AR5000 a Multiple Talent

By Klaud Wings, DL9KAS.

The AOR AR5000 receiver works from 10 KHz to 2,5 Ghz in all usual modes and bandwidths and has been available for two years now. I bought mine 18 months ago for control purpuses at our beacon transmitters DB0JW on 2m, 70cm, 23cm and 13cm. At once I used it as a calibration tool as it outdoes several more expensive devices by 1 Hz scanning steps and a TCXO (crystal oven). If you connect a spectral analyzer (i.e. HP141T) to the IF output you get a super fine analyzer with a sensivity of -129 dBm. But the device is more powerful yet - and that is interesting to ATV people. In TV-AMATEUR I read about FM-ATV reception with the AR5000. That took my attention, and I considered to test this function for myself. The device "FM DEMO 20" from "Schuster" was already at hand, I only had to convert the 10,7 Mhz IF output to 70 Mhz.

In my scrap box I found a TTL crystal oscillator and a Schottky mixer, so -get up. On a small universal circuit board I mounted a 5V regulator, the oscillator for 60 Mhz, a low pass filter made of one Neosid coil Nr. 5061 and two SMD capicators in order to suppress any harmonics from the oscillator. The filtered 60 Mhz signal runs via 8,2 pF and a 3 dB attenuator - made of three SMD resistors - to pin 1 of the ANZAC mixer MD108. Its pin Nr.8 gets the 10,7 Mhz IF out of the AR5000 - and there is the new 70 Mhz IF at pin 3+7 of the MD108. This signal is fed through another Neosid filter Nr. 5061 to the "FM DEMO 20" or any TV sat receiver with looped through 70 Mhz IF (like Echostar SR 50), and now you are equipped for FM-ATV reception. To my greatest pleasure a superb picture from our ATV repeater DB0KWE appeared!

Encouraged by this I went on to the 13 cm band - on 2343 Mhz (DB0CD) nothing was to be seen! Somewhat disappointed I scanned to 2329 Mhz and directed my antenna to DB0QJ in Siegen, 129 km away. Oh boy, I got spoiled by a B5 picture. Similarily DB0NWD (89 km away) came in at once. Then another try to get DB0CD. With an exactly directed aerial I happened to have a decent picture quality.

Now I compared the results with a Chaparral Arabsat LNB and found both systems - using a suitable preamp - being equally useful. But with the AR5000 you know exactly which frequency to tune to, and you have an (uncalibrated) S-meter reading. You can save every repeater frequency to one of the plenty memory locations. Another interesting feature is the possibility to demodulate AM-TV signals (commercial or on amateur radio bands from 70 cm to 13 cm) using a modern hyperband TV receiver connected to the converter described above.

Its circuit diagram is too simple to require any explanation. The adjustment should bring no problems: direct your antenna to the next ATV repeater, tune the AR5000 to its output frequency and adjust L1 and L2 to the best posible picture quality - thats all. If you can equip yourself with a spectral analyzer you are able to optimize the filter passband.

Have fun with building and experimenting!

Courtesy of TV Amateur, DL9KAS and DL4KCK.



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