I wonder what ACMA plans with 56-70MHz?

[VK5GR]

Has anyone heard anything about what ACMA plans to do with the old Band I analogue TV spectrum?

It doesnt strike me as being overly useful for land mobile due to Sporadic E and large reuse distances (I dont think the remaining 70MHz band is all that well populated anyway). Cellular/trunking systems couldnt use it effectively because you cant pattern shape antenna footprints effectively at those frequencies to allow cellular reuse at anything like the density of the UHF bands. If land mobile doesnt want it, is it just going to lie fallow?

The segments in question are: 45-50MHz (part of Channel 0) (suspect wind radars might use that), 56-70MHz (Channel 1 and 2) and 85-87.5MHz (the bottom of Channel 3 - the rest of which was in the FM band). Thats 21.5MHz of prime Low-Band VHF spectrum potentially just lying fallow.

Band II Channel 5A is curious as well, although much more useable for land mobile services (which I think have in some areas already been allocated there).

Just curious if anyone has heard of any comms service having designs on it or has anyone any information on the density of useage of the existng 70MHz band in their local areas? Also has the ACMA made any statement on what they see the band being used for now that broadcasting has shunned it?

Regards,
Grant VK5GR

[VK4TS]

I wonder how long this post degenerates into a spat attack on everyone who asks any questions..

Seriously ? There are several suitors for the old 6M band and don't believe for one minute that this spectrum space won't have Commercial interests all over it

[VK5GR]

Trent,

OK - but you said there are people interested. If that is the case, who might they be?

Considering for example across all of Victoria according to ACMA there are only 189 assignments total in the 70-85MHz segment which totals (if each assignment is a unique channel) barely 15% of spectrum used already, who are the remaining interests wanting the other 21.5MHz of now freed up spectrum?

I have heard the rural wireless broadband lobby bleat in the past, but one single base even if it ran LTE could only deliver 75Mbit/s (since MIMO would likely be hard to achieve with the size antennas involved potentially - pesimistic - it would partially work just not very efficiently) - thats enough to serve 6 simultaneous users under the NBN wireless speeds model - or if you are lucky 60 total customers over an area probably 150km across or over 500 sqkm. That is very sparse and a very expensive way to deliver it. So I discount them as a serious usergroup.

Hence, back to my question - who seriously would actually want it? Should perhaps hams lobby for it to run DVB-T ATV on (in place of all of the UHF spectrum we have lost? We dont need the reuse and probably dont care so much about sporadic E causing "interference"). Just one crazy use suggestion!

So yes I am looking for a serious discussion and am seeking an understanding of what is happening in that part of the radio spectrum today. Can you contribute more than your throwaway line?

Grant

[VK2ZRH]

Grant,

There's a clue in the letter from Maureen Cahill, General Manager, Communications Infrastructure Division, ACMA, to the WIA concerning 50-52 MHz, dated 13 December 2013. Paragraphs four and five are of interest:

With regard to the broader issues about channel 0 spectrum, the ACMA recognises the opportunities that the closure of analog television services represents. These opportunities include all VHF channels between 45 and 144 MHz (channels 0 - 5 and 5A). Accordingly, I intend to discuss how best t progress a review of this VHF spectrum with the Department of Communications.

Any review, will of course include discussions and consultations with interested parties, including the WIA.

Wind profiler radars already operate just below 50 MHz, but new ones have not been deployed here for many years.

It is likely that the vacated VHF TV channels will be the subject of a consultation process, probably to be concluded before the next revision of the Australian Radio Frequency Spectrum Plan.

You will find the mentioned letter here: http://www.wia.org.au/newsevents/news/2 ... /index.php

[VK2AAH]

There is enormous potential for the interested parties to negotiate an outcome. Just looking at the existing assignments between 70 and 74MHz in NSW there are many legacy wideband PMR services that would have to be elderly now. Many of those are government services which rightly belong up in the 400MHz government spectrum. ACMA would be within their rights to give notice that these need to be narrow-banded and move up to UHF. That could see a reduced mid-band land mobile band for private organisations in rural areas (outside of the high density areas) of about 76.0-82.0MHz. There are some opportunities for the WIA to negotiate some new spectrum and of course some risks that there could be some losses in the medium to longer term.

