[Elecraft] Balun Questions

[Bob McGraw K4TAX]

I'm one of the other Bob's or Robert's........

Since the assembly of coax wound around a toroid doughnut style bobbin 
is typically not exposed to vibration, such as might exist in an 
airplane, boat or space vehicle, the use of a solid conductor coax such 
as RG-303 would not seem to be of concern.  The more important point and 
my experience and as related by others, the use of coax which has foam 
dielectric in a tight radius bend has been proven or shown to be 
problematic.    As to if the manufactures bending radius dimension is 
being violated, I find to be of little concern.

After all, as a rule, hams are noted for pushing things to the limit and 
then some and getting buy with it.  If hams choose to "stick to the 
rules 100% in all aspects of their stations"............I'd say 75% of 
the stuff we use and methods employed would put most of the station 
stuff in the trash.

73
Bob, K4TAX





On 2/9/2016 8:45 AM, Guy Olinger K2AV wrote:
> Hi Bob, et al,
>
> Thank you all for your careful attention.
>
> I read it wrong, as several have pointed out overnight. I transposed that
> to a percentage in my memory after reading it. One of the reasons for
> referring people to the original material in these cases. Someone will get
> it right.
>
> That makes it two and a half hairs :>)  Doesn't appear to change the
> argument. To me anyway the method is still a crude measurement instead of
> watching a wide frequency scan while bending the cable along with other
> performance specific measurements.
>
> I still would not use the solid center conductor versions (RG142/303) on a
> winding.
>
> 73, Guy K2AV
>
> On Tuesday, February 9, 2016, Robert Nobis <n7rjn at nobis.net> wrote:
>
>> Hi Guy,
>>
>> I am not sure how you arrived at the “2/1000 of an inch” figure from the
>> ANSI spec? The spec actually says “A change in ovality from a given
>> sample’s initial measured value of 0.010 inches or more (> 0.010)
>> represents the point of non-acceptable bending performance.”
>>
>>
>> 73,
>>
>>
>> Bob Nobis - N7RJN
>> n7rjn at nobis.net <javascript:_e(%7B%7D,'cvml','n7rjn at nobis.net');>
>>
>>
>> On Feb 8, 2016, at 18:01, Guy Olinger K2AV <k2av.guy at gmail.com
>> <javascript:_e(%7B%7D,'cvml','k2av.guy at gmail.com');>> wrote:
>>
>>
>> I also suggest that everyone carefully study the ANSI standard until it is
>> clear what they are doing mechanically and see what they are actually
>> measuring:
>>
>> http://www.scte.org/documents/pdf/standards/ANSI_SCTE%2039%202007.pdf
>>
>> The method of measuring is in section 4. They are looking for a limit of
>> 1% surface deformity when bending.
>>
>> In the case of RG400 with .195 inch OD, that would be 2/1000 of an inch
>> (yes, that's three zeros, two one thousandths of an inch) bending deformity
>> at the surface of the teflon jacket, or half the thickness of an average
>> human hair.
>>
>>
>>
>>
>>
>>