M104C Project

[TimmyTheTorch]

I am replacing the Maco V58 on a 30 foot pole with a 40 foot tower with manual winch, Maco M104C mounted horizontally and the V58 above it without the groundplane radials. The antenna arrived yesterday.

Now all that is left is:

1. Snow to melt and ground to firm up.
2. Get Digger's Hotline person to come out and verify no services run where the main tower hole will be dug. I am 99 percent certain we are okay because the same area was excavated 5 years ago when we had an egress window installed as part of having our basement finished. But if there is a problem, stop until a plan B is devised.
3. Purchase used 40' Rohn 25G tower. I have one located a few hour drive away, just waiting for the seller and I to be able to arrange the pickup date/time. And hope it is in as good condition as seller states. If not, I also know where to find a 40 foot tall US Tower 15-40 a few hours away too. If I end up buying the 15-40 instead it has the advantage of no guy wires, anchors, guy wire bracket) but requires a bigger hole and larger concrete pour (should only increase cost a bit due to less-than-full concrete delivery surcharge..
4. Purchase tilting base plate, wall mounting bracket, guy wire rope, 10' schedule 40 or 80 aluminum mast (not sure what OD yet), guy wire base posts.
5. Purchase or make a guy wire bracket for the tower.
6. Purchase Yaesu G-800DXA rotor, rotator plate and controller cable.
7. Test rotator to make sure it works.
8. Purchase (and test) more RG-213 coax, any additional grounding supplies.
9. Take down existing antenna and pole.
10. Dig 3'x3'x4' or so hole for tower base. I do not plan on doing this digging myself. Age has tempered my male ego.
11. Dig/drill one or two 12" hole for pipes for guy wire bases. See above about digging this myself.
12. Fill big-a$$ holes with several yards of concrete, position anchor rods/anchor pipes and post for winch. See above about age/ego.
13. Install 3 to 5 guy wire anchor points on appropriate roof perimeter locations.
14. Temporarily install one tower section to get exact placement for required mounting bracket (the highest I can install the mounting bracket is about 10' due to shape of roof), then install mounting bracket and remove tower section.
15. Assemble tower, do a test run of standing it up by itself to make sure the winch works as expected, then lower.
16. Install rotor plate, rotor, mast.
17. Assemble and tune M104C and V58 on ground, probably about 10' up is most I can do.
18. Install M104C and V58 on mast.
19. Run coax and rotator control cables.
20. Stand up tower, finish grounding/running stuff inside, etc.

After listing this general task list, the V58 is not working too bad at all! I have no specific deadline in mind, just whatever can reasonably be accomplished given all the things that can intercede.

 

[Marconi]

Welcome to the forum TTT, and good luck with your M104C setup.

 

[fourstringburn]

Sounds like you have your tower planned well!

I would go with sched 80 on the mast and use a structural grade aluminum. Better to go as strong as possible with the set-up your doing. 2 inch diameter is what I would use.

I didn't see a thrust bearing mentioned, definitely a must with 2 antennas on a rotor. The used tower you mentioned may have one already.

If not, get a bearing plate that mounts on top of the tower and secure the bearing to the plate.

Good luck with your project and post some pics for us to see!

 

[Riverman]

. . . Maco M104C mounted horizontally and the V58 above it without the ground plane radials.

I know some antennas are designed to work without radials (Antron 99, Imax, Ringo, etc.), but does the V58 work well without them? Just wondering.

 

[Marconi]

1I know some antennas are designed to work without radials (Antron 99, Imax, Ringo, etc.), but does the V58 work well without them? Just wondering.

Jim, my Eznec model of the Maco V58 shows strong currents on the radials. I have also heard plenty of chatter on the Internet about this idea, and I'm not sure what is right or not.

I once put my Starduster with radials up about 8'- 9' above my vertical 4 element horizontal yagi, and the SR'r radials ended up real close to the yagi elements.

I saw no difference in the match on either antenna.

The radials on the SD'r were mostly vertical and on the V58 the radials are horizontal, so I figure that may make a difference when TTT gets to check is results.

TTT, be sure and keep us posted.

 

[TimmyTheTorch]

After listing all the extra steps and mounting bracket/guy wire stuff I need to get if I buy the Rohn 25G tower, I'm now leaning toward getting the Universal Tower 15-40. I'd still need to get the B-22 footings and pour a bit more concrete, but I think I'd end up with a stronger tower for the same or less $$$$.

 

[TimmyTheTorch]

It's definitely not easy to undertake this project in an area with not a whole lot of concrete companies especially during a building boom in the general area. I do not want to have to buy 100 80# bags, rent a mixer and hire someone to lift that many bags for me.

So far I have not been able to locate any short load companies within a few hours of my location. I have also been in touch with a few general contractors that have done work for me in the past, asking them to keep an eye out for anyone else that they are working for that is getting less than a full 10 yards delivered and maybe we can pool our resources. I figured I'd never know unless I asked. Getting the concrete from the truck on the road on the east side of the house the last 200' to the tower location adds another challenge. Approaching from the south side is 10' shorter but also 11' uphill. Sounds like a lot of fun with a wheelbarrow.

We got another 8 inches of snow yesterday so the yard is not in a condition to be doing anything about this yet regardless. Mother Nature is not done with her winter antics.

