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General Category => General Radio Discussion => Topic started by: Tim Bucknall on August 24, 2018, 1506 UTC

Title: expanded FM band in Americas
Post by: Tim Bucknall on August 24, 2018, 1506 UTC
Hi all,
Have any more stations in Brazil or the entire Americas moved to the 76-88 range or is the 84.7 station still the only one?
Title: Re: expanded FM band in Americas
Post by: R4002 on August 24, 2018, 1749 UTC
Which countries have adopted the 76-88 MHz expanded band for FM?  I wasn't aware that any country had actually implemented the expanded band with the removal of mid-band VHF TV stations.
Title: Re: expanded FM band in Americas
Post by: Tim Bucknall on August 24, 2018, 2042 UTC
I only know about Brazil
They  licensed radio Pan Jovem on 84.7 as a trial but I haven't heard any follow up as to whether the trial was considered a success.

The idea was that AM stations would transfer to the expanded band
Title: Re: expanded FM band in Americas
Post by: Capt. Kidd on August 25, 2018, 0018 UTC
I remember reading somewhere that the FCC thought about extending the Fm band after analog tv was shut off but there wasn’t enough public interest.
Title: Re: expanded FM band in Americas
Post by: Tim Bucknall on August 25, 2018, 1045 UTC
Thanks Capt.
shame
speaking as a UK  dxer,  reception of US A5 at good levels was not ultra rare, often with audio (81.75) and colour, but that last few mhz to the US FM band  seems to just be a bridge to far here in Northern England. (my full FM band above 88.0  doesn't help either)
My best ever from my home patch was canadian audio on 87.75 on 24th June 2004, strictly a one time thing sadly
 
so if the US had started using  76-83 mhz for FM we could have looked forward to  a couple of good TA fm openings each season

i'm all for insane optimism but Brazil is just too far to contemplate

Title: Re: expanded FM band in Americas
Post by: BoomboxDX on August 25, 2018, 1346 UTC
Tim in the UK,
Do you ever get any of the OIRT 66-74 Mhz stations from the former Communist bloc countries of Eastern Europe?
Title: Re: expanded FM band in Americas
Post by: Tim Bucknall on August 29, 2018, 1754 UTC
Yes, but this summer was unusually poor to the East
It was so suspiciously quiet I wonder if Belarus has closed down on this band.
I hope not.

Ukraine  came in a couple of times this year but  last year was much better.

If I can find it would anyone be interested in an I/Q file of the Eastern FM band?
Modulation Is mostly lower than on 88-108 and some txs have unique stereo system

To make matters worse a new UK Comms net has started on 66-68!


Title: Re: expanded FM band in Americas
Post by: Tim Bucknall on August 29, 2018, 1835 UTC
here's an I/Q file of 71.66-74.0 mhz recorded on an ELAD FDM S2 during the excellent 2017 dx season
https://mega.nz/#!VktjCawS!caCppF1Y6pRFJnLFitz1km0xr7Vje4MMoJ4J5bI4iNY

i don't know if theres any ids, i could upload more if anyone had webspace  i have a file at midnight Moscow time  you can hear the national anthems

do you want me to tell you whats here or do you want a surprise? :-)
there was intense auroral E's at the time so its all northern stuff


here is southerly conditions from this years disappointing season but at least theres lots of talking

https://mega.nz/#!41kgyYZQ!U4SMekYWZ3dldvF9Y0n66a3CtVGGdrn4aSMWHvmDQXg
Title: Re: expanded FM band in Americas
Post by: R4002 on August 29, 2018, 2211 UTC
Yes, but this summer was unusually poor to the East
It was so suspiciously quiet I wonder if Belarus has closed down on this band.
I hope not.

Ukraine  came in a couple of times this year but  last year was much better.

If I can find it would anyone be interested in an I/Q file of the Eastern FM band?
Modulation Is mostly lower than on 88-108 and some txs have unique stereo system

To make matters worse a new UK Comms net has started on 66-68!

What do you mean a new UK Comms net on 66-68?  I was under the impression that the 66-88 MHz "mid band" was used as a land mobile band in Europe, similar to how 25-50 MHz is used in the Americas.  In other words, its used, but not nearly as much as it was 20-30 years ago, as businesses have moved to higher frequencies and/or digital trunking systems and cellular networks. 
Title: Re: expanded FM band in Americas
Post by: BoomboxDX on August 30, 2018, 0439 UTC
here's an I/Q file of 71.66-74.0 mhz recorded on an ELAD FDM S2 during the excellent 2017 dx season
https://mega.nz/#!VktjCawS!caCppF1Y6pRFJnLFitz1km0xr7Vje4MMoJ4J5bI4iNY

i don't know if theres any ids, i could upload more if anyone had webspace  i have a file at midnight Moscow time  you can hear the national anthems

do you want me to tell you whats here or do you want a surprise? :-)
there was intense auroral E's at the time so its all northern stuff


here is southerly conditions from this years disappointing season but at least theres lots of talking

https://mega.nz/#!41kgyYZQ!U4SMekYWZ3dldvF9Y0n66a3CtVGGdrn4aSMWHvmDQXg

What is an I/Q file? I see it is zipped. But is it mp4 or something that plays on media players? Or is it merely for SDRs.
Title: Re: expanded FM band in Americas
Post by: OgreVorbis on August 30, 2018, 0442 UTC
I remember reading somewhere that the FCC thought about extending the Fm band after analog tv was shut off but there wasn’t enough public interest.

I've heard people say multiple times that since analog TV is gone, then those frequencies should be free. Maybe I'm misunderstanding, but I always thought that the digital stations used the same frequencies for broadcasting that the old analog stations used. Am I correct? If not, then what frequencies are they using?
Title: Re: expanded FM band in Americas
Post by: Tim Bucknall on August 30, 2018, 0734 UTC
the file is only for sdrs, apologies

here's some  info on our new 66mhz plague in the UK https://en.wikipedia.org/wiki/Ambitalk
as all the other analogue bands go dead this is sprouting like a weed


good question re: VHF  mid band digital tv,  i have no idea of the current situation in North America
Title: Re: expanded FM band in Americas
Post by: R4002 on August 30, 2018, 1705 UTC
So its next-generation MPT1327 trunking effectively?  Makes sense.  At least the frequency spectrum is being used.  I presume 30-50 MHz in your part of the world is military/government only? 

66-88 MHz gives good propagation I would imagine.  The 30-50 MHz "low band" (the US definition of low band anyway) is dead in some areas but heavily used in others.  Some states (California comes to mind) have their primary Highway Patrol radio system operating in the 39 MHz - 46 MHz region.  Low band gives better range and covers rural/backcountry areas quite well.  Others use VHF low band as a backup and inter-agency interoperability network to supplement their primary VHF high band (150-162 MHz) system (i.e. Virginia State Police) or use VHF low band to supplement/back up their 700/800 MHz system (i.e. Massachusetts State Police).

In some parts of the USA, VHF low band is extremely heavily used.  While it may not be the latest cutting edge digital trunking system, some times it doesn't need to be.  Sometimes with radio communications networks, the more simple it is, the better it is. 
Title: Re: expanded FM band in Americas
Post by: Tim Bucknall on August 31, 2018, 1000 UTC
yes pretty much exclusively military so it seems dead unless you live next to a base
there are Studio Transmitter links on 48mhz,  Hospital Pagers on 49mhz and possibly still on 31.775- i can't check from here

qrn is getting worse, VHF low band now has a noise floor as bad as HF