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Re: 2.4 GHz Reception Indoors?



>From: "John Stephensen, KD6OZH" <kd6ozh@gte.net>
>I have a similar problem. There are several 60 foot trees to the west and
>southwest of my antenna so reception is spotty until AO-40 reaches 25
>degrees of elevation. To the east the there are no tall trees and reception
>is good from about 3 degrees of elevation.
++snip++
>From: "Greg D." <ko6th_greg@hotmail.com>
>> Humph.  I could barely hear the beacon when shooting through a
>> sparcely leafed oak tree the other night, and he gets enough to decode
>> telemetry looking out a brick wall...  Go figure.
>>
>> I've been doing an informal survey of my receive ability, now that
>> I have the "tower cam" in place.  It seems the biggest contributors
>> to *not* hearing AO-40 are shooting through vegetation and having a
>> high squint angle (> 20 degrees).  Distance is not really a factor,
>> since it is tied inversely tied to squint, and squint wins easily.
>> Vegetation in the form of an oak tree trunk is an absolute killer.
++snip++
>> >Last night I could just hear the beacon with a bbq inside going through
>the
>> >back wall of my basement.  Putting it outside resulted in
>> >about 4-5 dB better signal strength. 
>> >I think if you go with a good sized dish, 3-4' with a CP feed you
>> >would be able to do it.  That could be a bit difficult in some attics
>> >though.
++snip++
>> >>From: Jesse Morris <w4mvb@juno.com>
>> >>Hi Steve,
>> >>
>> >>I worked W2NBJ last week while he was using a home made dish in his
>> >>attic.  Al was receiving the bird better than I was with my 30 turn
>helix
>> >>on the mast.  When i last talked to Al a couple of months ago he had
>been
>> >>unable to hear AO-40 indoors with a helix.  I was so impressed I started
>> >>building my own dish.  I can't put it on my mast but I plan to use it on
>> >>the ground (or close to it) in the back yard.  I'll still need the helix
>> >>on the mast for low elevations.
++snip++
>> >> >Has anyone had success receiving the AO-40 downlink indoors? I'm
>> >> >considering
>> >> >an attic installation.
>> >> >
>> >> >Thanks 73 . . . Steve, WB8IMY

My first reaction to this question was to shake my head and click on to the
next message...now a few replies later, I have to say that it could be done
depending on how transparent [to microwave] the roof material is.  That
will only be determined by comparison with outdoor reception.  One reply
pointed out that the roof would add considerably to thermal noise...sounds
right.  Then the experience of a few others showed it not impossible?  I
guess it depends on what performance you are willing to accept?

My experience with my roof-mounted dish is that shooting thru the solid
mass of trees to my east results in no reception and a rise of the noise
floor one s-unit.  Shooting to the SW there is a single line of cottonwood
trees along the street [similar to popular birch] the noise floor isn't
noticeably affected and signals are only lowered maybe one s-unit from
clear sky reception.  Finally, I have an eight foot dish that is enclosed
inside a fabric and aluminum hexagonal-frame radome that operates fine on
1.4 GHz...no noticeable rise in noise temp from the radome.  I suppose
there might be a tenth or two attenuation but I haven't detected it.  {as
you would expect for a radome}

So experiment and see...I guess is the correct answer!

ED
PS: I have the same experience that squint and agc-loading are the two most
significant factors affecting my operation on AO-40; range is not a
problem.  Sleep and going to work is a factor ;-)

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