BATC Forum

Hello all.

Recently I have acquired a F6DZP MiniTioune kit with Sharp tuner and pleased to receive a repeater and another station 60km away on 23cm with my 23ele yagi and DB6NT preamp connected to the Sharp tuner. The constellation display on both these signals is arranged in four yellow "suns" which I gather is correct.

Testing with a high power station on 3cm and using my 10ghz dish and LNB ahead of the Sharp Nim tuner the constellation display shows one large diameter circle but I cant decode the picture. The signal strength is large enough to black out my 3cm Analog receiver screen and is healthy when viewed on my spectrum Analyzer. Does anybody know what this large circle on the constellation display means? The station sending the 3cm digital signal can monitor off air and produce a picture and constellations arranged as four suns.

Baffled with this digimode. Have previously taken P5 FM ATV signal on 3cm from this station so its not lack of signal. Frequency is verified correct and various symbol rates have been tried with the same result.

73 de Denis G3UVR

Hi Denis

Usually either symbol rate, code rate or tuning is wrong. I assume this is a digital LNB and not a DRO ?

Mike

Mike

Thanks reply. The RX LNB is old style with DRO. The sending signal is injected into the IF of a DB6NT transverter at 440mhz producing a final output at 10,376mhz then passed on to an EME amplifier chain run at reduced power to keep the amps ultra linear..

Next time your back in Bolton at least I will be able to RX you at reduced symbol rates from 144mhz up (wide band extended range NIm arrives next week) It was because I couldnt look for your signal at Christmas I decided to go for the Minitioune software and hardware.

We are continuing tests

73 de Denis G3UVR

Hi Denis,

I don't think a DRO LNB will be good enough for digital, especially at low symbol rates - it might work but maybe start by upgrading to a PLL based one? You can get them to a convenient IF if you take out the 27MHz crystal and lock them to an appropriate frequency. They Octagon ones seem to tune OK - see http://g4jnt.com/OctagonExtLo.pdf

Mike