Air Distress - Now 121.505 MHz ?

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Re: Air Distress - Now 121.505 MHz ?

Postby Minus1 » Sat Dec 15, 2018 11:55 pm

Scan125 wrote:Well Santa is bringing me a Yaesu FTA-250L Airband Transceiver for Christmas.


I have one, works well distinguishing adjacent 8.33 kHz channels, though I find the audio is not as clear as it could be, compared to a 25 kHz transmission on the UBC125XLT.
Wise to disable the transmit function in the menus, lest anyone accidentally press the PTT.
I think you can get a Windows prog to program the FTA-250L's channels.
I reserve the right to ignore people who have made no attempt to the read the manual, and expect others to do it for them.
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Re: Air Distress - Now 121.505 MHz ?

Postby G4RMT » Sun Dec 16, 2018 1:22 pm

I wonder what they were thinking in selecting a channel spacing plan that involves lots of decimal places, and the idea of rounding up and down in this way to reduce the number of decimals really is beyond belief. I wonder what the actual performance specs really are? Not the published ones, they're clear enough but the practical ones. I don't have a 8.33KHz approved radio to check, but I wonder how tight the filtering is in practice. Does a strong signal one channel up or down still get received? It's AM so I would expect it to simply be there, but quieter. Anyone with an approved radio who can try this and report back?
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Re: Air Distress - Now 121.505 MHz ?

Postby m0lsx » Sun Dec 16, 2018 2:06 pm

G4RMT wrote:I wonder what they were thinking in selecting a channel spacing plan that involves lots of decimal places, and the idea of rounding up and down in this way to reduce the number of decimals really is beyond belief.



Sadly this kind of bolognaise is what happens when you do something via committee.
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Re: Air Distress - Now 121.505 MHz ?

Postby Scan125 » Sun Dec 16, 2018 6:36 pm

I could say what numpty chose 25kHz in the first place. 20kHz would have been far more sensible. Then they could have split to 10kHz and as technology/front end discrimination improved gone for 5kHz. That would have produced a 4:1 as opposed to the 3:1 we now have.

It is what it is an until a radical change happens, e.g. going digital or allocating alternate spectrum then I guess we have to live with it. Oddly it is only the amateurs who care. For pilots, ATC, etc. (as I've said before) they do not give a monkey's what happens under the covers when it comes to radio comes. All they want to do is dial/set a value, (could be ABCD.EFGH and phonetically more accurate in poor radio conditions - alpha bravo Charlie etc) and find someone or some service at that setting.
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Re: Air Distress - Now 121.505 MHz ?

Postby Scan125 » Sun Dec 16, 2018 7:19 pm

Minus1 wrote:
Scan125 wrote:Well Santa is bringing me a Yaesu FTA-250L Airband Transceiver for Christmas.


I have one, works well distinguishing adjacent 8.33 kHz channels, though I find the audio is not as clear as it could be, compared to a 25 kHz transmission on the UBC125XLT.
Wise to disable the transmit function in the menus, lest anyone accidentally press the PTT.
I think you can get a Windows prog to program the FTA-250L's channels.


Thanks Minus1

Yes Yaesu have (if you can find it) a free program (YCE16) for programming the FTA-250L. You do however need their custom interface lead and drivers (SCU-37). Thankfully Santa is bringing me the SCU-37 as well.

Then I will be able to use my UBC125XLT alongside the FTA-250L and evaluate the differences for myself. One objective I have is to see if it makes sense to and a new virtual display function to Scan125. Scan125 already has airband correction in that 8.33 spaced frequencies as called by ATC/Pilots are changed/aligned and stored with the actual frequency used. No problem there except for the fact that a user enters one value and then sees another value BOTH in Scan125's display and the UBC125XLT display.

I could change Scan125 to do display (in the airband range) what ATC call but still store and use the real frequency. Same/reverse for when scanning the airband. Scanner will land on a real frequency and display it but that is not what Pilots/ATC actually have set. However Scan125 could display the Pilots/ATC set value.

Quite a bit of work and testing required for what is a stable program. One could also add/ask why should Scan125 being a general purpose scanner that works on "real" frequencies have to try an clear up the mess/misunderstanding? I did it with my airband correction on entry so that when pilot/atc set 123.456 the real frequency is set but to do the reverse for a general purpose scanner only goes to "mask" scanner users from what is really happening which they should understand if they are airband addicts.

The alternative is for airband addicts to buy a dedicated airband kit like the FTA-250L which many private pilots, microlite, parachute jumpers ….. are using as the quickest and cheapest way to get 8.33 compliant/certified.

Regarding the PTT on the 250L. Yes an absolute must that this is knobbled along with VOX. We probably all know the old WWII RAF stories of pilots remaining in transmit mode and thus blocking life saving shouts from fellow pilots to each other and save their bacon.

I have very strong views on "compliance and responsibility" especially when ownership is not an offence but use of is. So for me I'm not a pilot or involved in any air activity so have no legitimate reason to transmit. Questionable as to reception but then the very strict rules of privacy, no divulgence, use of privileged information etc. come into play.

If I write a real time control program for the FTA-250L then transmit will NOT be supported UNLESS the program is to be used by a glider or parachute or similar club and they will be given or have to purchase a transmit function registration key. I'm not going to be an accessory or of assistance in illegal use.
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