Skip to main content

136kHz receiving noise in WSPR window at nights

Darrin KE9NS did release  P-SDR Version 2.8.0.149  supporting the MCP23017  I/O expander.
Big thanks great job!
Automatic bandpass selecting / hopping now also works for the "XVTR" bands 2200m and 630m.
The Flex1500  needs external Bandfilters for 137 / 475 kHz  i.e. below 482kHz the bandfilter section is bypassed.
2200m and 630m are added as XVTR bands and use the  BNC port XVTX/C for external bandfilters and antenna. in TX the output is about 0dBm over the XVTX/C port
The I2C flexwire is connected to MCP23017 I2C i/o expand band switching

The MCP23017  external slave address lines: A0=A1=1(Vcc) ,  A2=0
Then 474kHz /630m band    GPIO A0=low  A1=high = 3.2V
and 136kHz /2200m band  A0=hi    A1 =low
The GPIO are active high in on state so the circuit can be kept very simple.
Only output A0 is used
To switch the small relays of my dual bandfilter only an TUN o.c. is needed
GPIO A0  active high 3.2V  4k7k at the base of o.c. TUN to select band pass filter 2200m



aeProduct.getSubject()aeProduct.getSubject()
MCP23017 Ali Express 0.95€  including shipping....

DCF39  near Magdeburg  is direction East
The best signals i have on the west BeverageI
do not know why signals east of me at 137 kHz are stronger on the West Beverage.
Both West and East  have the same length about 300m checked them several times no faults found.


The picture below shows the WSPR 200Hz window as a grey bar
137.400 -- 137.600 kHz
the high peak 80dB  over noise is DCF39
Clearly there is some extra noise peak exactly within the WSPR window
i looks like one of the side bands IMD ? but that noise is only at night time
the window is clear during day when DCF39 is still about the same strength 70-80 dB / noise
I do not know the origin of this noise that reduces receiving s/n with 20dB
it sounds like fast FSK modulation


Night 
Day


never the less i can receive here
 last 2 weeks LF reception 136kHz USB dial WSPR
15 spots:
TimestampCallMHzSNRDriftGridPwrReporterRGridkmaz# Spots
 2020-01-09 07:40  K3RWR  0.137527  -29  0  FM18qi  1  PA0O  JO33hg  6279  45  1 
 2020-01-04 07:50  K3MF  0.137406  -28  0  FM19sr  1  PA0O  JO33hg  6162  46  8 
 2020-01-04 07:08  N1BUG  0.137438  -26  0  FN55mf  1  PA0O  JO33hg  5297  52  128 
 2020-01-04 19:08  UA4AAV  0.137522  -22  0  LO21  1  PA0O  JO33hg  2578  290  75 
 2020-01-14 23:34  UA3DJG  0.137572  -18  0  KO95  0.2  PA0O  JO33hg  2089  277  14 
 2020-01-08 22:30  SV8CS  0.137510  -18  0  KM07js  0.1  PA0O  JO33hg  2038  332  1 
 2020-01-06 23:32  EA5DOM  0.137532  -16  0  IM98xn  1  PA0O  JO33hg  1713  15  16 
 2020-01-04 19:12  OE3EMC  0.137441  -27  1  JN78jo  0.001  PA0O  JO33hg  772  315  74 
 2020-01-04 22:20  G8HUH  0.137450  -18  0  IO81mg  0.1  PA0O  JO33hg  688  67  24 
 2020-01-04 19:40  2E0ILY  0.137550  -2  0  IO82qv  0.5  PA0O  JO33hg  619  82  101 
 2020-01-06 05:56  F4GUK  0.137456  -27  0  JN18gt  0.2  PA0O  JO33hg  572  28  2 
 2020-01-15 22:54  LA3EQ  0.137551  -27  0  JO28xj  1  PA0O  JO33hg  571  176  1 
 2020-01-04 18:14  DL7NN  0.137440  -6  0  JO60it  1  PA0O  JO33hg  498  306  356 
 2020-01-04 18:22  G6AVK  0.137582  -22  -1  JO01ho  0.05  PA0O  JO33hg  447  63  31 
 2020-01-07 00:06  DC0DX  0.137426  -12  0  JO31lk  0.1  PA0O  JO33hg  205  354  44

Comments

Archive

Show more

Popular posts from this blog

2011-01-22 DIAMOND 2m 70cm 1m30 Colinear inside

Having relative poor signals on the local 70cm / 2m channels using this X50 Diamond collinear 70/2  1m antenna at a height of 25m. I needed to investigate what could be wrong. Measuring the cable only 3W is left for the antenna of the 10W 435MHz output from a IC451E The cable is 30m type H100 Z50 10mm outside diameter it is semi air-spaced but has an impossible 4mm² solid CU inner conductor not much air left. I preferred the H43 Z75 cable having lower loss and mechanical better ratio in conductor size. My antenna uses SO239 connector UHF type semi air spaced isolator.  3W should be enough for a comfortable noise free FM signal. But only 27km away at PA0A the signal is weak too weak something must be wrong? I made a simple reference dipole of 2x17cm CU wire. With this dipole the signals where totally worse. So the Diamond does work? I got curious to look inside. Maybe moisture penetration degraded the antenna. This  antenna is rainwater close in its n...

SPF5189z Low noise preamp 23cm

 14-4-2018 updated Above the low noise  preamp 50 - 4GHz    ebay  6€ Tested  2 small porto antennas 1 Baofeng UV antenna left   2nd best signal on PI2NOS 2 eBay DIAMONDSRH805S  wide band 144/432/1200  it works for its size as expected 3 piece of wire :   best signal in the setup... Unit under test at workbench. It was stable  50mA  at 5V   few days,  but sudden the current went up to 100mA And i could  no longer adjust it with the negative bias Voltage. The - Voltage went to zero and the SPF input port became low Z. This SPF5189z was broken  no oscillations, no input overload just it broke while i was receiving the PI2NOS 430.125 using a small antenna at the workbench. The specs of  SPF5189z  say it has an internal circuit  regulating the bias current. Replaced . again   with an other of the 5 spare SPF i have. The new one again could be adjuste...

TS790 cat interface

A CAT interface  for the old TS790 144/432/1292 tranceiver to work with N1MM  including the internal CW keyer DTR and "PTT" RTS and WSJT MSHV with "PTT" control Using the 3€ FTDI USB serial interface picture bottom page first i bought the Kenwood USB serial interface cable that cable has the TS790 special 6 pin DIN plug this interface works well ...as long as you cut the 4-5  wire bridge on the ACC din.. with the wire bridge it did go offline after 30 seconds or so  Kenwood interface cable with CH330 eBay 15€    This type Kenwood interface cable uses a tiny 6 pin USB CH330 chip  The driver is CH340 known for Arduino it workes in W7/10 64  It has only TX RX Usart function no DTR RTS available  The TS790 settings are 4800b 8bit data 2 stop  default  N1MM does not list the TS790 it has the TS890  but that one does not support modes the TS2000 does support freq and modes and let you switch 2/70/23 it seem...