50 Years on 50 Megs Click here to go back to the home page
by Steve Gregory VK3OT and Eric, VK5LP


In August this year, the 50th anniversary occurs of a radio contact made from Adelaide to Hawaii, at the height of Sunspot Cycle 18, between VK5KL and W7ACS/KH6, a distance of 9000 km. It appears appropriate to celebrate the making of this contact and what better way, than to tell the story of how the six metre band developed, from what was regarded as another useless bit of real estate to pass on to the amateur service, into a truly international band with a world wide following.

Much of the research of documented DX contacts and the frequency changes that occurred to the amateur allocation, were carried out by Ken VK3AKK and Eric VK5LP, without whose assistance, this article would have not been written.

The search for documentary evidence was as a result of an ulterior motive, to find the two way QSO reported to have been made between VK3 and ZS1, in the late 1950s. Thanks also to the Geelong Amateur Radio Club, who provided the Amateur Radio magazines from 1950 to 1960, and the DX contacts and spectrum information.

Frequency Allocations

According to an article written by Brian G3COJ for the UK Six Metre Group, the first allocation for the six metre amateur band was probably made during a conference in Washington DC in 1927, when a world-wide allocation of 50 to 60 MHz occurred.

Some interesting work was done on this band in the 1930s according to QST, when G5BY was heard in the US in 1936 and GM6RG in 1938. At the Cairo WARC in 1939, according to Brian Bower G3COJ, the allocation was reduced to 58.5 to 60 MHz to make way for Band 1 TV.

In the 1947 post-war WARC, European amateurs lost any spectrum between 29.7 and 144 MHz whilst those in Oceania gained 50 to 54 MHz. US stations were first heard in Europe during 1946 and conducted cross- band QSOs to 28 MHz. Some permits to operate were granted by the British Post Office and the first two-way 50 MHz trans-Atlantic QSOs occurred in late 1946 by F2 layer.

The 58.5 to 60 MHz band was withdrawn from UK Amateur use and it was not until 1983 that restoration of 50 MHz was to occur in Britain, following a long campaign by the RSGB to use frequencies between 50 and 54 MHz.

Although it is not clear in Australia when the Six Metre band was first allocated, the official journal of the Wireless Institute of Australia, Amateur Radio, lists the following dates and frequency allocations over a ten year period. No doubt some "old timers" will confirm this.

Frequency Allocation Period of Occupancy
50 to 56 MHz 01/01/1947 to 01/11/1955
56 to 60 MHz 01/11/1955 to 01/12/1957
50 to 54 MHz 1/12/1957 to 01/12/1958 I.G.Y.
50 to 54 MHz /12/1958 to 01/12/1960
50 to 54 MHz 1/12/1960 to 01/12/1962
52 to 54 MHz 1/01/1964 to 01/07/1989
50.00 to 50.200/52-54 1/01/1989 to 01/07/1995
50.00 to 50.300/52-54 1/07/1995 current

Access to the 50 MHz band during the International Geo-physical Year in 1958, with further extensions to that permit being granted up until the introduction of the Australian 13 Channel TV. Australian amateurs then received a letter from the Postmaster General's Department, informing us that the 50 to 52 MHz portion of the band, was "not available after 1 January 1964".

The 50 to 52 MHz allocation was to remain legally out of bounds for 6 metre operations until 1 July 1989, some 24 years later. Any breach of operating rules, such as slipping down to alert an overseas station to the presence of an opening to Australia to "QSY to 52.050" usually brought the radio inspectors down on the hapless individual. It was reported that RI's used to scan overseas magazines for any reports of 50 MHz operation by VK amateurs, during Cycle 21.

DX Contacts documented.

Ken VK3AKK read all the AR's from 1950 until 1962 looking for documentary evidence of two way contacts and says that "the early years of six were not all that busy until the late 1960s". Apart from the ZL and VK9 contacts the significant contacts listed below were all there were unless some person has some old logbooks or QSLs.

