Hey YFR, check out the new area here (up top) called "HAM shack"! Now we have a place especially for this stuff

 

Not sure why you need to be up 72ft, need a yagi or need 500 watts.

A simple dipole in the trees work fine..

 

Dipoles in the trees work fine DEPENDING on the wavelength your dipole is cut for and what you want to do with it. IF you are working 20 meters and you want DX (long range HF comms like to Japan or Europe or New Zealand) then the necessary height above ground for your dipole to have a low takeoff angle is approx 1/2 wavelength or 35 feet. I don't have any trees that tall. Once you get the dipole down under 1/3 wavelength then you have most of your signal going straight up. Now for 40 meters that means a dipole up at least 70 feet and even worse for 80 and 160 meters. I am not content to only work 10,11 and 20 meters except off of a beam with the gain that a Yagi antenna provides. I desire to work the other bands too. It's the same reason why I scrimped and saved to buy an Elecraft K3 radio - so I can talk to people that other people can't even hear. The other nice thing about my K3 is it will never go out of date. The Elecraft is a software defined radio and Elecraft provides all of the software upgrades to the radio for FREE. The radio didn't cost any more than a mid priced Icom 7410.

 

..................My tower setup was 70 feet of Rohn 25 G tower , had a 3 element triband beam , HYgain 20-15-10 meters , and a 40 meter single bander made by Cushcraft ! Mast was a 21 foot stick of 1 7/8's galvinized pipe x 1/8 in wall thickness !
.................The ENtire setup was A Crankover , I used a 3500 pound , 2 speed hand crank winch with 1/4 inch stainless aircraft cable . I built my own steel "V" shaped brackets with a pulley attached . People told me the tower would break in half because of the load at the very end of the tower . But , I fabed a "Sway brace" made from Standoffs and a steel cable that ran the full length of the tower with a turnbuckle anchored at the base . Once tightened the the load at the end of the tower was transferred down to the base and the tower became a Rigid digit . IT was SO strong I could Hang off the mast when I had it crancked almost all the way down which was about 200 lbs . , fordy

 

Fordy,

A neighbor has a 40 ft +/- Rohn tower she wants to give me if I can get someone to help me take it down - Safely. I never in a million years thought that I could put a hinged base on it and then be able to crank it down - HMMMMMM, that makes fussing with antennas on it a whole lot easier. I may need you to draw me a diagram of the way the cables were run if you might be so kind.

 

...................For several years I could talk too Australia on 40 meters from midnight till about 7am , 7 days a week ! Somewhere twixt 7.150 and 7.180 . , fordy

 

Fordy,

A neighbor has a 40 ft +/- Rohn tower she wants to give me if I can get someone to help me take it down - Safely. I never in a million years thought that I could put a hinged base on it and then be able to crank it down - HMMMMMM, that makes fussing with antennas on it a whole lot easier. I may need you to draw me a diagram of the way the cables were run if you might be so kind.

............Not a problem . , fordy

 

Oh goody goody goody - now to get the tower down. What kind of concrete base did you have in the ground and was the tower guyed??

 

A neighbor has a 40 ft +/- Rohn tower she wants to give me if I can get someone to help me take it down - Safely.

What size Rohn? 6 and 20 are the most commonly used for TV antennas, which is usually what non-hams try to give away to save them the expense of taking it down themselves. 20 or 25 is what you want, not 6.

73 de Peg

 

Oh goody goody goody - now to get the tower down. What kind of concrete base did you have in the ground and was the tower guyed??

..................You don't necessarily need a solid concrete base ! I built a 3' x 5' steel table out of angle iron and cemented 4 'Weld' plates on 4-9" diameter holes about 3 feet deep ! The base of the tower was about 2 feet off the ground . The basic Rohn foldover base was mounted on one end of the table and the Gin Poles were mounted on the opposite end . They were made out of 2"x3"x1/4th." angle iron , ~20 feet long which put them up around 22 feet high . For this system to function properly it will take most of a 220 foot role of 1/4 inch steel cable ! The main thing is to make sure the steel table is Level !
...................You will also need to install 3 deadmen for 2 sets of guy wires and each corner of the gin poles can be anchored to 2 of the deadmen as well ! Send me your mailing Addy in a PM and I'll draw up a diagram of the cable and pulley layout . I'm not an artist so you're forewarned ! You can save yourself a lot of $$ if you like to weld as I did . There is alot to this setup , but the BIG ADvantage is you can stand on a step ladder and mount your beam(s) and make adjustments without having too pay someone big $$$ to fix a problem . , fordy

 

Oh goody goody goody - now to get the tower down. What kind of concrete base did you have in the ground and was the tower guyed??

