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 40m dipole half size g5rv 
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Post 40m dipole half size g5rv
ok folks I made up a 40m dipole with flexi weave wire and rg 58 coax this was put at 15ft apex inverted v the ends were 5ft off the ground the coax went straight to the 969 atu noise level on 80m 40m 20m etc was s7 to s8 so I removed it after two days now have a half size g5rv in the same place and hight noise level now s3, now I always thought that dipoles were supposed to be better antennas than others but this sort of proves the wrong anyone else had the same effect with a dipole, ps there were no baluns used, dave


Sat Jul 13, 2013 8:55 am
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 40m dipole half size g5rv 
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Post Re: 40m dipole half size g5rv
If you are going to do comparisons how long between the dipole results and those from the G5RV's was it same day, same hour, same time?

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Sat Jul 13, 2013 9:21 am
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 40m dipole half size g5rv 
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Hi Peter it was yesterday I changed the antennas took 20min the dipole was up for two and a half days I tried the radio thru out the days at first I thought it was band conditions as I have seen this happen years ago


Sat Jul 13, 2013 9:35 am
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 40m dipole half size g5rv 
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Post Re: 40m dipole half size g5rv
noise levels mean very little with nothing to compare them to.
maybe the noise on the dipole was higher because it was actually working?
if I put a 2foot piece of wire in my Pro3, I guarantee I will get a lower noise floor than on my Mosley 5 band yagi.
does that mean the wire is better?
of course not.

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Sat Jul 13, 2013 9:39 am
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 40m dipole half size g5rv 
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sorry but if the noise is s8 its no blooming good to anyone unless your talking to someone down the road I could not hear hardly any stations on any of the bands ones I did hear I could not hear who they were talking to


Sat Jul 13, 2013 9:48 am
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 40m dipole half size g5rv 
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Post Re: 40m dipole half size g5rv
I get a noise level of about S7 or S8 on 40m, and have managed to work Indonesia, Australia, New Zealand, the Americas and many more.
I stand by what I said, a lower noise floor doesn't necessarily indicate a more efficient antenna.

it's no good having an S3 noise level if everybody is S2 cos the antenna is pants!

beside which, it's a bit of an unfair comparison, since the G5RV was designed as a multiband antenna, and the 40m dipole is just that, adding an AMU at the end of the coax doesn't suddenly turn it into a multiband antenna.

personally, I'd have tried a choke balun at the feedpoint of the dipole, removing the run of RG58 from the equation, you'll probably find the coax is acting as part of the antenna cos you've done nothing to stop it.

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Sat Jul 13, 2013 9:59 am
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 40m dipole half size g5rv 
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Post Re: 40m dipole half size g5rv
here is a very rough drawing of my qth
Attachment:
house2.png
house2.png [ 9.09 KiB | Viewed 2525 times ]


Sat Jul 13, 2013 10:01 am
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 40m dipole half size g5rv 
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Hi the g5rv is put my receive back to normal hearing stations that are low and high without the noise, I have used dipoles at other areas I lived at with no bother but here its a no go even a long wire does the same noise


Sat Jul 13, 2013 10:07 am
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 40m dipole half size g5rv 
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Post Re: 40m dipole half size g5rv
If you didn't have a balun, the dipole's coax was acting as a third antenna wire. Did either end of that coax (antenna wire) get near to any equipment in the shack or house that might have created noise?

Steve G3TXQ


Sat Jul 13, 2013 7:38 pm
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 40m dipole half size g5rv 
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Hi Steve the coax is put thru the top of the window then into the atu same way for the g5rv and wire I have the radio atu pwr supply all on the window sill side by side


Sat Jul 13, 2013 9:17 pm
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 40m dipole half size g5rv 
Silent Key

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You can't make valid comparisons of two antennas unless you are sure you are listening to those two antennas and not their feedlines. To do that you need a 1:1 current balun at the dipole feedpoint, and you need a 1:1 current balun at the ladderline/coax transition of the G5RV.

Steve G3TXQ


Sun Jul 14, 2013 7:50 am
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 40m dipole half size g5rv 
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Post Re: 40m dipole half size g5rv
Hi Steve both of my commercial made full size and half size g5's don't have baluns fitted instructions don't say to fit one, I did have a full size g5 that did have one at the top of the ladder line a couple of years ago ,


Sun Jul 14, 2013 8:37 am
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 40m dipole half size g5rv 
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Post Re: 40m dipole half size g5rv
mi0hgn wrote:
I did have a full size g5 that did have one at the top of the ladder line a couple of years ago ,


I think you will find it was just a plastic box at the top, had it been a balun it would not have worked or have been a G5RV design

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Sun Jul 14, 2013 9:14 am
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 40m dipole half size g5rv 
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Hi Peter it was a balun as I did break the seal to see if water had got in it as the antenna went faulty it was ok it was the bottom pl259 connector water had got in and caused corrosion


Sun Jul 14, 2013 9:21 am
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 40m dipole half size g5rv 
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Post Re: 40m dipole half size g5rv
mi0hgn wrote:
Hi the g5rv is put my receive back to normal hearing stations that are low and high without the noise, I have used dipoles at other areas I lived at with no bother but here its a no go even a long wire does the same noise



I have just taken down an antenna that was very quiet, and received very well. It was a good few S points down on noise. I could hear everyone very well.

Unfortunately they could not hear me very well. It worked, but it soon became obvious that even allowing for some others using much more power, and much better antennas, the antenna was not working at all well on transmit.

This morning on the old antenna, although I has S8 noise on 40, going down to S3 on 10, I have worked stations 80-10 without problem.

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Sun Jul 14, 2013 9:24 am
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