Thursday, January 6, 2011

My first 137kHz HAM signal received. & the night at .510kHz for WE2XGR test


My first ever 137kHz  HAM signal  G8IMR  -23dB    on the IC706 USB + preamp.  I listened  only 15 minutes on 137 it became too late already again  glad that it worked  i saw 3 traces of G8IMR    it decoded 2 times. The tracking screen was relative clean although the DCF39 was still s9 in the USB filter  of the IC706. There where some weak thin lines drifting  and clearly distinctable the frequency stable and exact timed  trace of G8IMR.


Last night I finished my preamp http://ea4eoz.ure.es/lfpream.html   
thanks Miguel  A. Vallejo, EA4EOZ


Although  it is a simple thing it took me 2 evenings  to build and get it working.
Needs a small  modification for use with a 50 Ohm signal source  like my K9AY antenna.  It did not work  with the high impedance C 33p  input antenna connection not even the DCF39 signal could come trough!
 
I connect the K9AY coax  at the low impedance (13uH)  2 pin coil of the first band MF transformer that is not connected in the original.
I use a metal can CA3140 from the junk box  this is also a J-Fet hi input impedance  op-amp like the TL081.


The DCF39 data signal at 138.8kHz became 9+60  at the IC706   Using my receive only port modification done years ago for a 50MHz preamp.  http://www.ke3ht.org/ic706-rx-port.html


Now the preamp is protected against unwanted RF from the IC706 whenever the TX /PTT is switched in by mistake.


Before going to sleep I tuned USB 0.510000 kHz WSPR  for the rest of the night and switched of band hopping to have 100% receive time for : 
WE2XGR/6   WE2XGR/2  and WE2XGR/3
 Id did not know what signal to expect. Last week was poor  only 4 decodes /night for WD2SXH/17  at 501090 (Dial USB 499.600)
But real SUPER SIGNALS !!
WE2XGR/6  200+ decodes  continuous strong trace over the screen  with no interruption  to -1dB
Best signal ever from USA   audio strong would be a 559 or more i guess that would be  simple CW  or even SSB level to copy.
Last decode was 07:50  in broad daylight  -27dB


also   WE2XGR/2  copied  48 times   -9dB
and    WE2XGR/3              72 times  -16dB


No comments:

Translate