Callsign Date Station Worked Country Distance
VK5KL 26/08/1947 W7ACS/KH6 Hawaii 9000 km
VK2WH 30/12/1953 VR2CB Fiji Islands 4000 km
VK4NG 22/01/1956 JA1AHS Japan 8000 km
VK4ZBF 05/02/1958 K6RNQ USA 13000 km
VK4NG 20/03/1958 KX6AF Marshall Is. 6000 km
VK4NG 25/04/1958 LU8OL Argentina 12000 km
VK6ZAV 19/04/1958 VS2DO Malaya 6000 km
VK6CL 06/08/1958 DU1SW Philippines 5500 km
VK2ADE 07/04/1959 VE7AQQ Canada 13000 km
VK3ALZ 02/05/1959 XE1FU Mexico 13400 km

The final contact above was to set an Australian distance record which was to stand until 3 April 1979, nearly 20 years later, when it was increased by a mere 300 kilometres.


There is neither the time nor the space to document all the types of radio equipment and antennae used on 50 MHz, in the 1950s and 60s, but I am indebted to Eric VK5LP, for providing information from his book, "Memories of a Past Era in Radio," entirely written, and published by Eric.

A close relationship with Wally VK5ZEH (now VK5TW) at Gumeracha, saw Eric become a licensed amateur in 1960, operating on 50 MHz under the callsign VK5ZEJ (now VK5LP), located at Forreston, near Gumeracha, in South Australia.

For the 50 MHz band, Wally and Eric constructed "similar transmitters" each using a 7C5 crystal oscillator, 7C5 buffer amplifier and in Wally's case a single 807 at 25 watts, amplitude modulated by a pair of 6V6G valves. Eric used a pair of 807s at 100 watts modulated by a pair of 807s. Both transmitters were crystal controlled, not VFO.

The only commercially available six metre transmitter I was ever aware of was the 56 to 60 MHz version of the Geloso transmitter, which used the 6146s in push-push doubling mode, from 28 MHz for AM and CW.

The 4 element beam built by VK5ZEH was constructed of wood for the boom and electrical conduit. (It is sufficient to say that an antenna larger than six element yagis were rare, as one can observe in the ARRL handbook of the day.) Eric VK5ZEJ, allowed himself "the luxury of a true six metre antenna, building a William J. Orr version of the six element beam mounted on a 20 foot length of water pipe and rotated by the "Armstrong method". On this last point alone, a long distance fleeting European radio signal would probably disappear before the unsuspecting amateur got back into the operating chair, if in fact there was enough signal to peak up the antenna on. I think Len VK3ZGP built a larger eight or nine element; I saw one large array in the hills in South Australia in the early seventies, but generally speaking the basic antenna in use from 1950 to 1970 was the smaller yagi. Log Periodic LPYs and longer arrays were designed and produced in the beginning of Cycle 21 between 1975 and 1985, whilst the modern Create, M Squared, Cushcraft Boomers and NBS designs, were all later products.

One of the first commercially available six metre receivers was the KCR6/10 tuneable converter, fed into a Kingsley Radio AR7. This is what Eric VK5ZEJ used to work stations "on the downside of Cycle 19," from all over Australia, New Zealand and occasionally New Guinea. "The band was crowded, often with signals spread out every 10 or 20 kHz from 50.000 to 50.500", says Eric, "and if you were unfortunate enough to have the same crystal as some other operator, then you caused each other QRM". Eric in fact, owned not one but three AR7 receivers including one with the very rare FF coil box which tuned 20 to 45 MHz. Eric spent many hours stabilising the converter voltages and upgrading the 6K8G to an ECH35, in an effort to improve the receiver performance at the 45 MHz end of its range.

The next receiver that Eric purchased was a Hammarlund HQ-150 which tuned up to 32 MHz, and provided the all important "slow-tuning IF" for Eric's VHF converters, which he constructed in September 1963 from the pages of the magazine Radio and Hobbies, the forerunner of Electronics Australia. One only has to look in this magazine, to see the type of converters and receivers used to intercept 50 MHz signals.

