Manx Radio oddness?

A place to discuss the HF and Shortwave listening side of the radio hobby. Discuss equipment, frequencies and antenna systems etc. Anything HF!
Post Reply
User avatar
Andy
Top Poster
Top Poster
Posts: 2113
Joined: 01 Jun 2004, 09:00
Location: Cheshire
Contact:

Manx Radio oddness?

Post by Andy »

Anyone out there in range of Manx Radio with an SDR? I wonder - could you take a look at Manx Radio on 1368? It seems to have a big lower sideband splashing right out to the next lower channel, and the waterfall display shows a strange 'sweeping' effect of stripes. I've attached a screenshot which shows it up quite well. The big signal from Asian Sound on the HF side stops me seeing if there's a matching upper sideband. I'd be surprised if there wasn't.
I can hear it also on my analogue RX and as far as I can tell it isn't a mix or overload effect.
It's been there for a few nights now, but due to the poor daytime signal I can't see it during daylight hours.
You do not have the required permissions to view the files attached to this post.
'SOMEONE GET ME A SAW!'
Andy.
grafter
Radio Addict
Radio Addict
Posts: 804
Joined: 05 Oct 2007, 06:31

Re: Manx Radio oddness?

Post by grafter »

It looks like propagation effects to me with selective fading of the sidebands. I grabbed a couple of images this morning taken a few minutes apart. The first is using a MW flag antenna hence the lack of other Euro signals, the second is with a Wellbrook loop. Anyway, you can see the difference in the sidebands on each one.
1368.jpg
I see that effect on ionospheric prop even FM via Sporadic E and F2, I made this some time ago of an OTHR on 10m, you can see the effect as well as hear how it effects the sound of the SSB signal.

https://www.youtube.com/watch?v=piunB8pTQwQ
You do not have the required permissions to view the files attached to this post.
my friend grafter, seems like you are using a very offensive tone in the reply.
User avatar
Andy
Top Poster
Top Poster
Posts: 2113
Joined: 01 Jun 2004, 09:00
Location: Cheshire
Contact:

Re: Manx Radio oddness?

Post by Andy »

Thanks for taking a look, Grafter. Yes, I did think it may be selective fading, but it looked too neat and steady to me. You're probably right.
What do you think of the extent of the sidebands? They seem to extend out to +/-8 KHz which seems a bit bold to me. Around 5 (sometimes 6) KHz is the norm. Apparently the spec is 7.5KHz @-20dB and 9KHz @-40dB. I didn't get chance to note what it was last night, and on real modulation it would only be an estimate. It sure *looks* a bit pushy. Maybe I should get out more...
'SOMEONE GET ME A SAW!'
Andy.
User avatar
Clipper
Super Member
Super Member
Posts: 190
Joined: 28 Nov 2014, 23:40
Location: Lancashire

Re: Manx Radio oddness?

Post by Clipper »

grafter
Radio Addict
Radio Addict
Posts: 804
Joined: 05 Oct 2007, 06:31

Re: Manx Radio oddness?

Post by grafter »

I think the current spec of digital audio processors have such a steep roll off at HF they can put the bandwidth to the max without splashing over. Caroline's DSPX-AM unit used on 648 is one such device and they do squeeze every last drop out of it.

Does IOM come under Ofcom jurisdiction, like who's going to tell them off if they push it a little bit too hard sometimes? FWIW nothing will beat the audio quality of Radio Caroline back in the 80s using the old 963kHz TX and Orban Optimod, some of the recordings I have (plus others online) sound very close to processed studio recordings, dread to think what the sidebands looked like on that!
my friend grafter, seems like you are using a very offensive tone in the reply.
User avatar
Andy
Top Poster
Top Poster
Posts: 2113
Joined: 01 Jun 2004, 09:00
Location: Cheshire
Contact:

Re: Manx Radio oddness?

Post by Andy »

I don't think Ofcom have any power over them, it's down to the IOM CC I think. I have let the station know they are almost completely overlapping the upper sideband of the station on the LF side of them and they have acknowledged my post. I can't see them doing anything about it though!
'SOMEONE GET ME A SAW!'
Andy.
grafter
Radio Addict
Radio Addict
Posts: 804
Joined: 05 Oct 2007, 06:31

Re: Manx Radio oddness?

Post by grafter »

Just as a point of interest and nothing really to add to the thread but Manx radio have potentially gained quite a few new anorak listeners since the BBC locals have switched off. We've lost Surrey and Manx is available on demand pretty much all the time using the flag antenna.
my friend grafter, seems like you are using a very offensive tone in the reply.
Sparkgap
Registered New User
Registered New User
Posts: 3
Joined: 07 Sep 2018, 18:10
Call Sign: G1BED

Re: Manx Radio oddness?

Post by Sparkgap »

Are they doing what Atlantic 252 did and using (I think) single sideband + carrier? Apparently it's supposed to help under poor propagation conditions.
User avatar
Andy
Top Poster
Top Poster
Posts: 2113
Joined: 01 Jun 2004, 09:00
Location: Cheshire
Contact:

Re: Manx Radio oddness?

Post by Andy »

Sparkgap wrote: 07 Sep 2018, 18:50 Are they doing what Atlantic 252 did and using (I think) single sideband + carrier? Apparently it's supposed to help under poor propagation conditions.
No, both sidebands are there and a bit better look at them shows they are equal. But overall it is definitely W-I-D-E.
'SOMEONE GET ME A SAW!'
Andy.
User avatar
Tigersaw
Radio Addict
Radio Addict
Posts: 895
Joined: 19 Oct 2013, 15:48
Call Sign: GW6RRL
Location: Llanwrtyd Wells Powys
Contact:

Re: Manx Radio oddness?

Post by Tigersaw »

Funny enough I put up a 80m loop the other day and had a browse in the MW band. I get radio devon S9 and very clear, Manx is just as strong but sounds 'wierd' with washing and mutter type effects
User avatar
LeakyFeeder
Top Poster
Top Poster
Posts: 2020
Joined: 07 Feb 2011, 23:00
Location: In the BedWreck Cafe

Re: Manx Radio oddness?

Post by LeakyFeeder »

Not long back from the IOM but only used VHF for 2m and secure DMR for bike to bike comms
User avatar
Farty
Veteran
Veteran
Posts: 3694
Joined: 20 Oct 2008, 14:40
Location: IO92ND

Re: Manx Radio oddness?

Post by Farty »

The top technical bod at the station is a keen ham. E,all him via the station and I'm sure he'd be happy to chat.
In Before The Lock Champion of Total Magnificenceness May 2016
Post Reply