Category Archives: Tropo

Strange Conditions Today

January 1st, 2020

I got up quite early today and decided to check the beacons on 23 cm. When beaming to LA1UHG, there was a noticeable signal in F1 about 1 kHz above its frequency. It was easy to read it as DB0LB from the back of the dish. But it seemed, there was another faint signal right beside the spacing carrier. With the help of my SDR radio I could set very narrow filters and after a while of listening, I identified it as LA1UHG, JO59FB, 1028 km. Wow!

But the signal faded out more and more and at least it disappeared.

LA1UHG just 140 Hz below the space carrier of DB0LB

Later this morning, the dish still pointing north, I heard Kurt, OE5XBL, chatting in SSB with Rudi, OE5VRL/5, both with very strong signals on 23 cm. Expecting a huge signal, I turned the antenna to Kurt, but there was no significant increase in signal strength. I called in and the three of us were talking about the conditions and to meet for a beer at the GHz convention in Dorsten next February, when Kurt was called by Dave, G4RQI. I had tried with him earlier without any success, and so, to be honest, I was a little annoyed by this. Even, when turning the dish to the UK, I couldn´t copy anything of Dave’s transmissions, while he was working Kurt and Rudi. These were enough indications, that the inversion was at a too high altitude for me, to enter it. So I went for a long walk with my XYL in the nearby vineyards.

The inversion is at an altitude of about 1000 m (Courtesy DWD)

In the evening I performed another beacon check. It was funny to see beacons, the dish was pointing to, as well as others from the back of the dish

Dish pointing southeast: DB0UX, DB0VC, DB0AAT (from left to right)

Turning the dish, confirmed the experience I had in the the morning: Pointing southeast I saw DB0VC, JO54IF, next to DB0AAT, JN67HU. Turning the dish towards Kiel in the north, the signal of DB0VC increased just a little. Maybe, it has been reflected by a mountain range about 50 km southeast of me.

Dish pointing north: DB0UX, DB0XY, DB0VC, OZ7IGY (from left to right)

F5ZNI: Beacon #34 on 13 cm

December 29th, 2019

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

F5ZNI and DB0UX in PowerSDR

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:

BeaconNominal FrequencyLocatorLast SpottedLast FrequencyStatus
F6DWG2320.900JN19BQ2019-05-312320.898Dead/lost
HG3BUC2320.900JN96CC2019-10-112320.897Operational
OZ5SHF2320.900JO45VX2019-08-242320.900Operational on spot date
DB0MJ2320.900JO31UB2019-12-292320.905Operational
ON0TB2320.900JO30BM2019-09-202320.897Dead/lost
DB0UX2320.900JN48FX2019-12-292320.900Operational on spot date
F1ZCC2320.900JN08XSUncertain - new spot required
SR1SHS2320.900JO73PG2019-12-302320.900Operational
IQ5FI2320.903JN53SR2019-12-282320.901Operational
F5ZNI2320.904JN19BQ2019-12-302320.899Operational on spot date


Depending on the location and the conditions, there will be more or less interference on 230.900 MHz

So I am urging all beacon keepers to make use of the service provided by the
IARU R1 VHF/UHF/MW Beacon Coordinator. When designing a beacon, please respect chapter 11 “Beacon Requirements” in the IARU-R1 VHF Handbook.

OZ7IGY and friends

December 22nd, 2017

Tonight I monitored OZ7IGY on 2,320.930 MHz via aircraft scatter. It was nice to see other beacons appearing shortly in the waterfall diagram.

OZ7IGY and friends in time lapse

From left to right:
2.320.900: DB0UX, JN48FX, 105 km, tropo
2,320.910: DB0XY, JN51EU, 263 km, aircraft scatter
2.320.920: DB0VC, JN54IF, 509 km, aircraft scatter
2,320.930: OZ7IGY, JN55WM, 670 km, aircraft scatter

The dish was bearing 20° to OZ7IGY. The -3 dB beamwidth is just 3.2° on 13 cm.