The converters used a 6ES8 twin triode valve developed for TV use and in Eric's words, "the converters were excellent performers on the six metre band, especially when coupled to a good receiver".

Other designs included modified TV turret tuners ahead of a 28 MHz IF, and in the early 1970s, a series of transverters were designed to work ahead of HF transceivers of the era, including the Yaesu FTV650, the Kenwood TV506, and later the Yaesu FTV6 solid state receiver unit, introduced for the FT101B.

According to Eric VK5LP, as late as 1966 some stations were still using receivers like the super-regenerative design. This was rather startling, given that such receivers would have long since disappeared from the six metre scene, just like double side-band operation of push pull amplifiers.

The first revolution in six metre dedicated design occurred when Icom, Yaesu and Kenwood produced the IC551, the FT620 and the TS600 transceivers at the beginning of Cycle 21. A typical rig was an FT200 all valve plus an Ftv650 transverter, also all valve. Swan radio made a dedicated six metre rig called a Two-Fifty, or if you didn't own one, a "too drifty."

In the late 1970's, Yaesu made a wonderful FR101 receiver which tuned both the six and two metre bands using internal converters. The cost was in excess of $600, a small fortune in those days.

What was occurring in the amateur world, was the birth of the calibrated receiver, enabling us to accurately find beacons and calling frequencies. Further to this the advent of disposal 30 to 50 MHz FM military radios, like Eric's PRC-10 VHF FM transceiver, which boasted a power output of 700 milliwatts on six metres, and with which Eric worked stations in Adelaide from Forreston!

The ability of amateurs to snoop below the 50 MHz band, revealed a truly amazing world of out-of-band commercial signals. This method of tracking the rising MUF was not to find true usage until Cycle 21 in the late 1970s, previously it was a source of curiosity. Radios like the PRC10, at least predicted propagation to Asia in Cycle 21, as hundreds of Russian 49.750 TV video signals pounded into Australia.

The IC551 would tune down to 49 MHz and perform well, but dropped off at 48 MHz near the E2 band 1 TV stations. The FR101 could have different crystals placed to allow a lower tuning range and would reach 48 MHz without any problems. Various Plessey military units would receive and transmit from 30 to 60 MHz.


During the 1970s Tony VK6ZDY became the first member of the Six Meter International Radio Klub (SMIRK) when he worked Japan, Guam and Korea. Many VKs had worked New Zealand and New Guinea in the 1960s and 1970s but little else, except for a few JAs and those contacts documented above.

If readers care to browse the AR magazines of that era, you will see that alongside the VHFCC certificate awarded, the number of countries would be totalled, and usually mounted to two or three. There were exceptions to this including several stations from Darwin and North Queensland, but as these gentlemen choose to withhold their details, we can but speculate on what was worked, and have to rely upon overseas reports and research.

The Six Meter International Radio Klub was formed to encourage the making of International radio contacts. You required three countries to be eligible for the award. Ray Clark K5ZMS was the secretary, Tex Kennedy N5TX the President, and hundreds of amateurs qualified for SMIRK.

SMIRK members gathered or congregated on the International Liaison Frequency 28.885 MHz to exchange news and gossip about the events that were unfolding, as well as spotting DX working frequencies, from time to time. The magazine Six-Shots was produced and the first extensive 50 MHz beacon lists were published as well as receiver modifications to enable them to tune below 50 MHz onto the various TV stations.

Without 28.885 many two way contacts would have been impossible, passing each other like ships in the night. There are those who say that many reports were passed over 28.885 instead of on 50 MHz, and my only comment is that operating achievement and efficiency was at its highest in the period 1979 to 1981 when records in many states of Australia tumbled.

The Worked All VK Call Areas VHF Award.

Up to the mid 1960s there were two awards available for VHF operators, the Worked All States (WAS) for contacts with all States of Australia and the VHF Century Certificate for contacting 100 different stations. When Macquarie Island was activated by VK0FF, VK0ZVS and VK0WW, it was prized for its status in the Worked All VK Call Areas VHF Award, not as a new DXCC country. In fact even as late as 1984, there was speculation that no amateur would ever reach 50 countries, let alone 100 but more on this later.

