This year's papal visit was no small task; we had to "grind out a few prayers" to get the radio system up and running. Two years ago, we already had the opportunity to help the Scouting contingent of the Pope's visit communicate. Back then we deployed eChat internet-based transceivers. because, due to the many locations, almost all of Budapest had to be covered by the system, for which the unlimited range of eChat transceivers meant the ideal solution. But now it was to be a much more difficult scenario.
This year we were approached again by the association and given a very exciting task to be completed in just three weeks. During this visit, the scouts worked in a much more confined and crowded area, Budapest’s Kossuth Square and the surrounding streets, where it would have been risky to use eChat internet-based transmitters.The main risk was that the mobile networks would be overloaded due to the capacity of mobile communication networks, not designed for the demands of a large crowd. This could make communication of mobile-internet dependent transceivers to be disrupted or suffer high levels of latency. Therefore, only DMR devices could be considered. As we had no prior information on the position of the users, the shielding effect of the occasional structures on the site and the potential interference with the radio frequency devices expected on site due to the event, we needed a good solution to increase the safe range of the radios.
- DMR repeater installation, commissioning and licensing?
- And even provide power for everything near the Parliament building?
- Get the frequency licence from the NMHH (Hungarian Telecommunication Authority) in a few days?
Not an easy task during such a high profile event!
After gathering the necessary information, we assessed the options. The scouts' designated points were in Kossuth Square in Budapest and the streets surrounding the square, so we had to ensure stable communication within a radius of about 500-2000 meters... where several repeaters and other UHF communication equipment were operating, of course, potentially interfering with our DMR radios.
Because of the handheld units, the coverage and the urban environment, it was a sensible decision to use an SFR (Single Frequency Repeater) repeater to reinforce the range of our DMR fleet. With an SFR software license, we can extend the range of our radios without having to install a regular 2 frequency repeater. Not only is this cost effective, but it also saves on frequency spectrum as we only need to use a single frequency.
Brainstorming was easy so far, but a power supply problem was soon discovered. In the light of this, we decided to use the handheld PH690 itransceiver instead of the Caltta PM790 mobile transceiver. The Caltta PH690 fits into a small space, does not consume much power in standby mode and can be easily fitted into a waterproof suitcase. In the rush to design it, we also had to take care of a custom made power supply. The solution was a portable SFR box that is simple, quick and easy to set up. The waterproof and shockproof SFR box still has room for an 18Ah battery, and an external antenna can be connected to the box.
After several changes in the original plans, the SFR repeater position was fixed. There were ongoing negotiations about the installation of the repeater at the given location, but the Scout Contingent successfully solved this with our cooperation: Hungary's leading mobile service provider provided a location for the SFR box at and the antenna for the Scout Contingent at its own temporary mobile tower site in Kossuth square. But the excitement didn't end there!
After we assembled the box, it turned out that due to security at the site, after the installation on Thursday, no one would be allowed near the SFR box until the dismantling on Sunday, i.e. for almost four days! There is no possibility to handle the charger, or to restart it in case of failure. The question was whether the battery would last four days. According to our preliminary calculations, the 18Ah battery should last a good four days. In addition, the low power consumption of Caltta's devices, based on our prior experience, gave us good reason to be optimistic.
The Scouts' logistics team then took the SFR box to the designated location, where it was installed by the specialists of the telecom company that also hosted several other telecommunication equipment.
- But how was the scouts’ experience?
- Did they share any of our excitement?
- And how did our hastily assembled SFR box perform in the end?
Árpád Bánhidi, from the Scout contingent of the Pope's visit, was in constant contact with us and the preparation and operation of the communication took place under his surveillance. We asked him to briefly explain the main events of the three days from a communication point of view.
What tasks did you have to perform that were helped by radios?
The radios were useful throughout almost the whole programme, as we had to move our tracks several times on the spot depending on the tasks.
As you were not using eChat radios and did not have unlimited range, how did this change your planned tasks?
When we were planning the pre-programme, we tried to adapt the technology to our foreseeable tasks. This is precisely why the use of SFR was considered, so that we could adequately cover the expected mission coverage area, which we did. Without the SFR we would not have been able to do this.
How nervous were you about the constant changes? Even on deployment day you had to make decisions on certain issues.
I am used to certain changes, I have gained experience in this at previous Scout and non-Scout events, such as the 2021 papal visit. Reacting to changes and looking for solutions can be stimulating to a small extent, as long as you manage to make the right decision. What was different this time is that we were the first ones to use this SFR box. In this configuration, under these conditions, the system had never worked before and I had to make a decision that would affect the work of more than 250 scouts. And the result of my decision will only become clear at some point during the event, when I will no longer be able to make another decision. This has caused quite a stir.
What were the points that were furthest apart on the ground?
The two furthest points were Kossuth Square and Bajcsy-Zsilinszky Road, which is about 600 m as the crow flies.
How did the radios cope throughout the day? Were the spare batteries needed?
The spare batteries were not needed, thanks to the evening charges (although they were not long) the radios handled the whole day very well.
Was there any noticeable interference with communications?
We did not experience any disturbances in communication.
Did the scouts get used to the digital sound on the radios easily?
The sound was not so important for us, as we used call signs to identify the caller and the called party. We had a lot of help from the radio section of the scouts, who had previously developed a radio usage protocol, which was the basis for our communication.
Was there a useful experience at the end of the event that you would mention for the next such mission?
It is important to get to know all the parameters of the system earlier and to strive for at least one test period in relation to the SFR, adapted to the length of the event.