185 KHz K3SIW G4WGT 1618 m OPERA 3811 miles 7 Feb 2018 @ 23:57:14 #opera
2018-02-07 23:57:13 K3SIW AA G4WGT IO83QO 0 136  -45 Op32__~45dB
For some reason, LF reception at my qth has yet to match MF, however ..
After a exchange of emails with Gary G4WGT , [who has a excellent history of VLF and LF reception] ,
around the possibility of detecting K3SIW on the USA lowFER band , K3SIW sending on 185185 Hz
using a multi mode beacon, one of the modes being Opera OP32 , normally deployed on 136 KHz.
Opera reporting 185 as 136 to the data base and the psk-map
Gary set up watch on 185185 with his home-made up-converter and IC706 , LF to 4 MHz , after 7 nights , the assumed
impossible occured, Opera made a single detection of K3SIW signal on 185185 at -45 dB s/n
So the problem now being , as the spot was from the correlation detector , was it real of false , not wishing
to rush things , over the following days , we made a series of checks ,
Where there any false detections during the 7 days previously , NO
No detections are showing for G4wgt on the 2200 band , before or since
Was there a parallel detection or decode at the same time slot - YES
Nk9M , made a full decode at + 6 dB s/n, Time stamp is added by
RX- PC and is inside system expected variation
23:58 136 K3SIW de NK9M Op32 +6 dB F:4% in Oswego, IL. 1499.7 Hz
23:57 136 K3SIW de G4WGT Op32 Deep Search -45 dB in Chorley, NW England 1500.7 Hz
Was G4WGT station frequency correct . YES
Testing with BBC radio 4 on 198 KHz , produced 1500 +/- fractional Hz audio tone.
Was path possible , YES , experience with op32 on 136 KHz has shown , that detections are possible
2 or 3 hours before each end of the path is in darkness , in this case , the time matches , darkness
tx and rx.
As to what amount of signal reached G4WGT cannot be quantified, as the correlation detector , treats the total TX time as
a single ''bit'' , but a minimum of 40% of the Tx at a average of -45 dB is required .
Good result all round , stations wanting to monitor K3SIW can download Opera from the web site listed ,
Set RIG control to VOX , [ not cat]
Set Frequency to 136 KHz , set's op32
Set RX usb to 185185 - 1500 Hz = 183.685 KHz
web linked PC is needed to update the deep search list , of the call may be added
by editing the opera.ini file for stand alone
Opera download link
Opera on line data base [2200 meter]
Day night showing same time ................................................................................................psk-map some time later ,