Yes there is no way a monster fan dipole would work here. Small lot. I did try
one and it was too obtrusive as well as high SWR on every band contradicting
all theory. First I have heard of using any "choke bead" for a G5RV. If it's
getting hot then it's wasting a lot of your RF power.
Best regards - Brian Carling
AF4K Crystals Co.
117 Sterling Pine St.
Sanford, FL 32773
Tel: +USA 321-262-5471
> On Apr 26, 2015, at 12:22 PM, Grant Saviers <grants2@pacbell.net> wrote:
>
> My G5RV at QRO stopped working when the purchased bead choke at the
> coax/ladderline junction got so hot it melted the coax. They need several
> thousand ohms of choke impedance, usually not found in most of the off the
> shelf bead chokes.
>
> OTOH two 80/40/20 fan dipoles (at right angles) I modeled and built worked
> super at 65' high. They worked on 15m with a tuner (<2.5:1 swr) and perhaps
> on 10m if the coax is cut for a match or there is enough loss. I separated
> the ends by 24" using 3/8 sq pvc rod which makes for mechanical complexity
> and difficulty winding it up (I use 10" diameter concrete column forms).
> Eznec models are reasonably accurate if you follow the recommendations on
> modeling by Cebik, #108-111 at http://www.antennex.com/w4rnl/
>
> re VE7RF's conjecture that the center of every dipole may not need to be
> connected: Since I had a working EZNEC model, I disconnected the
> transmission line connections to the 40 and 20m dipoles and fed only the 80m.
> There is coupling but very poor swr; 4:1 on 40m, 10:1 on 20m, 8:1 on 15m, so
> it's not a good idea.
>
> Grant KZ1W
>
>> On 4/26/2015 1:26 AM, Steve Hunt wrote:
>> The 51ft "G5RV" performs well on 40m, 20m and 10m - bands where the SWR(50)
>> at the ladderline/coax junction is moderate. On other bands the SWR(50) is
>> high, and how well it performs will depend on the length and quality of your
>> coax run.
>>
>> On 40m you will notice little difference compared to a half-wave dipole; on
>> 20m it has a small amount of broadside gain over a half-wave dipole; and on
>> 10m the azimuth pattern has broken into 6 major lobes, with best performance
>> at 45 degrees to the direction of the wire
>>
>> Using a good CM choke at the coax/ladderline junction is important - it will
>> reduce radiation from the ladderline section and noise pick up on the coax
>> run.
>>
>> Steve G3TXQ
>>
>>
>>> On 25/04/2015 21:11, Dick NY1E wrote:
>>> I'm operating from a small lot in Florida winters, I have a 40M dipole up
>>> but it doesn't quite fit my opening, it is into the branches 5 or 6 feet. I
>>> wonder what the 51' G5RV would perform like compared to the dipole on 40,
>>> and as a bonus I might get some other bands... Any ideas???de Dick
>>> NY1E/4www.ny1e.com
>>> _______________________________________________
>>>
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