More DSP Experiences with Filters and DSP Radio's.

From 432 And Above EME Newsletter, Februari 1996:


HB9BBD, Dominique reports:

I had a very interesting QSO on 23 cm with VE1ZJ for initial #67(419/559) on Sked. The interesting point was the initial of course, but technically there was a big surprise to report!
I tested for a few hours the DSP TS870S-AT some weeks ago. Unfortunately I could only test it with 1296 beacons and on HF traffic due to time limitations. Now I got the change to test it on the moon.
It took me 3 x 2.5 minutes to find the signal of VE1ZJ. He is using a 3.7 m dish, and may be 150 W at the feed,. (Normally I copy just fragments with this type of setup.) Once I located the signal, I could improve copy somewhat by reducing the BW to 50 Hz, and by shifting the pitch to 500 Hz. There was no ringing. Then I tried the so called adaptive filter with short periods for the signal analyses. After a second of total silence, the two callsigns came up out of the noise in one string! Not one dot was missing. The noise had practically disappeared. This I would not have believed. (The former equipment was TS850 with a Timewave 59+ digital filter.)

I thought I had to report you about this experience. Maybe other small EME stations can test these new DSP rigs as well. I want to make one thing very clear, I am neither a shareholder of Kenwood nor do I have any commercial interest in amateur gear.(Those who are using the TS850 with transverters will miss the automatic low power response when injecting + 12 V dc through the coax into the transceiver. The TS870 does not offer this practical feature any more. I had to build a relay into the new rig to automatically bypass the final amp. when switching to the transverter)


Pease report here on your experiences with DSP in Weaksignal Communication.

Return to Top Page.



E-Mail Address for Comments:W6/PA0ZN