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Re: indoor vs. outdoor downconverter



Hello This is Yoshi.

At 2002/04/08 18:51:19 eduardo j valdez wrote:
> i am considering getting a downconverter for ao-40 receive at 2.4ghz
> with 2 meter IF. UEK brand
> the cable run will be 50 feet of 9913 co-axial cable.
> antenna would be a ssb electronics dish.
> 
> what is the difference of the indoor from the outdoor downconverter
> from UEK? will i be able to hear ao-40 with either? rig will be an
> ft-847.

  Maybe No. The coxial loss on 2.4GHz is too much for any common
cable. We have to keep it minimum between the feedpoint and the
first receiving amplifire stage.

> without regard to the technical aspect, i prefer the indoor type
> because it will be protected from the elements.  i shall install it
> in the philippines which gets a good amount of sun and heat.

  There are two choice.

(1) Set your downconverter at (or close to) the feedpoint of dish
    to reduce the effect of coxial loss. Even if you use a good
    NF preamp as 0.7dB, the 5dB loss of coaxial cable reduce your
    total NF bad as 5.7dB. Of course the downconverter will be
    warmed by sun or or showered by rain...

(2) Set a good performance preamp which has enough gain at the
    feedpoint of dish, then set your downconverter inside of your 
    room. That preamp will cover the coaxial loss and you will get
    a good ear, and also the stabilized LO frequency of downconverter.
    Yes still the preamp will be warmed by sun....


Yoshihiro Imaishi JF6BCC/KH2GR
GL:PM53JV, ex KC6IY(T88IY),V63BP
mailto:jf6bcc@jarl.com
<http://plaza16.mbn.or.jp/~palau/index-hame.html>

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