[OFARC] 1:1 unun question?

[sc flowers]

Hey Dom,
Good evening.  In my understanding of this, the unun is an unbalanced to unbalanced transformer which uses an inductor and as such, together with stray capacitance, will act as a filter of specific frequency ranges.  

So it is possible that the suppressed QRM frequencies that you mentioned , populated a particular frequency range and that range was “cutoff" by the unun.  In other words, it’s entirely possible that the filtering action inherent in the unun was indeed cutting off your QRM.

It would be interesting to delve into this idea, and quantify it, by using a spectrum analyzer such as the TinySA Spectrum Analyzer <https://www.amazon.com/Upgraded-Karagas-0-1MHZ-350MHZ-240MHZ-960MHZ-Frequency/dp/B08C8RNX17/ref=asc_df_B08C8RNX17?tag=bngsmtphsnus-20&linkCode=df0&hvadid=80127030278136&hvnetw=s&hvqmt=e&hvbmt=be&hvdev=c&hvlocint=&hvlocphy=&hvtargid=pla-4583726556022657&psc=1>.  One could then use it for an "A/B test" with and without the 1:1 unun. 

Just my 2 cents.

Regards & 73,
Stephen (W2WF)


 

> On Dec 1, 2022, at 8:22 PM, Dominic Mazoch <domemt at juno.com> wrote:
> 
> I just put a 1:1 unun in my coax.  Seems it cuts out some QRM.  Is there something I am not hearing?
> 
> 
> Dominic Mazoch
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