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Author Topic: Air Dielectric Cable  (Read 1173 times)
W2RWJ
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« on: December 01, 2012, 05:22:37 PM »

Anyone using Air Dielectric Cable?  I have a project underway that will be using ~350 of HJ7-50A  underground (in 4" conduit)

Looking for advise or items to be aware of when installing or attaching fittings.

73 Martin
W2RWJ
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W0BTU
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« Reply #1 on: December 01, 2012, 08:44:38 PM »

It's recommended to flush and pressurize air dielectric cable with a suitable dry gas to keep moisture out. Are you planning on doing that?

You don't even need 1 PSI to do the job, IIRC.
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K2DC
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« Reply #2 on: December 02, 2012, 03:14:54 AM »

Martin,

   Pressurizing the cable is not just a recommendation, It's almost a must-do for use in an uncontrolled environment.  It's the only thing that can prevent condensation inside the cable.  You also need to pay very careful attention to minimum bend radius to keep the center conductor centered.  IMHO you'd be much better off with LDF7-50.  No pressurization, less likely center conductor movement, and the loss at 100 MHz is almost identical.

73,

Don, K2DC
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W2RWJ
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« Reply #3 on: December 02, 2012, 04:53:10 AM »

Pressurizing the cable is not just a recommendation, It's almost a must-do for use in an uncontrolled environment.  It's the only thing that can prevent condensation inside the cable.  You also need to pay very careful attention to minimum bend radius to keep the center conductor centered.  IMHO you'd be much better off with LDF7-50.  No pressurization, less likely center conductor movement, and the loss at 100 MHz is almost identical.

It's recommended to flush and pressurize air dielectric cable with a suitable dry gas to keep moisture out. Are you planning on doing that?

Mike & Don,
We have the Andrew compressor / dryer for the cable, including the alarm switches and nitrogen regulator if it turns out a backup system is needed. 

I see the point re the foam dielectric cable, however the air dielectric Heliax was essentially free.  I'm hoping to find an Elmer who can show me how to attach the connectors (or at a miniumum can point me in the right direction via e-mail)

73 Martin



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K2DC
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« Reply #4 on: December 02, 2012, 06:33:23 AM »

Martin,

   Here is the Andrew installation instructions for tuneable gas-barrier Type-N connectors for HJ7-50.  Links for both the male and female lead to this same page:

http://www.commscope.com/catalog/andrew/doc/Tunable_Connectors_for_HELIAX__HJ7-50A_and_HJ7P-50A_Cables.aspx?id=0000010%2ft009_r02753_v0.pdf

If you're looking for DIN, go here first:

http://www.commscope.com/catalog/andrew/product_details.aspx?id=1461&tab=2

Click on the Air Connectors link, then click the Documents/Toolas tab.

Hope this helps.

GL & 73,

Don, K2DC

BTW- Andrew Heliax is absolutely the Bomb!  I use FSJ4-50 almost exclusively that I was able to obtain surplus or on eBay.  I've had some of it in the air for 20 years and at least some of it was 10+ years old when I got it.
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K2DC
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« Reply #5 on: December 02, 2012, 06:34:27 AM »

Martin,

   Here is the Andrew installation instructions for tuneable gas-barrier Type-N connectors for HJ7-50.  Links for both the male and female lead to this same page:

http://www.commscope.com/catalog/andrew/doc/Tunable_Connectors_for_HELIAX__HJ7-50A_and_HJ7P-50A_Cables.aspx?id=0000010%2ft009_r02753_v0.pdf

If you're looking for DIN, go here first:

http://www.commscope.com/catalog/andrew/product_details.aspx?id=1461&tab=2

Click on the Air Connectors link, then click the Documents/Toolas tab.

Hope this helps.

GL & 73,

Don, K2DC

BTW- Andrew Heliax is absolutely the Bomb!  I use FSJ4-50 almost exclusively that I was able to obtain surplus or on eBay.  I've had some of it in the air for 20 years and at least some of it was 10+ years old when I got it.  It will probably outlive me.
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