# LMR 600 ???

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by N4MTB, Nov 20, 2018.

Is it worth using LMR 600 (or is equivalent) on HF, VHF or UHF?
At what distance does it make a difference?

For UHF, sure. For VHF, probably for a long run. For HF, probably not, unless you are doing a really, really long run of cable.

The data sheet for LMR-600 is available online (*). The thing to do is calculate the losses you will get over the length you hope to run, then decide if the cable (and connectors, don't forget the rather \$\$\$ connectors) is worth the lower loss you will get with 600 vs. some other type.

(*) I find it interesting that Times didn't even bother to show the losses for HF frequencies in the graph in their data sheet.

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As posted above it really depends on what frequencies, run length, how much loss you'll tolerate and of course the cost and hassle factor of working with larger diameter and heavier coax with specialty connectors.

This online calculator let's you play with different scenarios with different types of feedline to see whether it's worth it to you: https://www.qsl.net/co8tw/Coax_Calculator.htm

For instance with a perfect match (not likely) at 146 MHz with a 100' run of cable you'd expect roughly the following cable losses:

- LMR-400: ~1.5dB
- LMR-600: ~1dB

At HF it would be hard to justify half a dB, at VHF it might start making sense but that's up to you.

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4. ### WB2WIKPlatinum SubscriberPlatinum SubscriberQRZ Page

On HF I sure wouldn't bother for a run anything shorter than 500 feet.

On UHF, I would bother even for 75 feet. On VHF, maybe anything over 150 feet.

But it's expensive, uses specialty connectors which are also expensive and is not flexible at all, so it's kind of like wrestling with hardline. One advantage: If you use a run straight to your wattmeter, you won't need a shelf for the meter as it can just hang in midair from the coax.

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5. ### N0IOPHam MemberQRZ Page

In my planning and figuring am finding that heliax is more cost effective than LMR600 in most cases.

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6. ### NH7ROHam MemberQRZ Page

And probably easier to install the humungously expensive connectors for either...

LMR-600 is good for saving tenths of dbs and burning lots of \$\$\$. Like a top of the line Mercedes or BMW; nice if you can afford it but not really necessary 99% of the time.

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7. ### WB2WIKPlatinum SubscriberPlatinum SubscriberQRZ Page

"My Maserati does 185
I lost my license, now I don't drive..."
-WB6ACU

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8. ### AA7QQHam MemberQRZ Page

The 1/4" & 1/2" connectors are not bad to get. I use RG8X connectors on the 1/4" (Shield soldered to PL-259 adapter).
I ran 1/4 to a Discone. I can run 1KW on UHF with it. The Discone can take it. Real nice that it conforms to the house & CATV clips work fine.

Ed

9. ### WB2WIKPlatinum SubscriberPlatinum SubscriberQRZ Page

LMR600 uses .600" connectors and they are pretty special.

I'd invest in this for UHF-SHF work, but for HF seems silly.

Most SHF work is done using the TX/RX equipment right at the antenna, so the "downfeed" is at a baseband frequency like 28 MHz. Then, RG-58/U works fine for that.

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10. ### KM1HHam MemberQRZ Page

At those prices used Andrew 1/2" and 7/8" Heliax (or comparable competition) is a fraction of the cost and often with connectors. Plus it is direct burial capable and also makes for efficient hanging verticals.

Carl

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