[TenTec] Ten Tec 238 coupler and 160 meters

[Carl Moreschi]

If you use coax for an 80 meter dipole and run it on 40 meters with 
coax, the loss will be very high.  That's because the additional loss 
from a high SWR (around 100 to 1 in this case) is huge.

If you run open wire line on an 80 meter dipole and use it on 40 meters, 
the additional loss is not that bad.  That's why we use open wire line 
on a single band dipole to use it on more than one band.

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

On 11/9/2013 6:49 PM, Ken Brown wrote:
>
>> 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.
>>
> The loss in coax at HF frequencies is not that high, and the additional
> loss due to high SWR is also not that high. (At least compared to what
> happens at VHF) For HF systems keeping SWR low on coax is still a good
> idea, but it is more to reduce the possibility of HV arc over than to
> minimize the loss. (A matter of opinion no doubt, but if you work out
> the numbers you may have the same opinion) If the added line is short
> and makes it easier for the tuner to match, the additional loss in the
> coax is likely to be less than the reduced loss in the tuner when it
> sees an easier to match impedance.
>
> DE N6KB
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