Tag Archives: Inversion

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.

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.

Presentation “Let´s Bounce” III

My presentation “Let´s Bounce” will be given on two more dates:

October 25th, 2014 on the 4th Hessian GHz Meeting in Fernwald

Short version of the lecture with focus on aircraft scatter and ISS bounce.
We meet at 15:00 MEST on the car park at the town hall. There will be a flee market for GHz stuff and the opportunity to test own equipment or to have QSOs with other participants.

Gaststätte “Ratsschänke”
Oppenröder Strasse 1, 35463 Fernwald-Steinbach
Locator: JO40JN33VG

November 7th, 2014, 20:00 MET on the monthly meeting of DARC OV Miltenberg, B24

Full Version with overview of propagation modes, aircraft scatter, ISS bounce and visual moonbounce.

Deutscher Amateur Radio Club e.V.
Ortsverband Miltenberg, B24
Gasthaus “Goldenes Faß”
Kirchstraße 13, 63920 Großheubach
Locator: JN49OR64JJ

If you like to attend or need further information, just send an email to dj5ar (at) darc.de

Presentation “Let´s Bounce” II

September 1st, 2014

ISS Bounce Title

After giving the presentation in english language in Clonbur, Ireland on August 25th, there will be two more dates in Germany:

September 13th, 2014 at the VHF/UHF/SHF Convention in Weinheim as a short version.

September 27th, 2014 at the “Distriktsservicetag” of DARC districts K (Rhineland-Palatine) and Q (Saarland) in Saarbrücken.

I will talk about how to surmount the horizon on VHF and up.

After giving an overview over the classic propagation modes Es, Aurora, MS and Tropo, I will explain, how aircraft scatter and ISS bounce work. EME will be subjected too and the presentation will be completed by an introduction to “Visual Moonbounce” as performed by Daniela de Paulis.

For the short version in Weinheim the overview over the classic propagation modes will be left out.

Article in “Funkamateur” magazine July 2014

June 22nd, 2014

German Funkamateur mgazine has published my article “Abenteuer Bakenbeobachtung von 144 MHz bis 10 GHz” in its recent issue July 2014. As many topics are related to posts on this website, some of them are compiled here. Links to certain other websites can be found in the link list to the right.

Weather, rainscatter:

Rainscatter on 23 and 13 cm
Impressive Thunderstorm

Weather, troposheric ducting:

Another strange constellation (Update)
Strange Conditions
Opening September 21st 2013

Aircraft scatter (video):

PI7ALK via Aircraft Scatter

List of beacons, heard by DJ5AR in Mainz, JN49CV

My new beacon list

Another strange constellation (Update)

February 6th, 2014

While performing my beacon check on December 16th, 2013 at 8:30 UTC, I stated that all beacons seemed to be at a normal level. Except, when looking for DB0FGB (JO50WB) with the dish heading 85°. There was a constant carrier of about 20 dB 15 kHz up, keying F1ZBK (JN38BP). Expecting a big signal, I turned the dish to France. But the beacon was only 15 dB with QSB, when beaming directly to it at 228°. Then I turned the dish back to 85° and noticed, that HB9EME (JN37KB) joined the party.

2013-12-16 09_30 F1ZBK HB9EME 85deg

DB0FGB, F1ZBK and HB9EME with dish heading 85°

The rain radar didn´t show anything unusual and the F5LEN Refractive index forecast for Europe promised only marginal tropo conditions for this area. Only DL7QYs Condition Index for south Germany has been on a level of 7 (1 = poor; 10 = extreme).

2013-12-16 09_00 F5LEN index

F5LEN Refractive Index

DB0FGB was a bit above normal at about 15 db with little QSB up and down. F1ZBK was constantly at 20 dB, when beaming 85° and around 15 dB with QSB heading 228° (direct). HB9EME was up to 20 dB in 85° and peaking 15 dB in fast QSB when beaming 198° (direct).

Green: Paths from Mainz to the beacons
Orange: Paths of the beacons to the area of the supposed reflection point

I checked HB9BBD, F5ZBS, F1ZBI and others, but couldn´t see any similar effects. The angle was very small. When turning the 3 m dish 5° left or right, the signals disappeared. These conditions lasted for about one hour.

Path DJ5AR to DB0FGB (by AirScout)

Topographic profile between DJ5AR and DB0FGB

The horizon in 85° is about 80 to 90 km off. A plausible explanation could be a strong troposheric duct between the beacons and a reflecting topographic formation.

Update:

In issue 2/14 the german magazine “Funkamateur” published an article by Matthias Hornsteiner, DG4MHM “Prognosekarten für troposphärische Überreichweiten” (Prediction maps for troposheric ducting). Matthias explains the basics of ducting and analyses the models, the well known refractive index maps of F5LEN and W. Hepburn are basing on.

So I had the intention, to ask him about a possibility for a reconstruction of the wheater constellation of that day. I have to thank him very much for his comprehensive answer.

As Matthias explained, the situation, shown on the map, was quite common for this, as he describes it, “anti-winter”. But it holds the possibility, that warm air might glide onto cold air at ground level. And indeed, when he reviewed the data of weather balloons launched at Stuttgart on that day, he found indications for a strong inversion in an estimated level of 400 to 600 m over south Germany. That matches!

In a distance of 200 km from here, the the topographic profile shows a formation, high enough to reach the level of this duct, as well as the mountains of the Fichtelgebirge do, where DB0FGB is located. The distances from Mainz to the area of the supposed reflection point is between 200 and 250 km. From F1ZBK and HB9EME it varies between 400 and 500 km. So the total path should have been between 600 and 750 km.

 

Strange Conditions

December 11th, 2013

It is funny to check the beacons tonight. Most remarkable are two constellations, shown below:

2013-12-11 21_59 DB0VC and DB0AAT

While looking for DB0AAT in JN67HU, DB0VC in JO54IF could be received too. When beaming to Kiel, DB0VC can be heard even on 2320 MHz. It is beacon #9 on 13 cm.

 

2013-12-11 22_23 DB0NCO beats DB0FKS

DB0NCO beats Frankenstein

From my QTH DB0NCO has the same bearing as DB0FKS. The location of DB0FKS, the  Frankenstein Castle, can be seen visually from here in a distance of 34 km. DB0NCO is 203 km away but tonight it is stronger than DB0FKS, when coming up in QSB.

Opening September 21st 2013

September 21st, 2013

While performing a last beacon check before going to bed and all local beacons were quite normal, I took notice of a weak carrier 1 kHz up of F1ZBK on 1296.855 MHz. After optimizing the antenna and using a narrow filter I heard EA2TZ in IN93BF over 1073 km for the first time ever.

2013-09-21 20-50 EA2TZ

Left signal: F1ZBK/B, right signal: EA2TZ/B

 EA2TZ/B as received by DJ5AR over 1073 km on 23 cm

After posting this information in the ON4KST chat, Matej, OK1TEH sent the phone number of EA2TO and told me that Javier is currently QRV on 23 cm from IN83. After exchange of a few SMS he came back on my CQs and we could complete a QSO: A new DXCC, a new square and a new tropo ODX of 1173 km on 23 cm!
When closing down the station I had a quick look on 70 cm. There he was again: EA2TO in SSB. We had a nice chat and for me: A new DXCC, a new square and a new ODX of 1173 km on 70 cm!

Only 2 QSOs tonight, but I am very happy with it.

Opening November 14th – 16th

November 18th, 2012

Just a few contacts could be logged, because I was short in time during this opening. But some new squares were worked on 23 and 13 cm. SM7ECM in JO65nq was a new country on 13 cm.