[TenTec] Ten Tec 238 coupler and 160 meters

Carl Moreschi n4py3 at earthlink.net
Sat Nov 9 17:14:15 EST 2013


That's a new one on me.  How could loss be less with high SWR on a short 
length of coax?  It makes no sense.

Carl Moreschi N4PY
58 Hogwood Rd
Louisburg, NC 27549
www.n4py.com

On 11/9/2013 5:07 PM, Steve Hunt wrote:
> Interestingly, when using *short* lengths of coax the loss can be lower
> at high SWR than when it's matched. For example, 10ft of RG213 has a
> matched loss at 1.9MHz of 0.03dB; but terminated with 500 Ohms
> (SWR=10:1) the loss is only 0.012dB - less than half. For a 2500 Ohm
> load (SWR=50:1) the loss is 0.046 - only 50% above the matched case.
>
> It's only true for high impedance loads and short lengths, where only a
> small portion of the standing wave pattern exists; but they could be the
> conditions in this case.
>
> Steve G3TXQ
>
>
>
> On 09/11/2013 21:10, Carl Moreschi wrote:
>> How much coax did you add? The main idea of open wire line is it is
>> much less lossy than coax at high SWR's. You therefore want to keep
>> the coax portion is short as practical. The SWR on the feedline could
>> be 100 to 1 or even higher.
>>
>> Carl Moreschi N4PY
>> 58 Hogwood Rd
>> Louisburg, NC 27549
>> www.n4py.com
>>
>
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