From distances beyond 1000km it is already better then the 30m high
> inverted-vee.
>
> For cq160 I usually add an inverted-L reflector for directivity to VE/W.
>
> If you are interest I will email the EZNEC file.
>
> 73
> Peter
>
>
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of
> wosborne44 at gmail.com
> Sent: Dienstag, 15. Dezember 2015 18:46
> To: towertalk at contesting.com
> Subject: [TowerTalk] Reverse Fed Towers
>
> I have a tower that has a base that is in concrete and grounded.  I
> would like to make it a vertical without installing insulators.   Has
> anyone used elevated radials with reverse feeding, i.e., connecting the
> center conductor to the radials and the shield to the grounded tower?  I
> see this in the ARRL handbook but I cannot seem to make a model of it
> work.  Any help would be welcome.
>
> Thanks,
>
> William Osborne--K5ZQ
>
> 270-205-9565
>
> Wosborne44 at gmail.com
>
>
>
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