Why they are helpful:
Radiobeacon transmitters, using
help us to find out, whether a receiving system is fully functional. On the
6m band this is an advantage, since an estimated 85% of the hours of an eleven year period nothing but noise can be heard at any
time at any place. To Switzerland and to the neighbouring regions this service is provided by the beacons HB9EME and HB9SIX.
Once having established the functionality of
system by method 1,
help us verifying the existence of a
propagation path to a remote region where a beacon is known to be active.
For both cases a 24/7 operation of the beacon is mandatory.
Additionally for case 2 the beacons QRG should be known for the purpose of
the verification of a marginal CW identification. 24/7 operation puts high demands on the reliabiltiy of the hardware, which rarely is met by off the shelf products.
By offering a low horizon an elevated position of a beacon is always an advantage. This most often brings exposition to extreme weather conditions and puts a higher than normal demand on the quality of every part of the beacon. It must be capable to provide a mostly unattended, reliable and frequency stable operation under all climatic and varying mains conditions. The groups willing to operate beacons under these conditions sacrify a considerable amount of spare time and capital, especially if the beacon is located at a place not reachable easily or during the whole year, e.g. outback, mountaintop or island. In addition, the licensing authorities requirements regarding location, power and frequency have to be maintained, if the beacon is operated unattended.
Where we find them:
Although the 6m bandplans of the countries of the various IARU regions vary in size, mode and allocation of subbands, we have to be thankful to all those, who insist on the strict adherence to the high degree of coordination reached in the global allocation of the 6m beacon subband:
It has been put at the very low end of the 6m band, i.e. 'the hard corner' at 50.0 MHz, which by tight coordination among the regions of the IARU is globally consistent and allows optimally for the static nature of beacons. Eager DXers, who, by observing the low end of the band, hope to detect the opening to a certain continent, will profit from a special bonus: By law of physics the low end of the band will be reached first by the slowly climbing MUF.
The tight worldwide coordination is a big advantage to all those monitoring the beacon out of interest in propagation, may it be DX- or scientifically based. Tuning from 50.0 to 50.08 MHz enables them to detect 90% of the worldwide 6m beacons, if a path exists, in a single sweep. For the 6m DX enthusiasts, who prefer to monitor beacons with a SDR and a soundcard limited at best to 200kHz bandwidth, the possibility to have the beacons of every spot on the globe concentrated within 80kHz, is of great importance.
Each kHz of the 80 kHz wide subband is statistically more than 4 times occupied by a beacon. This, thanks to the special character of 6m propagation, and if neighbouring beacons have not been allocated the same or a tightly neighbouring QRG, this does
mostly not pose a problem.
Although the lists of the basic parameters of 6m beacons found on the web are not very up to date, they mostly show the correct QRG of a beacon.The static feature of a beacons QRG over a long period of time is a prerequisite for every kind of successful beacon monitoring. It was not reached by the effort of the webmasters in charge of these lists, but by the fact, that the responsible persons did not dare to fiddle about with the primordial allocation of the 6m beacon subbands.