Re: LF: TXing 2200m WSPR

[Chris Wilson <dead.fets@gmail.com>]

Hello Andy,

Is  there  any point in Paul putting his dummy load on the end of his
75  odd meters of feeder co-ax outside? And then on the secondary of
his  matching  transformer when tapped one to one? In case the co-ax is
iffy or the impedance matching transfomer's doing something odd?


Sunday, December 24, 2017, 10:42:16 PM, you wrote:

> Well ...    Using exactly the values in the filter circuit diagram,
> 50R transforms through the filter to 48.5 - j2.86 (Ret Loss = 30dB, 
> VSWR = 1.07)   [Using GM3SEK's original Netcalc prog.]


> So that's pretty conclusive the ideal filter values will not be
> upsetting things at the fundamental frequency.    
> According to Google, the  T106-2 has a stated Al value of  13.5nH
> /turn^2  so 72 turns does indeed give 70uH.   So IF your core is correct, the 
> filter should be OK.


> It's a bit difficult from now on, at a distance, to try to work out what is 
> happening.
> Anyone else, any suggestions ?


> BTW ...


> Peak to peak of a { symetrical }square wave needs to be multiplied
> by 4/pi to get the peak-to-peak of the fundamental component.   So
> the amploitude you see will be lower by about 1.3 times for teh same 
> fundamental power component. 


> Andy  G4JNT





-- 
Best regards,
 Chris                            mailto:dead.fets@gmail.com