[TowerTalk] Six meter balun

[Jim W7RY]

On 7/2/2022 10:56 PM, Grant Saviers wrote:
> A minor matter, but RG142 center conductor is SCCS - silver plated 
> copper coated steel.  That makes it very strong but fatigue prone.  
> Some are concerned about TFE creep from the solid conductor and 
> recommend stranded RG400 as a result.  However, I've not had problems 
> in FT-240 toroid chokes wound 10 years ago with 142 made from Mil 
> 17/60-RG142 spec cable.
>
> Paternack specs their 142 at 2400w average power at 100MHz.  It will 
> get hot, but the TFE handles it.  Best to provide easy dissipation of 
> the heat as K9YC recommends.
>
> Another possible issue is to keep ferrite toroids away from the boom 
> and other conductors as the coupling can cause problems.



_*How far away? *__*
*_

_*73, Jim W7RY*_


>
>
> Grant KZ1W
>
>
> On 7/2/2022 16:13, Jim W7RY wrote:
>> Agreed.
>>
>> RG-400 works well to. The only difference between RG-142 and RG-400, 
>> is that RG-400 has a stranded center conductor. RG-142 has a silver 
>> plated solid hard drawn copper center conductor.
>>
>> 73, Jim W7RY
>>
>>
>> On 7/2/2022 6:09 PM, john at kk9a.com wrote:
>>> The 50MHz power average rating for RG142 is several kilowatts, why 
>>> do you
>>> think it is inadequate?*If it is a balun problem it is most likely 
>>> connection related.*
>>>
>>> John KK9A
>>>
>>>
>>>
>>> Dave Sublette k4to wrote:
>>>
>>> My six element 6M LFA is showing a high SWR and severe loss of receive
>>> signal.  This happened this afternoon as I was working the band with 
>>> 500
>>> watts from my KPA500.
>>>
>>> To this point, the antenna was very nicely matched with a 1:1 SWR over
>>> almost 1 MHz of bandwidth. The antenna is home brew and I made the 
>>> matching
>>> balun per the instructions from K9YC using two toroids with six 
>>> turns each
>>> of high quality teflon insulated, double shielded silver braid. I 
>>> think it
>>> was RG142 purchased new from a reputable vendor in Tennessee. It has 
>>> worked
>>> perfectly at the 100 watt level for three or four years.  I had 
>>> looked at
>>> the specs on the coax and thought it would be good for 500 watts.
>>> Evidently not.
>>>
>>>
>>> 73,
>>>
>>> Dave, K4TO
>>>
>>> _______________________________________________
>>>
>>>
>>>
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