GB3MCB current frequency?


Neil Smith G4DBN
 

I'm seeing a very very weak trace on 10368.97056 MHz coming from the right direction to be GB3MCB. It is a little bit wobbly, by up to 10 Hz. It disappears when I beam away or elevate, but I don't see any obvious FSK.  I seem to remember that MCB used to have a very very narrow shift, and tended to bounce a bit during the keying cycles, but it is so long since I heard it last that I might be seeing something totally different.  Just seems concidence that the signal is in the right direction, and somewhere near the right frequency.  MCB is 460 km away, so no wonder it's weak, but this doesn't feel quite right.  Can anyone confirm what frequency MCB is on right now, and whether is is using A1A or something instead of FSK?

Neil G4DBN


Andy G4JNT
 

10Hz random wobble on 10GHz over a period of tens of seconds is typical of a GPSDO
Is 'MCB GPSDO locked ?



On Thu, 4 Mar 2021 at 22:15, Neil Smith G4DBN <neil@...> wrote:

I'm seeing a very very weak trace on 10368.97056 MHz coming from the right direction to be GB3MCB. It is a little bit wobbly, by up to 10 Hz. It disappears when I beam away or elevate, but I don't see any obvious FSK.  I seem to remember that MCB used to have a very very narrow shift, and tended to bounce a bit during the keying cycles, but it is so long since I heard it last that I might be seeing something totally different.  Just seems concidence that the signal is in the right direction, and somewhere near the right frequency.  MCB is 460 km away, so no wonder it's weak, but this doesn't feel quite right.  Can anyone confirm what frequency MCB is on right now, and whether is is using A1A or something instead of FSK?

Neil G4DBN


Neil Smith G4DBN
 

I don't think it is locked, and it is miles off frequency.  This is an old trace from it in 2019 when it was hugely stronger.  The trace at present only shows up on a 262144-length FFT in Spectrum Lab and as a faint trace in WSJT-X at max contrast, hardly anything on the DUO IF trace even with contrast maxed.  My end is locked to a free-running Morion MV89A that is tweaked manually to within 10 Hz or so at 10 GHz.

The signal level feels slightly too steady, not scintillating like I'd expect with troposcatter. Also, there are no obvious doppler tracks or smears from the very few planes on the path.

I'll have another look later and see if it is still there.  This is with a 95cm dish up at 13m, waveguide relay and waveguide LNA, clear to the horizon out to 73km in that direction, so it isn't totally impossible.

Neil G4DBN

On 04/03/2021 22:23, Andy G4JNT wrote:
10Hz random wobble on 10GHz over a period of tens of seconds is typical of a GPSDO
Is 'MCB GPSDO locked ?




John Fell
 

Hi Neil,
GB3MCB is specified to use F1A keying .It does not have any digital add ons .

I do not think Brian G4NNS added any external locking to the LO , so periodic drift is probable .

I had a sniff from it in January this year , very short duration .At that time it was 10368.9685MHz - BeaconSpot lists a few other spots within 2 kHz of that area .

When I was last in GW , in Pembrokeshire 2019, it was a strong signal along the coast and its keying and short term stability  good .
In this direction (E) it has to get over the mass of Dartmoor , so I do not expect to hear it much , even though I had my West end Pine tree topped last week. .
I do not bother elevating my telescopic mast much but did in January "coz it felt right" kind of Tropogation - something that is in limited supply at the moment .
I have seen FNY more often !

With KBQ , CAM , RPE and effectively MHZ all QRT ,we could do with more Beacon sources on 10GHz .

What's occurring Chaps ?

73
John
G0API

On Thu, 4 Mar 2021 at 22:15, Neil Smith G4DBN <neil@...> wrote:

I'm seeing a very very weak trace on 10368.97056 MHz coming from the right direction to be GB3MCB. It is a little bit wobbly, by up to 10 Hz. It disappears when I beam away or elevate, but I don't see any obvious FSK.  I seem to remember that MCB used to have a very very narrow shift, and tended to bounce a bit during the keying cycles, but it is so long since I heard it last that I might be seeing something totally different.  Just seems concidence that the signal is in the right direction, and somewhere near the right frequency.  MCB is 460 km away, so no wonder it's weak, but this doesn't feel quite right.  Can anyone confirm what frequency MCB is on right now, and whether is is using A1A or something instead of FSK?

Neil G4DBN


Adrian G4UVZ
 

GB3KBQ   10368.870 MHz Now back on air after rebuild of driver...Now radiating with JT4G modulation !

Beacon Keeper G4UVZ


G8ACE
 

GB3MCB  has a rather mobile overtone crystal which is the unfortunate behavior of more recent crystal supplies and so it is likely to wander a little.  Its a 200 mile trip to attend to it which obviously has not been possible recently.  Brian says if anyone wants to source a stable and suitably aged crystal then he would fit it once travel becomes possible again.
73
John G8ACE


John Lemay
 

Thanks Adrian

 

Copied here within a couple of minutes of listening. No decodes yet because most planes only provide 5 to 10 seconds of signal !

 

John G4ZTR

JO01KW

 

From: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of Adrian G4UVZ via groups.io
Sent: 05 March 2021 14:24
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] GB3MCB current frequency?

 

GB3KBQ   10368.870 MHz Now back on air after rebuild of driver...Now radiating with JT4G modulation !

Beacon Keeper G4UVZ


Virus-free. www.avg.com


John Fell
 

Just peaked dish and GB3KBQ on a nice clear day with no rain on the map is at 40dB/noise floor in 11.7Hz RBW .Much too strong to get meaningful signal levels from the solid decodes .

73
John
G0API

On Fri, 5 Mar 2021 at 15:18, John Lemay <john@...> wrote:

Thanks Adrian

 

Copied here within a couple of minutes of listening. No decodes yet because most planes only provide 5 to 10 seconds of signal !

 

John G4ZTR

JO01KW

 

From: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of Adrian G4UVZ via groups.io
Sent: 05 March 2021 14:24
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] GB3MCB current frequency?

 

GB3KBQ   10368.870 MHz Now back on air after rebuild of driver...Now radiating with JT4G modulation !

Beacon Keeper G4UVZ


Virus-free. www.avg.com


Dave G1EHF
 

I intend to get GB3GCT installed and running once the COVID-related access restrictions are lifted from the tower.

It''ll be on 10368.935 MHz from IO91IJ51 and run PI4.

I'll announce on here when it's going.

73, Dave G1EHF