PI7RMD is on air for quite a while now on 13 cm. I already spotted it on May 3rd, 2020. Looking at the entry at beaconspot.uk wondered, why no one else sent any spots. So I had a look for it today and got some nice reflections via aircraft scatter.
PI7RMD is located in JO31AD, using a double quad antenna beaming 270° with 5W ERP. It is keying in A1A on 2320.8948 MHz (nominal 2320.895 MHz).
By performing my daily beacon check, I noticed a weak keyed carrier in between the spacing of the F1 signal of DB0UX on 2320.900 MHz. I assumed to see F6DWG/B, which I monitored around the .900 before. But it didn´t take long to find out, that the real signal (mark) was the lower carrier and after a while I learned, it was F5ZNI using reverse F1 keying. Later in the evening the signal increased due to good tropo conditions, as can be seen in the pictures. F5ZNI is the 34th beacon I received in the 13 cm (S) Band
I am always happy about new beacons, but this case is an example, why beacon coordination and using standards is most important. First of all, reverse F1 keying is always bad, as you are used to listen to the upper carrier of the signal. In case there is an unkeyed carrier in between the text, you can easily identify the mark, where to listen. But if there is text keyed nearly all the time, as F5ZNI does, it is rather time consuming until the mark is identified.
The DB0UX signal was strong and the frequency is locked to a reference, while F5ZNI is drifting a little. So it was obvious, that there was a second signal in place. If the french beacon would have been locked to 2320.900 MHz too and would use the standard A1 or F1 keying, there would have been no chance for me to monitor or even to take notice of it.
An excerpt from BEACONSPOT.UK shows the situation on 2320.900 MHz:
When looking for EA2TZ/B during a beacon check a couple of days ago, I mentioned a signal with strong doppler shift about a khz below. As I like the challenge to identify new beacons, I started monitoring it. It became a kind of a nightmare, trying to to catch the beacons callsign. It seems to be very chatty, transmitting a whole bunch of unuseful text. despite the fact I got a lot of good quality fragments via aircraft scatter, it took me hours to identify it as F1ZBK. At least I am pretty sure it is, as there is a second callsign in the end of the text: F1DND, maybe it´s the keepers call.
The text decoded so far is: —— beacon f1zbk jn38bp nancy … 854 khz … 5 watt … f1dnd … orange KA … ——- Where the “…” represent gaps and KA is the prosign for “Attention” or “New Message” (not to be used at the end of a message, like AR).
There are many beacons running in bad modes like reversed F2A or keying the subcarrier of F2A, but transmitting such a lot of stuff is worse.
As the weather forecast promised heavy thunderstorms for today, I was looking out for scatter points on 13 cm. Pointing to eastern France, I found a heavily scattered signal of DB0UX in JN48FX in 204°.
But the sound was quite strange and rhythmic. When taking a look out of the window, I saw the dish pointing at two windmills in 1 km distance.
This kind of scatter is not very helpful, but a nice experience anyway.
The whole morning I monitored EA2TZ/B in IN93BF on 1296.854 MHz over a distance of 1072 km, peaking up to 30 dB. The vertical profiles of 0:00 UTC from Paris and Bordeux showed an inversion at 1000 m altitude. F6DKW from Paris was booming here, but nothing could be heard of beacons close to the path or in tests with F6CIS, IN94WL and F6AJW, IN93EK. The duct was just too high.
Tonight Paolo, IK7UXW, JN80XP, asked me in the KST chat, to give it another try. We had discussed the possibility of combined propagation with aircraft scatter and tropospheric ducting before.
The path is perfect, as there is one hop over the Alps and a plain track over the Adriatic Sea.
On Tuesday last week, while I was watching the other Paolo aboard the International Space Station via HAMTV on 13 cm, Paolo had initial QSOs in this propagation mode with Daniel, DL3IAE, in JN49DG on 23 and 13 cm. That was a great effort! So I was more than poised for a try.
Paolo has a 2 m dish and QRO, so he started calling me in CW. I heard “musical noise”, EMEers know, what I mean, with very strong bursts from time to time, lasting for some seconds. After a while we decided to try in JT65c. And from the start I could decode Paolo in most of the periods.
The better decodes always correlated with airplanes, crossing the path within a specific window soutwest of Munich defined by a path with a virtual end at the coast of the Adriatic Sea.
Most impressive was the crossing of an A380-800
At the end some bursts could be seen again (after 30 seconds)
The whole Test took almost an hour to complete, as my TX power is about 10 dB less than Paolos. It is evident that JT65 with 60 second periods is not very useful.
Paolos reference for ducting on the Adriatic Sea is IQ3ZB/B. Tonight it was at S9 + 30 dB. With good conditions it can be at S9 + 60 dB. So we agreed in continuing the tests in other digital modes and in CW as well as on 13 cm.
The other day I had a look on Dominiques QRZ.COM page and saw, he claimed to have a beacon on 13 cm as well. The frequency seemed to be quite strange: 2308.037 MHz
It´s because the situation in Switzerland is different, than in other european countries:
2300 – 2308 MHz with special permission only
2308 – 2312 MHz License classes 1, 2 and CEPT
2312 – 2400 MHz with special permission only
My new Kuhne MKU 23 G4 transverter covers certain segements of the band. so I switched to 2304 – 2306 MHz and tried to listen on an IF around 148.037 MHz and was disappointed: nil. I expected a strong signal as the same beacon on 1296.050 MHz ist up to 40 dB above noise under normal conditions.
A weak trace can be seen at the IF of 1392.032 MHz (LO 916 MHz)
I contacted Dominique and he assured, the beacon should be on air. So I tried with the setup, I received ISEE-3 quite a time ago and monitored the path for airplanes. So after a short while, there was a trace to be seen on 2308.032 MHz. Even the keyed carrier could be heard deep in the noise, when larger aircrafts crossed or flew along the path.
Characteristic “hook” at the begin of the carrier after keying the call
So I proudly added beacon #23 to my 13 cm list.
HB9BBD/B: 2308.032 MHz, JN47GA, 1662 m. asl, PWR 8W, ERP 100W beaming north
March 23rd, 2017, Update
I had a second try with the MKU 23 G4 this morning and was able to receive the beacon with this gear as well on 2308.032 MHz.