coax choke question

[9deuce]

i have looked everywhere and cant find any advise on coax chokes for 11m....

i see some sites say 6 turns 8inch diameter... i was wondering if theirs less or more for the 11m band.... i am using LM400 LLPL atm and using 4 wraps for my dipole thats 20 to 25ft up....(so far so good....) the thing is tomorrow my maco v5/8 gets here and is gonna be put it up 30 to 35 ft.... so id like to get an exact number so i get the most out of it i dont want to limit the coax as i here you can do with to many turns...... but maybe thats snake oil who knows.... if you do know drop me a line


thnx all god bless have a great day

 

[M0GVZ]

All you want to know is here:

Common-mode chokes

 

[RatsoW8]

You'll find more on them if you search for "Ugly Balun" instead of coax choke. . I think I used 8 wraps of RG-8x on an empty 2 liter coke bottle for my 10 meter dipole. Electrical tape the crap out of it once it's wrapped tight on the bottle form and cut the ends off close to the coax.

http://www.hamuniverse.com/balun.html

 

[Big Dog 59]

This is how i did mine,

 

[9deuce]

thnx for the replys yes big dog i have the same thing but its at the base of my dipole so i guess i will move it up near the feed point for the maco v5


!!!!THAT LAKESIDEBOSS ON THAT BAREFOOTED MONSTER. AN I JUST GOT DOWN!!!!

 

[KC9Q]

Here's another site to look at: Broadband Baluns

Go to the bottom of the page and use the choke information for the 10 Meter band if you need one for 11 Meter's and nearby bands. There are forms given for either RG-8 (RG-213) cable or RG-58 cable.

 

[9deuce]

thnx

 

[Robb]

http://www.worldwidedx.com/cb-antennas/48415-ugly-balun.html

 

[Grogan]

I don't think they are ugly.

 

[vkrules]

aesthetically challenged.

 

[dave457]

When making one does the coax need to be flat each turn next to each other or can they be bunched up and zipped tied together?

Sent using tapatalk

 

[Hurricane145]

From the K1TTT technical reference
K1TTT Technical Reference

Conclusions
-----------
- A 1:1 coaxial balun with excellent choking reactance for 10 through
20 meters can be made by winding 6 turns of RG-213 on inexpensive 4
inch PVC sewer pipe.

- For 40 or 30 meters, use 12 turns of RG-213 on 4 inch PVC sewer
pipe.

- Don't bunch the turns together. Wind them as a single layer on a
form. Bunching the turns kills the choking effect at higher
frequencies.

- Don't use too many turns. For example, the HyGain manuals for my 10
and 15 meter yagis both recommend 12 turns 6 inches in diameter. At
the very least this is about 3 times as much coax as is needed, and
these dimensions actually give less than the desired choking impedance
on 10 and 15 meters.

This was the best article I found on the subject.
I made one for 10-20 meters with the 6 turns on 4" PVC. It was for a 5 band quad and seems to do the job well.

It really isn't an easy chore to wind RG-213 on a 4" form! I drilled holes in the form for wire ties to hold things together.

Although it is not specific to 11 meters, It is a lot of good info and may give you something to work from. They do need to be mounted as close to the antenna feedpoint as possible for best results.

 

[Beetle]

A 4" diameter pipe gives you a bend radius of ~2". This would be fine for RG58/RG8X, but not for RG213 or other 0.405" diameter coax. Bend radius should be 10x the coax diameter (4.05" - round to 4). Now remember that the diameter is 2X the radius.

For winding a coax choke using RG213, the form diameter should be at least 8". It's a lot easier to wind, also.

 

[GnG8d]

A 4" diameter pipe gives you a bend radius of ~2". This would be fine for RG58/RG8X, but not for RG213 or other 0.405" diameter coax. Bend radius should be 10x the coax diameter (4.05" - round to 4). Now remember that the diameter is 2X the radius.

For winding a coax choke using RG213, the form diameter should be at least 8". It's a lot easier to wind, also.

Times Mucrowave says their LMR400 can be bent to a 1" radius in a fixed installation such as a coaxial choke.

 

[Captain Kilowatt]

Times Mucrowave says their LMR400 can be bent to a 1" radius in a fixed installation such as a coaxial choke.

I wouldn't want to try that where the sun is beating down on it. I have to wonder if that is a simple bend like a right angle or if in fact it is for a full circle repeated several times like a choke. Isn't LMR400 solid centre?