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IARU REGION-1 50MHz BAND PLAN - EME USAGE

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Dave, EI3IO
Fri May 28 2010, 12:22PM
Dave, EI3IO
Registered Member #87
Joined: Tue Mar 25 2008, 04:34PM

Posts: 3
Hi from sunny Bahrain. You will not be surprised to hear me say that in an Es opening 50 MHz is manic here. I think it will be even more manic when we have F2 propagation again. In many respects I think the situation is worse than the HF bands because when the band is open the received signal levels are phenomenal, as we all know. However there appears to be little room to run conventional split frequency working i.e. spreading out the pile-up to enable the DX station to copy weak signals as well as the strongest. There is also the problem often found on HF, where the pile up of 1 DX station creeps onto the working frequency of another. Plus we have the difficulty of propagation movements and because of the spotlight effect being able to share frequencies some of the time but causing QRM on other occasions. What I am coming around to suggest is that there does not appear to be sufficient spectrum below 50.2 MHz when the band is open. Yet most administrations at least provide a band up to 50.5 MHz and many provide spectrum up to 52 MHz in ITU R1 and some in Africa 4 MHz to 54 MHz. The most popular data modes tend to be used to facilitate EME or MS communications. Yet these modes are not prevalent during ionospheric propagation events (including Es). Why are we therefore moving towards a band plan which people interpret as limiting a lot of spectrum between 50 and 50.3 MHz to data modes, leaving 50.3 and above unused until 12.5 kHz channeling kicks in. I believe I have been criticised of running pile-ups above 50.2 MHz which encroach on the data band. Quite frankly I think the UK band plan and possibly the next generation IARU band plan may be flawed. As 6m gets more popular I think we need more CW and SSB spectrum which remain the bread and butter modes for DX working. If we're thinking of moving beacons towards 50.5 MHz lets consider moving everything up to 50.35 MHz and above. Or lets encourage more mode sharing. In my professional role as a regulator and instrumental in getting 6m released in A9, I see little value in keeping 2 MHz for the amateur service, it just won't be used. We could distribute 500 kHz to the amateur service across the 2 MHz band and transfer the rest of the band for non amateur applications. at least until there is an obvious requirement for spectrum. I think it's time to re-think the band-plan and not just tinker at the edges. As an experiment shall I run some SSB (or CW) in 50.3 -50.4 MHz or 51.7 - 51.8 MHz, 200 kHz of undefined spectrum! 73s Dave G3SDL, OZ3SDL, EI3IO, A92IO (to name but a few).
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Neil, G0JHC
Mon May 31 2010, 06:33AM
Neil, G0JHC
Registered Member #110
Joined: Tue Apr 01 2008, 01:51PM

Posts: 19
To Tinker or re-think?
Good morning Dave, you highlight the problem so eloquently. 6m has turned into nothing more than “another HF band” for the majority of operators, as it’s now a “ button press” on virtually every new commercial set. We have a band plan for 80’s and early 90’s, when there were a few hundred on 6m in the UK and a hand full more dotted around in a number of European countries. Now it’s somewhat different. You work 60+ DXCC in a month and 1700 contacts into Europe. E4X has just worked 2500 in their 1st 3 days! Things do need to change. There is little argument for suggesting many antennas wont operate a few hundred KHz up, or we could find ourselves on the wrong side of the MUF, or beacons become useless at 50.5. The benefits of making the bottom 400KHz SSB/CW only far outweigh any disadvantages. I would like to see a total re-think, tinkering gets us nowhere. Beacons are useful, but not at the expense of keep us off 50% of the most prized end of the band.
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Dai, G8FXM
Wed Jun 02 2010, 08:29AM
Webmaster

Registered Member #2
Joined: Mon Mar 17 2008, 06:10PM

Posts: 204
I think Trev's proposal in the latest Six News has considerable merit, i.e. a global, cordinated beacon network operating on the same single or same group of frequencies TXing on a time share basis. Just like the HF International Beacon Project. Not an overnight soluition however and costly to implement.
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Tony , EI7BMB
Mon Jun 07 2010, 07:34PM
Tony , EI7BMB
Registered Member #18
Joined: Tue Mar 18 2008, 04:00PM

Posts: 14
As a beacon Keeper I think the idea of several beacons txing on the same freq has great merit
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Christoph, DF9CY
Wed Jun 09 2010, 05:51AM
Christoph, DF9CY
Registered Member #65
Joined: Thu Mar 20 2008, 04:27PM

Posts: 31
Dai and Tony, good idea. In our "digital age" it should be no problem to share frequencies and operating times of beacons. I would like to see the beacon at the low end of the band. What do they help when the they are above the MUF, when the band is open and you don't see it ??

