HF APRS using 300bps AX25 Packet Radio

 

One of my other interests is APRS, but on HF. I occasionally use 144.800MHz FMN but find APRS on HF more interesting as it’s more dependant on propagation and of course the distances are much greater. The main aim is to plot and send messages to distance stations without any Internet involvement.

 

 

I use UI-view32 and UZ7HO’s soundcard modem. Ui-View is easy to set-up and you can produce your own maps, but there are other options like AGW Tracker & APRSIS32 which use online mapping sources. I prefer to stick with Ui-View32 as I find its message handling easier to use.

 

Andrei UZ7HO, has produced a superb soundcard modem similar in operation to AGW Packet Engine, but it is easier to set-up and much more sensitive under noisy conditions.

 

 

You can also choose different sound cards or as in my case choose to use external soundcard interface like the Tigertronics Signalink SL-USB interface.

 

 

 

Depending on the speed of your computer CPU you can add multiple decoders making decoding of weak signals under noisy conditions more likely.

 

Screenshot of the modem decoding received packets from Andy F6EWX, despite QRM from a constant carrier.

 

 

Andrei’s earlier versions were just single channel 300bps modem, but he has now released a version that is dual channel (left & right sound channels) and both channels can be set-up to be either 300 600 or 1200bps modems.

 

Ui-View32 can be downloaded and registered from here > http://www.apritch.myby.co.uk/uiv32_uiview32.php?lang=english

 

UZ7HO Soundcard modem and user guide written by Jon G7OMN can be downloaded from Andrei’s  web site >  http://uz7.ho.ua/

 

Andrei is constantly developing and updating his modem so check his web site often for the latest version.

 

HF APRS frequencies.

Allow +/- a few Hz depending which Tone Freq standard,

KAM or PK,  @300bps you are using.

 

10.147.6 USB, 14.103MHz LSB, 28.140 USB.

 

 

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