Single VS dual heterodyne receiver results.
ShawnLG, Sun Aug 05 2007, 06:34AMI have finished my dual heterodyne reciever. I was told that a second IF with a narrow filter can help improve the signal to noize ratio. I did not notice much difference in the signal to noize ratio. You can see the narrow bandwidth filter at work from the noize lump in spectran.
Re: Single VS dual heterodyne receiver results.
Sulaiman, Sun Aug 05 2007, 09:22AM
I assume the spectran results are with no aerial?
Every extra stage of electronics will increase the noise of the receiver
The important thing is, does it improve the received signal to noise ratio by reduciing received noise?
Sulaiman, Sun Aug 05 2007, 09:22AM
I assume the spectran results are with no aerial?
Every extra stage of electronics will increase the noise of the receiver
The important thing is, does it improve the received signal to noise ratio by reduciing received noise?
Re: Single VS dual heterodyne receiver results.
ShawnLG, Sun Aug 05 2007, 03:54PM
"I assume the spectran results are with no aerial?"
I did use an aerial. Why would you think otherwize? I use a small RF oscillator as the RF test source.
"The important thing is, does it improve the received signal to noise ratio by reduciing received noise?" Not really. It only attenuated outer sidebands of the 455khz filter. This is only good for recieving weak CW when there is a very strong carrier near by.
ShawnLG, Sun Aug 05 2007, 03:54PM
"I assume the spectran results are with no aerial?"
I did use an aerial. Why would you think otherwize? I use a small RF oscillator as the RF test source.
"The important thing is, does it improve the received signal to noise ratio by reduciing received noise?" Not really. It only attenuated outer sidebands of the 455khz filter. This is only good for recieving weak CW when there is a very strong carrier near by.
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