[hpsdr] Possible added feature request

[Scott Traurig]

MFJ made it work...



On Tue, Nov 3, 2020, 14:01 Helmut Oeller <oeller at freenet.de> wrote:

>
> Both ideas/approaches are unworldly. While the implementation of a VNA
> software is no big deal, a hardware reflection bridge has to be inserted
> and in particular calibrated.
>
> But even when you get a reasonable result of R and jX  at your radio
> input, it's not enough information for an automatic tuner: the tuner's
> position in the feedline and the length of the feedline determines the
> necessary transformation. It would be much easier to utilize the SWR, e.g.
> available at a bidirectional coupler, used for the PS feedback loop.
>
> 73, Helmut, DC6NY
>
>
> Am 03.11.2020 um 17:55 schrieb Scott Traurig:
>
>
> There was work in this regard done a long time ago but it is hopelessly
> stale and it also requires additional hardware:
>
> https://openhpsdr.org/wiki/index.php?title=VNA
>
> It would undoubtedly be easier to adapt a NanoVNA. Not only is the
> hardware ready to go, the software is simpler and a lot more accessible. It
> would be easy to embed in a home brew tuner:
>
> https://openhpsdr.org/wiki/index.php?title=VNA
>
> Finally, it's worth noting that the only tuner on the market that
> actually makes a complex impedance measurement and jumps right to the exact
> answer in one step is the MFJ-939. If MFJ made a legal limit version of
> that tuner I'd buy it in a heartbeat.
>
> 73,
>
> Scott/w-u-2-o
>
>
> On Tue, Nov 3, 2020 at 11:32 AM <radio at netins.net> wrote:
>
>>
>> Pure signal uses one RX channel to provide feedback.
>>
>> Is it possible to use an RX channel to determine just the phase and
>> resistance of the RF signal in the antenna system feed point?  If so,
>> this could be used to automate a home brew antenna coupler.
>>
>> John,  W0GN
>>
>
>
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