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.