 ON TWO METRES FROM SNEZKA (60 years ago) Foreword For VHF traffic in the 1950's (and the beginning of the 1960's) separate transmitters and receivers were used. Transmitters were usually in the output power category of around ten up to a few tens of watts, and the driver was a fixed frequency crystal oscillator. The most usual transmitting mode was CW, or for local voice operation, simple but not very effective AM modulation with an un-suppressed carrier. No SSB or narrow band FM was available at that time on VHF. Each station operator tried to publish his fixed transmitting frequency as widely as possible. Because the density of operation on 2m was low and there were no packet radio or FM repeaters, QSOs between two stations on the band, with each of them on a different fixed transmitter frequency were more or less the rule. Of course, it required quite a different kind of operation (particularly in contests) than it does today. On the receive side, front end converters with valves were used - such as ECC88 and similar, mostly in "cascade" (similar to TV set tuners), which surprisingly had quite a good noise performance - some even less than 3dB. On the IF side different HF receivers were normally used, very often these were surplus receivers from the Second World War. One of them, a German "Emil" was used by OK1VR for these record contacts.
Much more effective transceivers,
which allowed the transmitter to be tuned over the whole band together with the
receiver, became routine (particularly in contests) for VHF amateur radio
operation in the second half of 1960's, mostly in
conjunction with an SSB driver and demodulator. With permission from Jindra OK1VR [1] we publish here a transcript of some of his old articles, originally published in 1959.
On Two Metres from Snezka ... When I decided to do some tests on 145 MHz from Snezka ("Snowhill") [2] (the highest mountain in the Czech Republic, 1602m asl, in the Krkonoše Mountains), there were a number of reasons. Firstly I wanted to verify some knowledge about tropospheric propagation on VHF, which I had learned during my observation of meteorological situations in connection with vhf propagation during the previous two years, and secondly, I wanted to achieve many contacts over longer distances when these conditions occurred. From my home QTH in Prague I have a good takeoff in the directions from east round to south and south-west. Other directions however (from a VHF propagation perspective) are not good because I have a very close horizon, with a relatively large angle to the horizon. Therefore I cannot benefit in these directions even in the event of favourable conditions for long distance contacts. These are the very same directions, where in the present situation it is possible to make DX contacts, i.e. it is only in these directions that there are stations at a greater distance (800 to 1200 km) who are QRV and prepared for long distance contacts. It does not mean, that in France, Italy, Yugoslavia or Hungary there are no stations to work, but it is however general knowledge, that operation from the home QTH is still not very popular there. Of course, in France VHF traffic is very intensive, especially on 72 MHz [3] but international contacts on 145MHz especially in an easterly direction, are less frequent and achieved mostly during contests. In considering the realities, I concluded that in my current situation and with the equipment I used, I couldn't expect much from my home QTH. I would not be able to succeed in making any tropospheric contacts longer than 530 kilometres, which I made to the south-west, almost on the French border.
Left: Krkonose's mountain "Giant valley" from Snezka Having told you the second reason why I decided on Snezka, in the Krkonoše Mountains, it is a pity that similar interests are not shared between at least several other VHF amateur radio operators. That would surely increase interest in VHF transmission from many other advantageous places, mostly situated in beautiful mountainous regions of our native country, and the OK prefix would be heard more often by other long distance VHF ham radio operators abroad. Well, I want to apologise for this small diversion, and I promise that from now, I will try to avoid descriptions of nature, and to pay attention to our common interest. Unfortunately it is unlikely that interest in transmitting from portable QTHs will grow, when even those who have suitably accessible hills (even by cable car) close to their homes, have not visited them except during VHF contests.
For the very first time, I turned on my equipment on Snezka (my 15th VHF portable QTH since 1948) for the operation on 12/10/1958 shortly after noon. The day before, we had arrived at Pec below Snezka village in the company vehicle, to do some voluntary work to the company recreation cottage which we had to prepare for the winter season. Originally I didn't have any intention to do any radio transmission on the Saturday, but I changed that decision when I found out that Saturday would be the last ride of the funicular, because the holiday season had finished. I hastily shipped all of the equipment and supplies using several seats, and in about twenty minutes I unloaded it at a height of 1602m. After a quick check that everything seemed to be OK after the journey from Prague, I returned to Pec on foot to fetch those things which I had not taken, or rather which I had forgotten in my haste. I returned in the evening, with a fully loaded knapsack. Although I took a week’s holiday for this, my first trip to Snezka, I was happy that I finally did it. I did not expect any special conditions in a westerly direction, or to the north-west or north. At that time, there was a low pressure centre which did not promise any hopes of good VHF propagation. Essentially it was more promising in an easterly direction, where the area of high pressure weather moved slowly away to the east, which created the good conditions for VHF propagation a week previously. Anyone who does not remember can check in his log that the conditions were good. OK2VCG from Brno (Moravia) was received in west Bohemia during the previous week with a very strong signal - maybe the strongest he has been in any of his previous activity. (Note: OK2VCG, later OK2WCG is now ZS6AXT).
