On 9/13/2011 3:51 PM, Steve Jones wrote:
> Thanks to all for your comments on my new conduits. I'm now thinking the
> LDF5-50 sounds like it's hardly worth the hassle for a few tenths of a dB at
> 30 MHz. Do many of you have experience with LMR 600 coax? Any suggestions
> regarding suppliers and/or connectors?
I use mostly LMR-600. It's not quite as stiff as 3/4" hardline, (More
like 1/2" LDF-4?) but I find it more rugged and it will take a much
tighter bend both repeating and non repeating and it doesn't tend to
kink like LDF-4 or LDF-5 if you try to bend it too tight...within
reason<:-)) N connectors are quire reasonably priced unless compared to
the cheap stuff at swaps. Typically I pay around $10 to $12 each for
brand name crimp type. For low bands and particularly 160 and 75 I much
prefer UHF connectors. N do not do well when running the legal limit
into a high SWR. I've also lost a few due to thunderstorms, but nary a
single UHF. Unfortunately the UHF to fit LMR-600 generally cost a small
fortune as in $70 to near $100 each. However Davis Electric found some
imported ones of good quality clamp type that were around $12 IIRC. I
did modify them a bit by opening up the small inner opening. At those
frequencies it doesn't even show up as an impedance bump.
So, I have gone to all LMR-600 *except* on the drops from the center
fed, half wave slopers. There I use Davis BuryFlex(TM) and 8X.
BuryFlex(TM) is a tad heavy and it also has more wind resistance than
8X, but it'll handle the high voltages at the band edges of 160 and 75.
8X works fine on the 40 meter sloper even at the legal limit. I tried
CNT-240 but the center conductor kept breaking so I finally gave up on
that. Besides, 8X is so much easier to work with, is very flexible,
and fairly rugged.
So it's LMR-600 from the patch panel in the shop to the six pack at the
tower and from the bulkhead connectors on the back of the house by the
den to the six pack. It also runs from the patch panels to the 144/440
antennas. Then there are the runs within the shop conduit to the tower
on the West end.
I ended up with a bunch of UF versions of both LMR 400 and 600 before I
discovered it did not hold up will out in the elements and it wears fast
in rotator loops. So that has mostly gone into the underground conduit
or in locations where it can be easily replaced.
73
Roger (K8RI)
>
> 73,
> Steve
> N6SJ
>
>
> ----- Original Message -----
> From: "Steve Jones"<n6sj@earthlink.net>
> To:<towertalk@contesting.com>
> Sent: Monday, September 12, 2011 2:14 PM
> Subject: New Conduits
>
>
>> I need to install underground conduits to my new HDX-589 crank-up tower.
>> The distence between my garage wall and the tower foundation is about 125'.
>> I plan to put in straight conduits with a 90 degree sweep at each end where
>> they come up out of the ground. I plan 4 #10 copper conductors in a 1" PVC
>> conduit for 220VAC power to the raising winch. For the coax I'm hoping to
>> score some local surplus 7/8" LDF5-50 heliax. I have been thinking of
>> using one 4" conduit for three runs of the 7/8" heliax, and a second 4"
>> conduit for various control cables (RF switches, rotor cables, SteppIR
>> control, etc.). So I'd have two 4" conduits and one 1" conduit in the
>> trench. Those of you who have experience with such installations, please
>> tell me:
>>
>> 1. Are these conduit diameters adequate for my proposed loading? I have
>> put in 4" PVC water pipe and it's unwieldy stuff to work with, so if I can
>> get by with smaller conduit pipes I'd prefer to.
>>
>> 2. What is a good source for electrical boxes to terminate these cables
>> above ground at each end?
>>
>> 3. Is there a better way to control the rotor, switches, SteppIR etc. by
>> using Ethernet in the conduit and local AC power at the tower?
>>
>> 4. Is there something better than Ivory liquid for a cable lubricant?
>>
>> 5. What have I not mentioned that I need to address?
>>
>> I appreciate any and all advice!
>>
>> 73,
>>
>> Steve Jones
>> N6SJ
>>
>
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