The WIA WAVKCA VHF award was a highly sought after and prized award and came within reach of many following the activation of Norfolk Island by VK9ZNG in 1975, following the 1969 through 1971 activation of VK0 Macquarie Island. The qualification for the award required three contacts with each state, one VK1, one VK8, one VK9 and one VK0. As late as 1985 only 10 or so certificates had been awarded and by 1990 at least 10 JAs qualified for the award after working VK9YQS/0, Macquarie Island.

There is only one USA WAVKCA and that is certificate number 50 awarded to WA6BYA. There is one WAS awarded to Jack N6XQ.

Australian Distances recorded State by State.

Using the WIA Callbooks as references, is it possible to track the improving equipment, techniques and distances as the following tables show.

State Contact made Date Distance
VK1 VK1RX to KP4A 08/04/91 16082 km
VK2 VK2WH to VR2CB 30/12/53 14000 km
  VK2ADE to VE7AQQ 08/04/59 11778 km
  VK2BYX to W6XJ 06/04/79 12093 km
  VK2BA to ZF2DN 02/04/81 14696 km
  VK2BA to WB4OSN 06/04/84 15069 km
  VK2ASZ to VE1ASJ 06/04/81 16555 km
  VK2JSR to FC1BYM 08/02/91 17164 km
  VK2FLR to CU3/N6AMG 27/11/91 19424 km
  L-Path VK2BBR to 6W1QC 02/03/91 21384 km
  VK2BA to 9Q5EE 06/04/91 26252 km
  VK2AMK to 9Q5EE 06/04/91 26289 km
VK3 VK3ALZ to XE1FU 01/05/59 13545 km
  VK3OT to XE1GE 09/04/79 13769 km
  VK3OT to VP2VGR 17/03/81 16663 km
  VK3OT to KP2A 27/03/89 16700 km
  VK3OT to F6HWM 19/10/89 16888 km
  VK3OT to G4UPS 19/02/91 16922 km
  VK3OT to GW3MFY 19/02/91 16924 km
  L-path VK3OT to 9Q5EE 06/04/91 27186 km
VK4 VK4NG to JA1AHS 22/01/56 8000 km
  VK4ZBF to K6RNQ 05/02/58 13000 km
  VK4NG to KX6AF 20/03/58 6000 km
  VK4NG to LU8OL 25/04/58 12000 km
  VK4ZAZ to K6ERG 16/03/58 8536 km
  VK4ZEZ to N6CT 02/03/79 11857 km
  VK4AYX to DL3ZM/YV5 18/03/81 15582 km
  VK4KK to G4CCZ 15/02/92 16515 km
  VK4KK to GU7DHI 15/02/92 16791 km
  VK4DDG to GJ4ICD 15/10/89 16850 km
  L-path VK4BJE/KHZ to 6W1QC 02/03/91 21754 km
  VK4ZAZ to 9L1US 16/10/90 22550 km
VK5 VK5KL to W7ACS/KH6 26/08/47 8626 km
  VK5KK to XE1GE 09/04/79 14078 km
  VK5NC to GJ4ICD 18/10/91 16808 km
VK6 VK6ZAV to VS2DO 19/04/58 6000 km
  VK6CL to DU1SW 06/08/58 5500 km
  VK6BE to JA8BP 30/10/58 8833 km
  VK6RO to GI8YDZ 28/02/90 14904 km
  L-path VK6JQ to TL8MB 03/04/91 28397 km
VK7 VK7LZ to JA9IL 03/12/59 8788 km
  VK7JG to W5FF 17/04/82 13765 km
  VK7IK to W4EQM 27/04/90 15343 km
  VK7IK to PA0LSB 08/02/92 17053 km
VK8 VK8GB to 9Y4LL 10/04/82 18665 km
  VK8RH to 8R1AH 02/04/89 18858 km
VK0 VK0AQ to VK3OT 17/11/93 3800 km
  VK0IX to VK2QF 14/01/95 4517 km

In the VK9 area, the longest record distance according to FTAC was between VK9AU and KH6DBY on 30/04/60 at 6938 km. There have been no VK9 claims since 1962. John Martin VK3KWA, hopes to flush out some claims by VK9 stations in the future.

