Malewithatail
28-10-2016, 09:13 PM
Hi all, just a comment re using an old sattelite reciever for radio astronomy.
The modern units are digital, and at no time within the reciever does the signal appear in analogue form. Also, the 1.5 ghz reciever itself is not very sensitive, most of the sensitivity in the system is obtained in the LNB and its associated circuitry. There are a few older analogue recievers around that will work as Recievers at 1.5 ghz. A small rf amp using a gasfet or similar makes a reasonably sensitive reciever for the milky way noise etc. Feed into a chart recorder or computer data logger and analysed ( integrated etc), can be very rewarding, and who knows you may discover something new. Sun noise can be picked up on an analogue tv set with a reasonable aerial, and jupiters noise is easy to get at 20 mhz or so with a half decent radio reciever and a simple filter. Many years ago I had a 3.5 meter dish and used an old tv black and white set (Pye I think it was). Picked up the sun and milky way noise. When I moved I couldnt bring it with me, so I gave it away. I realigned the reciever audio channel to give a peaked response instead of the wide band one originally, and upgraded the front end with a high gain rf amplifier cascaded valve amplifier. I think I used a frequency around channel 6 (VHF), as the other channels were all used.
The modern units are digital, and at no time within the reciever does the signal appear in analogue form. Also, the 1.5 ghz reciever itself is not very sensitive, most of the sensitivity in the system is obtained in the LNB and its associated circuitry. There are a few older analogue recievers around that will work as Recievers at 1.5 ghz. A small rf amp using a gasfet or similar makes a reasonably sensitive reciever for the milky way noise etc. Feed into a chart recorder or computer data logger and analysed ( integrated etc), can be very rewarding, and who knows you may discover something new. Sun noise can be picked up on an analogue tv set with a reasonable aerial, and jupiters noise is easy to get at 20 mhz or so with a half decent radio reciever and a simple filter. Many years ago I had a 3.5 meter dish and used an old tv black and white set (Pye I think it was). Picked up the sun and milky way noise. When I moved I couldnt bring it with me, so I gave it away. I realigned the reciever audio channel to give a peaked response instead of the wide band one originally, and upgraded the front end with a high gain rf amplifier cascaded valve amplifier. I think I used a frequency around channel 6 (VHF), as the other channels were all used.