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OSCAR subband for activating

I have noticed quite often that activators in other regions of the US posting alerts for 144.41 or around that frequency. I have never seen it for the South East US. Everyone I know around here uses the designated ARRL simplex frequencies (as there are many). Is there a reason why people are using frequencies that could cause interference with satellite operators when so many other options exist?

That part of the 2 meter band is used all over the country for various
modes, SSB/CW/Packet/Beacons/EME, etc. My experience has
been that the satellites we use are using the 145-146 part of the
band. Which is also full of repeaters and simplex FM activities.
I recall many instances of FM simplex folks from the USA and Latin
America talking to each other in the uplink band around 145.9-146 MHz with signals so strong they were making the satellite unusable.
73,
John, K6YK

I follow part of what you are saying. 144.41 falls in the new OSCAR subband. I guess it was moved to that part of the 2m band to get away from interference only to have some SOTA people move with them. We don’t want to be picking fights with the AMSAT people. I use one of the several dozen designated 2m FM simplex frequencies that don’t compete with other subsegments/ groups when I activate.

It was my understanding that the Amateur Satellite Service was granted 145.8 to 146 mhz. VK has beacons in the 144.4 area.

Is it possible that 144.41 is a typo error and intended to be 144.1?

Andrew VK1DA/VK2UH

Andrew, I think those Arizona folks use that for their local simplex
frequency. Maybe one of the Arizona folks will drop a note about
that. This area has packet/ APRS, etc. in that area. And I think
the lower part 144.0 to 144.1 is CW only in the USA, above 144.1
can be used for other modes. I can’t recall working any satellite
below 145.8 on any mode. And I’ve worked a LOT of satellite
QSOs, maybe 20,000 or so, CW/SSB/PSK31/SSTV, etc…
Also, that 144 MHz area is shown on the ITU frequency allocations
for satellite,but don’t know if any birds have used it or not.
73,
John, K6YK

In a July 2020 post to amsat-bb, Paul N8HM (AMSAT Executive VP) said he believed the “new OSCAR subband” of 144.300-144.500 was proposed decades ago but never adopted by the IARU. There are no current amateur satellites on 144.410. Most use 145.800-146.000.

73, Scott N1AIA

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Hi John,

There may well have been developments I’m unaware of, but as I understand it the ITU made provisions for the Amateur Satellite Service specifically and separately from the Amateur Service. Unless the AMSAT proposal referred to by Scott @N1AIA was included for action at a WARC, it seems unlikely to become approved.

Apart from that, it would seem essential to align frequency usage with practices elsewhere in that part of the country, not only to avoid QRM to and from other groups, but mainly to ensure that dx possibilities can be realised when conditions suit. I’ve done a bit of weak signal dx on 2m and higher bands both from home and in the field. What comes through every time is that dx only happens when operators at each end align for the principal factors: frequency, time, mode and to a lesser extent, antenna directions. Random dx is extremely rare. Propagation is the one thing the operator cannot control, but without the other factors aligning, the best tropo conditions are wasted. On 2m, frequency locking isn’t essential for modern rigs, but on higher frequencies it become increasingly important especially for digital modes.

Apologies for long rant. rant mode off.

73 Andrew VK1DA/VK2UH

Seen several more spots in the last day for 144.41 FM, all from guys in the W7A area. My antenna has high SWR down there unless I use a SSB horizontal antenna, but they are using FM. Doesn’t seem to make sense. If I was there I would tell them sorry, can’t chase you my antenna doesn’t work down there for FM, you have SSB horiz? BTW, 2m SSB/ CW has some really good range when you are on a mountain, hundreds of miles.

Band plans have many advantages, mainly seen in the number of contacts in the log and the distances achieved. As you say, ssb/cw on 2m can be remarkably effective even with low power and simple antennas, in situations where fm struggles due to the threshold effects in receivers. Of course you have to be willing to copy voices in the presence of noise, something radio amateurs are normally very good at.
Let’s hope the advantages become clear to more operators…
73 Andrew VK1DA/VK2UH

In the UK (and I believe EU) the SSB band is 144.15 - 144.40, !44.40 to 144.50 is designated for beacons. It is hard to believe that anyone would put a satellite in competition with the beacons, that makes no sense at all.

Hi Ryan,
I had to come terms with this when I visited W7A a couple of years ago. Yep - SOTA in the Phoenix area is on 144.41 FM.
The locals explained that this is the legacy 6m DX Liaison frequency, now the W7A default SOTA 2m simplex channel, and probably not used much for its original purpose any more.
If 146.52 (etc) works better for you, go for it. If you are on a summit, they’ll still work you - hi!
My FT60R didn’t complain after a bunch of contacts on 144.41.

2 Likes

The problem we have here is people seeing things on the internet and assuming it’s true.

As Scott N1AIA says there was a proposal for a new OSCAR subband at 144.300-144.500 but dropped years back. All those band plans you can find for Region 2 that show it as new OSCAR sub band are years and years out of date.

You all could go and check the OSCAR websites and see if there are any satellite using that part of the band too.