[OZAPRS] HF Beacons Heard.

[Noel Rowe]

 I have been into APRS since it first surfaced in ZL.  However the
extension of APRS on to the HF bands is fairly new and I doubt any of us
in VK or ZL, me certainly included, are yet what could be called expert.
We are all feeling our way, and when I bring things to peoples attention
it is not to try and be smart (or worse) , but to try and further our
hobby for the good of all.  If my thoughts are wrong, but the end result
is that ZL, VK, and the USA etc get on exactly the same 30m tone
frequencies, then I will be more than happy.
 
I run an APRS node here with several terrestial and satellite VHF ports,
and at least one HF port.  My system links on RF to an internet gateway.
The gear runs 24/7, and understandably I dont want to waste power by being
on a different frequency to everyone else.
 
It was my understanding, from discussions a while ago, that we had agreed
to use on the 30m band the tone frequencies of 10.149.200 and 10.149.400.
I think it was Bob Bruninga who gave us those as being ones likely to be
internationally used and the ones I believe he recommended VK/ZL to adopt.
 
Because my TNC is an MFJ using 1600/1800 tones, on 30m I set my rig mode
to USB and the dial to 10.147.600 - ie I subtracted 1600 and 1800 from
Bobs tone frequencies.  I think my calcs are correct.
 
Now Brian (get well soon!) said he is:
 
>Using DSP-12 TNC
>300 baud
>Tones 2125/2325
>FT-897 Reads:
>40m 7.036.53 LSB or 7.034.42 USB
>30m 10.149.90 LSB or 10.147.60 USB
 
Well maybe I have missed something here.  On 40m LSB both our tones are
(within 5 Hz) the same - allowing for our different TNCs we are in sync,
and I have copied you so that all makes sense.  But if  I was still on LSB
and you went to the USB frequency given, we would miss - if your tones are
2125/2325 then surely you need to shift the dial 4450 to change sidebands
and have the tones stay in the same place, ie in your case dial up
7.032.080.  Or have I overlooked something?
 
Now on 30m - if I subtract the 2125/2325 tones from your LSB dial of
10.149.900 I get tone frequencies of 10.147.775 and 10.147.575, and if I
add the tones to your USB dial of 10.147.600 then I get 10.149.725 and
10.149.925 - and that is both different on each side band, and none are to
Bob's tone frequencies.  However your USB setting would be perfect with
1600/1800 tones, as it is +525 with 2125/2325 ones.  And this is where I
feel the VK stations have got it wrong - the station you all netted to got
the wrong sideband/TNC combination.
 
I am currently falsifying my frequency by running the HF rig set for tones
of 1600/1800, for my MFJ TNC, but feeding the audio also to decode with
AGW soundcard software which looks for 2100/2300 tones - effectively
looking 500 Hz high.  That is, tones of 10.149.700 and 10.149.900, and
these match your USB example above within reason.  I am decoding VK3WRM
and VK3MY-3 with this setting.  But I would much prefer to decode them via
the MJF set to where I think we all should be!
 
Your mobile:
 
> Tigertronics TM-1 for mobile use......... 
>40m 7.035.53 LSB
>30m 10.148.60 USB
 
OK the tones here are 1100/1300, so on 40m that gives 7.034.430 and
7.034.230, and this is within 30 Hz which is quite reasonable allowing for
small rig differences (I have a +50 Hz local error with my rig).  On 30m,
the transmitted tones would be 10.149.700 and 10.149.900 - this is exactly
+500 Hz so that comes on the button to my AGW based temporary (and
incorrect) system.
 
Conclusion - on 40m VK and ZL are likely to be in the same ballpark, but
on 30m there is a 500 Hz difference between the VK stations and the
frequency used in ZL and the USA.  What do we have to do to get you to
change into line with the rest of us?
 
Noel, ZL3GR
 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://second.aprs.net.au/pipermail/ozaprs/attachments/20040330/26577c4e/attachment.htm 
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: ATT04991.txt
Url: http://second.aprs.net.au/pipermail/ozaprs/attachments/20040330/26577c4e/attachment.txt