[TowerTalk] Used Heliax ?

Jim W7RY jimw7ry at gmail.com
Sat Dec 24 13:35:39 PST 2011


I agree Gerald, N connectors have been in use for years around my shack and 
tower with no issues.

The only problem with 7/16 is the availability and price of them for RG-8 or 
other flexible cable.  N connectors for RG-8 sized cable are dirt cheap!

I run RTTY contests at 1500 watts with no issues.  But then again... I still 
use the BN-86 on my TH-7. Never have burned one of them up!

73 and Merry Christmas!
Jim W7RY


--------------------------------------------------
From: <TexasRF at aol.com>
Sent: Saturday, December 24, 2011 1:23 PM
To: <balmemo at sympatico.ca>; <K8RI-on-TowerTalk at tm.net>; 
<towertalk at contesting.com>
Subject: Re: [TowerTalk] Used Heliax ?

> Hi All, N connectors seem to get a bad rap for some reason.
>
> I have used them in my eme systems on 2m and 70cm for over 20 years and
> find them to be very reliable. There have been quite a few contests run 
> for
> hours at a time at the 1500 watt level even using the JT65 digital mode 
> that
> is  full carrier key down for 50 seconds and key up for 70 seconds.
>
> I have had a couple of failures in flex loops where the shield worked 
> loose
> and the insides of the connector overheated and turned into charcoal. Even
> that  problem has disappeared since learning to reinforce the connector
> with a length  of heat shrink tubing. Have never seen a center pin 
> failure.
>
> For Heliax, the connector choice is limited. As far as I know, there have
> never been any C connectors offered. Maybe LC but not too sure about that.
> As  Roger, K8RI mentioned, there are plenty of 7-16 DIN male and female
> connectors  available for excellent prices. They are the ultimate for 
> robustness
> and easy to  install.
>
> 73,
> Gerald K5GW
>
>
>
>
>
> In a message dated 12/24/2011 2:21:24 P.M. Central Standard Time,
> balmemo at sympatico.ca writes:
>
> N-connectors are not much better than BNC and they don't stand up  to much
> power! ;-) A better choice is C-connectors but they are a rare  breed.
>
> Merry Christmas and a Happy New Year to all!
>
> Bert,  VE3NR
>
>
>
> -----Original Message-----
> From:  towertalk-bounces at contesting.com
> [mailto:towertalk-bounces at contesting.com]  On Behalf Of K8RI
> Sent: Saturday, December 24, 2011 1:55 PM
> To:  towertalk at contesting.com
> Subject: Re: [TowerTalk] Used Heliax ?
>
> 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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