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

Chris Moulding chrism at crosscountrywireless.net
Mon Mar 1 10:27:32 UTC 2010


Matti, OH2MQK asked:

Could you document these preambles and flags somewhere?

I've put a document " 
<http://f1.grp.yahoofs.com/v1/IJCLS8aggjmDKKIYTDMgN_iSVkQH3xxeTt7X2dJDNr06uzyTOqlGYaJFRgqs93lYFBAmF5B0ZdKbjwaUbpJPEw/APRS%20over%20PSK-63%20-%20How%20it%20works.txt>APRS 
over PSK-63 - How it works" on the CCW Yahoo Group:

  http://uk.groups.yahoo.com/group/cross_country_wireless

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  



Matti Aarnio wrote:
> 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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