VK9NS Norfolk Island worked into Europe during the ZL opening in 1992 which computes to somewhere in the order of 18,500 km. FY7 was also worked from VK9 Cocos in 1982 at an undetermined distance. The introduction of Long Path distances, although creating extreme controversy, were in response to the 400 or so reported long path contacts made throughout Cycle 22. In cases where the long path contacts were credited to the Australian data base, this was clear proof that enroute signals were being heard, for example within the USA during a path to Africa.

How did all this take place?

OK, you have read all this rhetoric so far, and scanned the list above, you look at your rig on the table, and twiddle the dial and all you can hear is the computer next door on 50.000 and maybe the VK5WI beacon. So where did all this foreign DX come from, what time of the day did it occur, what sort of antenna would be most effective, in short, how does one work DX on six metres?

A fairly valid question and one which could take as long as a solar cycle to answer!

Solar Cycles.

Let's start with the question about solar cycles. What are they and how long is a solar cycle? To answer that, I think we just went through the minima of Cycle 22, that is the period of lowest solar activity, in the middle of this year (1996). And I think we went through the minima of the last cycle, number 21, in the middle of 1985. That's about 11 years, if I can add up correctly.

Another factor that makes me think we have embarked upon Cycle 23, is the perceptible increase in the solar flux figures in the past three months, from around 78, to a small peak in November of 104 and now a drop back down to 98. Along with this steep rise in late October and November, came reports of two way contacts between Japan, our nearest Northern six metre neighbour, and VK4 amateurs. More importantly, although two way contacts were made on 50 MHz, there were also reports in October and November of reception of Australian, New Zealand and Malaysian TV Video signals on the Six meter Internet pages and on packet radio.

Where to get six metre news and information.

There are several sources of six meter news and information available both on-line or on two metre Packet. On Packet amateur radio try bulletins addressed to Six@WW or 50Mhz @WW, just set the switch to LC SIX or LC 50* and list out the contents on your local two metre BBS.

You will see daily and weekly bulletins from your scribe, from GJ4ICD, from the UK Six Metre Group, from G3WOS, from the ZR6 stations in Africa, in short from anyone who has any reports.

On Internet you can try the OH2BUA Home Page for the live cluster, the GJ4ICD Internet Six News at "user.itl.net/~equinox.itl" or the "www.uksmg.org" pages administered by Chris G3WOS on behalf of the UK Six Metre Group. A multi-media CD-ROM containing six metre information is available from GJ4ICD.

VK3OT runs a data base on both the GJ4ICD and G3WOS servers which enables an amateur to select any one of a wide range of frequency logging at the push of a button.

Solar Information.

If you have access to Packet radio, there are daily and weekly bulletins from the Australian Ionosphere Prediction Service under IPS@VKNET. There is also a package called the Stand Alone Prediction System, ASAPS, now available for Windows. Failing that try the OH2BUA Home Page where extensive daily world wide solar readings are posted.

A typical example of an OH2BUA weekly IP report, this one for 1996:

Date: 70cm Flux A K Geomagnetic Field.
03 Dec SFI= 78, A= 8, K= 1, LOW/QUIET-UNSETTLED
02 Dec SFI= 83, A= 2, K= 3, LOW/QUIET TO UNSETTLED
01 Dec SFI= 88, A= 2, K= 1, LOW/QUIET;LOW/QUIET
30 Nov SFI= 91, A= 4, K= 0, LOW/QUIET
27 Nov SFI=104, A= 5, K= 1, LOW/QUIET TO UNSETTLED

Making use of the Data

Using a dedicated 50 MHz transceiver which only tunes from 50 to 54 MHz is sort of like shooting ducks through a partially open window from the back of a room, with a double barrel shotgun. Sure you will hit one or two from time to time, but the tally would be quite low.

