440 Repeater

[pddispatcher]

Hey Guys,

Currently in the process of installing a 440 Mhz Repeater at 443.325 on a water tower. I bought this site from an existing plumbing business that no longer used it anymore and wanted to relinquish it and make alittle of their money back.

The site is using 7/8" Hardline about 160 feet worth going to an antenna at the very top. The antenna appears to be a Comet GP-9 or comparable to a Diamond but no one can tell me as that info is MIA.

There are two antennas on this site, one is for the road department on VHF ( which I installed a new repeater for narrowband for them and works great w/ 50 miles coverage range by mobile) and then my antenna...

Both antennas are crooked but one is far worse than the other one on the tower. Just by looking from the ground it appears there is no type of railing on the top that I could mount a better antenna too other than 2 little stubs that is there for the 2 fiberglass antennas currently in the air.

I have checked all the settings from the ground involving sensitivity of the repeater, the tuning of the repeater and all that.

The analyzer says 1.4 SWR on 443 with the current tilted antenna.

I have access to a DB-410 antenna but was curious if they make a mount that I can secure to the vent at the very top or could I mount it to the ladder rail of the water tower? I'm currently waiting on the city for their "understanding agreement" to see what they will allow me to do with it.

Any help would be greatly appreciated in regards to a mount that either mounts to the rail or secures to the vent or will allow me to mount my antenna securely.

Thank you.

 

[pddispatcher]

Here are pictures for the site I'm using.

I do not know which antenna is mine.

 

[Rt169Radio]

Well that's interesting, did you buy a antenna spot or the whole water tower?

 

[rapidcharger]

Well he did say it was a plumbing company but he also said he's waiting for a MoU from the city so I'm guessing the city owns the water tower.

 

[pddispatcher]

I bought the existing installation that the plumbing company has installed on the city water tower.

What do I need with owning a water tower? LOL

 

[LtDoc]

...rent out antenna space??

How do you feel about climbing that thing to see what mounting options you have? I don't think a ladder mount would be very safe, but I won't be climbing the thing anyway!
- 'Doc

 

[Skypilot007]

Those crooked antennae would drive me nuts looking at them, especially if one of them was mine. I would hire someone to go up their and determine which one is yours and fix the mounting issue. Unless you are a climber yourself then you save that money. Either way I would say that antenna mounting issue needs to be fixed.

 

[jhooten]

The second pic makes it look like the antenna is vertical and the tower is leaning.

Those crooked antennae would drive me nuts looking at them, especially if one of them was mine. I would hire someone to go up their and determine which one is yours and fix the mounting issue. Unless you are a climber yourself then you save that money. Either way I would say that antenna mounting issue needs to be fixed.

Agree.

 

[pddispatcher]

Better pics:

It would be determined that these antennas are stationmasters.

Thoughts how I would switch out to a DB-410?

]

 

[pddispatcher]

Those crooked antennae would drive me nuts looking at them, especially if one of them was mine. I would hire someone to go up their and determine which one is yours and fix the mounting issue. Unless you are a climber yourself then you save that money. Either way I would say that antenna mounting issue needs to be fixed.

Trust me I know its driving me insane as well and it is affecting how my repeater works.

 

[KZ9G]

More than likley the mounts that are up there were never designed to have that much antenna on them. I ran into this years ago on a site and ended up making a clamp mount that went around the access hatch base on the top of the tower. The ring was about 8 inches tall and was 3/8 plate that was bent and had tabs to bolt the two halves together. It also had four posts spaced off of it for mounting antennas. The reasoning for that type of mount is that the agreement with the city specified that we could not drill or weld on the tank itself. About five years after we put that up there a cell company came up and added multiple mounts for antennas. There is a company that makes a magnetic mount that will support the antenna you have up there. Yes magnetic. Not a joke and pretty strong. Its an array of those 4-6" magnets that mount on a plate that has a post for your antenna.

 

[SCPD]

I did an install on a site that looks identical to this one. On the top, is the vent tube. It was held in place with 3 mounting brackets and 3 bolts. I removed it, and used a whole saw bit and used 1" threaded pipe stub (like used on an electrical service), approx 18" long. I used the locknuts to hold the pipe mast in place out of the top of the vent cover. Then we mounted an Antennex fiberglass 6' 7db UHF antenna on it. There is no way to support the windload of a DB products antenna on this setup. One would have to weld masts on top of the tank to do so. I have done installs on the climbing ladders before. However, per OSHA rulings, had to make a standoff to keep the antenna off a certain distance from the climbing path. This was done on some VHF yagi antennas. We stood them off 24", which was more than required. Another idea, would be to put an Omni on each side of the tank and use a power divider from Tessco. Just an idea. Ive done it with yagi antennas before, but not omnis. But should give you the 360 coverage you need.

 

[SCPD]

Another thing i have seen, but not personally tried.....

Take a straight and a top section of Rohn 25G and a base plate. Mount the base plate to the walk way around the lower tank. Then put standoff support from tower sections, to the overflow tube. You will have to take measurements and fabricate (2) half circle rings that have tabs to bolt around the overflow tube. Then 2 pieces coming off of that to the 2 legs of the tower, to brace it.

( )=[>

 

[pddispatcher]

Ladies and Gentlemen:

I have you the finished project:

168 feet at the tip according to the engineer and what a word of difference.

 

[pddispatcher]

The other antenna is the county road department antenna that I also maintain and we had to straighten that one as well.

Problem solved for both and both repeaters are functioning beautifully.

 

[Rt169Radio]

Looks good, nice job!

 

[K4APR]

Depending on the amount of wind you get there, you'll be dealing with a chaffed cable in a year or so with it rubbing against that bracket like that. Might want to get them to go back up and secure the hardline below the bracket. I would never pass THAT off as ok.

 

[AC2OY]

If you climbed that tower you are one courageous human being!!! WOW,!! One time at band camp..at work I went up about maybe 50ft on top of our surge tower to take down and reinstall our flag and it was windy and scary...but I suppose if it meant getting on the air I would acquire the courage!!

 

[pddispatcher]

Wind isn't a huge deal here. It can occasionally get windy but not very often. I will make note of your finding.

 

[K4APR]

Wind isn't a huge deal here. It can occasionally get windy but not very often. I will make note of your finding.

Good, you might also want to tell them to use actual zipties, preferably UV rated, instead of just a couple loops of electrical tape. One good hot summer day and that tape will peel right off.