Right: Czech hut at the top of Snezka - silent witness to many OK record connections on VHF - demolished in 2004 After midnight the first part of the SP9 Contest ended, and the band faded out. I still tried to catch several other stations from the east. To confirm that nothing more was on the band, I turned my antenna in the opposite direction, and after half an hour went QRT and went to bed, there was nothing more on the band. On the morning of the second day, I repeated QSOs with some of the previous day's partners, with a few SP stations, and also with many OK1 and OK2 stations.
On Monday in the late afternoon I returned to the summit of Snezka, which I had left on Sunday to cover my pledge as a voluntary worker. The weather and conditions were already considerably worse, and the only DX was OK3VCH from Trencin (Slovakia), and I was very pleased with that QSO. He said that he was on the band every Monday and until now he has made just a few, more or less local (up to 250km QRB) contacts with OK3VCO, OK2GY, OK2VCG, OK2VAJ and OK3KYY. I did not hear either OK3KYY or any of the other stations from the Bratislava area. I finished Monday’s transmissions with SP6CL, who is well known for his "180 element antenna". It is not his own antenna, but the broadband aerial of the Wroclaw TV transmitter on the highest channel of television band III (223 MHz). SP6CL used only a very simple transmitter with a 6N3P vacuum tube to transmit into that, and after the end of TV transmissions he was always on the band. With that arrangement he even made contact with HG5KE in Budapest. Although this aerial is out of the 2m band, I am quite sure that it has much more gain than other amateur radio antennas and if SP6CL had better equipment, he would have perhaps been surprised at what he could work. But of course there remains the question of whether his transmissions could still be called a ham radio operation. SP6CL was the very last station that I worked on 14/10/1958 from Snezka Mountain. Snow and rain, and more snow and rain brought my "holiday" to an untimely end. At that time however, slowly but surely, the conditions were forming for an improvement in the weather as well as in VHF propagation. Above the eastern part of the Atlantic Ocean a large area of high pressure was building, which very slowly began to migrate towards the European continent. Cold front disturbances moved much further away above northern Scandinavia to the east. Every day at 07:50 I checked attentively the detailed weather report on the Prague II broadcast station.
25/10/1958 - The second visit to Snezka On Saturday morning 25/10/1958 a high pressure area began to move from Great Britain over the continent. From a detailed analysis of the whole meteorological situation, I concluded that in the next few days there would be quite a high probability of DX contacts, and because of that I decided go to on another visit to Snezka, this time with the intention "to do" something. Weighed down by my bulky knapsack, I started the 170km trip to the Krkonoše Mountains on my old JAWA motorbike where I arrived after more than 3 hours drive at 16:30. The last task was the ascent up Snezka, which was complicated by slushy snow and a local change of weather had caught me half way up. Finally I was happy that at 19:00 I was inside the Czech hut on Snezka [4]. Because the wind gusts were more and more intense, I had no chance of working any DX, particularly because it was impossible to erect a mast and my 6.5m long antenna because the weather conditions were so bad at that time. Probably the southern edge of some minor cold front hit the northern part our country and created wind gusts over 120kph. Because I was unable to construct a full antenna outside the building, I made a half size antenna inside the roof space. After several CQ calls I made my first QSO with OK1AZ (silent key 2003) and after that with OK1QG, OK2VCG, OK1VMK (Mirek was in 2003 still active!), OK1KCG and OK1VBB. I heard DL7FU, but did not make contact with him. Next day, on Sunday, the wind was weaker, but still it was not good enough to build my long antenna outside. The best DX on Sunday was OK2AE and finally after 22:00 DL7FU. On Monday, as I expected, the stormy atmosphere of the northern Czech border region started to become calm enough to be able use the front part of the high pressure area. It had moved slowly to the east, but the first morning view from the window did not promise anything positive. It was still the same weather as on Sunday, thick fog with visibility only up to 20 metres, and the wind although a bit weaker was still quite strong. I waited impatiently for the main morning weather forecast on the Prague II broadcast station. Fortunately it was brilliant. The high pressure area had moved very slowly to the east, the southern tail of the previous frontal disturbance had also moved to the east, and other similar disturbances moved more to the north-east and created a relatively high level temperature inversion which became more and more intensive. Well - although we still had a relatively strong wind, I began (with the help of SP6CT/p) to erect my long Yagi aerial. My first CQ with an eleven element Yagi on a 6.5m high mast above the highest Czech mountains was in a south-easterly direction. I wanted to test the VHF path to Bratislava, from where during my first transmissions from Snezka I got a very nice report. But there was only noise on the Bratislava station’s frequency. My second CQ was answered by OK3VCH from Trencin with RST 589, which confirmed that it was possible to contact Bratislava on VHF. After a short QSO with OK1KLR at 17:35 I tried again several times to call CQ OK3. It was not easy to keep the ice-covered antenna in that direction, because