In my opinion, what the dissemination of solar information and the advent of wide-band receivers has done for six metres, is to effectively turn that window into a panoramic curved design, where we now have the capability of tuning from 30 to 60 MHz and beyond, opening up a huge slab of band space from which we may extract data, and pre-empt six metre openings.

A Close Shave or Near Miss?

On 24 December 1988 at 0745 UTC, Seppo Sissato at Epsoo in Finland, happened into the ham-shack around 9 am local time on Christmas Eve. In his own words, "the rotor was frozen and wouldn't turn around and the heater was off, so the shack was just 5 degrees above freezing", so he was not about to hang around.

About the same time in the sweltering heat of an Australian summer a couple of six metre types were discussing the reception of 48.250 video signals into VK8 and VK1 from Malaysia, over 28.885 MHz, the six metre liaison frequency. Also at the same time, your scribe was also investigating the same 48.250 video signals and found that they peaked up towards South East Asia, as best you could with a five element yagi cut for 52 MHz. I put out a couple of CQ calls on 50.110, the International Call Channel, and receiving no reply, went to tea at 6:45 pm Daylight Saving Time).

Another interesting fact about the opening, was the presence of 53.750 raucous wide band FM sound, very strong and impossible to copy clearly. Try reading the 51.672 sound on WIN Channel 0 from Toowoomba and see what I mean. Without the correct decoder, on normal deviation (approx. 50 kHz) it is outside the capabilities of all the normal amateur transceivers, even in the FM mode.

The opening of 24 December 1988 was extensive, but as no one was alerted and it was not possible to identify the source of the TV transmissions, no two way contacts were made. If it were not for the alertness of OH1VR, then the first signals reported of Oceania by Scandanavia would have passed by un-noticed.

The resultant furore about the close shave, near-miss, call it what you like, had amateurs at both ends of the planet scratching their heads and there was much soul searching for answers. The aim was to try to predict when the next opening was likely to take place, and hopefully not be caught with our pants down, when it did occur.

What a fix we were in

The events of December 1988 polarised many six metre operators into a plan of action. Fax links were established with the Helsinki University Club station OH2TI through chief operator Jukka OH6DD. Every known frequency from VK/ZL and OH/SM was exchanged by fax and frequencies were measured down to the fourth decimal place, and plotted on grid square maps.

The 28.885 MHz liaison frequency was manned by UK Six Metre Group operators, particularly on weekends. Mt. Mowbullan near Toowoomba Queensland, has mounted upon it approximately 500 feet above the hilltop, a series of horizontal dipoles about the size of drain pipes and stacked 24 to a bay, on four sides of the tower. Couple into this array of antenna 10,000 watts of video signal, and man you have a signal. Wagga Wagga has the same set up, so does Wellington in New Zealand and Moscow in Russia and KVZK Pago Pago in American Samoa, and Bangkok Thailand, and Muro Portugal.

While single hop skip is not uncommon, that second hop necessary to produce trans-continental or inter-continental DX is comparatively rare. Adding to the mess is the fact that there are 11 different ways of transmitting TV, on standards using either or 625 lines, 50 or 60 frames, and NTSC, PAL, or SECAM for colour, the situation gets truly bizarre when factors like video and audio offsets are considered.

While the CCIR system is pretty uniform, there are at least four different PAL sub-systems, and three for SECAM. Even a country on CCIR, may not be using NTSC colour: Argentina and Brazil use PAL on the same channels used in the rest of the hemisphere with NTSC colour.

Adding to the problem is that much of Europe and Africa are abandoning Band I and going to UHF. The remaining users are a few Pay-TV operations in France (Scrambled SECAM with negative video as opposed to the positive standard in PAL and NTSC countries like Spain, Portugal, and Italy.

That is not to say that the propagation doesn't occur! European TV Dxers have reported North American TV up to channel 5 as recently as Summer 1995, and a Canadian FM broadcast station was received in the UK. So what, you say? How can you tell when you are receiving Muro Portugal, or when you are receiving ABCV Channel 1 Bendigo Victoria?