................A 70' Rohn tower made of 25G will need atleast (2) sets of guys , and (3) would be even better ! I made up all my guy wires up , myself , used big egg insulators every 11.5 feet .
...............QTH.com is THE best website for All things Ham Radio , especially the towers and equipment section . Texas Towers is also an excellent resource for towers and related equipment but they are.....$$$$$...! , fordy

 

"What size Rohn? 6 and 20 are the most commonly used for TV antennas, which is usually what non-hams try to give away to save them the expense of taking it down themselves. 20 or 25 is what you want, not 6."

73 de Peg


OK Peg - I'll bite - How do I tell one Rohn from another??

 

I looked up Rohn 6 on Google and it definitely is not Rohn 6. I'll have to go and look at it again and measure to see if it meets the size specs of Rohn 25. It's a pretty heavy duty tower that is guyed in at least 2 places maybe 3. It has a huge old TV antenna on it - I guess I should save that and see what I can homebrew out of it. I'll bet the TV antenna (which looks from the ground to be in great shape) is at least 15 feet long and has 8-10 reflectors and directors.

"A 70' Rohn tower made of 25G" No No No No - Whatever is there plus a new tilt base is what I have to work with (4 sections with a top section). One thing I didn't check is to see if the antenna has a rotor on it - wouldn't that be a hoot!!!. Got to go and pay a neighbor a visit tomorrow morning.

 

[FONT=Verdana,Arial,Helvetica][FONT=Verdana,Arial,Helvetica]Yucca, I don't have my Rohn cheat sheet with me but found this by googling "difference between Rohn 20 and 25":

20g steps are 18" apart.
25g steps are 12 1/2" apart.

The steps would be the horiziontal parts of the zig zags. Even if you want 20 and end up with 25, it makes good trade bait if nothing else. Or the bottom part of your tower can be 25 and the top part 20.

A TV rotor may not be heavy-duty enough for your planned HF beam.

73 de Peg
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"[FONT=Verdana,Arial,Helvetica][FONT=Verdana,Arial,Helvetica]A TV rotor may not be heavy-duty enough for your planned HF beam."

Agreed, but I can sell it on Ebay and then use the funds to put towards a proper rotor.

Thanks for the info on the 20 and . I will go and measure it tomorrow. From the street I did see where the people who had put the tower up have it guyed with 4 guy wires off of each leg. They must not have wanted that thing to come down.

I just want the thing to work. I wasn't all that interested until Fordy said I could hinge the base. He is sending me photo's of his 70 foot Rohn tower that was hinged so I can see how he did it. I am way way way past the age that I am going to be climbing any tower to change out antennas. They come down to me or it goes somewhere else.
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Try to get the control box along with the rotor if you can.

My cheat sheet says that Rohn 20 has 7 cross bars per section and 25 has 8, if you can't measure the distance between. Handy if you need to make an offer on an existing tower or sections.

I hope you can get someone from your club to help take it down safely.

We buy very little ham gear on eBay. The classifieds on eham.net or sale listings on the various Ten-Tec reflectors are preferred here. Actually, we have bought our last two radios (Paul's Ten-Tec Omni VII and my TT Eagle) via the company's Trade-In Used/Demo sale page and they came with warranties.

73 de Peg

 

I have purchased a power supply and other assorted small parts on Ebay. That said - more and more radios are advertised on Ebay as that is where they get the most visibility and the highest prices. As with most everything else the pursuit of the almighty $$$ can be the end or diminishment of other sources of things like radios. I guess if I were selling a radio with designs on using the $$$ to pay for a different one, I would be out to maximize my return too and to Max out return you need visibility. Ebay and Craig's List surely do maximize the visibility.

 

and worked Argentina the other day.

 

You must have some trees taller than I do. The G5RV needs to be up 33 feet from the ground (I think) in order for its open ladder line to fall perpendicular. I don't have any trees even close to that height - about 25 feet being my max. and most not that high.