the wind was constantly fluctuating, and turning. After a short break at about 19:00 I called CQ OK3 again, and heard nothing. Once more, I tuned up and down the band - - and then - - suddenly on 144,24 I heard very weak telegraphy. It was relatively fast but I heard OK1VR OK1VR de G5YV G5YV +k. In that very first moment it seemed improbable, but then he went over to receive. I answered quickly, and soon received RST 559 QTH Leeds 300 kilometres north of London operator Harold, and the first contact between Czechoslovakia and England on the 145 MHz band became a reality at 27/10/1958 at 19:40 CET (QRB = 1220 km). It was indeed Harold Beaumont, G5YV, one of the most successful VHF enthusiasts, who in recent times had made a lot of VHF DX contacts with amateur radio operators in distant countries. It was the same G5YV to whom I had sent a message before my departure to Snezka via OK1KPR and OK1UK. I definitely didn’t think that it would have been possible to make a DX QSO so early in the evening, not because of the propagation, but because I knew that western European stations started activity on the 2m band mostly after 22:00. G5YV evidently got my info, and was so keen not to miss the opportunity of a first contact that he had started to keep a watch on my frequency much earlier than I had indicated in my message. As quickly as he had appeared, so he disappeared. The antenna was without doubt beaming north-west, and it stayed so, even when I let go of the icy antenna mast. A continuous north-west wind kept it in that direction very neatly. Never had the wind been so kind to me as at that time. I started to scan and watch the band carefully, in an effort to catch some more DX stations. Very carefully and slowly, I tuned the receiver from the bottom of the band to the top, and back again. It was difficult and tiresome especially with strong interference from tens of beats from the video sidebands of Dresden TV [5] which near the vision carrier frequency created a continuous strong hum in my headphones. The relatively wide IF of my Emil receiver was not able to tune in between the stronger and stronger sidebands every 15khz close to the vision carrier and it was followed by periodic fluctuations in my S-meter, which didn’t drop down much, even between the beats. However there was nothing I could do about it. I wasn't able to take my second IF receiver with a really narrow IF, which I normally use in conjunction with my Emil at home, due to its weight. There remained therefore, nothing else that I could do other than to make the best of the situation, and to resolve it only with my available resources. On the contact with G5YV I was already convinced that I had the antenna in the right direction - by misaligning the antenna to both sides. The signal in both cases quickly faded out, which was understandable because of the small side lobes (25 degrees). Based on that I had an idea that the interference from Dresden TV could possibly be reduced somewhat, if the antenna was adjusted so that the Dresden direction was in the first minimum between the main and first left side lobe. I guessed that the direction of Dresden must be somewhere to the left of the direction to England (I didn't have a map). Moving the antenna from its current direction on both sides of the TV vision carrier however always moved the S-meter like a skyrocket, which meant that Dresden was already in the null of the antenna. Nothing could be improved, but the situation in the end was better than I had hoped. Above all this, I had some hopes that after 22:00 the television transmitter would become silent. However I wasn't confident about the stable and favourable conditions continuing, or whether the contact with G5YV was just matter of short-term improvement, although this second explanation seemed to me unlikely, due to the general character of the weather situation above Europe. I had it on my mind, when I kept re-tuning the band, especially in the top and bottom thirds, where TV interference did not obstruct reception. I put out a CQ several times, but I got no response. When I was convinced that there was nothing else to hear, I answered a call from a local station at a much lower altitude. I wasn't sure what to think when the operator of that station answered me and said, "Why didn’t you tell him that I am on the band? I certainly think he should hear me as well!" I made a suggestion that he listens on my frequency, and that I would inform him about the frequencies of the next few stations in the event that I hear more of them, he replied that he could only be on the band for half an hour, not more. It was a shame. Perhaps he would also have made a QSO with G6LI because OK1YV had stayed listening to him on the band until 02:00 even though he had not yet finished building his transmitter. Once again, I returned to tuning the band systematically. At 21:30 I heard on 144,31 i.e. on a frequency that has not been used by any OK station, a weak CQ, CQ CQ - at RST 549. Again several times CQ CQ CQ, and then I heard . . .de G6LI G6LI. He repeated it again, and went over to tuning up and down the band. Once again, he called and tuned the band for a call. I called briefly, tuning the band for his reply . . . and straight away I receive G6LI. RST 559 Grimsby (1150 km) input 300 W, and some words of enjoyment on a beautiful contact, and a new country for him on 145 MHz. My mood had increased by about 100%. The conditions were there, but there were no other Englishmen are on the band yet. It was evidently too early for them. After that, I carried on tuning the band much more optimistically. Several times I called CQ, but nobody called me back. Within a short time my mood started to go down again. In the same way as G5YV had