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

[Wayne Kline]

 I had no problems  with any induced RF voltage on the feed lines or the control lines.  the lines on the tower were inside if that made any difference , and where they exited the tower . the two coax lines and on rotor line  draped to the ground the went vertical to a 12 X 16  Bud box that was mounted to two steel  tubes.
There was a ground buss on the transition 7/8"  50 ohm hard  . the control lines went through a few turns on a ferrite  donut and then to a screw  buss.  There were three 
ground rod   bod together and to the tower and the junction box.   This tower is 500 ft from the house  all coax and control lines are buried.
 
   I was running a small MM and   ran 160 and 40 at the same time. The only problem ever was the 160 guy could hear a motor HUM/BUZZ  when the 40 meter operator turned the rotor !   But how often is that and he should be using the BEVERIDGES !!!
 
 
Wayne  W3EA 

 
> From: dj7ww at t-online.de
> To: grants2 at pacbell.net
> Date: Tue, 15 Dec 2015 23:04:04 +0100
> Subject: Re: [CQ-Contest] [Bulk] Re: [TowerTalk] Reverse Fed Towers
> CC: cq-contest at contesting.com
> 
> 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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> >
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> >
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