[TowerTalk] [Bulk] Re: G5RV vs 40M dipole

[Bry Carling]

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 at 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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