[hpsdr] PING Preselector

[George Medakovich]

I'm not complaining at all.
It was just an expression of curiosity.
I thought maybe somebody would chime in with the specifics ;-)

George

Graham Haddock wrote:
> ***** High Performance Software Defined Radio Discussion List *****
> 
> George:
> 
> Are you complaining about needing a preselector? 
> 
> Or, are you complaining about needing relays to build the preselector?
> 
> ;-)
> 
> The higher the performance of the input ADC, the less likely you are to
> need a preselector.
> 
> BUT...
> 
> The higher the performance of the input ADC, if your application
> does require a preselector, the more likely you are to need to use relays
> to build the preselector.
> 
> If you look at the current block level diagram for ALEX, all of the
> switch symbols you see on the diagram are solid state switches, NOT relays.
> Most likely Hittite HMC226.  There will be some relays (you can not see) 
> inside the
> tunable filter, where solid state switches either have too high an
> ON resistance, or can't take the voltages that might appear
> inside the filter before the ADC goes into overload.
> 
> If some future improved MERCURY increased the IP3 by another 10 dB,
> then we would have to use relays everywhere in the preselector, today's
> Hittite switches are not good enough.
> 
> --- Graham
> 
> 
> George Medakovich wrote:
> 
>>***** High Performance Software Defined Radio Discussion List *****
>>
>>I'm reading as fast as I can, trying to learn enough to contribute something
>>besides a pun.
>>
>>Also wondering where DAC technology where have to be before we don't have to
>>use a board with relays as a preselector.
>>
>>George
>>ke5dng
>>
>>Eric Ellison wrote:
>>  
>>
>>>***** High Performance Software Defined Radio Discussion List *****
>>>
>>>
>>>
>>>------------------------------------------------------------------------
>>>
>>>Lurkers check in!
>>>
>>> 
>>>
>>>When AA4SW has to post the only message in a day on this Reflector 
>>>‘sumptins wrong!’
>>>
>>> 
>>>
>>>How about an April’s fool project on HPSDR? Sort of a wishlist of the 
>>>‘flash bang’ thing to be invented! Sounds like an FPGA project if I ever 
>>>heard one!
>>>
>>> 
>>>
>>>Ahti! – Sami! Rescue me! Have you heard the joke about the “Traveling 
>>>Salesman?”.
>>>
>>> 
>>>
>>>How about an HPSDR Tab/Project after the Norse God Loki? (fits Ellison 
>>>rite nice!)
>>>
>>> 
>>>
>>>http://en.wikipedia.org/wiki/Loki
>>>
>>> 
>>>
>>> 
>>>
>>>Let’s get rollin’ guys!
>>>
>>> 
>>>
>>>Say SOMETHING!
>>>
>>> 
>>>
>>>Eric – AA4SW
>>>
>>> 
>>>
>>> 
>>>
>>> 
>>>
>>>
>>>------------------------------------------------------------------------
>>>
>>>_______________________________________________
>>>HPSDR Discussion List
>>>To post msg: hpsdr at hpsdr.org
>>>Subscription help: http://lists.hpsdr.org/listinfo.cgi/hpsdr-hpsdr.org
>>>HPSDR web page: http://hpsdr.org
>>>Archives: http://lists.hpsdr.org/pipermail/hpsdr-hpsdr.org/
>>>    
>>
>>_______________________________________________
>>HPSDR Discussion List
>>To post msg: hpsdr at hpsdr.org
>>Subscription help: http://lists.hpsdr.org/listinfo.cgi/hpsdr-hpsdr.org
>>HPSDR web page: http://hpsdr.org
>>Archives: http://lists.hpsdr.org/pipermail/hpsdr-hpsdr.org/
>>
>>
>>  
> 
> 
> 
> _______________________________________________
> HPSDR Discussion List
> To post msg: hpsdr at hpsdr.org
> Subscription help: http://lists.hpsdr.org/listinfo.cgi/hpsdr-hpsdr.org
> HPSDR web page: http://hpsdr.org
> Archives: http://lists.hpsdr.org/pipermail/hpsdr-hpsdr.org/
> 
> 


 1176747335.0