Cheers

Richard
VK2AAH

[VK4GHZ]

Has anyone heard anything about what ACMA plans to do with the old Band I analogue TV spectrum?

Grant, a good question!

I found it interesting to look back through the ACMA's "Five-year Spectrum Outlook 2009-1013" document, released in March 2009, as we are rapidly approaching the end of this document's time frame.
To save you searching for it, I have attached this document below.
It is interesting to see what was proposed, and what has transpired since.

(Being a protected document, it doesn't allow cut & pastes, and I'm not about to manually retype huge chunks of it.)

It's a bit vague (surprise, surprise! ) , but refer to "ACMA's proposed approaches" - television section, page 43.

Page 138 is also interesting.
45 - 70 MHz
"... Defence has indicated some interest in expanding its existing usage of the band, the amateur radio community is interested in upgrading its 50-52 MHz allocation to primary status, and the band may also be suitable for the operation of some other fixed or mobile applications. There is also potential to use a portion of these bands for digital radio broadcasting using the foreshadowed, but not yet available, DRM+ technology."

This document points out, ad nausea, that the development of any policies for the future use of vacated spectrum rests with the Minister (currently the Hon. Malcolm Turnbull), and not the ACMA.

"...In that context, ACMA will gather information on the spectrum demands of potential alternative uses and will monitor the status of DRM+ development (and it's relevance to wider government digital radio policy)."

five_year_spectrum_outlook_2009-2013.pdf

(1.54 MiB) Downloaded 1357 times

[VK5GR]

Thanks Adam and Roger for your replies in particular as well as to others who replied constructively.

So my conclusions from reading all the references people gave are:

1) Defense will most likely want (and get) a portion.
2) Digital Audio Broadcasting in one of it's incantations appears to be a consideration for ACMA for the Band I spectrum as well (despite the fact they are wedded to DAB at 1.5GHz as the secondary band to VHF Band-III - seriously? Broadcasting at 1.5GHz? I think ACMA needs some reality checks there!)
3) It would seem more than likely that amateurs will formally be granted all of 6m 50-54MHz back as primary
4) Commercial Land Mobile users dont appear interested in the band (they barely use what they have already above 70MHz)
5) Wireless Boradband for the bush proponents probably think they are interested but perhaps need a reality check?

So, then, an interesting set of questions for the amateur community:

a) do we see uses for any sizeable chunk of the band ourselves? From a propagation standpoint, there probably isnt enough to learn that's different between 50MHz and 70MHz for a narrowband only segment?
b) Amateur use of wideband modes at low frequencies (i.e. DVB-T type transmissions for example) might yield some interesting observations perhaps?
c) Would the amateur service in Australia even use it if they gained access to it? (I actually suspect probably not in enough numbers to justify it).

What are your thoughts? Do we want/need to encourage the amateur representative bodies to lobby for more than just 4MHz of the 6m band to be returned?

Regards,
Grant VK5GR

[VK4EA]

IMHO a 4m allocation in VK would be awesome, I've seen first hand how good 4m works in G-land. And of course making it the same allocation as EU would be very sensible.

[VK5PJ]

Hello Grant,
welcome back from the wilderness Some time ago there were rumblings from CSIRO on using the CH0 TV space for the delivery of digital content to rural areas via a system they had under development that was going to work in tandem with the National Broadband Network, this was to be for people on the land to provide "the last mile" from more central nodes. I have not seen an update on this for a few years now so I would imagine it has been overtaken by other technologies.

I had read a proposal from the DRM (Digital Radio Mondiale) groups looking to get a chunk of low band TV so they could start up in competition to traditional FM broadcasters but like the CSIRO scheme, it may have been overtaken by the current digital radio systems.

As others have said, this is prime spectrum if you have the right use for it. Given the lack of any truly current information it would seem there is either a lack of interest or perhaps some serious behind closed door negotiations are happening, so time will tell if any of this speculation is any where near the mark or just out dated dribble on my part.