 

Peg,

The tower must be a Rohn 20. There are 7 cross sections per 10 foot section and the tower is taller than I thought. There are Four 10 foot sections and a base section which appears to be a regular section embedded in concrete leaving 5 Z's above ground. Then there is an approx 10 foot section at the top which tapers to the point. I am going to say the tower is 55-56 feet in height. Now to figure out if I want to leave the whole thing as one and try to hinge it ala Fordy's hinge method (sort of) or break it into two towers one of 35-40 and the other 15-20 feet. Maybe keep the small part down and order another top section to make it 25 feet and the other 40 feet. That would mean I have gone from no towers and not even thinking I need one to a 72 foot tower, a 40 foot tower and a 25 foot tower. That sure would give the freedom to utilize bunches of different antennas. Maybe I need to order a remote 8 antenna switch ) to keep track of them all. Maybe I'll get 3-4 radios and try to use them all at one time. Talk about multi-tasking!!!!

 

...............Pics should arrive tomorrow ! Does this tower have a house bracket attaching it to the eve of the house ? It should be safe to climb , but If you look on QTH.com you can probably purchase used Rohn 25G in decent shape for 50-60 bucks a section , ALready down and ready to be picked up within 150 to 200 mile drive of your home ...........for the same price you'll pay someone too take down the standing tower !
..............I used to take down standing towers when younger , they can be a real ***** when trying to separare the sections that have been together for several years ! , fordy

 

Fordy - Pics arrived today. That's quite a rig you Have/Had. No the tower is free standing and is guyed every 10 feet starting at about 18 feet - 4 sets of guys. Whoever put this one up never wanted it to come down. I am sure it is safe to climb. I have a local guy who has a small crane which is big enough to take this tower down in one piece, lay it on the ground where we can get it apart. Not sure what he would charge me and it would be doing my neighbor a favor too. I'll check into the whole thing and post pictures if I take it down. Your pictures will be coming back as soon as I can go and get them copied.

 

Fordy - Pics arrived today. That's quite a rig you Have/Had. No the tower is free standing and is guyed every 10 feet starting at about 18 feet - 4 sets of guys. Whoever put this one up never wanted it to come down. I am sure it is safe to climb. I have a local guy who has a small crane which is big enough to take this tower down in one piece, lay it on the ground where we can get it apart. Not sure what he would charge me and it would be doing my neighbor a favor too. I'll check into the whole thing and post pictures if I take it down. Your pictures will be coming back as soon as I can go and get them copied.

...............I had this same setup at a different location , had a HYgain tribander (20-15-10) at 72 feet , then had a Cushcraft 40-2 about 11 feet higher up the mast ! I mounted a Tailtwister rotor about 7 feet down into the very top section . I also mounted a second rotor bearing onto a regular rotor plate(a foot or so above the rotator) which was never meant for such so the mast was supported by 2 bearings . This setup does (2) things , (1)it removes all the vertical load on the rotator , and (2) it allowed me too completely REmove the rotator fron inside the tower after I had locked down the mast , Usually southwest cause I QSO'ed every Am with the Auzzies . Note......I had to cut one of the diagional braces on one side of the 25G top section to mount the rotator inside the tower at a point of My choosing .
.............One other thing of note I did , was , I obtained a set of Quick disconnects with 8 conductors ........I attached one with about 5 feet of 8 conductor cable so I could simply UNplug the rotator from it's supply cable and lower it down to the ground , fixit and reinstall while the tower was still guyed and standing . I didn't mind climbing (back then) and working on the rotator and such , But I never did antenna work on the beams UNless the tower was crancked down within about 10 feet of the ground . It was really interesting watching the faces on 10 hams while I slowly crancked the Whole mechanical contraption down as low as I could possible get it ! They just couldn't believe that such a system could work so well but I put an extraordinary amount of work into the mechanicals to make it a reality . Guywires are a Pain the Butt and take the most time of any singular part of the lowering\raising of the tower . , fordy

 

Fordy - Pics arrived today. That's quite a rig you Have/Had. No the tower is free standing and is guyed every 10 feet starting at about 18 feet - 4 sets of guys. Whoever put this one up never wanted it to come down. I am sure it is safe to climb. I have a local guy who has a small crane which is big enough to take this tower down in one piece, lay it on the ground where we can get it apart. Not sure what he would charge me and it would be doing my neighbor a favor too. I'll check into the whole thing and post pictures if I take it down. Your pictures will be coming back as soon as I can go and get them copied.

..............See if you post those pics I sent you on Here , there maybe others who would like to see them . , fordy

 

I'll Try to get XYL to scan them and then post them. The rigging is impressive.