[TowerTalk] LMR600 male DIN

Sat Sep 10 02:37:28 EDT 2016

The bottom two photos on this page show a bit of the 1/2" CATV cable 
sticking out of connectors. I was talking about 
http://www.rogerhalstead.com/ham_files/conn.htm It's extremely fragile 
and rarely used in this area of Michigan. Nearly all is now 3/4 except 
for the drops.  I still have over 200' left  o 3/4" out of nearly a full 
spool (only the outer layer was shot)
The 1/2" CATV stuff  is bare, thin  AL with no protective jacket and 
extremely fragile.  The 3/4" stuff is also bare Al but it's tough.  
Nearly all CATV runs in this area are the bare 3/4" except for the few 
new upscale subdivisions where everything is underground

I don't share the opinion of the 1/2" Andrew coax. I had a short piece 
stepped on in the yard and the imprint from the man's foot was quite 
visible.
As the longest run to the top antennas was 228 feet. 200 feet to the top 
of the tower and 28' pigtails to the antennas, I'd gain little by going 
to hard-line on HF.   If it was farther to the tower, you bet I'd be 
using 7/8ths.

What's the difference in loss and cost per 100' comparing 1/2" Heliax 
and LMR 400 and 600 at 30 MHz?
LMR400 is 0.7db while 600 is 0.4db So replacing my LMR 400 with 600, 
saved me 1.4-.8, or 0.6 db on HF. On 50, 144, and 440 it was 
progressively more.  I'm too lazy to look up the figures as it's 2:30 AM

Pulling hard line through conduit?  If the conduit is large enough and 
the messenger cable strong enough, it's shouldn't be that hard to do.  
We pulled three, 00 copper cables through roughly 150 feet of 3".  Each 
end consisted of two sweep 45s. When the Consumer's crew arrived and saw 
the installation with the big messenger cable his face lit up, he had a 
big smile and hollered back to the crew, "You guys are gonna love this!"

Even relatively long pulls of multiple cables do not have to be overly 
difficult if the cables are properly prepared. Soap/lube the living 
daylights out of the original pull and any additional cables.  put the 
originals loosely wound on a spool so they go straight in. Pulling 
through proper size conduit  is easier than pulling the same length 
across a yard.  Of course, 300 feet of 7/8ths Heliax, or even LMR-600 is 
a lot of weight.  Nor does pulling more cables need to cause worry if 
the conduit is large enough. Try to find wider than normal sweeps for 
hard lie even if you have to order them. Tape the leading edge of the 
large coax into a cone. If necessary, use a bunch of the yellow foam in 
a can that cures hard.  trim it to a cone shape for the end of the 
entire bundle and cover it with plenty of tape.  Soap well. With 
hard-line there is little need for worry about water. Most other cables 
are available in Direct Burial versions with the space between the 
jacket and dielectric filled with a jell.  They are more expensive, but 
replacing a 200 or 300' run can be work, plus money.
NOTE: Don't make the mistake of taping the coax cables together except 
at the leading end!

If the pull is fairly long. get some Tygon tubing and force a stream of 
lube along the entire length of the conduit.  Of course, thinking ahead, 
this could be done 20 feet at a time during assembly. It's actually 
easier than pulling 20 feet at a time during the conduit assembly.  The 
first time you pull through a thoroughly lube conduit with a lubed 
bundle you will be surprised at how little effort it takes. Just be 
generous with the lube!

I no longer glue the conduit sections together.  I simply grease the 
inside of the joint with an ample coat of Silicone grease. That allows 
the section going in to bottom out in the joint and seals adequately, at 
least in central Michigan.  Officially the code still thinks the frost 
line is 28, or 30 inches.  I don't think it's gotten that deep under the 
driveway in 20 years.  The last 10, it's only made 6 or 8 inches under 
the yards and fields. I don't remember restrictions on the roads last 
spring. If there were they were on for a very short time.  I try to have 
a bit of compression pressure on the run, but I doubt it's necessary.  
If you are not draining and live where it gets cold in the winter, make 
sure the conduit is below the frost line.

73

Roger (K8RI)

On 9/9/2016 Friday 7:56 PM, Bob K6UJ wrote:
> Steve,
>
> For a newbie to these cables, is this an example of the smooth wall 
> aluminum hard line you are talking about ?
>
> https://www.tessco.com/products/displayProductInfo.do?sku=452440
>
>
> Bob
> K6UJ
>
>
>
>
> On 9/9/16 4:16 PM, Steve Maki wrote:
>> On 9/9/2016 13:05 PM, Jim Brown wrote:
>>
>>> John,
>>>
>>> FWIW, I find LDF4 very reasonable to handle.
>>
>> Yes, and so does almost everyone who uses it on a regular basis. It's 
>> very robust, and takes some serious abuse to damage it. I've seen 
>> both LDF4 and LDF5 run over by cars on pavement with nary a dent.
>>
>> I'm sure the thinner shield AVA5 or equivalent would be squashed in 
>> that scenario.
>>
>>   The "hard line" I find quite
>>> delicate are the varieties designed for use in CATV systems. I've got
>>> some and I'm using it on two monobanders, but it requires VERY careful
>>> handling. What I have is 1/2-in, 75 ohms, Cu-coated Al center, Al
>>> shield, so it's very easy to kink.
>>
>> Yes, and smooth wall 50 ohm aluminum hardline is the same, quite 
>> fragile. In particular you must be EXTREMELY careful not to nick the 
>> shield while installing a ground kit. A nick will turn into a 
>> complete break of the shield as soon as you bend the cable near the 
>> ground kit. We learned the hard way of course.
>>
>> -Steve K8LX
>> _______________________________________________ 

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