Wednesday, February 15, 2012

28MHz propagation bye bye

No VK at all this morning.
The solar magnetic storm cleared all.


Yesterday morning  ZK2C  7012kHz CW  not easy 
Great expedition.
It will be difficult to get them on 80m tought I heared some weak CW this morning at 80m 3512  ???  must have been my imagination
still hangover from the marathon CW PACC run?
During PACC Sunday morning I heard FW0NAR at 40 CW very very weak on the K9AY loop working to EU possible I was to late local 10:30 already to have success.  They could not copy me ( PA switched on)




I had to  play lumberjack to improve my firewood stock.
Heavy job took all evening.


Then saw there had been some aurora. Possible i missed some signals at 70MHz.
Got some new tuning C  Arco462 and Philips Teflon types.
Tried to improve the performance  of the BLF177 Amp
Not really could improve it.
But could leave out one tuning C  without drop of performance.
The Arco462 in the top middle seems to be redundant. 
    
Now the BLF177 Drain goes over the 5 turns coil over the 1nF DC uncoupler C  in the 2 stage phi filter the input has a fixed 47p C to gnd  replacing that one by a tuning C  did also not bring anything.
The 2nd coil 6 turns 6mm 70nH got a bit warm tried to replace with thicker wire coil measuring same 70-100nH  but had to place back the original seems there is a difference in value  I lost the output tuning.


In FM  my modulation is reported as very good  using a simple CB type dynamic microphone at the Flex1500.
Monitoring my signal at the IC706 showed a echo sound  caused by the digital processing  0.5 -1 second. 
Monitoring the CW  signal makes you can not send code anymore ... the timing delay confuses your mind too much. 
But in linear mode USB it sounds a bit distorted.
Then checked the bias currents of the driver stages  a bit low for class A-B  36mA BLY87 and 150mA for the MRF238  that is driven to 2Amps have to be increased  and also switched off during receive. 
Regularly I have to reset the Power-SDR  to get the audio out of the "noise hash error"  I hope this can be solved soon. This is my main issue with the Flex1500  It is very nice to be able to switch the FM deviation between 2.5 and 5kHz.  PA1AT not so far but being very weak could be copied better in small band FM.
At 70.350MHz
Again it was way after midnight when I finally switched off the lights.







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