done, G6LI also disappeared and except for our local station and TV interference, nothing else was heard. An hour later I heard (on the frequency 144,65) someone calling my call slowly and at length. The signals were very weak. I waited impatiently for the call sign, and at last from the unknown station I picked out SP5AU from Warsaw. I then turned my antenna towards him and in a short contact informed him of the news on the band conditions. After that contact, I returned the mast and the icy antenna to the original direction. The wind was already very weak, but it still kept the antenna in the right direction, where there was minimum wind resistance. Fortunately, the wind was blowing exactly from the north-west. I then started to call CQ without first tuning across the band. I went over to receive, and I was then tuning very slowly from the frequency of SP5AU towards the bottom of the band. On 144,2 someone was calling in German. It was DL3YBA, who informed me that G3HBW was calling me on 144,14. I tuned about 60 kHz lower and there I heard G3HBW at strength 559. The contact occurred at 22:45, and I got RST 569 vfb = QTH Bushey (1250 km) = name Arnold …and once more full of enthusiasm, we exchanged some brief words about the contact.
Left: Top of Snezka in Summer. Contacts were made alternately. Either I called CQ, or I answered the calling stations, which transmitted the CQ. It really was an amazing hour. After 23:00 when Dresden TV became silent, I had no interference and could make all the contacts 100% reliably, and at S3 or S4 signal levels. What was interesting, is that on not one occasion did I see any fading on the signals, which is what usually happens on reception of DX signals. Every station I received was at the same level throughout the contact. This put me in mind of early morning 80m traffic in winter, when there are just a few stations from the periphery of Europe or from North America on the band. After the QSO with G3CCH at 23:41, I stopped calling CQ and carefully checked the entire band. I felt, that beside G stations it would be possible to work something else. Suddenly at that time I became aware that except for G stations I was not hearing any continental stations. I did not even hear any of the DL stations, which the Englishmen had contacted. The only receivable DL station was DL3YBA and that was only when he turned his antenna to the east, to call me. In my VHF work I had not had that experience before. It seemed that all of continental western Europe lay in some "dead zone" similar to what happens on the HF bands. Several times I turned my antenna to the north, but it was the same - no signals from there. Well, I returned to the previous direction. Only G stations, which I had already worked, were on the band. Some of them switched from CW to voice with signals about RS 57. On average, the received signal level of all the G stations had increased slightly, but not much. Unfortunately my search for any GM or GW stations was not successful. At 00:43 I called G5YV again, I heard him now 579. He gave me 589 vfb and we exchanged some information about conditions. I told him that SP6CT/p would be on the band the next evening, and asked him whether there was anyone from GM or GW on the band, especially GM2FHH and GM3HLH, who I knew were active. Harold G5YV told me, that during the evening GM3HLH was on 144,140 MHz, GD3UB (!) was on 144,030 and GI3GX? was on 144,025. After the QSO with G5YV I tried searching the band again, especially in the bottom third. All the G stations I heard were up to 144,600 but no higher. I had already stopped calling CQ. It was already quite late (after 01:00) but I was not very tired yet. On the contrary, I've never perhaps tuned with so much concentration and listened to the noise so intensely. With my eyes closed, I tried to "fish" any weak beats from the monotonous noise. Shortly after one o'clock I caught on the edge of the band, perhaps on 144,03, a wafer-thin beat, which from time to time popped up slightly from the noise. It sounded like an AM telephony carrier on the band. It was a perfect stable crystal beat, hardly perceptible above the noise or rather amongst the noise, into which it sometimes disappeared, so that I rather anticipated it than heard it. For several minutes I listened intently to it. If it was an amateur station, it was evidently working on voice. The wafer thin beat however went on endlessly with slow fading all the time. It seemed to me to have already gone on too long. Perhaps it was a harmonic, which I had not heard earlier. The aerial was pointing in the right direction, and by moving the antenna in turn to both sides, the signal quickly disappeared. I tried looking for other signals, but there was nothing except noise and several sporadic beats on known G station frequencies. I returned once more to 144,03 . . . only to hear noise. There was no signal there. Then there was a station. I then tuned only at the edge of the band and at the same time looked at the log notes for my contact with G5YV. Only now I was aware that it could be GD3UB on 144,030 or GI3GX? on 144,025. I was almost holding my breath, when I realised it. On 144,03 however (I was unable to read it with better accuracy from my receiver) there was only noise for several minutes. Now and then it seemed to me that I heard some beat, but it could actually be just in my imagination. I put down the headphones, a bit tired, and there was total silence. I had not heard that before on Snezka. The wind had died down, and there was silence and calm. The moonlight marked the ridges of the Krkonoše Mountains over which, slowly and almost imperceptibly a lump of fog rolled in. The nearest fog cloud was moving slowly across the ridge that marked the border.