With the help of a tuneable receiver like those from Icom, Yaesu, or Kenwood, the video or audio signals can be monitored. You'll need a World Radio TV Handbook to identify the video and audio frequencies, and find the likeliest source of the transmission.

For example, get someone near Bendigo to tune their six metre receiver to 57.240 MHz and measure as close as possible, the frequency of that video carrier. Then you inform myself, or Bob Cooper ZL4AAA, or SMIRK, or K6FV, or Pete VK3AMX (SK) or someone else who spends a great deal of their operating time compiling an international data base.

By exchanging information freely with our overseas colleagues, we have been able to compile a pretty spectacular data base. You may have seen monthly updates passing through the Packet radio system. Those huge lists of frequencies, are all promulgated to give you half a chance at predicting the next time the six meter band is going to open.

But what if I don't have out-of-band tuning, you might ask? Son, if you don't have out-of-band tuning capacities, or a nearby friend who has, then you are quite frankly just a tourist, and hanging on for the ride.

Harsh words? There was never a greater progress in distance worked than when six meter enthusiasts started to use all the tools at their disposal, such as low band paging services in the 35 to 45 MHz band, and TV video signals in the 45 to 55 MHz band. This has only occurred effectively with the advent of high sensitivity receivers like the TS680S, TS690S, IC575, FT650, IC-R7000, 7100 and 7200 et al.

Coupled with a large international six metre population, an exchange of information, a Six Metre Liaison Frequency (28.885) and several information sources (The 50 MHz DX Bulletin, Five Nine Magazine, Amateur Radio Action & The World Above 50 MHz) and the stage was set for a wonderful and productive Solar Cycle 22.

Types of Propagation on 50 MHz.

The importance of understanding propagation cannot be overstressed, because as Hauser says, "unlike the short-wave bands, you can't just turn on the six metre receiver, tune around, and expect to get faraway stations". On six, the normal situation is no DX, until some abnormal propagation occurs, and also, unlike short-wave, there are several different kinds of propagation above 30 MHz.

For the purpose of this article DX is regarded as any signal outside of Australia, which to work effectively and evaluate the signals, you need to be able to tell the difference between the various propagation modes, as well as knowing when they are likely to occur.

Fortunately, the propagation modes are sufficiently different from one another, according to experts, that by combining a little experience with the descriptions to follow, you should seldom have any difficulty assigning one definite propagation mode to each DX contact.

Propagation questions for VK Amateurs

Why is propagation so important if all you care about is the number of countries worked on six metres? You may be able to pick up a given station by two, or even three different propagation modes, for example, K6QXY worked KG6DX on F2, E-layer and EME. The EME QSO will undoubtedly be much rarer than the other QSOs.

A Channel 0 TV station 1500 km away is relatively easy to hear via sporadic E, while the same station is very seldom subject to tropospheric propagation over such a distance. On the other hand, a Channel 7 TV station will seldom cover such a distance, when it does it will do so more readily by tropo than by sporadic E.

The first investigation of propagation will be confined to E layer, because it is now in our summer time and this is the likely mode of propagation that is occurring at this moment. The discussions about F layer propagation is more complex and will occur later.

Sporadic E skip (Es), has a set of characteristics which, when taken all together, set it apart from all other forms of DX propagation. It builds up from the low VHF or high HF frequencies to a certain maximum usable frequency (MUF) which may vary widely from minute to minute, and opening to opening.

Es always commences from the lower frequencies first, but it may not get above Channel 0. Of course, if the skip is coming from a sparsely populated area, there may be no Channel 0 TV so check Channels 1 and 2 as well.

Trans-equatorial Propagation.

Trans-equatorial propagation (TEP) reaches south to the Tropic of Capricorn, and often links up with Es or Tropo and extends even further south. DXers in the north of Australia should be on the lookout for TEP in the spring and autumn, with March and October being the traditional start of the fall TEP season.