 

A digital evening on 23 cm

October 25th, 2017

There was nice activity in JT9F on 23 cm tonight. It seems this mode works fine with aircraft scatter. I first worked Conrad, PA5Y in JO21VO (255 km) and Sam, G4DDK in JO02VO (540 km) via Tropo. Then logged a QSO with Neil, G4BRK in IO91HP using mainly aircraft scatter. In another test I decoded Neil, G4DBN in IO93NR (756 km) by reflections on airplanes. PA0JME and ON5KTO were calling CQ, but not replying to my calls. Instead I worked John, G4BAO in JO02cg (619 km) in an (too) easy way.

Worked stations in green, the heard ones in blue.

Anyway, it was a promising and exiting evening!

Addendum October 27th, 2017

Yesterday I logged Rien, PA0JME, Wim, ON5KTO and John, G4ZTR, also in JT9F on 23 cm.

Chatting with John, G4BAO, last night, I learned, he recently initiated a “Digifest” on the microwave bands every Wednesday. This resulted in what happened two days ago. In my opinion it´s a very good idea to have such an activity evening beside the regular contests.

Windmill Scatter

August 30th, 2017

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.

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.

Nice Tropo this Afternoon

December 20th, 2016

There is some nice troposheric propagation this afternoon. It looks promising for the NAC, IAC and UKAC this evening on 23 cm. When looking for DB0XY I saw this situation:

2016-12-20-14_00-23-cmHopefully it will last for some hours!

Strange Tropo today

September 28th, 2016

During the morning I was able to monitor GB3FM in IO91OF on 1297.050 MHz and G8MBU in IO90IR on 1296.800 MHz. Now in the afternoon F5ZCS in IN87PT on 1296.959 MHz came out of the noise with a strong signal of 549 with fast QSB. It is my 53rd beacon on 23 cm. The weather here in Mainz doesn´t look like tropo: 8/8 cloudy and wind at 40 km/h.

2016-09-28-13-00-f5zcs

Listen to F5ZCS:

2016-09-28-f5zcs

Opening February, 10th and 11th 2015

February 12th, 2015

The first remarkable opening for quite a long time happened from 10th to 11th of February 2015. F5LENs refractive index forecast promised good conditions for these days. It started with some stations from G, appearing on 2 m. While the activity contests were going on in Scandinavia and the UK on 70 cm, a few operators dropped into the microwave chat. At least two new DXCCs could be worked before going to bed: Steward, GM4AFF in IO86TS and Gordon, GI6ATZ in IO74AJ as no. 30 and no. 31 on 23 cm. Only a few beacons could be heard via tropo: GB3FM in IO91OF, GB3MHZ in JO02PB, PI7ALK in JO22IP, OZ5SHF in JO45VX and OZ1UHF in JO57GH as a new one.

Green: Stations worked on 23 cm Red: Beacons heard on 23 cm

In the morning the inversion had moved to the north-east and never before heard beacons from Sweden became audible on 23 cm. SK6UHI in JO57TX, SK6MHI in JO57TQ, SK6UHI in JO97CJ and SK4BX in JO79LI over 1138 km as my new beacon ODX appeared on the band. Many of the Swedish stations were as loud here as locals. Some of them could be worked on 13 cm as well.

Chaos on 1296.942 MHz!

November 28th, 2014

2014-11-28 10_13_55-OK0el vs DB0AJA

There are good tropo conditions to the east from here for quite a while. I worked OK1MAC on November, 26th with an outstanding signal. OK0EA, SR6LHZ can be monitored constantly. I missed OK0EL on 1296.940, but solved the miracle today. The frequency shifted to .942 and the signal has been covered by DB0AJA. It´s nice to listen, how OK0EL in 526 km distance is battling against nearby DB0AJA,131 km away. As can be seen, DB0AJAs signal is accompanied by several dopplershifted reflections on airplanes.

 

It is interesting to see, that F5LENs refractive index as well as Hepburns tropo index don´t really illustrate the real conditions today. The conclusions is: Always perform a beacon check before switching off! The result may be surprising.

2014-11-29 09-00 F5LEN DJ5AR OK0EL