Down in Karpaci on the Polish side several lights shone. I
looked up at the icy antenna. The beam was sagging a little at the ends from the
weight of the ice and all the elements were a little thicker, but it was still
elegant and upright, covered in white sparkling frost, and there was not the
slightest movement in the moonlight. It was magnificent, but no sentences
written in the excitement could do justice to the serenity of that moment. I took one more look at the ridges along the border and then I returned to the receiver. The incandescent rectangle of the tuning dial, the reddish light of the stabiliser, the glowing red cathodes of the tubes in the transmitter, the weak hum of the transformer and the weak noise from the headphones return me to 30 kHz above the edge of the band. Once again I heard the sound of a wafer-thin beat, but by now the transmission intervals were shorter, and from time to time I looked around during the breaks. It was already half past one, and there were only two G stations heard on the band. Back again on 144,03 and . . . in the noise is a very weak peep . . . .G3DVK G3DVK de GI3 - - GI3G?? + k. . . . It is GI then. I shuddered in my back to think of it. I retuned quickly to 144,32 where at 11:08pm I had worked G3DVK. But there were no signals from him. He had evidently turned his antenna in another direction. I came back to 144,03 and waited, and then I heard GI3 again. I tuned impatiently a few kHz around his frequency . . . and then I heard a stronger peep just coming out of the noise - - - so nw qru = tks abt OK1VR = hi hi = and will look on his freq = hi = so 73 es gb dr G3DVK de GI3 - - + sk. G3DVK had evidently informed him about the contact with me and GI3GX? (the last letter was still uncertain) responded - "hi hi" - as if he did not think it likely that he would work me. In all events it now looked very hopeful. I knew that this was the most favourable moment, so I started to call him and after that sent +sk several times. I don't know how to express the feelings that I had in the next few seconds. 144,025 . . . only noise . . . no, a very weak peep . . . It just rose above the inevitable noise. . It was not readable, it was very weak . . . It was a shame that I didn't have my second IF there. I occasionally received some fragment, several letters. It was evidently an unfavourable moment when even a slight fade drowned the hardly perceptible signals hopelessly in the noise. All the time I was not sure whether it was for me, although I believed that it was. At last the signals became stronger, and by now it was the end of his transmission - I entered in my log "GI3GXG + k". I answered relatively quickly and briefly, so I could catch his reply at a sufficient level, the same as at the end of his last transmission. I switched over to receive . . . and GI3GXP was replying clearly and legibly . . . most ok om es tks fer fb rprt = ur rst 549fb = qth Kilkeel nr Belfast = call hr is GI3GXP GI3GXP = hw cpi? +. I replied with my report for him 539, QTH Snezka 120km NE Prague plus some other necessary data. His last transmission = rfb Jindra solid - ur rst 549fb = name Bill = hw qru so tnx fer fb qso best 73 es gb + sk. End It was almost two o'clock in the morning of 28/10/1958, but I tuned the band several more times up and down, to see whether anybody else was calling me, but I did not heard any more stations. On switching off all the equipment, the shining rectangle of the tuning scale got dark, the hum of the transformer stopped, the neon stabiliser went down slowly as if it didn't want to, and the cathodes of the tubes discoloured from dark pigeon's blood and went black. The transmitter and receiver at that moment were radiating energy only in the infra-red spectrum and I warmed my numb hands on the pleasantly warm case of my good Emil receiver, which has passed the test!
