On 12/24/2011 12:06 PM, Jim Brown wrote:
> On 12/24/2011 8:44 AM, F5vjc wrote:
>> I'm thinking to buy some used Heliax locally. I have a couple of
>> offers, one is LDF4-50 which I am familiar with, the other is LDF1-50
>> which I am not. I have of course looked these up on the net and can
>> find and compare the specs of both.
>>
>> This is for an HF only installation (up to 50 MHz) 150 feet in length
>> so losses are not my major concern.
> Then why do you want Heliax? The primary advantage is lower loss. The
> only other one I can think of is robustness against rodents. I use
> LDF4-50 and LDF5-50 for 100m runs to my tower.
>
>> However in general is there anything to watch out for when buying used
>> Heliax of any type? I believe it is Andrews. The LDF 4-50 will come with N
>> type connectors so that is a plus,
> LDF4-50 is very nice cable, connectors are widely available at moderate
> cost, and the loss is significantly lower than the best RG8-size coax.
> I'm using LDF4 to go up the tower and LDF5 for the longer run on the
> ground.
I do not like the 1/2" heliax. I've found it too easy to kink and gave
away most of what I had.
I have one brand new N connector for the 1/2"left, but unfortunately
some where in the last 20 years the center pin seems to have walked off.
I like the 7/8" stuff for VHF, UHF, and 160 meters. Running the legal
limit on 160 with the resulting very high SWR at the band edges the
voltage is high enough to take out type N connectors. Also the 7/8" has
better current capability. Currently I'm using LMR-600 and modified UHF
connectors for 160. No problem there other than UHF connectors for
larger coax can be kinda pricey and difficult to find. I don't run
enough power on 144 and 440 for it to be a problem, but there I like the
low loss.
Unfortunately even with a remote tuner I have to run feed line from the
tower to the slopers. It can be window line, or true open wire, but I'm
not a fan of either. I guess the window line would be the most convenient.
It's roughly a 228 foot furn from the rig to the top of the tower.
I hear of those "free" deals, but I always seem to be a day late <sigh>
Two years ago at the local swap there was some 7/8" at a good price, but
unfortunately the lengths were too short, so for the time being I have
multiple runs of LMR-600 up the tower. That and the 600 is a whale of a
lot easier to pull through 4" conduit. If I find enough 7/8" I'll have
to dig up the 4", or add additional conduit runs ...which might be easier.
73
Roger (K8RI)
>
> 73, Jim K9YC
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