[hpsdr] Multiple receivers on single mercury with down converters

[David McQuate]

If you want phase coherence, you'll need to generate the two local 
oscillators for the two down-converters very carefully--or they will 
have random, and varying phase relationships.
Dave
WA8YWQ

On 8/27/2012 12:38 PM, Glenn Thomas wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> I have to ask - are your proposed two down converters phase coherent?
>
> A more basic question, does the polarity diversity processing you are 
> proposing require phase coherence?
>
> 73 de Glenn wb6w
>
> On 8/22/2012 1:11 PM, mark kilmartin wrote:
>> ***** High Performance Software Defined Radio Discussion List *****
>>
>>
>>
>> Just wanted to see if an idea I have been considering would be 
>> possible/practical to implement.
>>
>> Firstly what I'm trying to do.
>>
>> I would like to receive dual polarization signals (initially for EME 
>> and on the 2M band, but later on higher bands and terrestrial work)
>>
>> I assume this would be fairly easy with two Mercuries followed by two 
>> down converters.
>> But what I was wondering is would this be practical to implement with 
>> two down converters each using a separate IF and fed into a single 
>> Mercury that was in turn configured with two receivers.
>> e.g. down converter 1 with an IF of 50 MHz and down converter 2 with 
>> an IF of 40 MHz and both down converters then combined and fed into 
>> Mercury.
>>
>> I'm thinking this might allow the two receivers to be started with a 
>> consistent phase relationship which currently seems to be an issue 
>> with multiple Mercuries (and at a lower cost)
>>
>> If the above is possible would it be practical to implement a similar 
>> arrangement for transmit with Penny (not sure if multiple 
>> transmitters have been implemented yet.
>>
>> I won't be able to do any work on practically testing this for at 
>> least a few months but wanted to get an opinion on the practicality 
>> first off.
>>
>> Thank you
>> Mark
>> EI4FNB
>>
>>
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