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 antenna 
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Post antenna
hi everyone thought id ask a couple of questions
1 I have the cushcraft r6000 that im going to put up on a 10 to 15 foot pole at bottom of garden was thinking of guying it so was wondering if I can use para cord if so would 3mm cord be fine to use or a bit thicker cord also what sort of guy ring would I use and where to get them and how far up the antenna to put it

2 I took my cobweb antenna down to repair the 20metre element as it got ripped in a tree branch earlier in the year during high wind and when I opened the balun box up it was full of condensation and all the choc box screws have rust on them so must have been causing a short due to the water ingress so now I have to repair it the one I have doesn't have the torroid ring fitted its a piece of coax as the balun and and twin speaker wire it worked 100% when I used it with good dx before it got ripped and the water in it
was thinking I can repair it or someone can put me in the right direction to buy a new balun box with a torroid ring and elements attached just to put back on my cobweb frame or is the repair a better option as i use an ft2000d 200watt version as i notice some cobwebs you can only use 100 watts
any advice appreciated


Fri Oct 21, 2016 12:46 pm
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 antenna 
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Post Re: antenna
http://www.hamgoodies.co.uk/cobwebb-balun-box


Just what you want. :good:

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Its not the class of licence the amateur holds thats important but the class of bias the prat applies to his amplifier


Fri Oct 21, 2016 9:21 pm
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 antenna 
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Post Re: antenna
The boxes are cheap from Screwfix, then just replace the choc blocks! :good:

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Fri Oct 21, 2016 9:55 pm
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 antenna 
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Post Re: antenna
You can't fit the toroid balun unless you rework the elements ,you might as well just stick with what you have.
I used to run mine with 400w without issue so i'm sure you will be fine with 200w once you rebuild the box ,don't forget to put a couple of drain holes in your box or it might just fill back up with water.

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Sat Oct 22, 2016 11:57 am
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 antenna 
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just thought id give you all an update on the cobweb situation on the corrosion issue it was quite bad so decided to build a new balun box for the twin speaker wire that was on the cobweb so got everything there just to build it when I come home from work I got a bigger box and im going to use heavier guage electrical wire as the wire that was originally used wasn't all that good
heres a couple of pics for you to have a look at just in case anyone else has the same issues just a thought


Attachments:
new box waiting to be built.jpg
new box waiting to be built.jpg [ 139.78 KiB | Viewed 1210 times ]
corrosion on coax balun 1.jpg
corrosion on coax balun 1.jpg [ 108.55 KiB | Viewed 1210 times ]
corrosion in box 1.jpg
corrosion in box 1.jpg [ 130.42 KiB | Viewed 1210 times ]
Mon Oct 24, 2016 8:24 pm
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 antenna 
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Post Re: antenna
Hi Pat,
I recently had to do the same, as the inside of the box was a rusty mess. I re-used the original box which in hindsight was probably a mistake. The new chock-block connectors weren't the same spacing so I had to drill some new holes in the box. Taking the advice of several Gurus I ditched the messy coiled-up coax that is supposed to act as a BALUN, and made an external ugly BALUN from RG58 coiled round a plastic pop bottle former. I later replaced this with a choke made from ferrite beads with two passes of the feeder through the column of ferrites.
Next time It's down for maintenance I plan to replace the chock-block connectors with a PCB, and the wire elements soldered to the board which will eliminate the corrosion problem.


Tue Oct 25, 2016 10:31 am
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 antenna 
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just thought id give an update on progress got the new box just about finished I used new 30amp choc blocks from screwfix packs of 10 for a tenner and not your nasty cheap ones that was inside my original balun box
the new cable I used for inside to connect the choc blocks up was the heavier electrical cables that they use in the mains sockets in your home as its a better cable
only thing I haven't done yet is make a new coax balun as I cant remember what length of coax to use inside the box maybe someone can tell me hi
and also was wondering if I could get away with placing a choc block and the rear of box and just connect the screen and center core to these 2 bits of choc block instead of soldering the 2 wires together as the way is was originally done would it work the same way
and the other end soldered to the so239 chassis plug for the coax feed
I will put pics of the finished box up once its completed


Mon Oct 31, 2016 9:32 pm
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 antenna 
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what length of coax should I use for the coax balun and best to use rg58 or rg8 if I could get rg213 in the bloody box id use that hi
and would I get away with attaching another choc block with just the 2 inlets and outlets on the back of box inside without soldering the wires and jumpers together would it work better just a wee thought


Thu Nov 03, 2016 8:20 pm
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 antenna 
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I would use a 1:1 current balun wound on a ferrite or 2 far better than a scramble wound effort that will give questionable results.

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Neill
Its not the class of licence the amateur holds thats important but the class of bias the prat applies to his amplifier


Thu Nov 03, 2016 9:26 pm
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 antenna 
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Hi everyone just finishing off rebuilding the new box coming along fine just the coax balun to do and was wondering would using rg8 work as good as rg58 as i have used rg58 on some antennas in the past and i have noticed when ive checked them that the centre core of the coax is black for some reason it might be cheap coax and thats why it goes black
So was thinking rg8 would be a better option as i have got plenty of that anyone have any thoughts


Sun Dec 04, 2016 12:13 pm
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 antenna 
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Pat, You seem to be ignoring the advice given from several people to ditch the scramble-wound choke/BALUN thingy in the original box. If you look on-line at the several sites about DIY Cobwebs you will find they all recommend either an ugly BALUN outside of the box, or a 1:1 current BALUN wound on a couple ferrite rings. I would strongly recommend the latter.
You have done a great job with the antenna so far, so why spoil it by using a useless BALUN design?


Tue Dec 06, 2016 6:13 pm
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