Tag Archives: JT65C

Disappointing Morning / Amazing Evening

August 17th, 2017

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.

G8MBU – JT65c Beacon via Aircraft Scatter

July 5th, 2017

After installation of new transverters for 23 and 13 cm with stabilized LOs a couple of months ago. I gathered some experience in using JT65C mode on EME. So I undertook a new attempt to receive and decode G8MBU via aircraft scatter today. As antenna I use a 3 m dish with a dual band ringfeed.

Path DJ5AR to G8MBU

The beacon is located at Cowes on the Isle of Wight, IO91IR37, 683 km from Mainz, JN49CV. It runs 2 W power into an omnidirectional dual alford slot antenna. The mode used is JT65c. Nominal frequency is 1296.800 MHz. To successfully decode the signal, the SSB dial should be set to 1296.7986 MHz, to get a tuning tone of 1400 Hz in WSJT.

There is a small window between the Isle of Wight and Mainz, where high flying aircraft can be “seen” from either places. But only a few airplanes cross the path within and fewer fly along the path. Reflections of G8MBU could be seen from time to time, but mostly too weak and too short to provide decodes. It took nearly 3 hours until the first decode happened at -22 dB and just some minutes later a second one appeared on the display at -21 dB:

1158 -22  4.0 1282 #* G8MBU IO90IR
1206 -21  3.9 1268 #* G8MBU IO90IR

In total I monitored G8MBU for 5 hours. The propagation conditions were normal today, no tropo at all.

Moon Bounce on 13 cm

April 28th, 2017

Sometimes you hear words that hurt. Especially if they are true: Some years ago I tried 13 cm EME with Dan, HB9Q, and couldn´t copy anything of him. His comment after the test: “There is no way, not to hear me!” This is frustrating.

So I forgot Moon Bounce on this band and had fun with other activities, mainly on 23 cm. But the over 30 year old equipment caused more and more problems. So I started collecting parts and modules for a new transverter system covering 23 and 13 cm. It had been finished for the last VHF/UHF/SHF contest in March and was tested with good results. In the end of March I tried EME again after 2 years of absence. On 23 cm it worked fairly, but on 13 cm the drift was a serious problem. In a test with Alex, ZS6EME, I could decode his strong Signal, but not vice versa. So I added 10 MHz Double Oven Controlled Oscillators as references to stabilize the transverters.

PY2BS in WSJT-X Wide Graph

Today I tried with Bruce, PY2BS, and heard him strong in the speaker during his prior test with Toshio, JA6AHB:     1131  -6  2.5 2305 #* JA6AHB PY2BS GG66
At this time his elevation was -1.7° and the moon still under the horizon. After the moon set in Japan, we started:

1155  -8  2.9 1184 #* DJ5AR PY2BS GG66
1157 -13  3.6 1157 #* DJ5AR PY2BS GG66
1159 -10  2.7 1137 #* DJ5AR PY2BS GG66
1200  Tx      1500 #  PY2BS DJ5AR JN49 OOO
1201 -10  3.1 1114 #* DJ5AR PY2BS GG66
1202  Tx      1500 #  PY2BS DJ5AR JN49 OOO
1203  -9  3.3 1089 #* DJ5AR PY2BS GG66
1204  Tx      1500 #  PY2BS DJ5AR JN49 OOO
1205 -10  2.9 1066 #* DJ5AR PY2BS GG66
1206  Tx      1500 #  PY2BS DJ5AR JN49 OOO
1207  -9  3.1 1043 #* DJ5AR PY2BS GG66
1208  Tx      1500 #  PY2BS DJ5AR JN49 OOO
1209  -9  2.7 1019 #* DJ5AR PY2BS GG66
1210  Tx      1400 #  PY2BS DJ5AR JN49 OOO
1211 -10  3.0  994 #* DJ5AR PY2BS GG66
1212  Tx      1400 #  PY2BS DJ5AR JN49 OOO
1213 -11  2.2  969 #* DJ5AR PY2BS GG66
1214  Tx      1400 #  PY2BS DJ5AR JN49 OOO
1215 -22 -2.5  946 #  RO
1216  Tx      1400 #  RRR
1217 -10  3.1  919 #* RR -20 DB
1218  Tx      1400 #  73 BEST -8

As he switched his RX from 2304.070 MHz to my TX frequency 2320.070 MHz at about 12:14, we completed very fast. I am very pleased now with my first initial on 13 cm, a new grid square, a new ODX, a new DXCC and a new continent! After setting up a new Initials List for 2320 MHz and writing this blog entry, I enjoy my “Radio Operators High”!

Digital World – Digital Moon

March 11th, 2013

Despite all the discussions about using digital modes in moonbounce I want to gather own experiences. After installing WSJT last Xmas I could decode a couple of stations on EME without any problems. First TX tests resulted in an intolerable frequency drift, which could be limited with the installation of a crystal heater. Then I started with real tests, but in all skeds no one could decode me! I had no clue what went wrong. So I changed – quick and dirty – the PC producing the audio stream. Now OK1CS, HB9Q and G4CCH could be worked in JT65C. Last sunday morning I saw a big signal in the waterfall diagram of my SDR. It was JA6AHB and it was a question of a few minutes to put him to the log. All stations worked so far, have been audible in my headphones.

I think, in general it is nice to use digital modes to work others via EME. But there is much more skill in involving the ears to have success in completing an QSO. It´s always great to HEAR the final rogers. Despite that I will not deny the use of digital modes. Why not working someone digital and then, maybe after some improvements, top it in working him in CW again? As long as all information like callsigns, reports and rogers, necessary for a complete QSO, have passed the radio channel, it will be a valid QSO. This is my position.

I will continue to explore digital modes:


The TX signal will be processed on my FT-987 with a seperate PC. RX is done with my SDR and another PC. By not typing in the other callsign or using call3.txt on the RX side I am quite sure in ‘really’ receiving the callsigns.