[OKDXA] Feed Line Problems NOW BALUN RECOMMENDATIONS

Sat Apr 27 10:19:51 EDT 2013

Thanks, those seem to be the most available and inexpensive baluns that are 
offered commercially.

73 John AF5CC

----- Original Message ----- 
From: "Kim Elmore" <cw_de_n5op at sbcglobal.net>
To: "Oklahoma - DX news and information" <okdxa at mailman.qth.net>
Sent: Saturday, April 27, 2013 1:52 PM
Subject: Re: [OKDXA] Feed Line Problems NOW BALUN RECOMMENDATIONS

> Hi John,
>
> Sorry for the delayed replay! The W2DU type of balun (lots of ferrite 
> beads over the coax) is probably the easiest to get or make. If you decide 
> to roll your own, get a coupe le of 2.4" #43 ferrite toroid cores, stack 
> them together and wind as many turns of hefty parallel magnet wire (16 ga) 
> in a single layer. Put this in an enclosure, seal it up, attach an SO-239 
> on either end, and have at it.
>
> Or, go buy about 20 or so ferrite beads (77 is best, 43 will do) that will 
> fit over the end of the coax (they make sizes that work with either 
> RG-8, -8X or -58. Cut off the old connector, string them on, figure out 
> how to keep them in place (silicon rubber will do if you find some big 
> heat shrink to put over it), reattach the connector and you're done.
>
> 73,
>
> Kim N5OP
>
>
> On 4/21/2013 9:04 PM, John G. wrote:
>> Hi Kim,
>>
>> You get to a question that I was getting ready to ask.  My only need for 
>> a balun is to try to keep the RF off of the coax shield. Originally I 
>> have a 4:1 voltage balun thinking I needed it for impedance transforming, 
>> but that was before I knew as much about antennas as I do today.  What is 
>> the best type of balun for this-the one with the ferrite beads over a run 
>> of coax, or the one with the wires running thru a torrid donut shaped 
>> device?
>>
>> 73 John AF5CC
>> ----- Original Message ----- From: "Kim Elmore" 
>> <cw_de_n5op at sbcglobal.net>
>> To: "Oklahoma - DX news and information" <okdxa at mailman.qth.net>
>> Sent: Sunday, April 21, 2013 3:46 PM
>> Subject: Re: [OKDXA] Feed Line Problems NOW BALUN RECOMMENDATIONS
>>
>>
>>> Do you need an impedance transformer as well as a balun? If all you need 
>>> is a balun for coax, a 1:1 current balun (balances current rather than 
>>> voltage) is probably what you want.  If you need an impedance 
>>> transformation, you may want to use something purpose built for that.
>>>
>>> Array Solutions is a good bet: their stuff is pricey, but high quality. 
>>> They have baluns for various transformation ratios: 1:1, 1.5:1, 2:1, 
>>> 4:1, 6:1, 9:1, 12:1 and 16:1. They also carry an Unun in 1.5:1 and 4:1. 
>>> DX Engineering is a another good source.
>>>
>>>
>>>
>>> Or, you can roll your own; they aren't hard to make. For 1:1 current 
>>> baluns, a long string of ferrite beads on some coax, all sealed up, is 
>>> always a good bet, though these can become inefficient under conditions 
>>> of a large mismatch. In the end, since (ideally) you spend your time 
>>> instead of your money, it's a matter of what you have the most to spare. 
>>> Sometimes you spend just as much money PLUS your time, but there's still 
>>> the knowledge gained, which you might not have gotten otherwise. If you 
>>> roll your own and need an impedance transformer, I'd suggest a dedicated 
>>> Sevick-type transmission-line transformer followed by a 1:1 current 
>>> balun.
>>>
>>> 73,
>>>
>>> Kim N5OP
>>>
>>> On 4/21/2013 9:29 AM, John G. wrote:
>>>> Thanks for the advice Roger.  Do you know what type of balun it was? 
>>>> Also, since I am going to be getting a new current balun, any 
>>>> recommendations as to brand? One that is built to last?  I am only 
>>>> going to be running 100 watts
>>>>
>>>> 73 John AF5CC
>>>> ----- Original Message ----- From: "Roger Simpson" <rksimpson1 at cox.net>
>>>> To: <okdxa at mailman.qth.net>
>>>> Sent: Sunday, April 21, 2013 1:38 PM
>>>> Subject: [OKDXA] Feed Line Problems
>>>>
>>>>
>>>>> I agree that the problem is likely a bad connection, bad coax,  and/or 
>>>>> relay contacts that have corrosion/dirt.
>>>>>
>>>>> The problem I had once with a balun was not actually the balun itself. 
>>>>> It turned out to be the the wires from the balun were soldered to an 
>>>>> SO-239 and the wire from the balun to the outside of the SO-239 was 
>>>>> connected to a solder lug that was screwed down to the SO-239. In my 
>>>>> case I took the balun out of the old case and built a new case for it 
>>>>> out of some 2 inch PVC pipe with a couple of PVC pipe caps. Then I 
>>>>> used a new SO-239 and soldered the wires from the balun to the new 
>>>>> SO-239. This fixed my problem.
>>>>>
>>>>> The balun I am describing I originally bought back in the early 1980s. 
>>>>> It was up for about ten years before it started giving me problems. I 
>>>>> am still using the balun today on my 30m / 40m Inverted “V”. So the 
>>>>> problem was not with the balun itself, but with a flaky connection. 
>>>>> These flaky connections can definitely act differently on different 
>>>>> bands. In some cases a flaky connection can look like a leaky diode on 
>>>>> certain bands.
>>>>>
>>>>> These cases are so difficult to trace that I think it is easier to 
>>>>> just replace stuff until the antenna works again. Also, these problems 
>>>>> can be so flaky that they are intermittent. So you might think 
>>>>> something is OK after checking and that have it to go back again later 
>>>>> to its broken state.
>>>>>
>>>>> The way I isolated that the balun was the problem was that I replaced 
>>>>> it. Once I knew that the problem was the balun I tore it apart to 
>>>>> discover the corroded connection to the SO-239.
>>>>>
>>>>> 73  Roger   K5RKS
>>>>>
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