I was looking around, among the sleeping ridges and the valleys of Krkonoše, a last view of the silent antenna and at 02:30 at last I climbed into my cold sleeping bag, but with a warm glow from a job well done. I was very pleased with myself at that moment. I had a taste of achieving a record contact. The joy was even bigger, because it wasn't easy, but it was hard earned from start to finish. These impressions were so vivid that I was unable to fall asleep until sunrise. I paid special attention to the morning meteorological situation report for gliders. I needed to know more about the atmospheric conditions of last night. It matched my assumptions, and in addition the conditions should be even better today. Unfortunately I could do nothing, since my holiday was over. I then wished Lesek SP6CT much success on the band, but unfortunately I had to return to Prague. If only I could have stayed on Snezka at least one more day! I knew that I probably would never make a longer distance QSO again, but it was still a unique occasion to QSO with more new countries. But during that evening, Lesek SP6CT/p on Snezka achieved what I was unable to do, since I had left the mountain. Conditions were really magnificent again. Even with only a 5 element Yagi in the roof space SP6CT/p worked with G, SM and LA stations. These were (except for SM) "first" contacts with Poland. My signals were received in England at an average RST 55/59, but SP6CT put a signal into England for a few hours with 599 plus. How I wished I could have been there with my long antenna... I knew that I must return to Snezka again. Not immediately, but during suitable tropo conditions. Partly to try to make more DX contacts, but largely to prove the correctness of my theories about the connection between certain weather characteristics and VHF propagation. Essentially, what it came down to was that it could only be a Saturday, because unfortunately I had no more holidays left. The Saturday that would be planned as a result of my theory was 22nd November 1958.
October 1958 - A review The DX contacts made during the last week of October 1958, particularly on the 27th, 28th, and 29th still retain the interest of the VHF section editors of almost all the European ham radio magazines. I would therefore like to make a short and fascinating overview of those days, before I inform you briefly about my third visit to Snezka on 22/11/1958. The circumstances of the DX contacts and the facts about those days are so interesting that even five months later they are still topical. Between the 27th and 29th October 1958, for the first time in history, the occurrence of so called tropospheric "ducts" high above the surface of the European continent was demonstrated. Also for the first time, that duct was utilised for DX contacts between Snezka and England on 27/10/1958 at 19:40 CET. These ducts are known by experts in coastal regions, where similar ducts occur just above sea level and can make it possible for VHF and even shorter wavelengths to travel hundreds of kilometres beyond the horizon. But the phenomena that occurred on these days may have been rather different. The conditions that create a duct above sea level are probably not identical to the conditions that create a duct high up above the Earth's surface. Similarly, their characteristics relating to the propagation of electromagnetic waves are different too. In a duct just above sea level, the electromagnetic waves are carried between the water surface and the inversion layer. In the case of high ducts, two layers are necessary to carry waves in between them, and the minimum frequency that can be propagated is related to the vertical distance between the layers. But definitely there are some similarities. Signals moving in such an "air waveguide" limited by two layers, are carried for a considerable distance, and evidently only return to the Earth’s surface in places where the lower inversion layer is disappearing. This phenomenon occurred several times during these particular days. I had already anticipated the existence of such an air waveguide at that time, when except for G stations I did not hear any other continental station make contact with these G stations. That is with the exception of DL3YBA and DL7FU whose signals were very weak over the short distances between us. I did not hear stations OK1EH, DL3SP and DL6MH at all, and these stations would normally be quite strong on Snezka in normal conditions. These stations conversely did not hear any G stations. When ON4BZ, a well-known "145 MHz countries hunter", found out by listening to English stations that they had made contacts on the band with Czechoslovakia, he turned his antenna eastwards to try to make contact with me. Although he knew my frequency, he did not detect even the weakest signal. Instead, he made contact with DL7FU, which was a new country for ON4BZ. Similarly I knew that ON4BZ was on the band and from time to time looked on his frequency (144,925), but however I did not hear him either. Contacts between ON4/DL7 were made my means of a lower inversion layer, which prevented me from being heard in ON and PA. (Beside ON4BZ several PA stations tried to catch me as well.) The first contact between ON and OK was within reach however, because ON4BZ had told a foreign magazine that he had heard a very weak OK1EH. The high pressure had evidently created favourable conditions for the formation of a high-level inversion layer (2200 m) above all of Europe, and at the same time has (thanks to that high pressure) created a second, lower perhaps more widespread inversion layer. This was not formed above sea-level, so that the electromagnetic waves were only returned to the surface at the edge of Western Europe, transported in an air waveguide or duct between these two inversion layers. The signals of the English stations on the contrary could also penetrate below the lower layer as well as above it into the duct. During the night of 27th/28th October the contacts between Snezka and England were the only ones, and distances less than 800kms were bypassed. The other contacts were more or less local between ON, PA, DL and G stations. But the day of fantastic conditions was however reserved for the next day, on the night of 28th/29th October, that is at a time when unfortunately I couldn't be on Snezka. All those who have been interested in monitoring DX conditions over a period of several years would agree that in such conditions, not everything was observed. SP6CT/P on Snezka with only a 5 element Yagi in the space below the roof was S9++ for a few hours in England and in other Western European countries, and beside G stations he had worked ON4BZ, more PA and DL stations and even had a QSO with LA8MC. As a matter of fact, LA8MC had used only a QRP transmitter with about 8W input and a 3 element Yagi. All these stations received Lesek, SP6CT/p at very strong levels and he heard them even without an antenna - only "on a screwdriver". That day could be called on a European scale a day of really fantastic conditions, when enormous distances were covered - from England and from southern parts of DL to the North were best for them. G5MA - SM5ABA, 1440 km, DL6EZA (Rotteweil) - SM5BDQ (20 km north of Stockholm), 1400 km, DJ3ENA (Feldberg) - SM7YO, 1138 km, G8MW was heard trying to contact SP5AU in Warsaw - but sadly, had not made contact with him. All of these contacts were made on days of optimum conditions, such as on the night of 28th /29th October. It is indeed interesting that many stations were again unsuccessful, although they were on the route of many other long distance QSOs. So for example, although DL3YBA is not far from Hanover he did not hear any SM or LA stations, in spite of the SM stations signals having to cross this region in contacts with PA, ON and DL stations in the southern part of Germany. Again it was due to the existence of a tropospheric duct high up above the Earth's surface, which carried signals between stations in Scandinavia and Southern Germany, and signals from that duct were unable to leave this duct to reach the stations below.
