The North 40 Foot Office Tower

With all the various repeater project unfolding in the summer of 2012 I decided that it was time to put up a forth tower here at the house just outside my office window for the radios on my desk.

I have been planning this project for several years, and had already purchased seven ten foot sections of aluminum tower, I just never found the time to get the new tower sections installed.

I made the decision to install four of the ten foot sections on the back of the house right next to my office window with a 24 foot mast nested in the top section which would allow me to mount a new G7-144 antenna at approximately 55 feet that I could dedicate to 2 meter FM simplex activities.

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I would also be able to install 1/4 wave ground plane antennas for 28 and 52 MHz that would let me have dedicated radios/antennas for playing with the low band FM repeaters on ten and six meters and a small dual-band ground plane for 146/440 MHz that I could use to monitor the local repeaters and public service (police & fire) action in town.

 

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Once I decided to move forward with the project I once again enlisted the help of my brother-in-law Scott to fabricate new hardware that would be used to mount the 24 foot mast into the tower sections.

While Scott was busy fabricating the custom top shelf and rotor plate Dad and I got to work installing a new house bracket and bolting the hinge base plate to the concrete outside my office window.

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I chose this location for several reasons. There was already concrete available to secure the hinged base plate, it was right next to my office / desk where the radios I use for FM simplex activates, and it is an equal distance away from the other two towers on either side of the house.

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Once the house bracket was assembled, and loosely mounted onto the first two tower sections, I stood the tower up vertical in place so I could locate the correct position to secure the bracket onto the house.

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 Once the house bracket was secured to the house I was able to plumb the tower and locate the holes needed to install the bolts into the concrete that would secure the hinged base plate.

 

My Brother-in-law took the blank 6061-T6 aluminum stock that I picked up and made me two sets of custom mounting plates to mount the 24 foot mast in the top section of tower. (The second set is for my "next" tower project)

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Dad and I spent several days the October 8th while I was on vacation assembling all the tower hardware and mounting antennas. After days of tilting the tower up and down, making custom stand-off brackets, mounting antennas and feed-line, we finally had the first five working antennas tuned and on the air by the weekend of October 13th 2012.

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I finished terminating the five new feed-lines with new Type-N connectors, used heavy heat shrink with adhesive for strain relief, color coded all the lines, labeled them with tower, height, and antenna model, and protected the labels and color tape with clear heat shrink...

... The labels should hopefully last a very long time!

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The ten meter antenna is a modified M-184 ( parts of it are actually from the antenna that I ran my radio-phone on back in 1985) photo of Dad KA1VKD working on the original M-184.

 I took a new GP-52 mount that has four droopy radials (short for 52 MHz) extended them with four radial extensions from two of my old M-184 antennas, and replace the 55 inch center whip for 52 MHz with a 105 inch whip for 29 MHz and then trimmed it down for a good VSWR in the ten meter FM band.

FREQ	Watts Fwd	Watts Rev	VSWR
29.40	100	9	1.86
29.45	100	8.5	1.82
29.50	100	10	1.92
29.55	100	10	1.92
29.60	100	10.5	1.96
29.65	98	10.5	1.97
29.70	96	11	2.02
29.75	96	11.5	2.06
29.80	94	11.5	2.08

 

Update... the Ten meter 1/4 wave antenna works great!

Wednesday afternoon October 17th, 2012 I made a direct FM Simplex contact on 29.600 MHz with Ken KC5TDM who is 1,445 miles away in Konawa, OK.

We talked for a good ten minutes and the QSO was DFQ like I was talking to someone five feet away from me in the same room and Ken said my signal was 60 over S9 at his station. My little modified Kenwood commercial radio does not have a signal meter but his audio was loud and crystal clear hear in RI as well.

That little modified M-184 droopy radial quarter wave antenna is working like a champ!

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There is still a lot more work before this tower project will be complete with several more antennas to be installed...

... Hopefully we will get them all up in the air before the snow fly's this winter!

 

More update as they become available

This page is still under construction and is being updated very often

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