Antenna Height/location/etc.

[radiokatz]

LtDoc -

I know, all you say is true...

The thing is, that's about all I can do at this point. I've been reading a ton of material over the past few months, so now I'm anxious to make things happen, you know? I hate to purchase a radio beforehand & then have it sit here unused for a couple more months if I don't have an antenna to transmit with.

I'm going to contact my local club & see who's good with antennas & run ideas by him. I'm sure he will be able to give me some good tips since he will be able to see it firsthand. It may seem like I'm rushing, but in reality I'm really not.

I just realize that if I don't start making plans & move ahead now, the summer will be here & gone before I ever get started on the project - you know how that goes, I'm sure.

N5TWB -

Great points about the structure of the tower. I seem to recall seeing a manufacture sticker on it someplace. The only use the tower gets at this point is when I climb it to clean the chimney from our wood burning stove.

Also, I have not mentioned up until now; The previous owner of this ham was a ham, and he actually used this antenna for that purpose. I didn't mention it because I figured you gents would have further questions about that, and I know nothing else about it other than he was a ham, and now passed on. A "Silent key"...

Halfway up the tower is an old TV antenna, and at the top is the remains of his ham antenna that has since fallen apart. It was a homebuilt one, had the appearance of a "box kite", which I've since learned was a 4 element quad. There is a rotator on it, I wouldn't know if it still works or not, it's probably over 25 yrs. old at this point.

The base of the tower is in cement - I do not know how deep it is planted. There are 2 existing guy wires off two points, and a third guy wire that goes over a "stand-ff" pipe on the antenna & connects to its' base. Sorry if I do not have all of the terminology exactly correct - I hope what I'm explaining can be understood.

At any rate, the tower appears structurally sound, no cracks, deterioration, etc. that I have noticed.

 

[N5TWB]

Glad to see you have some encouraging factors working for you. The manufacturer info is really key for your future research and planning. If it held up a quad, that is also a good sign because they can have a pretty fair wind load.

 

[radiokatz]

I checked the base, climbed the tower & looked all over for any markings. The only thing that I see is a yellow caution sticker, no other info. at all as to manufacture, rating, etc.

The tower legs are 1 1/4" dia., and the measurement between each leg is 12". Does that give any useable information? I'll try to get a picture to post in the next few days as soon as the weather cooperates.

They are calling for snow/sleet over the next couple of days.

From the remains of the quad, I would say each element was maybe 1 1/2' square and the total length looks to be 4' or 5'. I didn't measure it, I'm just eyeballing from the ground.

 

[N5TWB]

I checked the base, climbed the tower & looked all over for any markings. The only thing that I see is a yellow caution sticker, no other info. at all as to manufacture, rating, etc.

The tower legs are 1 1/4" dia., and the measurement between each leg is 12". Does that give any useable information? I'll try to get a picture to post in the next few days as soon as the weather cooperates.

They are calling for snow/sleet over the next couple of days.

From the remains of the quad, I would say each element was maybe 1 1/2' square and the total length looks to be 4' or 5'. I didn't measure it, I'm just eyeballing from the ground.

That info points to a basic Rohn 25 guyed tower so use that for some research to compare what you have to what is on the tech sheet at the Rohn website. Pay particular attention to the diameter and pattern of the cross-bracing on the faces. Rohn made a smaller tower for TV called the Rohn 20 but I think the legs were 1" OD with a 12" face. The website should be definitive and research is a good way to spend the time during the non-antenna/tower season.

 

[radiokatz]

That info points to a basic Rohn 25 guyed tower so use that for some research to compare what you have to what is on the tech sheet at the Rohn website. Pay particular attention to the diameter and pattern of the cross-bracing on the faces. Rohn made a smaller tower for TV called the Rohn 20 but I think the legs were 1" OD with a 12" face. The website should be definitive and research is a good way to spend the time during the non-antenna/tower season.

That's a very good guess, but I realize I haven't given enough info. here. I completely forgot to mention that he tower has no diagonal structure of any type, no "Z" or "W" supports between the legs. Definitely a big negative, as far as I'm concerned.

From some googling, I came across some other threads that suggest this may be a light duty TV tower, possibly from the 60's by the "American Tower Company".

So, that's what I have. I will try to get some pics for reference as soon as I can. I suppose if I wanted to proceed with my *tentative* plans of creating a tilt-tower, I could weld in diag. bracing to make things stronger. Seems like a lot of work though.

 

[N5TWB]

Forgot about American Tower as a possibility -- that's a good lead, especially considering the lack of diagonal structure. I agree with your conclusion about that being a negative you'll have to address in some fashion.

 

[radiokatz]

This is interesting.

This small FM station is using a Tri-Ex crank up 55' tower, that is constructed almost the same as mine, less the crank up. No diag. structure, wide spaced rungs. I'm thinking, "if it's good enough for them, it ought to work for me", yes?

It is a smaller triangle than mine, I suppose that would make it stronger?

Commercial-Free KVLP 101.5-FM

 

[radiokatz]

Random (dumb) question here -

When assembling the tower sections, do you apply any type of sealant at the joints to keep water out?

 

[KC4RAF]

Didn't use any sealant.

BUT I did use grease on the bolts' (2 per leg) threads and nuts, (didn't use stainless).

 

[LtDoc]

That's not a particularly 'dumb' question. 'Sealing' the bolts/nuts may not harm a thing, except getting them loose later. Also providing a 'drain' for tubular 'legs' is a good idea. Even if they are 'capped', moisture will get in there and it's not a bad idea to give it a way out (weep hole?). You should be careful not to compromise the structural integrity of the tower, I figure that's the biggy.
- 'Doc

 

[radiokatz]

The reason I asked is that I read on another forum where a person was preparing to drop a tower for scrap, and when they cut the legs to let it fall they were full of water.

A drain for tubular legs? Simply drill a small weep hole at the bottom of the legs? Do manufacturers take this into account and provide drain holes?

 

[HF-Mobile-Antenna]

Your best bet for an antenna will likely be a 40 meter loop at the maximum height you can achieve.

 

[LtDoc]

All tower manufacturers don't provide a 'weep hole', or if they do it's probably in the 'base' assembly, not the tower sections. All of them using tubular tower legs do recommend some means of draining and/or 'capping' the top ends of tower sections, or using a 'top section' that's already closed.
- 'Doc

And just for grins. That height above ground means exactly that. Height above sea level doesn't mean anything for antennas unless that antenna is at sea level.

 

[gunmasternd]

well from what i know is if you plan on doing vhf/uhf you wanna be above the tree line.

best to start off with HF.

That tv tower you have plan on scratching that. I doubt those would even hold a tv antenna

 

[radiokatz]

Update - I'm getting a local farmer to help me take this tower down. He has big front end loading equipment with buckets/etc. that can easily accomplish this. Plus, he has experience with this sort of thing around his farm.

Once I get it down I can give it a good inspection as far as the inner structure of the legs, unseen corrosion, etc..

Hoping I can salvage this one, as I see I can run into money real quick in this hobby if I need to start from scratch, esp. considering my less than ideal location.

I guess a temporary option would be to throw a dipole up into the high trees on the property & see what I get.

 

[LtDoc]

Sounds like it would probably work, good luck. As for that dipole in the trees, it works for a lot of people, why wouldn't it for you?
- 'Doc