AR7030 Power Supply Fail

After sixteen years of reliable operation, the model 952452 power supply for my AOR 7030 receiver finally died.

I was tuning around listening to CW and datamodes stations that sounded like they all had raspy notes. A quick check on the PSU voltage with a voltmeter revealed it was sitting at 17v whereas it should be 15v. Substituting the PSU with another (AOR) 15v power supply cleaned up the raspy signals again so I decided to investigate if it was repairable.

AR7030 PSU disassembly

Continue reading AR7030 Power Supply Fail

Multimode APRS – V2

aprsis32_multimode_v2 aprsis32_multimode_v2

I’ve made some changes to the Multimode setup to give it more flexibility.

The main feature is that I’ve added the SV1AGW Packet Engine – AGWPE. This is an extremely flexible program that allows me to share the SCS Tracker (or any other TNC) over  a tcp/ip connection. I just needed to change the APRSIS32 port configuration from a KISS serial port to a second AGWPE port and configure AGWPE itself to allow connections on 8001/tcp. (8000/tcp is already in use by UZ7HO SounddModem).

This now allows me to run an AX25 monitor program (such as UZ7HO’s  EasyTerm) so I can trace activity on the RPR channel.

Developing things further, AGWPE and UZ7HO_SM accept multiple tcp connections and therefore multipe applications can share a single TNC (unfortunately Messenger doesn’t yet). I can now make connections from other hosts on my network, for example I have Xastir running on a Rasperyy Pi connecting to AGWPE. I’m now considering running just the TNC/modem radio interfaces on the shack PC and the APRS applications can live elsewhere!



Multimode APRS RX Setup

Click for full size
System Diagram


Download aprsis32_multimode system diagram – PDF.

I’ve been experimenting with APRS on 10MHz. Mainly reception at home and also some portable operation. After spending some time with UIview32, I changed over to APRSISCE/32 which I find more suitable for my needs.

For 300baud FSK packet I use the UZ7HO SoundModem. This uses a soundcard for TX and RX and emulates the AGW Packet Engine interface. It can be configured to use two audio frequencies simultaneously and has a waterfall display to aid tuning.

Chris G4HYG has just released version 3.29 of his APRS Messenger program. Not only does this interface with a standard TNC. It also supports sending and receiving APRS traffic over PSK, GMSK and MFSK16 modes. This makes use of the MMVARI engine which he has configured to run as multiple receivers. It will also connect the the UZ7HO SoundModem but presently this only works on receive. Stephen WA8LMF has also written some extensive notes on configuring APRS Messenger and using with UIview.

APRSISCE/32 is more flexible in this respect, so I configured an additional text port to connect to APRS Messenger port 8063. In this setup, APRS Messenger is used purely as a PSK/GMSK/MFSK16 receive decoder.

Finally I bought the SCS-Tracker TNC. After placing my order back in April, I had a few months to wait due to a re-design of the enclosure. This is configured to run in Robust Packet Mode and connects to the APRSISCE/32 host using KISS protocol over a USB serial connection.

Audio Frequency Settings

  • The receiver is set to 10147.30kHz USB dial frequency.
  • A PBT offset of +500Hz shifts the top end of the audio passband up to 3kHz.
  • The HF modems in APRS Messenger are set for 2400Hz.
  • The HF modem in UZ7HO SoundModem is set for 2000Hz.
  • The RPR modem in the SCS Tracker is set for 1500Hz.

Both APRS Messenger share the same sound card. Both applications should be set for a sampling frequency of 11025kHz and the SoundModem should be calibrated for best results.

APRSCE/32 Port Settings

  1. APRS-IS – Your normal APRS Internet connection (not shown in the diagram).
  2. KISS TNC – connected to SCS-Tracker TNC via USB.
  3. UZ7HO_SM – AGWPE connection to tcp/ip port 8000.
  4. APRS_MSGR – TEXT connection to tcp/ip port 8063.


10Mhz APRS seems quite active and I’m hearing a lot of traffic on RPR, probably more than on 300baud FSK. There isn’t much PSK/MFSK activity and I’m hoping to contribite to that mode with my portable setup.

See the system diagram above (click on it for full size or download the PDF!) to see how it all fits together.

Check the Digipeater Users list at DB0ANF.

5MHz Beacon Monitor Program

I’ve just discovered that the GB3RAL.EXE program, written by Peter G3PLX, is no longer available from . This is the software used to monitor the UK 5MHz beacons – GB3RAL, GB3WES and GB3ORK

After digging back through my emails, I found the most recent version that Peter sent me which supports  both conventional (mono) input and I-Q inputs for a SDR. This is the version I last had running with my Softrock receivers. As the documentation is in the now depreciated Windows .HLP format,  I’ve added the notes that Peter originally provided to the zip file in text format.

It should still run on any version of Windows from Windows 98 up to WIndows 8.1 (I must test this!). Just unzip the file into it’s own folder e.g. C:\beacons and run the program GB3RAL.EXE. If you’re installing on Windows Vista or later then don’t install under the program files folders as Windows will complain noisily! It can also be run on systems such as Linux and OSX using the Wine emulator.

It’s now available for download from here –



I’ve just started experimenting with WSPR – a weak signals digital mode, using the Icom IC703 and 5W to a 15m end-fed wire. I’d been transmitting on and off for around an hour, checking in the WSPRnet spots database to see how far away I was being copied.

Imagine my surprise when I saw this one.

2014-05-20 19:32 G4IRX 10.140155 -26 0 IO92jv 5 VK5MR PF96lh 16221 72

I double-checked VK5MR’s reported spots – he was hearing lots of EU and some Japanese traffic so I guess he must be operating from home! Now if only I could get that far on 10MHz APRS…

Site Move

Well no, not quite. I’ve now added a WordPress to the site which will allow me to post material more reguarly.

How web publishing has changed sice I started this site, Many hours were spent writing and debugging the php scripts that served up the old pages, particularly the 5MHz comparison charts. Those scripts are still there generating the graphs with help from the excellent jpgraph plugin.

WordPress also has apps to publish from mobile devices. I can even post from my Blackberry!