Weather Sat Images thread..

[smoggy07]

Has anything moved or closed local to you that would have VHF comms? It could be that something was wiping the pagers out (something close to the pager site?) so you haven't noticed them until now

The main problems with pager bleed over is they're so wideband and all high powered +/- 25W so building a realistic filter is not really going to help if you're close to the site, especially if the site is using directional antenna rather than omni directional and you live in its path.

If it is pagers you'll hear something like these
512 Baud http://www.kb9ukd.com/digital/pocsag5.wav
1200 Baud http://www.kb9ukd.com/digital/pocsag12.wav
2400 Baud http://www.kb9ukd.com/digital/pocsag24.wav
Credit for the samples goes to Digital Modes Samples

Install this, plumb your VAC into it and let it run on the freq that's causing problems PDW Paging Decoder

It should start to decode messages for the Fire service, Ambulance service, Doctors, Solicitors and more

The one thing I can suggest, and it might sound daft, is raising the height of the antenna, back in the old CB days I'd notice, when I had the antenna on a 20 foot pole, I'd crack out quite far but still get good local comms, as you would expect, but, when I picked up a cheap telescopic 40 foot mast, I'd lose local comms over DX, even when propagation was low and there was no skip about
If you can do it safely and securely, before you give up hope on it, see if you can add even just 5 foot of pole to the bottom of the antenna

 

[Vipersan]

Has anything moved or closed local to you that would have VHF comms? It could be that something was wiping the pagers out (something close to the pager site?) so you haven't noticed them until now

The main problems with pager bleed over is they're so wideband and all high powered +/- 25W so building a realistic filter is not really going to help if you're close to the site, especially if the site is using directional antenna rather than omni directional and you live in its path.

If it is pagers you'll hear something like these
512 Baud http://www.kb9ukd.com/digital/pocsag5.wav
1200 Baud http://www.kb9ukd.com/digital/pocsag12.wav
2400 Baud http://www.kb9ukd.com/digital/pocsag24.wav
Credit for the samples goes to Digital Modes Samples

Install this, plumb your VAC into it and let it run on the freq that's causing problems PDW Paging Decoder

It should start to decode messages for the Fire service, Ambulance service, Doctors, Solicitors and more

The one thing I can suggest, and it might sound daft, is raising the height of the antenna, back in the old CB days I'd notice, when I had the antenna on a 20 foot pole, I'd crack out quite far but still get good local comms, as you would expect, but, when I picked up a cheap telescopic 40 foot mast, I'd lose local comms over DX, even when propagation was low and there was no skip about
If you can do it safely and securely, before you give up hope on it, see if you can add even just 5 foot of pole to the bottom of the antenna

I seem to remember trying this software ..unsuccessfully..before ...
I think the problem was a driver issue that was non compatible in win7 .
Has anyone had PDW running on anything other than XP ?
rgds

 

[smoggy07]

I seem to remember trying this software ..unsuccessfully..before ...
I think the problem was a driver issue that was non compatible in win7 .
Has anyone had PDW running on anything other than XP ?
rgds

I've had it running on windows 7, I'm almost certain of it? It works on Win10, I've just installed it but can't find my jack to jack aux lead to fire it up

Set it up as below
Found in options:

Found in interface (where my soundcard is disabled as there's no aux plugged in, choose your VAC):

Select the correct mode as shown:


That's how I ran it last, ignore the S-Meter in the top right corner, it does move when it hears pager data but it's not accurate.

You'll need to mess with the input volume on each pager freq to get a good decode as the quality differs by freq.

[EDIT] I'm not sure why it's showing both desktops on the print screen

 

[Vipersan]

I've had it running on windows 7, I'm almost certain of it? It works on Win10, I've just installed it but can't find my jack to jack aux lead to fire it up

Set it up as below
Found in options:
View attachment 95216
Found in interface (where my soundcard is disabled as there's no aux plugged in, choose your VAC):
View attachment 95217
Select the correct mode as shown:
View attachment 95218

That's how I ran it last, ignore the S-Meter in the top right corner, it does move when it hears pager data but it's not accurate.

