Saturday, December 8, 2012

How low can you go

Have been busy to improve  receiving 137kHz  2200m.

I got DCF39  now 70dB s/n sometimes 75 dB  that's as strong as our MW Broadcast stations
1008 and 747kHz
Replaced the preamp IC by an LH005 op-amp tested some others
we have some real expensive low bias FET op-Amps at QRL  like the LH005 AD549 I could test
replacing the CA3041  some difference found in gain and IMD.
the OPA124p gave to much IMD possible to much gain
The best performer was the LH005  having not to much gain in the used ciquit.

Found the K9AY is not good enough  for this bandThe inverted-L gives best s/n
trying to decode  WE2XGR at 137.700  last night
had the best receiving results until now.

TimestampCallMHzSNRDriftGridPwrReporterRGridkmaz
 2012-12-07 06:16  GV7FTX  0.137688  -26  0  QG75  0.1  PA0O  JO33hg  15870  329 
 2012-12-07 00:40  G8HUH  0.137617  -24  0  IO81mg  0.05  PA0O  JO33hg  688  67 
 2012-12-07 01:28  DF6NM  0.137580  -8  0  JN59nj  0.5  PA0O  JO33hg  532  326 
 2012-12-07 20:22  G1SLE  0.137543  -22  0  IO93if  0.02  PA0O  JO33hg  526  86 
 2012-12-06 23:30  DK7FC  0.137620  0  0  JN49ik  1  PA0O  JO33hg  450  342 
 2012-12-06 22:28  PA0A  0.137500  +9  0  JO33de  0.5  PA0O  JO33hg  24  67 

GV7FTX is a ghost decode that can happen sometimes with interference  
first time received G8HUH  many decodes
and DK7FC  several +4dB decodes
but no WE2XGR seen yet
There are 3 strong 137kHz signals Worldwide
DK7FC  PA0A  and  WE2XGR
Dk7FC  was decoded in USA last night!
It  is not a band for QRP  and small antenna's

ZL9HR  no more QSO's   tried RTTY 30M  even there was police and deliberate QRM
80m never heard  anything else but tuners and QRI
Should have been easy 30m cw  but when in the shack they are somewhere else
or just stopped 30 and qsy to some band that is not open for us
Propagation was not favourite this week
Only tonight  again WSPR 80m  VK7DIK was back in



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