This thread is about EME; so in my view EME may "happen" anywhere in the band, but anything close to 50.000 .. 50.020 should be avoided. Have you ever tuned around there ? MANY modern machines use oscillators that run on 50 MHz +- something or have strong harmonics there. Best known are satellite receivers, DVB-T stuff, TV sets ... Even in my small village with a few houses around, the lower 30kHz are full of birdies and and useless for beacon reception and EME of course.

Band plan .. DL and some other countries are restricted to at least 50.080+ MHz. Last year I copied U.S. stations calling CQ around 50.073 MHz. They gave up, as noone returned their CQ. So shifting CW lower as it is now will exclude these few bandplan-limited countries from DXing.
But I am shure a common agreement will be found. That should not be too difficult.
73 Christoph
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Murray, G6JYB
Sun Jun 20 2010, 10:09PM
Murray, G6JYB
Registered Member #910
Joined: Mon May 04 2009, 02:42AM

Posts: 20

The 'Digital Age' for beacons is also reflected in an update to the IARU Region-1 guidance  - see the new v5.42 doc at http://www.beacons.org.uk/
- which came out of a separate paper and working group at the February IARU-R1 Vienna meeting  - the same meeting that discussed the 6m beacon sub-band change
I would also comment that the trend in VHF-Microwave is towards precision time/frequency locked continuous operation CW+MGM etc (helped by DDS technology) for automated monitoring - not the time-shared HF IBP style.
This may imply that an eventual  replan either spaces systems out and/or needs to prompt a thinning out of less effective/vanity ones
regards
Murray G6JYB
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Trev, EA5ISZ
Mon Jun 21 2010, 10:08AM
Trev, EA5ISZ

Registered Member #13
Joined: Tue Mar 18 2008, 01:43PM

Posts: 143
Murray, many thanks for your input.
I have read the updated paper with interest however I firmly believe that, even within the narrow remit of the paper, there are areas that do not easily sit with 50MHz; specifically:

1. The need to submit beacons with an ERP of greater than 10W. Whilst a 10W ERP beacon at 2m or 70cms will generally have limited coverage this is not the case at 6m where many of the beacons fall into this category. Even lower ERP levels have potential for interference at this frequency and need co-ordination.

2. Mixed Mode beacons unfortunately require a significant time slot to transmit all of the data. I had originally hoped that some form of weak signal data mode would be very useful along with time shared frequencies. However, if we need to co-ordinate world-wide beacons within a narrow frequency band this would not be possible without compromising the time available for each beacon. In my opinion, the best compromise is to use a similar time shared system to the IBP at HF.

3. Unlike higher frequency bands, there is a need to co-ordinate beacons on 6m globally rather than Regionally. Even the very low power beacons are reported internationally especially at sunspot peak years when F2 is sufficiently high. Even outside this period, multi-hop Es allow inter Regional beacon reception.

Outside the scope of the paper there is the issue of which area within the band is to be allocated for beacon useage. There is a firmly held belief that MUF transition should be the key factor when deciding where to place the beacons within the band. This issue is peculiar to 6m where the MUF (especially F2 related) often creeps slowly through the band and may not reach the bands upper limits. Even when it does, this may be some time after the MUF passes 50.000 MHz. Moving the beacon band at 2m and above essentially has little effect upon the beacon's utility; at 50MHz it could be the difference between hearing a strong beacon or nothing at all. Of course beacons have other uses than propagation warning however, this is a key use at 50MHz and any move of the beacons higher in frequency would remove that facility.

IBP style beacons in a 20 or 30KHz slot at the lower end of the band (eg 50.020 to 50.050 MHz) could be the answer. If beacons in a defined geographical area (eg N Europe) were to be time shared on a known frequency, it would allow stations with an interest in looking in that direction to monitor a single frequency yet have the possibility of hearing a range of beacons. Equally so for other areas defined by individual IARU Region planners. This has the advantage of allowing each Region to co-ordinate its own beacons without the need to co-ordinate with the others. So, for example, Region one uses a 10kHz slot from 50.020, Region 2 from 50.030 and Region 3 from 50.040.

Even with 10kHz worth of time shared slots, some of the current beacons would need to be re-located elsewhere. It would be up to the Regional co-ordinator to determine which beacons are allocated a 'prime' time shared slot. Other unco-ordinated and personal beacons could be accomodated at a higher frequency (above 50.4 MHz?) in an effectively 'free for all' beacon segment.

I believe it is vital that we treat 50MHz quite separately from its higher frequency neighbours when it comes to beacon planning. It has much more in common with HF than VHF in this regard. At present it seems that this is not happening
Trev
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