You'll need to mess with the input volume on each pager freq to get a good decode as the quality differs by freq.

[EDIT] I'm not sure why it's showing both desktops on the print screen

Cheers Smoggy ..
A project for the weekend methinks..
;)

 

[Analoguesat]

[EDIT] I'm not sure why it's showing both desktops on the print screen

Print screen always does that if you have multiple monitors - ou need to import it into a graphics programme & crop it if you just want to show one.

 

[Archive-8]

I seem to remember trying this software ..unsuccessfully..before ...
I think the problem was a driver issue that was non compatible in win7 .
Has anyone had PDW running on anything other than XP ?
rgds

I have used pdw under Windows 8.1 ok.

 

[smoggy07]

Print screen always does that if you have multiple monitors - ou need to import it into a graphics programme & crop it if you just want to show one.

Ah..... I know what went wrong now, I used CTRL+Print Screen instead of ALT+Print Screen, when printing screen at work they want the full display not just the active window so it's become a habit using CTRL (I didn't know it snapped both displays but thinking logically it wouldn't know what display to snap)

 

[Vipersan]

Well fwiw I tried PDW ..

I have PDW unpacked and in a diectory in the root of C
32 bit win7 OS
Sadly nothing displayed ..
The meter ..thing...doesnt even indicate the presence of ..well...anything really ..it just sits there ..
I have to assume I have the audio ported correctly via VAC 1 ....and since there is no actual start button on PDW and nothing actually installs ...I have to assume it is active from the moment I run up the .exe
So ..
Either I fooked up somewhere ..or this 'digital' data is unrecognised by PDW ..
Doh!

 

[Vipersan]

Got a positive test by going to sigidwiki.com and playing a Flex sample ...outputting audio to VAC ...and yes it PDW does indeed decode the sample ..
I can only therefore conclude that this is a newish data system nor recognised by PDW ..maybe not even a pager afterall ?

Had a thought ...
Smartmeters ?
Not that I have one ..but neighbours might ?
Does anyone know what frequency(s) they operate on ?

 

[Lazarus]

Interesting question.

According to this they use two comms modes, one to interact with the user's Home Network and another for the WAN.

Sadly, it doesn't say whether the WAN is a 5GHz one like I use or whether it uses Mobile Phone frequencies.

 

[Vipersan]

Thanks for that G ..
Unlikely then that this is the cause of my frustration ..
cheers

 

[smoggy07]

I've just had a smart meter fitted, it uses a SIM Card for the WAN and something like zigbee for the HAN (local connection between the electric meter and gas meter and the connection from the elec meter to the in home display), I think it creates a hidden short range 5Ghz wifi network, I'll have to rig up netstumbler or something to have a looksee

Pagers are like DVB or DAB, all or nothing with glitches here and there, you might need to mess with the volume on the VAC

Is the noise bleeding over like flex but in short bursts? If it is, check out http://www.kb9ukd.com/digital/mpt_1327.wav MPT1327 trunked, I'll bet a pound to a penny it is, the nation grid still use shared control channels in the 137Mhz range, one station broadcasts it's network ID, followed by the next station in line, and so on.

You need yet another software, trunkview, this can follow the control channels broadcasts and show their network IDs and on the remote chance that it receives a goto voice channel instruction, it should route the SDR to the voice channel so you can monitor whats said.
- TrunkView :: MPT1327 Protocol decoder -

You'll be able to ID the remote sites but won't hear a lot of voice at all, maybe one voice call per night at daft o'clock in the morning

You'll find a few trunked nets on VHF between 160Mhz and 170Mhz between the taxi data (I have a decoder for that too) and you'll find the odd one on UHF between 440 and 460Mhz

If you use this for working out the base frequency/logical band plans, it'll know what channel numbers are on what freq, then it should (if it can control your SDR) jump to the voice channel, going back to the control channel after decoding the cleardown message - TrunkView :: MPT1327 Protocol decoder -

[EDIT] See here UK Radio Scanning Forum • View topic - National Grid/power line work frequencies?