Any real VHF ham cannot understand how radio amateurs, who work and even live in such an extraordinary place (2550m asl), in a comfortably furnished first-class meteorological station can neglect the VHF bands. The same is true for OK1XN on Klinovec [7] and to a certain extent to any of those, who have not used such easily approachable hills, like for example Jested hill [8]. Right: view from Lomnicky peak in High Tatras mountain (Slovakia, KN09CE)
22/11/1958 - The third visit to Snezka On my next trip to Snezka on 22/11/1958 from a VHF propagation perspective, there was a repeat of the same meteorological situation as at the end of October. It would be a good opportunity to confirm one piece of knowledge gained during my last transmissions from Snezka. I was free on the Saturday, so I arrived in Pec, below Snezka, by noon - chilled to the bone. With a certain amount of pleasure, I saw that the funicular wasn't operating, because the winter season had not yet begun, and I knew that the difference in elevation of 800m would give me the opportunity, loaded with a bulky knapsack, to warm up. Lower down it was -1° and foggy. From 1000m to 1300m asl it was -3° and thick fog, from which appeared the outlines of magnificent mountain spruces covered in hoarfrost like phantoms. At the 1350m level the cloud finished abruptly, and as I gained height, the temperature increased and there was sunshine. It was one of the most beautiful days that I have seen in the Krkonoše Mountains. Above me was the deep blue sky and incandescent sun, which lit up the last remains of the untimely October snow and down below the hill an infinite sea of white fog, from which the unfamiliar shapes of the main Krkonoše ridges stood out like an island. Otherwise it was entirely silent, absolutely calm and beautiful and warm for November. I was convinced once again that autumn in the mountains is probably the most beautiful season, and just like the weather, the VHF conditions were beautiful as well. At 18:45 I switched on the receiver. I found, and for over an hour listened to and called 3 Dutch stations who were at strength S9, but with no success, whilst they talked among themselves about harmonic oscillator converters. After several times spent calling CQ PA I was answered at 19:45 by G6XX who gave me a 579 report. At 20:10 I was at last called by PA0LQ from Leiden with a report of RST 569. Of course I was not successful with the first three PA stations. After finishing their discussion they had gone QRT, and none of them had taken a look on the band. At 20:25 I heard Harold G5YV again, now calling me using phone modulation. He was S9+ and gave me 589. He was followed by G3HA, G3GFD, G3FJR, G6LI, DJ1EY, G3FFV, DL7FU, DL3LR, and DJ3NN. The levels of the received signals were rising all the time, so I decided to switch to phone transmission, although I knew that the quality of my voice modulation was not very good. The report from DL3VJ however was S9 despite my modulation. I finished my last contact of the Saturday/early Sunday transmissions with PA0HRX at 00:28. Hans, PA0HRX, had tremendous pleasure from the phone contact with me, and said that even in his dreams he wouldn't have considered it possible that he could make such a good voice contact with Czechoslovakia. It wasn‘t only him who was so happy, but me too. On Sunday morning I started with OK2AE at 08:52. I needed to wait a long time for OK1, until OK1SO and OK1VAE appeared on the band. At 10:43 G5YV answered my CQ again, and gave me 559 fb, and I sent him 549. He complained that there were no stations on the band, in spite of conditions not being bad, though already slightly worse than yesterday when he heard Dresden TV S9+ but today it was only S6. Unfortunately I must agree with his opinion, especially when I heard him until noon and nobody answered his CQ calls. It was the same for me - no response to my CQ DX calls. So except for my contact with a G station it was only DL3NQ, who in a contact with a GM on Saturday had covered a distance of 1090 km. It seemed that foreign VHF radio amateurs also go into hibernation during the wintertime, as well as those in OK. At 11:12 I terminated my transmissions from Snezka after a contact with OK2AE.
