Re: LF: RE: Todmorden receiver

[DK7FC <selberdenken@posteo.de>]

Am 23.12.2017 15:45, schrieb Paul Nicholson:
> About to run E rx amplitude cal, I'll try to get
> that done before Stefan's EbNaut starts at 15:30.
Fine fine Paul! Now how does my spectrum peak look on your new RX? :-)

I found a few hours to come back here to correct the antenna current.
For all frequencies between 17470...2970 Hz i'm using the same ferrite 
transformer. But the coils have different (DC) resistances and i'm 
running different antenna currents. So i need different taps on the 
secondary winding.
On 8270 Hz i connect to '70%'.
17470 Hz was just at '50%'
Due to heavy stress last evening (i had to buy a christmas tree, and in 
25 minutes the store closed!) i unintentionally connected the coil to 
the 70% tap. Thus the antenna current didn't rise above 260 mA.
Now i connected to the usually used 85% tap, and got the expected 300 mA 
antenna current.
The interruption was just for 30 seconds, so i think it is now worth to 
mention the exact times.
260 mA to 300 mA is +1.24 dB. I didn't want to miss that during the 
EbNaut transmission that has already started now. With some luck and low 
QRN, Alex may decode the message after just 2 nights? He said he will go 
to the garden on monday, so this will be exciting :-)

Now back to 970 Hz coil winding...!

73, Stefan