Hi Andy ,
Andy Talbot a écrit :
Jean - Pierre...
Is the circuit diagram correct ?
Yes my diagram is correct
Your two final op-amps used as
differential amplifiers both have their inputs taken from teh same ndes, yet
are labelled to deliver I and Q.
No is not I/Q
The first pair of op-amp do correctly
take I and Q channels from the FST3253 mixer, but then their outputs are
summed (differenced !) together.
Owing to the fact that it is not I/Q, that makes it possible to have the
OL /2 or /4, the two exits are for two separate PC! the rejection of the
frequency image is made by the selectivity of the filter of entry, the
IF is of 10kHz (spectrum lab)
As far as I can see, I and Q outputs
are the same signal. Also, there is very littel audio gain in the circuit,
so the receiver as shown requires plenty of RF input to deliver enough audio
for teh typical soundcard
An ERA-5 is a rather exotic device to use in the preamp - it
has considerable gain right up to 8Ghz and could be difficult to kep
stable. Better to use a MAR-3 at LF.
The ERA-5 resists very well the strong signals, I am to 80 km of France
Inter (2MW on 164kHz) and 50km of HWU (200 KW on 22kHz) not of problems,
(see my grabber)
Andy
www.g4jnt.com
73 Jean-Pierre f1afj
On 21 February 2010 08:33, "Jean-Pierre Méré (F1AFJ)"
<[email protected]>wrote:
Hi Scott ,
Please , loock at : http://jpmere.online.fr/Grabber/Setup/Setup.htm
It is my grabber on 2200m !
73 qro Jean-Pierre f1afj
Scott Tilley a écrit :
Hi All
I was wondering if there is a simple solution that is fairly well
documented for converting a softrock type receiver over to 2200m use?
Any other suggestions on how to get a SDR on 2200m with a minimum of
effort would be greatly appreciated.
Regards,
Scott
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