FYI, the Sark-110 also allows selection of feedline impedance, and the ability
to display resonance and SWR and other parameters of interest.
Great user support. Check out Melchor Varela or Sark-110 on Google for
examples. You-tube demos describe ease of operation. In my opinion the most
advanced of its ilk, before leaping into two-port land.
Ed McCann
AG6CX
Sent from my iPhone
> On Jun 7, 2019, at 12:04 PM, Jim Brown <jim@audiosystemsgroup.com> wrote:
>
> SWR on a transmission line is determined by the match between the load (the
> antenna) and the line. Most SWR meters are calibrated to 50 ohms, so will
> give an incorrect reading. Among other things, this will show resonance at
> the wrong point. So to find that resonance, you want to set the meter to 75
> ohms if you're using RG11.
>
> On the other hand, power amps are designed to work into a 50 ohm load, and
> some (especially solid state amps) will reduce power to protect their
> transistors if the match is poor.
>
> I feed my high dipoles for 40 and 80M with RG11 to reduce line losses, and
> use matching networks to make the power amp happy. I use stubs for this, but
> most hams use an antenna tuner.
>
> 73, Jim K9YC
>
>>> On 6/7/2019 3:09 AM, Kostas SV1DPI wrote:
>>> read SWR referenced to 25, 50, or 75 ohms. VERY useful if you want to find
>>> the resonance of a high dipole fed with RG11. Used it five times this week
>>> to do that.
>>
>> Hello Jim
>>
>> Can you explain it better? If I use rg11 (75ohm) coax to connect the dipole,
>> do I need to switch the analyzer to 75Ohm? If I have it to 50ohm what do I
>> count?
>>
>> ...73 de Kostas SV1DPI
>> (One of SZ1A-EP6T)
>
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