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My coax debate

avistar23

Active Member
May 17, 2005
182
32
38
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Nassau Bahamas
So i need some coax for my new antennas and amps

ive used

CNT 400
LMR 400

and im happy with both, runs will be 40 feet up the tower and 10 into shack, 50 total.

i can get a good deal on 1/4 heliax, but it wont be able to make it into the radio as its too stiff, and would jumper a couple feet with LMR 400 or CNT

ive also been looking at jefa tech coax

what would you use, and why
 

Of the choices you gave I would have to say the LMR-400. But only if this is for VHF/UHF. If it's for HF, then all three of the choices are very much 'over-kill'. Even for VHF/UHF the heliax isn't exactly reasonable.
- 'Doc
 
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I have lmr on everything including my HF beam, i have 213 to my dipole, i like the LMR, but the 1/4 heliax although is quite small has nice loss figures
 
Aw go on and go for it 23, that heliax will really get you out. Just keep us posted on how it works out.
 
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In order to make a suggestion on cable type, more information is needed. Output power and frequency of operation would be the first things to look at.
How flexible does it need to be? Will it be connected to a rotating antenna or expected to blow about in the wind?

For a run of only 50 feet you won't worry much about attenuation.
 
One run is for the larcan, Feeding ultimately a 6m7jhv or similar antenna, N connectors both ends, no rotation fixed antennas. hardline would make it within 6 feet of radio, where a flexible cable would be used, however i have devised a way i THINK i could feed the hardline threw the wall right into the back of my larcan cabinet.

the second run, will go to my gulph alpha antenna i ordered in my 2m dx ssb thread, again, permanently fied facing south Florida, again this could make it into the wall within 6 feet of radio and go flexible, OR, if i decide to go with a second larcan amp as i emailed you earlier, i may again be able ot hardline into the cabinet IF i get a 2m amp.

i can take lmr400 or similar cable right into the radio.

N connector will be used wherever possible, also considering changing connectors on the back of my 847 to N
 
Attenuation on 50 feet of LMR400 is about 0.45dB @ 50MHz, 0.75dB @150MHz. LDF4 will be 0.22dB @ 50MHz and 0.40dB @150MHz.

Once your signal leaves the antennna, if you find anyone that notices 0.2dB to 0.3dB signal difference he's spent too much money on test equipment. No one anywhere will ever tell the difference.

Unless your power exceeds about 2.5kW @ 50MHz or 1.5kW @150MHz the LMR400 is entirely adequate. I wouldn't bother with the added hassle of dealing with LDF4 for what you're doing. Save your money for something else.

Type-N connectors are considerably better than SO-239 / PL-259 connectors in every way I can think of. You can get an adapter for the back of your 847 to turn it into a Type-N. No need to open the radio. Remind me and I'll include an adapter with the other amplifier... :)
 

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