Tough question, but I'll try to answer.
Depends on whether you're talking about 75-ohm or 50-ohm hardline.
75-ohm hardline is plentiful and you should be able to snag whatever you
need for nothing or next to nothing. Cable TV companies discard lots of used
75-ohm hardline and even useful lengths of new 75-ohm hardline from the ends
of spools.
It's hard to find deals on 50-ohm hardline. I assume that's what you're
looking for. Brand-new LDF5-50 is $5.75 per foot from The RF Connection. I
assume that's close to the list price. For comparison, the list price for
LMR-400 ranges from $0.88/ft $1.35/ft, and LMR-600 is $1.70/ft. Note that
cable prices have surged in the past few years due to the rising price of
copper.
I couldn't find any used 7/8" heliax for sale on ebay for comparison.
If the cable is in good condition, I would think something in the
neighborhood of $2/ft or less would be a decent deal. In the past I would
have recommended $1/ft or less, but I think that's unrealistic now. You may
be able to find something in that range or even less from a club or a ham
who has accumulated spool ends from commercial installation (I have a source
who has *free* 7/8", but that information is proprietary to my contest
club!) Back in 2007 I snagged 600 ft of 1-5/8" for $1/ft from a club that
had its meeting place right next to a cell site with dozens of spool ends.
That was an incredible deal. The stuff went for $10/ft back then. I think
it's closer to $15/ft now. If you look hard enough, you may find a rare deal
like that. Or, you might find some free 7/8" hardline like I did. It all
depends on how hard you look and how long you're willing to wait.
As for condition, you want to make sure the hardline hasn't been
contaminated with water. If it's on a spool or off the ground, there's a
good chance it's OK, particularly if it has connectors or the open ends have
been capped or sealed with sealer and tape. If it's been lying on the ground
and has connectors at both ends, it's probably OK, especially if the
connectors are weatherproofed with sealer and tape. If it's lying on the
ground without connectors, it'll depend on how good a job was done sealing
the ends with cap, sealer, tape, etc.
I think the biggest issue would be water contamination in the center
conductor. I think it's pretty hard for water to get between the foam and
the two conductors or between the outer jacket and shield. In any case, I
would cut a couple of feet off and saw it in half lengthwise to check the
condition. Water in the center tube may not be a huge problem. You can
manipulate the cable to drain it, and let it dry thoroughly before putting
connectors on. Again, you'll want to chop of some end pieces and saw them
lengthwise for inspection.
Probably the most important thing to check is the physical integrity of the
cable. Make sure the jacket is intact along the entire length, with no cuts
or openings. Also make sure there are no sharp bends, dents or dings in the
outer shield. Obviously, there should be no holes.
If the cable looks good, you should still check it before use. Put a
connector on one and test it with a TDR or equivalent, if you have one, or
put a connector and dummy load on the other end and check with an antenna
analyzer or rig and Power/SWR meter.
73, Dick WC1M
-----Original Message-----
From: Drax Felton [mailto:draxfelton@gmail.com]
Sent: Wednesday, June 15, 2011 6:21 PM
To: towertalk@contesting.com
Subject: [TowerTalk] Used heliax buying
I found a source for many runs of 150 to 300 feet lengths of used 7/8"
heliax hard line. What's a good price for it and any cautions about buying
used I should be aware of?
Kb3x
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