Regards,
Peter, vk5pj
(ex vk8zlx)

[VK2GFR]

After reading some of the comments...
Remote interfacing/linking of amateur repeaters?
How about a similar service like in New Zealand (they have their "National System" on UHF), where a city/state/national communications linked network is available 24/7 to anyone to use.
Obviously (like in NZ) it is frowned upon to "hog" the network for long overs & so on, but still the physical & technological boundaries could be expanded to cover such a network in the low band segment.
And with so many low band emergency services being moved from the 70-85Mhz allocation, to the newer 400Mhz allocation (Govt Radio Network in NSW, PMR in digital) where they appear to be interconnected by a few "common" liason frequencies.
Also the equipment is already there!!! (unless already sent to the scrapyard)
ATV on DVB-T is an interesting point, imagine the possibilities... VK2 to VK6, VK7 to VK4 with no more than 20-50w? (and good conditions)
As with any thoughts we amateurs may put forward, you need to be reminded that the "bean counters" will try & find any way to make something proifitable (no matter how stupid/non-technically viable the offer)!!
If the small allocation 70-74Mhz was available tomorrow, I'd be there with bells on.

[VK4UH]

I think lobbying by the WIA for access on a secondary basis to a small segment at 70MHz would be a tremendous asset for the community.

More and more countries around the world have provided such access to 4m.

I used this band in the UK for many years and still have my home brew transverters.

Bring on more new ideas like this please!

Lets hope the Institute will pick up on this - in fact I think I will write to them to formalize this suggestion and suggest more could do the same

Kevin VK4UH
Brisbane

[VK2ZRH]

I hear you, Kevin (and others).

Indeed, in anticipation of the interest you (and others) have evinced, I have already done some "homework" regarding 70 MHz allocations around the world, and 70 MHz propagation, applications and usage of the band in other countries, etc.

Disclosure: I am a member of the WIA Spectrum Strategy Committee and a member of the Regulatory Liaison sub-committee.

No harm in "putting our hand up".

Back in the 1990s, the issue of a 70 MHz allocation was canvassed with the then-ACA when I was a member of the WIA-ACA Liaison Committee. The issue was dropped from the agenda at that time (after some to-ing and fro-ing) as it was explained (IIRC) that land-mobile licensing was still strong.

[VK3YE]

Also of interest is that the bottom 240 kHz of a 70 MHz band is allocated for class licensed LIPDs for any purpose/any mode with a rather generous 100mW power limit (and numerous experimental possibilities). http://www.comlaw.gov.au/Details/F2013C00396

One wouldn't think that such substantial powered LIPDs would be allowed if the spectrum concerned was occupied by important commercial/military/broadcast users.

Whereas amateurs, CBers and narrowcasters can have allocations that share with LIPDs (the latter with no interference protection against other users and outputs substantially lower than 100mW).

Eg we share the segment around 434 MHz with probably a thousand times more LIPDs than exist on 70 MHz. Around 151-152 MHz there's sharing between LIPDs and numerous ethnic/religious narrowcasters. Also 27 MHz has some sharing (provided LIPDs stay off the CB channels).

[VK3XRI]

I would be up for a allocation on 4m or 70mhz , its great in the bush ,, ive had a fair bit of experience with it on a commercial freq and its a great band to play with even on a commercial freq there were some very interesting results ,

this would be handy for the "wicen " type guys that do the car rally's in the middle of the bush ,

it would be even more interesting to allow repeaters on this band ,

while I don't have to tell you it operates pretty much the same as 6 m with a few different factors ,,

like I said after playing around with 70mhz on a commercial side , I would support it with in the vk community

there are not many users of this band any more in VK3 , im not sure about other areas ,,

[VK4GHZ]

...there are not many users of this band any more in VK3 , im not sure about other areas ,,

Easily done using the ACMA's Search Assignments by Post Code and/or Frequency Range.
For instance, there are 194 assignments in QLD (I specified postcode range 4000-4999) between 70.000 MHz - 72.000 MHz.
Mostly councils and mining companies.

[VK2AAH]

That only tells part of the story... years ago you could see when the license was first issued but that isn't possible any more... but the emission designator gives away many of the old wide band services that are still licensed but are either about to be replaced or very old & obsolete. There a very few modern services still using the spectrum.

