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Re: Cable attenuations for 2.4ghz? (And Ft736r output power)?



>From: Al Lawler <alawler@us.oracle.com>
>  The table in my "satellite experimenters handbook"
>is pretty out of date.
>
>  Does anybody know the attenuations per 100' at 
>1.2 and 2.4 ghz for:
>
>RG-6 (Tv cable)  ...my guess is 12 dB at 1.2G ...not listed for 2.4
>RG-213             ...8.0 at 900 MHz...guess 10 dB at 1.2 and 12 dB at 2.4
>Belden 9913      ...5.6 at 1.5G ...6.7 at 2.0G ...guess 7dB at 2.4G
>LMR-400           ...5.1 at 1.5G ...6.8 at 2.5G

the above from listings on Times Microwave site:
http://www.timesmicrowave.com

Page 155 of the Pasternak Ent. catalog:
RG-6A ...11 dB/100-foot at 1.0G  ...30 dB at 5.0G
RG-213...9 dB/100-foot at 1.0G ...28 dB at 5.0G
PE-B3199* ...4.5 dB/100-foot at 1.0G ...12 dB at 5.0G
*similar to 9913

http://www.pasternak.com

BTW none of these cables is suitable for long runs[>25-feet] above 1.2G in
.  I recommend LMR cables over 9913 as the insulation is solid foam core
and not as subject to deformation [high swr] when bending, or moisture
contamination like 9913.  Price for LMR-400 is equivalent to 9913.  Try:
http://www.rfparts.com

I am using 12-foot LMR-400 AFTER my 2.4G preamp to feed my Drake
convertors.  I can tolerate the ~1 dB loss since there is 35 dB gain in the
preamp.  If used it before the preamp. my 0.6 dB NF would become 1.6 dB
NF!!!  ...a great waste of German technology [and my US dollars].

For long runs use LMR-600 [4.42 dB/100-foot at 2.5G][1.30 UDS per foot] 
or LMR-1200 [2.26 dB/100-foot at 2.5G][4.85 USD per foot].

So this is why microwave gear is mounted at the antenna!

Ed
PS: my preamp is removed from the dish for packaging in a wx-tight
enclosure...had rain Tues-thurs.



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