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Author Topic: Flat Coax  (Read 3584 times)
W8RID
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Posts: 45




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« on: June 03, 2013, 01:07:14 PM »

Looking to rework my shack.

I would like to not have to drill any holes.

I have looked for "Flat Coax" to go under windows and doors. The only one that I have come up with is the "Comet Window Feed-Thru Jumpers".

Are there any others out there?? Trying to stay with RG8X coax to get this done.

Are there any other suggestions for accomplishing this without creating a pass through for a window??

Thanks

Bob
W8RID
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KE3WD
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Posts: 5694




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« Reply #1 on: June 03, 2013, 01:33:24 PM »

Hi Bob,

Flat coax and other schemes would create an undesirable impedance bump, the good news is that you do not have to go that route. 

MFJ makes several different Window Feedthrough Panels for just this purpose, or, after looking them over, you may decide to get a piece of AL plate and make your own: 

http://www.mfjenterprises.com/catalog/mfj/Pages_069-102.pdf


73
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W1JKA
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Posts: 1619




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« Reply #2 on: June 03, 2013, 01:49:17 PM »

 About the only other way out is via HVAC ducts or area around ac outlets beside face plate (RF/noise issues??)Small coax size holes can be plugged very easily.  Basement? small hole in corner floor(like CATTV cable) into basement and through basement window frame or hole through sill plate. Attic? small hole in corner ceiling into attic then through gable end vent,window or drilled opening.Local hams around here(Maine)use the Comet jumpers(100W limit) to avoid the cold draft and security issues associated with other through window devices.And of course there is always the old steam radiator feed pipe through hole to basement and the overhead light fixture to attic trick.GL
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KE3WD
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« Reply #3 on: June 03, 2013, 02:59:05 PM »

Window pass-throughs can be made as simple as sawing a pine board to fit the width of the window, then drilling holes for your various coax passes, then ripping the board lengthwise right through the holes.  A few wallboard screws with drill to affix the bottom board in place, lay the cables in their respective half-holes, place the top board over them, shut the window and use a wallboard screw or two to keep someone from opening the window from the outside. 

Use some RTV or other caulking to seal it up from the weather. 

73
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WB2WIK
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Posts: 20559




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« Reply #4 on: June 03, 2013, 03:48:20 PM »

Looking to rework my shack.

I would like to not have to drill any holes.

I have looked for "Flat Coax" to go under windows and doors. The only one that I have come up with is the "Comet Window Feed-Thru Jumpers".

Are there any others out there?? Trying to stay with RG8X coax to get this done.

Are there any other suggestions for accomplishing this without creating a pass through for a window??

Thanks

Bob
W8RID

Everyone is making good suggestions.

The "flat coax" jumpers from Comet have limited power capability and although they "work," I've also seen them fail.

A standard pass-though "panel" is the common approach.  I don't like cables coming into my home at window height, so I don't use anything like that: I drill holes in the outside walls and pass cables through them to inside, then seal them up.  Only takes a few minutes per hole, even though my siding is stucco and uses up a masonry bit each time. Cheesy
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KA5IPF
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« Reply #5 on: June 03, 2013, 04:35:07 PM »

Not wanting to drill holes.Hmmmm... Sounds like a friend of mine. He had a new Ford PU and 3 of us were discussing where to mount the 2m radio and antenna. Now this is a guy that is serious about ham radio, manager of the local ham store etc. The other guy, un-named and I agreed that the best thing was to drop the dome light, punch a hole, and feed the coax under the headliner. That's the way we had always done installations, all three of us. The owner of he shiny new PU loudly declared he wasn't punching any holes in his new truck. The other guy reached into the glovebox, pulled out the 45 he knew was there and asked "where do you want that hole?". Since this was a lazy Sat afternoon and a few 807's had been consumed. The replay was I'll get the drill and the hole punch since he knew he was going to get a hole somewhere.

We laughed about that for years....... Where do you want that hole?

Clif

PS: the statute of limitations has run out, that was over 25 years ago.
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K8AXW
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Posts: 3722




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« Reply #6 on: June 03, 2013, 05:53:05 PM »

The window feedthrough suggestion is the easiest way to go.  The major problem though is that the feedthrough "board" needs to fit in the window slot on each side of the window.  Simply cutting a board this length won't work because it will jam before it drops into place.

Rather than getting into a lengthy discussion on how to do this (think an old time window screen that is shoved together, installing in the window slots and then slide open or expanded to fit tight) I'm going to leave that engineering problem to your own imagination.

Hint:  A hinge in the center will work!