Cheers


Richard
VK2AAH

[VK3ART]

I would like to encourage more usage of 6 metres FM before we consider the "additional" ? benefits of 70mhz. Many already have the equipment in their shacks and cars ( 706's 8900's ) but don't use it due to low activity levels. The Repeater infrastructure is already there. It's all I run in the car during summer and it can be interesting when the band opens up.
Regards
Russ VK3ART
Monitoring & Calling on 52.525 & repeaters every day.

[VK4TIM]

As far as usage goes, I can only comment of what I know from experience.

In ZL the authorities went to the radio communications industry and asked for submissions as to what could be done with the VHF radio spectrum freed up from the switching off of analog TV.
In ZL, both VHF low band (44-68MHz) and VHF high band (174-230MHz) have been completely cleared of television broadcasting, as all terrestrial digital TV operates in an 8 MHz channel in the UHF TV spectrum, or satellite Ku band from the Optus bird.
When the industry was asked for comment as to the use of the VHF TV low band, there was little, if any response, and no new technologies were identified as being commercially viable (at this time).
It was even considered at one point that the Amateur service could use channels 2 and 3 (54-68MHz) for ATV. I have heard no more about this possibility, so I can't comment further.

VHF low band is not feasable to use for wideband (broadband) digital systems because of the propagation that would cause mutual interference, man made noise, natural noise (eg lightning, solar bursts), and antennas are somewhat large and cumbersome. It would not be reliable enough for a service provider to use to deliver public data services.
As far as I know the only country that utilises VHF low band for digital TV is the USA, and they are known for doing their own thing.

There has been suggestions that 54-70 MHz may be able to be used for future digital radio services, if and when the technolgies are developed.
These standards would of course have to be designed to work across the world, and much of the development takes place in Europe (eg DVB-T, DAB+, DRM), and will therefore be employed in Eurpoean bands.
It would be more likely that the Europeans would use 54-68MHz if they were going to develop digital broadcast systems in the VHF low band.
The Europeans are deploying DRM services in the LW and MW spectrum that is used for AM broadcasting, as well as some of the higher HF BC bands.

In QLD there are still many users in the 70-72 MHz spectrum, including but not limited to SEQ Water, QLD Parks and Wildlife, QLD Fire and Rescue, and certainly many councils and private companies.
In areas where TV channel 2 (63-70MHz) was operating, the mobile radio services were operating above at least 70.5, and more often 71 MHz, to minimise the likelyhood of interference to TV channel 2 analog receivers.

I have read in one of the radio publications a while ago about a European digital two-way radio system being tested and rolled out in Europe that operated in the traditional 66-88 MHz spectrum, however I don't know any more than that.

[VK4TS]

354074-73173 70.085 MHz 16K0F3E Met/Rassonon Site MT KANIGAN (16621)
64819-55229 70.13 MHz 16K0F3E RFDS Site Mt Haren 3 km SW of KURANDA (21720)
64759-65558 70.13 MHz 16K0F3E RFDS Base Old Cunnamulla Rd CHARLEVILLE (15217)
1303462-1302732 70.16 MHz 16K0F3E Bream B Platform BASS STRAIT (300759))

If the RFDS could be convinced to move (or if it is not being used) then from 70.095 to 70.150 would make a pretty handy sampler band for 4M Narrow band and digital of course...

[VK2AAH]

Trent all this old wideband stuff should be given its Last Rites by ACMA. There shouldn't be any 5kHz/25kHz land mobile bases- period- no matter what the band. The ACMA have been focused on 400 and 800MHz in recent years, but this band needs to be next. Given the band uses a 2.5MHz repeater split why any remaining services couldn't be moved to between about 78 and 82MHz over about 5 years I have no idea. That would release nearly 8MHz for new technology and amateurs. For me I would be arguing a new amateur band from above the LIPDs to 74MHz. That gives 4MHz for potential commercial uses. If such a band was created a sound, workable band-plan providing for a variety of uses and some repeater assignments (based around 2.5MHz split, 12.5kHz channel spacing).

Just because 6m is not fully used is simply not a factor that should come into it... this band offers something to people who may not be interested in 6m. Like many techs I was trained on this band... the availability of 2nd hand radios, loads of SMD1s and cavity filters that no-one has wanted provides some great opportunities.

Cheers

Richard
VK2AAH