Zoom MFJ-890 ”DX beacon monitor”
MFJ is also a well-known American company in our country, which produces a wide range of amateur radio accessories such as antenna tuners (both automatic and manual), filters, antennas, VF measuring instruments…. Among other things, the company, led by Martin Jue K5FLU also offers various accessories for the radio amateur shack. One of them is a device marked MFJ-890.
What is it and what is behind the term “DX beacon monitor” the following article will try to explain it to you….
Most of you are certainly familiar with the IBP project – International Beacon Project. This is how this international network of eighteen lighthouses works, that each of the beacons transmits 10 seconds on one band and then retunes to a higher one, where it again broadcasts its mark and a series of dashes with different power and rests for a while after passing through five bands. The network consists of identical beacons synchronized by GPS.
The listener tunes to the frequency of the network on the band, on which he is interested in the propagation conditions. If it controls fast CW, after capturing the signal, it immediately knows where it comes from. Little, which CW does not control (or they do not control at a given speed), they can identify him from time, when the lighthouse was captured. It is enough to have an accurate watch and a timetable for broadcasting beacons.
The MFJ-890 also works on this principle. On the world map, the LEDs will gradually light up accordingly, which beacon is currently transmitting. There is still a power connector on the front panel, two buttons and a band switch.
With a button “Manual sync” the correct cycle is set and that's it, that we set 14 MHz band and press the button, when the minute hand of a precisely set watch reaches 3 o'clock, 6-that one, 9-your, etc.. a minute. After pressing the button “Atomic sync” the MFJ-890 will be synchronized with the atomic time base. Because of that, that a 9V flashlight can also be used for power supply, automatic synchronization does not happen every time 15 seconds, but once every ten minutes. The MFJ DX beacon monitor can be used with a variety of transmitters anywhere in the world. Choosing the best (or the only one) of the time normal signal is done by jumpers inside.
Power consumption ranges from 4 do 10 mA during synchronization. The light of the LEDs is sufficient even with such consumption. The interior design is very clean, the device can also be used on a portable device – it is very light.
Overall, I rate the MFJ-890 as a two. For those, who want to make a very aesthetic and eye-catching HAM shack, it is a good choice. However, at this price, I would prefer a two-way combination with a clock. In this way, the time stamp receiver would be used more efficiently – A radio amateur always needs an accurate clock.
