Custom made beacons for the 28 MHz band from AA7DJ

 

I recently came across this beacon for the 28 MHz band and it thought it might be of interest to others.

While most beacons are built from modified CB radios or home built from parts, there is an option to buy a 'ready to go' beacon from Vlad, AA7DJ in the USA. The beacon is shown above and it runs with an output power of 10 watts on the 28 MHz band although this can be reduced.

The frequency and callsign are given to AA7DJ and he then builds the beacon. Upon arrival, all a station needs to be do is to supply power to the unit and plug in an antenna.

The interior of the beacon is shown above with the frequency synthesizer inside the metal cage on the left and the power amplifier stage with low pass filter on the right.

On his QRZ page, AA7DJ writes..."The synthesizer board has PLL chip, VCO, crystal reference and microcontroller. The last one produces frequency code for PLL. Also it generates CW message and keying sequence for the amplifier board. "

Frequency stability is claimed to be about 10-50 PPM as determined by used crystal. 

The spectrum output with the level of harmonics is shown above. If additional suppression is required then another low pass filter could be added.

Permits... From my understanding, a special license is required to operate a beacon on the 28 MHz band in most parts of the world. In the USA however, the FCC allows radio amateurs to operate beacons on 28 MHz and the VHF bands.

This is specifically for the purpose of ...'observation of propagation or other related experimental activities'. The power limit of 100 watts by the FCC is quite generous in this regards.

In conclusion... While many may want to build their own beacon, there are others who will just want to order a ready built unit and put it on the air.

There is a small but active group of 28 MHz beacon enthusiasts in the USA and many speak highly of this unit built by Vlad, AA7DJ. I don't know how much a unit costs but several have mentioned that it is reasonable.

If anyone is interested in buying a unit then they should contact AA7DJ via his QRZ page.

Addendum - 2nd March 2023: AA7DJ has been in contact to say that he also does designs of 10 W beacons for 28, 40, 50, 144, 222, 432 MHz. Also 8 W for 903 MHz, 7 W for 1296 MHz and 4 W for 2304 MHz.