Sunday, March 19, 2017

Experiments with C4FM

We now have six stations in Galway operational on Yaesu Fusion. Steve EI5DD, Tom EI2GP, John EI1EM, Arthur EI7GMB, and Gerry EI8DRB,  have FTM400XDR transceivers and Andrew EI3FEB has a FTM100. Dermot EI7IX from Westport recently purchased an FT100, whilst Joe EI3IX, and John EI7FAB, from Castlebar Co Mayo, should be on shortly so the efforts have finally borne fruit. Arthur EI7GMB,  will have an FTM100 in Galway shortly. Gerry EI8DRB owns a Yaesu FT991 which incorporates C4FM. Nine on the air in a short time is impressive.

The Limerick area, due South of Galway,  have a Yaesu Fusion Repeater which provides a good signal throughout Galway and into Co. Mayo as far west as Westport. The current number of Fusion operators in the Limerick area would appear to be around ten or eleven.

Plans are to place a Wires-X gateway online by the end of April, which will serve Galway City and the surrounding area of 25 Km radius.

The first experiment was carried out between EI3FEB in Headford and myself in Galway City - a path of 23.5 Km but it had a few hills in between the two stations so was a poor path at the best of times. The path was chosen as this was probably the worst signal strength achievable.

Both rigs were set up to transmit 5 watts and the initial transmission was made on FM

As can be seen on the display the signal strength did not even register and the FM signal had the usual hiss encountered with FM signals received on the fringe area. For an S0 signal it was not too band. The FTM 400 recorded the returned signal as S 0.5 - S 1. Readable with plenty of hiss. Note the FM displayed to the right of the frequency displayed indicating this was in the FM mode. The lower green light indicates FM reception.

The mode was changed to C4FM and the signal received was most impressive

This signal was still received at a S 0 level but his time in C4FM. The quality of audio was crystal clear with absolutely no background noise. Note the DN displayed to the right of the frequency displayed denoting in digital mode. The blue light denotes the reception of a digital signal. When the digital signal is received other information is embedded within it which includes the Callsign and also GPS coordinates. The distance as shown was derived from that information.

Check out the YouTube video
Quite impressive with no R2D2 sounds from the received signal.

More to follow   .......................... 
Original work from the EI5DD/G4GFC pages Click here

Wednesday, August 13, 2014

Galway VHF Group APRS EI2GCP

The Galway VHF Group APRS system is to be completely overhauled. The introduction of an I-Gate at the Galway City site in Mervue will feed data directly into the International APRS network enabling tracks to be viewed live on A weather station feeding live information into the network will also be installed at Mervue.

Pictured below, is the setup for the EI2GCP APRS I-Gate to be located at our Galway City site, Mervue. From top to bottom, Tiny2 TNC operating in KISS Mode, underneath,  PC Engines WRAP embedded linux board running aprx iGate software and below this, the Philips PRM 80 VHF PMR radio programmed for 144.800 MHz.

Pictured below, is the Weather station under test at EI3FEB's QTH. Judging by the sky in the background, the weather station will get plenty of abuse as Galway aproaches the winter months. This Weather Station will be transferred to the Mervue site around the 25th of October.

On the 25th of October the APRS and Weather Station was installed at the Galway City Location in Mervue. The existing tranceiver was replaced with a Phillips PRM 80 Commercial PMR set operating on 144.800 MHz. Strangely, the Yeasu FT8900 looked as good as new and was working perfectly despite being left on the roof for almost 5 years. The APRS I-Gate was connected to the Tracker2. The whole system is located in a weatherproof box on the roof. As is obvious, the box has protected the equipment well over 5 years.

The Weather Station was clamped to the mast and oriented in the correct position. The "Bird-Box" contains the pressure and humidity sensors, the two other items are the Anemometer and the Wind Direction indicator. All being secure, power was applied and connection to the internet was initiated.

Initially, information was not showing up on as expected. Settings on the I-Gate were changed by remote access which allowed the Tracker2 to communicate with the system that had previously been set up for a TNC2. Everything sprang into life with the new settings and results can now been seen on in the illustration below.

The Weather Station symbol has been staggered slightly to make it easier to click on the WX symbol. By clicking on the WX symbol an information box will open and show the up to date parameters recorded by the Weather Station. No rain in Galway since the since the Weather Station came on line. This will undoubtedly show some readings in the very near future.

Since the tranceiver was changed, the setup seems more sensitive and is receiving more distant stations. Possibly conditions on 2 metres but maybe due to the different squelch system allowing weaker signals to be received.

Once the second Digipeater is added to the Knockroe site, traffic from further afield will be relayed back to the I-Gate in Mervue. This will extend our coverage considerably and result in coverge overlapping other systems located in the Midlands and to the South-East. This will make it possible to track seamlessly across the country. It remains to be seen just how far the coverage extends once the sytem is completed.

Frequency 144.800 

Callsign EI2GCP

                                                              Location       Mervue
                                                              Locator         IO53LG 
                                                   Co-ordinates  53.285981, -9.031202