The Four metre band was always referred to as the "Gentleman's Band" due to the relatively small community of operators who were on first name terms with one another. These were real radio hams as they either built their own equipment or modified existing ex commercial equipment. During VHF NFD, the norm was to work all the stations in CW during the first half of the contest and then in voice for the second half.
Until recently the Four metre band was not hugely popular in Ireland mainly because there were very few commercial black boxes and it was "just another VHF Band". For the more serious and dedicated operators, there was the option of a transverter, allowing SSB and FM operation, and, for general use, many would delve into the innards of Low Band ex-commercial equpment and align it onto the Four metre band. Some resourceful operators converted existing Six metre equipment for use on Four metre band, whilst many others designed and built their own transceivers. Twiddling with radios on the bench is primarily what we do, as radio amateurs, because it is part of the hobby and is cost effective.
Many operators from the 60s - 70s would have modified the old Pye Cambridge AM version although it did come in an FM version also. The Pye Cambridge would have been in use by the Police and Taxi Services. They had a great receive audio and were reasonably sensitive.
Many Commercial radios such as Pye, Tait, Motorola, Maxon, Kyodo, Cleartone, Ascom, Simoco, and Philips, to name but a few, were ideal for conversion.
In the last few years, more and more countries have allowed operation on the Four metre band although the actual band allocation varies in some countries. As a result of this, the amateur radio manufacturers have offered radios which include the Four metre band. Anytone, Wouxun and Retevis have produced some dedicated Four metre transceivers which perform admirably on the band.
Some countries do not have the Four metre allocation but will operate cross band from 6 metres and receive on 4 metres.
The ICOM 7100 was probably the first transceiver to offer 4 metre operation as standard. They have more recently included Four metres in their ICOM 7300 and the ICOM 9700. There is an added bonus of D-Star in the ICOM range. Subsequent ICOM models included Four metres. Nowadays, Yaesu have included the 4 metre band in their newer models. Obviously SSB and CW operation will give excellent results.
The Irish allocation for Four metres is 69.9 - 70.500 MHz although ComReg
opened up a huge chunk of spectrum of which there is a band from 54 -
69.9 MHz. Many of the dedicated Four metre transceivers will cover from 66 - 70.500
MHz. The segment from 66 - 69.9 MHz is permitted as a result of the recent allocation by ComReg.
The Propagation characteristics of the Four metre band make mobile operation more interesting as the distance covered is generally superior to Two metres. Auroral, Sporadic E and Tropospheric Propagation often result in some vast DX openings. Sometimes a DX station will appear on the operating channel out of the blue.
Normally Sporadic E season is noticeable from the end of April until the end of August. Recently there have been strong openings around 9 am Local time. Moving into the Summer Sporadic E is most noticeable around 5pm.
One of the most reliable tools for establishing Ionospheric Conditions in the Ionogram. The Chilton Ionogram can be accessed from >> Here<<.
The squares are colour coded: the Green squares show propagation from 30 - 50 MHz, the lighter green from 50 - 70 MHz, the Yellow from 70 - 90 MHz, the Orange from 90 - 110 MHz, the darker Orange from 110 - 130 MHz and a Red colour from 130 - 150 MHz.
Another display can be obtained from >>Here<< which plots uploaded logged contacts between stations giving a good representation of activity.
As illustrated, Sporadic E can produce some excellent results. By selecting different tabs, contact paths may be shown for 10, 8, 6, 4, 2 metres and 70cms. Forget those silly Ham Prop programs as the Ionogram and DxMaps is by far the best indicator for serious VHF operators.
Many years ago Dick Madigan, EI9Q from Waterford, used to be heard in South East London as regular as clockwork around 7 pm on Four metres CW. This was due to the SPoradic E openings at that time of the evening. Remember the Spanish TV interference on RTE1 (Band 1 TV)
Four Metres will produce good DX via tropospheric propagation. Aircraft scatter is particularly noticeable on this band with sharp rise and falls of signal strength. My home QTH in the UK was on the flight path into Heathrow so this was noticeable almost every day.
The Four metre band shares many characteristics with the neighbouring Six metre band. However, as it is somewhat higher in frequency it does not display the same propagation mechanisms via the F2 ionosphere layer normally seen at HF which occasionally appear in Six meters, leastwise not at temperate latitudes. However, Sporadic E is common on the band in summer, tropospheric propagation is marginally more successful than on the Six meter band, and propagation via the Aurora Borealis and meteor scatter is highly effective.While Sporadic E permits Europe wide communication, it can be a mixed blessing as the band is still used for wide bandwidth, high power FM broadcasting on the OIRT FM band in a declining number of Eastern European countries. Although this has lessened in recent years, it can still cause considerable interference to both local and long distance (DX) operation.
Antennas
A quarter wave antenna for this band is approximately 108 cms long which is a convenient size for mobile operation. Most amateur radio retailers now stock Four metre band mobile antennas, however a homebrew version should be easy to make. For base station use, a variety of beams and verticals are also available from retailers, but once again, a homebrew beam or vertical should prove easy to construct and even easier on the wallet.
Consider making a Halfwave Vertical or a Slim Jim Antenna which will only cost a few Euro to make and will give as good a result as any of the commercially made verticals.
Local Operations
Tests were conducted on many bands, by members of the Galway VHF group, especially in Connemara which has a very rugged and mountainous terrain. Bands from 70cms to 10 metres were included. Surprisingly, as VHF Bands go, the Four metre band actually gave the best signals over distances. 4 metres managed to circumvent many obstacles. It was concluded that the 4 metre band would always give better results whilst mobile in most areas. Tests over a given path from Salthill (3m Above Sea level) to Headford found a greater signal strength for a given power level over a fixed path on Four metres vs Two metres. Not surprising really, as the wavelength is longer than Two metres. From Salthill, there appeared to be a slight “flutter” noticeable on the signal. After much thought and ruling out the presence of aircraft in the area, it was decided that this may be due to reflections from the traffic on the M6 motorway.
In conclusion, the Four metre band is likely to give surprising results due to the unpredictable nature of the Sporadic E opening. Some interesting results can be obtained via Tropospheric propagation. One instance often quoted was a cold frosty morning with a light mist at ground level. One operator maintained a QSO with another in Ballyhaunis whilst driving from Castlebar, Co Mayo to Shannon Airport.
With the availability of more transceivers which include Four metres, it is certain that he level of activity will increase. Put out an occasional call on 70.450 and 70.2625. These are both calling channels so please QSY once the contact is established and do try not to hold nets on recognised Calling Channels. Park the car on a high location and put out a call - you will not be disappointed as the Four metre community is growing.
