[time-nuts] Spring cleaning and antenna placement

Magnus Danielson magnus at rubidium.dyndns.org
Mon Apr 20 22:17:56 UTC 2009


bg at lysator.liu.se skrev:
>> Brooke Clarke skrev:
>>> Hi Magnus:
>>>
>>> The improvement is probably due to a noise figure reduction from use of
>>> the LNA if it's near the antenna rather than at the receiver end of the
>>> cable run.
>>
>> So I am pretty sure that the improved S/N is mainly from gain and
>> secondary from improved noise figure. I don't know the noise figure of
>> the Z-12 antenna input.
> 
> I agree. You are most probably bitten by the finite range of the AGC on
> the recevier antenna port.

Probably. I should investigate just how the actual gain structure looks 
both externally and in the various receivers.

Adding another LNA improved the state further. I think severe close-in 
multipath is my main problem right now, not the gain.

> On the roof subject... Have taken the week off from work to do some roof
> maintainance. Must get the time to make some extra cable holes in the
> roof. ;-) And make some improvements on the GPS antenna mountings.

Hmm... maybe I should just hire you... I'll think I can offer beer, 
food, bed and interesting conversations over various gear as part of the 
compensation package. :)

Cheers,
Magnus



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