[TowerTalk] Fwd: RG-59

[Dave Sublette]

Is it possible that there is an antenna for a local AM broadcast station
near you?  If so, that might be upsetting the analyzer that you are using.
In that case, I use my rig and an SWR bridge and test the SWR with a few
watts.

Good luck.  I think Hans has a very good point also .  The quality and
material used in some coax can be a problem,.

73,

Dave, K4TO

On Sat, Aug 11, 2018 at 8:45 AM Hans Hammarquist via TowerTalk <
towertalk at contesting.com> wrote:

>
>  Hi Jeff,
>
>
> Something is definitely wrong. You should have no problem using the RG59
> for your dipole.
>
>
>
> It is not the easiest thing to get a good contact with the shield on the
> RG59 as the braid sometimes is made of steel or stainless steel. The "real"
> shield is the aluminum wrap under the braid.
>
>
> If nothing else use F-connector to make sure you have a good contact with
> the cable and then go from there. I am sure that will help.
>
>
> Just my penny thought,
>
>
> 73 de,
>
>
> Hans - N2JFS
>
>
>
>
>
> -----Original Message-----
> From: felix1063 <felix1063 at comcast.net>
> To: 'Grant Saviers' <grants2 at pacbell.net>; towertalk <
> towertalk at contesting.com>
> Sent: Sat, Aug 11, 2018 12:07 am
> Subject: Re: [TowerTalk] RG-59
>
> I should have mentioned that the shield on the RG59 is shorted with the
> center conductor at both ends.  My results with the dipole element cut for
> 80 meters is that the dipole is un-tunable with an antenna analyzer.  In
> fact, the antenna does not tune to anything from 1.8mhz to 14.5mhz.  At the
> cut frequency, the impedance is 50 ohms, but the SWR is greater than 10:1.
>  I have used RG58 with good results.  I used RG59 because it's diameter is
> larger than RG58 and should produce a larger bandwidth.
>
> What am I doing wrong?
>
> --jeff WB7AHT
>
> -----Original Message-----
> From: Grant Saviers <grants2 at pacbell.net>
> Sent: Friday, August 10, 2018 9:35 AM
> To: felix1063 at comcast.net; towertalk at contesting.com
> Subject: Re: [TowerTalk] RG-59
>
> Yes, assuming you mean using the shield as the conductor.  The larger the
> diameter, the greater the bandwidth, thus RG59 shield helps a bit.
> The formulas for diameter vs bw are in most handbooks.  The RG59
> insulation reduces the velocity factor and thus the antenna will be
> electrically longer by a few percent than the usual dipole formulas
> calculate.  NEC based modeling software can model the effects of thin
> insulation like on RG59.
>
> Otherwise, it is a dipole and a choke is a good idea.
>
> Grant KZ1W
>
>
> On 8/9/2018 16:14 PM, felix1063 at comcast.net wrote:
> > Has anybody ever used RG-59 as the radiating elements in a dipole?  If
> > so, what were the results?  Was it easy to tune? Did the bandwidth of
> > the dipole change appreciably from using a piece of stranded wire?  Was
> a balun used?
> >
> >
> >
> > Thanks,
> >
> >
> >
> > --jeff
> >
> > Wb7aht
> >
> > _______________________________________________
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