 

[Vipersan]

Well I tried it buddy ...
Nothing registered with Trunkview ..
I guess I _could_ be using the wrong method ..
I have my SDR set to WFM ?
I also listened to the sample above ..and mine is lower frequency I think ...so doesn't sound the same ..
??
Still not sure what this is but ...
I'll try and grab a longer full sample in Wav form ...and you can try for yourself to see if you have any success interpreting it ?
cheers Smoggy
VS

SDRSharp_20160718_221559Z_137704kHz_AF.wav

 

[smoggy07]

100% Pager
Pocsag 1200
http://www.kb9ukd.com/digital/pocsag12.wav

Having the SDR set to WFM won't help with the bleed over, can you receive the WeFax TX on NFM? I always try and use NFM to minimise bleedover, most weather satellites will stick to internationally recognised channel spacing i.e. 6.25Khz or 12.5Khz or a few still using 25Khz

Tune to 137.975 Mhz with one SDR and pipe the sound to PDW, if you can, listen to or record the other freq that's getting the bleedover, when it kicks in, check out PDW (as the bleedover starts the decoder will decode the messages).

That's the closest freq I could see to your freq but there might be others within a few Khz:
137.975 WIDE AREA PAGING POCSAG 1200 NATIONWIDE FM
Others are
138.075 WIDE AREA PAGING POCSAG 1200 NATIONWIDE FM
138.15 WIDE AREA PAGING POCSAG 1200 NATIONWIDE FM
138.175 WIDE AREA PAGING POCSAG 512/1200 NATIONWIDE FM

 

[Vipersan]

First job ..
I'll make a list of the centre frequencies of the offending data channels around 137mhz ..
They I assume all have the same source..

So ...made a short list of this crap and these are not all of them ..
The bursts do not neccessarily occur simulaneously ..but no give the impression of being chained somehow ..
If for example 3 are within waterfall viewing range at the same time ..
call them A B & C ..
C can activate followed shortly after by B ...then A ..
I guess this would be Trunking ? of some sort ?

So here are a short list of centre fequencies ..
Approx centres that is ..
137.975
137.923
137.850
137.752
137.700
137.627
137.531

and those nasty data bursts extend higher and lower than the frequency list ..
So ...no escape in this region of the spectrum.
I've given up hope of ever using this bit of spectrum in the future ...but still want to find out who is ruining it ?
rgds
VS

looking at your POCSAG list of frequencies Smoggy ..
we both list 137.975
???

 

[Vipersan]

Reduced the FM bandwidth...And finally ...A Hit ...
PDW decoded this short message ..
I think 137.975
Looking like this is possibly emergency medical ?
And I guess important ..

But why oh why is Cornwalls data appearing in Manchester ???

will redact the phone number and repost

And this is why I can no longer use this bit of spectrum ..
Constant emergency data from right accross the UK ...and is constantly appearing about every quarter meg ..
I give up..

 

[Vipersan]

...and in 20 mins ..
I have Kent ...Weymouth ....Bodmin ...Plymouth...the list goes on ...and on ...and on ...and on .....
doh!

 

[Captain Jack]

How does the Met office filter these out? Surely, they would be just as affected?

 

[Vipersan]

How does the Met office filter these out? Surely, they would be just as affected?

The Met office probably no longer use polar orbiting sats ...
All operations now moved to Geostationary sats I guess ..
The data is available to the public ...at a price....
but the cost of building a system plus access costs can run to many hundreds if not thousands..
cest la vie..

..A bit like 4G and terrestrial TV ..
Spectrum re-use ....is on the increase in this overconnected world.
doh!

 

[Captain Jack]

So who uses polar sats if noone else? Are these just left there to die?