Arie Dogterom  ~ PA0EZ

(QTH: Hilversum, The Netherlands.  JO22OF)

There can be few microwavers who have not heard of Arie, PA0EZ! He is one of the most well-known European microwave operators and his callsign appears in the logs of countless other amateurs for contacts on every band from 432MHz to 24GHz. He has a number of microwave "firsts" to his credit.

Arie is deeply involved with IARU Region 1 when it comes to UHF and microwave matters. He holds strong views on a number of important issues and particularly advocates the use of 432MHz rather than 144MHz for "talkback".

He has been using narrowband techniques from home for many years and has an impressive antenna system as you can see in the photograph. This picture was taken by a visitor when Arie was replacing a 2.3GHz preamp in the mast-mounted box. It clearly shows Arie's impressive home station antenna system as well as his obvious lack of fear of heights!

The lattice tower is 12 metres high and  stands on a chimney (!) on the roof of the house, making a total height of 20 metres to the bearing on top. The guys are of 6mm stainless steel. The length of pipe on which Arie is sitting serves as an anti-torsion bar. This has its own 3mm thick guys. If you look carefully you can just see the HF dipole and its 450 ohm feedline hanging below it.

Arie's home is just 20 metres above sea level. Holland's "hilltops" are the roofs of its taller buildings and so portable microwave operation is not as common as in the UK where our operators are spoilt for choice when it comes to choosing high sites.

The plastic box that Arie is working on in this photograph contains a 5-position, motor driven, coaxial relay which deals with the connection to the 2 metre diameter dish. This large dish is used on the 23, 13 and 9 centimetre bands. A log periodic dipole feed allows  multiband use. The preamps are housed in the box.

On the top of the whole mast structure you can see the 35cm offset dish for 24GHz. It just clears the local treetops! The stainless steel box, just below this dish, houses the 24GHz transverter. At the time of writing (August 1998), he was just finishing a construction to allow some vertical elevation of this system.

On the left of the picture is  a 75cm dish used on 10GHz. An elevation rotator is behind it,  as is a welded aluminium box containing the 20 watt TWT. The 10GHz transverter and  High Voltage power supply are just below it.

The dish on the right side of the photograph is also 75cm in diameter and is used on  the 6cm band. The 6cm preamp/relay box is just visible above the box that Arie is working on.

The yagis are for 432MHz.

The following extract, written by Arie, is taken from a recent posting of his on the email-based "waveguide" microwave discussion group. It gives a good insight into the workings of his all band microwave system:

"When building equipment, there are, of course several considerations. One is the choice of the IF. A rule of thumb is that from RF to IF the ratio shall be in the order of 10 .. not too much larger.

For 24 GHz, therefore, a 1.3 GHz is rather acceptable ( although 2 GHz would
be better, but on those frequencies good filters are easily made). Using 430 MHz for 3-10 GHz is not too far from the optimum and that allows me to use for TX ( I have as far as possible separate RX and TX) an old IC402. I think I will use it for 2.3 GHz TX as well, but currently I have a different TX system).

For 1.3 GHz I have 144 MHz as TX IF, but for the RX I use double conversion,
using a common basic oscillator....  the first IF near 300 MHz the second 28 MHz In fact all my rx's come to 28 MHz.

For 435 MHz I go directly to 28 MHz. As I have never contemplated to go portable ( where should I go to?) the station is rather complex but such things grow. I have been operational on 70 from 1962 onwards.

When transmitting with 300 Watts on 432 MHz I have some noise on the 9/6/3 cms IF
but not too much. In practice I can use 432.350 without problems.

Finally: All xtal oscillators for the convertors (TX and RX) are kept in place by my 10MHz station "clock", which is locked to the 198kHz Droitwich transmission. Even on 24 GHz, therefore, I am able to be able to be precise,  within  + or - 100 Hz."

Arie is always willing to try new paths and is available for microwave skeds. Just email him at:    pa0ez@amsat.org