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[aprssig] APRS Messenger now has APRS over PSK-63

Matti Aarnio oh2mqk at sral.fi
Mon Mar 1 09:56:06 UTC 2010


On Thu, Feb 18, 2010 at 10:20:47AM +0000, Chris Moulding wrote:
> 
> I've released the latest version of the APRS Messenger v 2.26 program.
> 

In interest of having interoperable softwares:

> The biggest change is that APRS over PSK-63 has been added. This has
> been tried before with an add-on to UI-View but that had problems
> sending packets with errors to the APRS-IS system. I've added a preamble,
> start and stop flags and a strong checksum to each packet so that each
> received packet is checked as correct before being sent to the internet.

Could you document these preambles and flags somewhere?

> The display will show all packets received even with errors so that
> weak signals can still be read manually. A frequency hopping routine
> has been added to the PSK-63 receiver to allow rapid signal acquisition
> over a +/- 50 Hz range. A Tune option allows the operator to send a
> carrier + 150 Hz in frequency to avoid interference to other APRS over
> PSK-63 users. The program uses the PC soundcard in a similar way to
> other digimode programs.
> 
> The program comes in three versions with different PSK-63 audio tone
> frequencies, 700, 1300 and 2100 Hz.

Anybody familiar with normal PSK-63 will probably know what these are,
and what is their meaning - so no additional documentation there is needed.

> The second change is the addition of a receive only Igate. All HF or
> VHF packets received can be sent to the APRS-IS. If the connection to
> the APRS server is lost it automatically retries 1 minute later.
> 
> Future developments will include a GPS option for mobile HF tracking.
> 
> If you want to try APRS over PSK-63 on HF I'm running an Igate on 10.1497
> MHz. Set your receiver to a dial frequency of 10.1476 MHz USB with
> the 2.1 kHz version. Please note that the dial frequency is the same as
> used for existing HF 300 bd packet APRS so it will work with existing HF
> APRS set-ups. In the US Lynn KJ4ERJ is also running an APRS over PSK-63
> Igate on 10.1476 MHz.

I see, on windows one always has everything bundled on same program...
  - modem
  - UI
  - igate

I am interested in adding the modem on UNIX environments.
There are PSK-63 codes already available, it needs just adding flags and checksumming.

> The software is freeware and can be downloaded from the following webpage:
>   http://www.crosscountrywireless.net/aprs_messenger.htm
> 
> A Yahoo group for discussion on this and other topics:
>   http://uk.groups.yahoo.com/group/cross_country_wireless
> 
> See you on the waterfall!
> 73,
> Chris, G4HYG
> 
> -- 
> Chris Moulding
> Cross Country Wireless (2009) Ltd
> 7 Thirlmere Grove, Bolton, Lancs, BL4 0QB, UK
> Tel/fax: +44(0)1204 410626
> Mobile:  +44(0)7752 391908
> Website: http://www.crosscountrywireless.net
> Company number 6780346 registered in England and Wales

73 de Matti, OH2MQK



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