Foam weather stripping of around 1/2" is available at any hardware store to seal the window in the middle where it passes the upper non-moving window.

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N7BMW
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Posts: 113




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« Reply #7 on: June 04, 2013, 12:53:53 AM »

I use a simpler window feed through.  I do not like the idea of an MFJ type board with connectors or any rigid board.  Adding connectors is adding potential problems like corrosion and water intrusion into the cable.  I take rigid closed cell foam packing material, not styrofoam that will disintegrate, cut it to the size of the window, cut a slot in it for ladder line and close the window on the foam.  A couple of strips of wood cut to the right length prevent the window from opening.  Over time cable movement has caused the slot to widen.  I just take a little of the same foam, cut a wedge and jam it into the slot next to the ladder line.  Two years and I have seen no deterioration in the foam.  Same could be done for coax.  The foam is a good insulator and by making it slightly larger it makes a good seal.  It is somewhat compressible so the wood strips holding it in place have been cut to apply some pressure.
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W5CPT
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Posts: 557




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« Reply #8 on: June 04, 2013, 04:08:27 AM »

Here is the problem with a window pass through, either an MFJ or home built.  When a double hung window is closed the upper part of the lower sash seals against the lower part of the upper sash.  When you open the window these two parts are no longer together.  You insert the pass through with the cables and close the window down on to it – BUT – now you have an opening between the two sashes.  To seal it you will have to stuff the gap with something that will keep out the bugs and the cold/hot (depending on the season) air that is coming in.  Foam rubber will effectively do it – BUT – it will eventually get wet from blowing rain and deteriorate and leave a gooey mess on the sealing surfaces of the sashes. From the amount of detail you can tell I learned this lesson by having it happen.     

Here is the way I got the cables out of the house when I lived in Texas.  My shack was in a spare bedroom and I passed the cables under the closet door.  This is usually not too hard because often closet doors have no sills and the door only seals against the carpet.  Once the cables were inside the closet I drilled holes for the cables in the ceiling of the closet into the attic.  In the attic I placed a one foot piece of 4” PVC on the sheetrock to keep the insulation from filtering down the holes. I then ran the cables to the eaves (HF on one side – 2&6 M on the other) out small holes in the eaves and up the tower and mast to the antennas and rotors.   Upon leaving the holes in the closet ceiling were easy to patch as were the holes in the eaves.

Clint – W5CPT -
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AC4RD
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Posts: 1236




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« Reply #9 on: June 04, 2013, 04:14:39 AM »

I don't like cables coming into my home at window height, so I don't use anything like that: I drill holes in the outside walls and pass cables through them to inside, then seal them up. 

Thumbs up on this approach--I can't use window passthroughs where I have my current home shack.  But instead of threading cable through holes, I use bulkhead passthroughs.  They work great, easy to install, easy to use!

http://www.hamcq.com/1-uhf-female-so-239-bulkhead-6-inch-uhffemaleso-239bulkhead6inch-239.html
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F8WBD
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Posts: 63




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« Reply #10 on: June 04, 2013, 05:01:02 AM »

Having the shack in a room with a pop-up window on the pitched roof (common in France), I am restricted in coax feed through options. I use the Comet window-pass and it works. However it is under great pressure when the window is closed. The instructions recommend not opening the window frequently. I don't. I also wrapped good electrical tape around the the entire length. I operate QRP only so power level limit of 100 watts is not a factor. Works well for me.
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KE3WD
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Posts: 5694




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« Reply #11 on: June 04, 2013, 07:00:39 AM »

Drilling the exterior wall for coax pass is not rocket science, furthermore, sometimes all you need do is flag down the guy in the Cable TV installation truck and use the gift of gab and a few bucks and perhaps a beer to get a fast and pro penetration job, often complete with pvc feedthrough, angled properly and all. 

73
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N6AJR
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Posts: 9913




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« Reply #12 on: June 04, 2013, 10:35:13 AM »

I just drill a 4 inch hole through the wall  below the desk in the radio room, and use a 45 degree PVC elbow to run the cables through.  If I ever  don't need it any more, it is easy to pull the pipe, fill the hole with expanding foam, and hit the  out side wit some concrete made to look like stucco, and a splash of paint.  But label the ends of the coax in the shack as they can become confused real easy otherwise.
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W5LZ
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Posts: 477




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« Reply #13 on: June 16, 2013, 09:34:16 PM »

Quit worrying about the small stuff.  Making a hole in a wall is NOT that big'a deal.  Do it correctly and it's not going to be a problem.  There are more holes in the walls of any structure than you'd ever believe.
 - 'Doc
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