Conclusion It would be possible to draw some conclusions from the above facts. Besides a lot of practical experience of experimental transmissions from Snezka, I acquired numerous interesting experiences of tropospheric propagation on VHF, which increasingly support pieces of knowledge gained by following conditions from the home QTH. Although it is impossible from these few attempts to make decisive and detailed findings, it is possible to say that the existence of ducts at certain heights above the continental surface allows contacts to be made over considerable distances under certain meteorological conditions from favourable high spots, by using common amateur radio techniques, and with relatively small power input. These possibilities can be used beneficially by hams in the mountainous countries of Central Europe, where favourable conditions for tropospheric propagation on VHF are not so frequent compared with flat countries near the sea in Western Europe. In Central Europe, quite a number of suitable high hills (or mountains) are available, which may enable them to get into tropospheric waveguide ducts formed between the inversion layers. It would be valid especially for Czechoslovakia, Austria, and Switzerland and in some directions for Yugoslavia too. In these countries at the present time, the maximum lengths of VHF tropo contacts made from home QTHs are only about 400 to 500 km, but I am quite sure that we have not spoken the last word on this, especially in a northerly direction. Similar results will be achieved of course only by those who are not lazy and who visit high spots, not only during contests, but also outside of contest times when favourable DX conditions accessible from these high elevations exist. OK, OE, HB and YU call signs will then surely be heard more often in the receivers of distant North or Western European countries by VHF hams, and the current 1518 km will be not be a European record for very long. In one of the European amateur magazines, the October 1958 DX contacts were noted as a significant milestone in the history of amateur VHF experimentation in Europe. The pleasure for us OK amateurs is that this milestone was reached with Czechoslovak assistance. Finally, I want express my thanks to the leaders and all the staff of the Czech hut on Snezka for a friendly welcome and for all their support. To all of our VHF enthusiasts then, I wish much success at making DX contacts either from home, or from the high mountains of our own picturesque country.
OK1VR, 1959 ____________________________________________________________________________________________________________
Footnotes (2004) [1] OK1VR - Jindra Macoun, an antenna expert, was the editor of the very popular VHF column in the OK ham radio magazine in the 1950s and 1960s. With his stories about VHF, he fascinated a lot of OK ham radio operators and started the very high activity of Czech and Slovak hams, who are even now probably still the most active world wide in relation to the number in the population. (See http://www.ok2kkw.com/contests/03/iaru2003_uhf_en.pdf ) Jindra is still active and in 2004 he was rewarded with a lifelong honorary membership of the OK-VHF Club. [2] Snezka ("Sniezka, Schneekoppe, Snowhill") - JO70UR, 1602m asl, the highest summit in the Czech republic in the Krkonoše mountains, just on the border with Poland. [3] In the 1950's France had a band at 72 MHz and there was bigger activity than on 2m [4] The Czech hut on Snezka was constructed almost 100 years ago, and in 2004 this wooden building was unfortunately demolished due to the “Greens” madness. Snezka is still accessible from the Czech side by funicular, although the “Greens” are trying to get approval for demolition of the funicular as well as the Czech hut. On the Polish side of the hill there is now a big metallic (Polish) meteorological observatory. [5] Dresden TV - in the former German democratic republic (DDR), ham radio operation wasn't allowed in the 1950's, and the vision carrier of the local TV transmitter was even placed on 145.250 MHz. The operation of that transmitter was terminated during the 1960's, when ham radio operation on 2m in that country began. [6] Lomnicky peak- KN09CE, High Tatras mountains, Slovakia, 2555m asl. meteorological station, accessible by funicular. [7] Klinovec - JO60LJ 1251m asl, in the Krusne Hory mountain range (which forms the border between North Bohemia and Germany). A famous contest site for Czech VHF hams. It also has a TV transmitter and is accessible by road. [8] Jested - JO70LR - In the Luzicke Hory Mountains, near the city of Liberec. It has a TV transmitter, and a funicular.
Related links: A list of OK VHF first contacts abroad: http://www.ok2kkw.com/abroad.htm A list of VHF milestones: http://www.ok2kkw.com/milestones.htm More abt. VHF DX-ing: http://www.ok2kkw.com/dx_en.htm ____________________________________________________________________________________________________________ Original article written by OK1VR in 1958, retyped by OK1TEH in 2001 for the web pages of OK2KKW, interpreted into English by members of OK2KKW with kind support from Robin G8APZ in 2006. Foreword and footnotes by OK1VPZ
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