2 additional connectors and a jumper at the antenna is still a potential source of trouble in the future, especially for someone who may not be familiar with how to install them properly. LDF4-50A is used extensively and almost exclusively in the cellular business for antenna jumpers.
Joe -------------- Original message ---------------------- From: [EMAIL PROTECTED] > Good N connectors are virtually lossless @ 450 MHz, & 4 ft. of RG-214 (2 > ft. each jumper) has 0.2 dB loss. I know there's a difference of opinion > on this subject, but I'd never directly connect LDF4-50 to an antenna.
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At 1/27/2007 06:47, you wrote:
>LMR-1200 has about .9dB loss for 100 feet
>LDF4-50A has about 1.45dB loss for 100 feet
>
>At first glance, it looks like you can gain a little more than 1/2dB by
>using LMR-1200. Now. the real world. LMR-1200 will require a jumper at
>the top and the bottom of the cable run. (It's too big to connect directly
>to the antenna or the duplexer at the bottom). This means that you will
>have to have 4 additional connectors and 2 short lengths of jumper cable
>when using LMR-1200. This will add up to much more loss than the 1/2dB
>you saved by using LMR-1200.
Good N connectors are virtually lossless @ 450 MHz, & 4 ft. of RG-214 (2
ft. each jumper) has 0.2 dB loss. I know there's a difference of opinion
on this subject, but I'd never directly connect LDF4-50 to an antenna.
However, the real reason not to use LMR-1200 in duplex feeds is the
braid-over-foil shield, which will eventually cause desense & IMD. The key
word is "eventually": maybe 6 months after install, maybe 30
years. Nothing like solid copper to keep those stray electrons in line ;)
Bob NO6B
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