Getting The Coax In

You won't get through to the floor above with a 4" drill bit!

How many different techniques for bringing a signal into the shack have you experimented with?  I’ve tried a number of them.  My first shack, outfitted with a Heathkit HW-101 transceiver, was in the basement.   Immediately to the left of the HW-101 was the foundation, sill plate, and as yet unfinished studded wall.  There was also a single window.   When I was using an end-fed long wire as my radiator I merely tied it
off outside the window and then continued inside with a short insulated extension that slipped under the frame of the closed window and terminated it at a post on an MFJ antenna tuner.  Everything changed when I switched to a G5RV fed by coax.  That time I drilled a hole directly through the outer shingles and plywood wall and on through my new inner wall (diagonal furring strips).  I lined the hole with a short piece of PVC tubing that was filled on both ends with Coax-Seal putty.

Things changed when I moved up one floor to the now vacant bedroom left to me by my son when he moved away to college.  I placed a copper-clad panel between the window and sill and studded it with through-mount SO-239 connectors.  These afforded me
access to a roof-mounted VHF antenna, a tree-bound G5RV, and a ground mounted
Gap Titan vertical.  At this higher elevation  the ground wire was getting a little longer than I wanted it (10 meter in-shack radiation was sometimes a problem).

Then we moved to the new house which is a colonial; two full floors and a basement.  First I adapted the window panel to fit my new second floor window.  Later I decided to change things because I wanted to install the shortest possible RF ground wire and put
the screen back in the window (I now have one-piece screens, they do not move
on a track).  An advertisement for the MFJ soffit entrance panel got me thinking about a new entrance for the transmission line.  If I purchased the MFJ unit I would have to figure out how to remove a section of the soffit that makes up part of the overhang of my second floor room.  I found that this involved the removal of lots of nails, molding, and panels.  I like to keep a job simple.  My solution was to drill a hole directly through the soffit right on up to the floor of my shack.  My soffit is covered with vinyl siding.  Under the siding is what looks like 3/4” plywood followed by about 9” of insulation-filled space which is topped by the floor boards and rug of my ham shack.  My room also has walls and a bookcase; I did not want my drill bit to come up in either one of those places.

So how did I do it?  I first made very careful measurements as to where I wanted the entrance hole to emerge from my rug.  This was in the corner of the room and about
5” from each adjoining wall.  If I missed my mark I could end up in the wall or under the bookcase.  I dropped a weighted line (plumb line) out the window and measured from the place on the rug where I wanted the hole to the edge of the line going out the window.   Then I went outside and marked the point on the soffit that was exactly
the same distance from the string line as the prospective entrance point was.  All I needed now was a depth measurement.  I measured from a point 5” inside the window to the outside vinyl siding.   Then I was able to find the intersection of the two lines; I had my drilling spot.  I purchased a long 5/8” x 16” spade bit (it will make a clean hole that is 14” deep).  I could have got one that was 1-1/4” in diameter, but that would have more than doubled the $10.00 price.  I drilled the hole from the outside and in spite of my careful measurements I was about 2” off, but not in the wall or under the bookcase.  I then opened up  each hole (floor, siding, soffit) with a 1-1/4” spade bit that only had to penetrate less than one inch on both sides.   Then I attempted to feed the coax through the hole.  That did not go well.  Although the hole was large enough the coax tended to go off to one side or another and never quite make it to the shack floor.  I solved this problem by

PVC entering hole which will be finished off with chrome wash basin bushing

cutting a piece of ¾” Schedule 40 PVC and lining the hole with that.  The end that protruded into the shack was terminated with a ¾” connector that is usually used to connect two lengths of PVC tubing.  The connector prevented the PVC from falling out of the hole.  On the soffit side I used some liquid nails to glue a chrome sink drain surround over the hole to make it look better and that was it.

The PVC pipe has been cut to size and capped with a 3/4" connector.

Now all I have to do is run in a ground wire and attach a ground bus bar to the wall where the coax enters.  I may also close off each end of the PVC with some sort of plug such as a piece of rubber or flexible plastic with radiating cuts in the middle to allow the coax to pass through.  I will tightly close off each entrance point with Duct Seal (a kind of putty used by electricians) so all weather and insects will remain outside.

List of Materials and Special Tools:

(1) 5/8” x 14” spade bit (wood boring bit)                                  $10.00

(1) 1-1/4” x 4” spade bit from a set                                                $1.50

(1) 1 pound package of GB Duct Seal                                            $ 1.75

(1) ¾”  Sched. 40 PVC junction                                                     $ 0.40

(1) 10’ x ¾” SCH 40 PVC pipe; ID 3/4″, OD ~ 1-1/16″              $ 3.00

(1) Wash basin drain surround                                                     junk box item

From top: 3/4" PVC connector, 3/4" ID PVC, 5/8" bit, 1-1/4" bit



Lots of room for cables; now all I need do is to weatherproof the entrance.


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