 

[2RT307]

you'll have fun with that antenna. I used to run one, only 25 feet up, and had great success with it.

73,
Brett

 

[TimmyTheTorch]

Sigh, I am going to have some difficulty digging the hole for the tower foundation where I want it. Turns out some buried electrical was re-routed when the window well was dug a few years ago when we finished our basement and it was moved further south along the west wall where I want to put the tower. Oh well. Improvise, adapt, overcome.

To at least get the beam up I may just mount it on a guyed pole. The rotor I have is beefy enough to handle the beam when the rotor is pole-mounted but there's not much safety margin. A local ham showed me this type of rotor mount that still lets you use a guyed pole but the rotor mounts to a plate so it has closer to the tower-mounted strength especially when a second mount is used for a thrust bearing. The guy wires would attach to the pole right below where the rotor bracket is attached. I may just give this a try. Experimenting is a big part of the fun for me, although sometimes my experiments don't exactly go to plan. Live and learn.

 

[TimmyTheTorch]

I ended up ordering a pair of these rotator/thrust bearing platforms. They should do the trick. Now to decide if the 11 gauge galvanized mast pipe I am using right now will be strong enough for the added weight of the 7 pound rotator and 20 pound beam. The mast is currently comprised of three 11 foot sections and there is a four foot long interior support sleeve at each of the two junctions. I may end up using the 10 gauge variant with interior sleeves at the junctions just for an added safety margin. In either case the mast will be secured by four to six guy wires and attached to the house by two standoff brackets like it is now. I also want to use a tilting base plate like this one but hopefully I can buy one in the USA instead of having to pay overseas shipping. Or maybe I'll borrow a friend's MIG welder and see what I can create.

The rotator will be mounted about 7 feet from the top of the 33 foot tall mast and the thrust bearing will be close to the top. This should lower the center of gravity. My plan is to mount the M104C horizontally and the V58 above it using a . Their combined wind load is between the rotator's mast-mounted and tower-mounted maximum wind load values and the configuration I am trying to use is closer to the latter than the former. I'll also figure out where to mount a few pulleys to help raise/lower it and gain some mechanical advantage.

At least that's my new plan but to paraphrase Mike Tyson... everyone has a plan until they get punched in the face.

 

[TimmyTheTorch]

The service line running right down the middle of my planned tower location does somewhat limit my options but I've been getting some good suggestions. I think I have settled on using a mast base plate like the one pictured below anchored to a 2'x'2'x2' concrete pad right where the current mast base plate sits. I still have not found one I like in the USA that doesn't cost and arm and a leg. I can get this one delivered from the UK to here for about $165 (including the base plate and shipping) which is a lot more than I'd like to spend but it's cheaper than buying a MIG welder (but not nearly as satisfying) or hiring someone to do it. I just want the end result to be fairly easy and safe for my wife and I to raise/lower this mast assembly ourselves. I could always just remove the bolts, holler "fire in the hole", then "timber....." and down it comes.


I also plan on standing up a gin pole using two of the 11 gauge galvanized pipes I already have (paired together and reinforced with the internal pipes currently at the pipe joints) to help lift/lower the mast via a pulley connected maybe 15-20' up the mast (TBD), a pair of pulleys on the gin pipe and maybe use my ATV winch initially to test it out. The pipes will be in about 3 feet of concrete and extend 8' above ground. I am replacing the existing 11 gauge 1-7/8" mast with 10 gauge 2-3/8". I will re-use the same wall mounts in addition to the guy wires.

My concrete needs are down to the mast base (still maybe 16 60# bags, 2' deep may be overkill for this simple mast application), the gin pole (5-6 60# bags) and one guy wire post (5-6 60# bags). The other guy wire mounts will all be attached to the rafters in the soffits. Oy, 26 bags of concrete is still a lot to hand mix.

A retired civil engineer friend of mine is mulling this all over for me. He's used to working with three dimensional, 40 lane freeway interchanges with lanes going every which way. I just hope he doesn't suggest building a ramp up to the rotor and bypassing the mast entirely.

 

[TimmyTheTorch]

Hmm, this home made tilting base is from a small windmill but it looks like it'd work well for a mast too. I'd definitely have a go at making this one myself. To my wife... "Here, hold my beer...".

 

[TimmyTheTorch]

And one day later...

 

[TimmyTheTorch]

The rotator and thrust bearing mounting plates have arrived as have the four 10-gauge, 11 foot long pipes. Three pipes are for the mast and one for the gin pole. The two mast joints will have inner reinforcing sleeves as will the bottom few feet of the gin pole.

 

[TimmyTheTorch]

It looks like the 10 gauge pipe I am using for the new mast (three pipes, so two joints) has an OD of 2.375", a wall thickness of 0.130" and an ID = 2.115" (53.75mm). Now to locate a suitable tube to slide inside the mast pipe to reinforce each of the two joints, maybe have 18" to 24" of overlap at each join like I have with the current mast. I see some 6061 aluminum tube with a 2" OD and 1/2" thick wall that might work. Or maybe it's better/stronger if the joint pipe goes over the mast joint instead of inside the mast. More research to conduct... I will have to check out the strength of it compared to the strength of the mast. I am hoping not to have to use steel pipe for sleeves here to save weight.