Baluns Revisited

[sideways]

Ok, have decided to use a Balun with coax upgraded to 213 on my maco V 5/8. A lot of different people have sent links etc. for Baluns. The most show a pvc form (here is where it gets ugly ) with 18' of coax in the balun , and others have just used 6-8 one foot loops of coax ( assume the 1' is the dia.of the loop). I also assume the reason for the form type is so the first and last wrap of the balun do not touch and also do not touch the mast which is grounded. does that also mean the coax should not touch the mast??? I'm trying not to split too many hairs just want to do it right the first time. This is my first attempt at a base, I have several neighbors picked out for TVI tests after the install, will start with a small (520 xl) radio and work up to the 2970, after the install to find the TVI thresh-hold if there is one. Yes my stick (corner lot no trees etc. will be out in front of God and everyone so there will be NO question as to where the tvi would be coming from so I need to nip it first, if at all possible.

[TwentyTwo-Zero]

I've had good luck in the past using the 6-8 1 foot loops installed just below the feed point (base) of the antenna. I go about 1 foot below the feed point and secure the coax to the mast with a couple plastic wire ties - leaving a little slack in it so it doesn't put undue stress (weight) on the antenna's coax connector. Then I measure down from that point another foot and loop the coax upward repeatedly to form my (6-8) loops (I use . Then I secure my loop about every 90° (4 points) with plastic wire ties, and secure the coax coming out of the bottom of the loop to the mast with a couple more plastic wire ties. Another plastic wire tie about every 2 feet secures the run of coax down the mast. When you loop the coax you want it to lay beside itself (not overlap). Securing the coax to the mast (so the coax and mast are touching) has no effect on how it works, but the looping method does. It may not be too pretty, but it's quite effective in helping to prevent common mode current (your signal traveling back down the shield of the coax and radiating). I have read about using the PVC pipe to make a balun also and I think the only reason they use it is aid in keeping the wraps of coax uniform because of the large amount of it they use. I have also noticed that depending on what band (frequencies) the balun is being constructed for seems to dictate the number of wraps. I read about the 6-8 1 foot loop design (for 27 MHz) on Signal Engineering's web site several years ago, and like I said I have had good results with it.