Signals are more disturbed by TEP than in any other propagation mode, since the MUF flutters with extreme rapidity. SSB may be almost unreadable. TEP usually builds up after sunset, peaking around 2000 local time; it may bring in the same station for hours at a time, night after night.

Distances of between five and eight thousand kilometres are not unusual, and even stations not strictly on the other side of the equator may come in by this method, if they're beyond 3000 km (KG6DX, KC6IN, V73AT etc.). TEP can reach as high as 65 MHz as Asian TV Channels 2 and 3 are often observed.


Of all ionospheric propagation modes, aurora is probably the one most observed on the high VHF bands but occasionally on 50 MHz. TV is often heard via aurora, with heavy distortion and interference from other co-channel services.

You may have a chance receiving the audio on Channel 0 Wagga Wagga, however the FM is severally distorted by the auroral multi-path signals.

DXing, with distances typically in the 600 to 1000 km range, but with no specific lower or upper limit. You may find that the signal is not coming from the direction you would expect. It is bouncing off the auroral curtain, which may be as much as 45 to 90 degrees away from the direction of the station, but not necessarily at due south.

Auroral activity is most likely around the equinoxes, but may happen at any time when the proper solar disturbances occur. Heavy auroral activity can also induce regular Es during the following day or two and at 27-day intervals coinciding with the rotation of the sun.

Southern stations often experience auroral signals, but it becomes less and less frequent at more northerly latitudes. WWV advises of magnetic disturbances and auroral activity periodically; you can also spot auroral conditions from short-wave blackouts and heavily distorted signals on 20 metres.

In November 1993, during the declining part of Cycle 22, the auroral and Es extension produced the world's first Antarctica to anywhere 50 MHz QSOs. Two years later, summer Es or Spread-F mode increased that path to nearly 5000 km.

In the Northern hemisphere, amateurs are yet to work similar distances across the North Pole between the UK and Canada, whilst Africa and South American amateurs have yet to work to the continent of Antarctica.


From a personal perspective the band opened, for me at least, on sufficient occasions between 1989 and 1993 to work 20 European Countries, 150 separate contacts to be made, and the VK3 distance record to be extended on three separate occasions.

When I compare the VP2VGR record of 16,666 km using an FTV650B transverter, with the meagre increases of 225 km, 34 km and 2 km in distances achieved using a 12 dB gain yagi, I tend to think that we were very fortunate, and we are operating at the cutting edge of distance propagation.

If I was asked to comment on what type of station one needs to work over the edge of the known six metre world, I would be inclined to say, one capable of EME performance, at least from Victoria.

But then every where is not Victoria, and there is a plethora of DX to be worked in the coming 5 years, and there are better places to work it from than Hamilton. The further north and east you move the better it is to USA and the further west and north the closer it is to Europe.

The logs of VK8GF, VK8ZLX, VK6JQ and VK6PA carry hundreds and hundreds of European contacts, whilst in VK5, VK2 and VK3 the openings were far less. The VK6 boys hardly had any US and KH6 openings whilst in VK3 we had dozens per year and in VK2 and VK4 they had dozens per week.

Having stated the obvious, what can you do to improve the odds of making successful two-way contacts with long distance stations? First bring your station up to an acceptable standard. Then have the capability to tune out of band using a tuneable converter or a more modern receiver with the necessary bands on board.

Check out the Internet sites for news and events and watch Packet radio for DX bulletins. On a lesser scale, watch the climbing solar flux and check the sunspot numbers at least once each week, or more often if appropriate. Ignore much of what is being worked elsewhere in the country and approach your DX window's as unique to your particular area.

Stay sharp, alert, informed and good luck. As they say, see you on the magic band!


Propagation by Glenn Hauser TV DX - How It Happens by John Pinckney and Bill Hepburn Copyright the UKSMG 50 Mhz CDROM. QST Magazine Amateur Radio Action 1982 to 1992 columns by Steve Gregory VK3OT Amateur Radio, the official journal of the Wireless Institute of Australia.


de VK5LP & VK3OT

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