Why a tower when you could have a mast for a third of the cost?

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KN4LGM, May 5, 2019.

ad: L-HROutlet
ad: l-rl
ad: L-Geochron
ad: Left-2
ad: Left-3
ad: abrind-2
ad: HRDLLC-2
ad: L-MFJ
ad: MessiPaoloni-1
  1. KN4LGM

    KN4LGM Ham Member QRZ Page

    About two months ago I was calculating how much it would cost to build a 30-foot tower, I came up with $2400 (not including coax because it is a variable), a little much for me and must Hams. I gave up the idea and started working on how to feed antennas that would be in trees over 200 feet away, and how to support the ends of the wires. Then today I realized "support masts should be are strong and durable.". Then I realized that those are the qualities of a good tower. Out of curiosity, I Googled "Antenna Masts" I was surprised when I found that not only were they out there but Rohn sells three different lengths. The tallest was 43.9 feet, 13.9 feet taller than the tower before mentioned (also the right length for a 60 M vertical). I was excited now, I calculated what the cost would be, and... I came out with $850, just over a third of the cost of the tower. Other advantages of the mast over the tower are: the concrete base will be MUCH easier to pour, and it will double as a 60 M vertical, lower visibility, and the mast is telescoping meaning that it can easily be lowered two 8 feet above the ground.

    So my questions are: why don't I see any posts on the zed about this and why seemingly few Hams use masts instead of towers?
    Note: the cost of the mast and tower included an antenna.
    73,
    Jonny KN4LGM
     
    Last edited: May 5, 2019
  2. K7TRF

    K7TRF Premium Subscriber QRZ Page

    Lot's of hams use Rohn and other push up masts to support wire and lightweight antennas including Hexbeams and Cobwebs. There have been a number of discussions here on the zed about using push up masts including ways of dealing with pushing them up (it's not as easy as it might first appear once you have load on it and consider the friction in the telescoping joints) and how to deal with guying them which is essential.

    A push up mast can be a great solution but it won't support big Yagis or other heavy antenna systems as well as an actual tower and you can't climb them for maintenance reasons so there are definitely tradeoffs. Don't forget to include guying plans as you'll need several tiers of guy lines to support a 40 plus foot mast, especially if it's holding up more than wire.
     
    WB5THT, AG5DB and KN4LGM like this.
  3. AA5CT

    AA5CT Ham Member QRZ Page

    I'm using two 22 ft tall stacks of those 4 ft mil tent poles, 6 each, to support a vertical loop, a loop that outperforms the 80m dipole I have strung over the house in a Zoro configuration with apex at about 30 ft, ends about 10 ft above ground.

    I was surprised the loop outperformed the dipole. There is so little actual, practical information of this type out there! I think ppl are afraid to try new things, mostly they just do the same thing someone else did, from back in the thirties ...

    Anyway, just saying there is more than one way to skin this cat.
     
    KN4LGM likes this.
  4. KN4LGM

    KN4LGM Ham Member QRZ Page

    Oh, I was not aware of the other converstions. And I will not forget guying.
     
  5. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    More hams use masts than towers, I think. You may not hear them discussed much since almost anyone can install a mast and there aren't so many questions to ask about them.

    However, this applies to your original discussion about "30 feet." A good, strong, clamped (to a house) or guyed (or both) 30' mast can often support a rotator and moderate HF beam, not to mention a few VHF beams. Very common.

    Towers become the norm for going much higher than 30 feet. It would be extremely difficult to install a 70' mast, which is an optimum height for a 20m beam and a good height for even a 40m beam. At 70' (or even much taller), a tower can be self-supporting and require no guys at all, if it's designed to do that. This allows hams to install 70' towers in a very small yard, as the foundation needn't occupy much yard space and there's no need for guying any of the self-supporting designs.

    Tapering towers with wide bases that taper to much smaller upper sections, properly installed, can easily to to 140 feet tall with no guys, no house brackets, no other supports besides a robust foundation (in that case, we're talking 10+ cubic yards of concrete, but most of it is in the ground). My 55' self-supporting tower is anchored in only 2.5 cubic yards of concrete and with multiple beams it's fine in 70 mph winds -- no guys.

    This is the "why.":)
     
    AK5B, K2CAJ, KN4LGM and 1 other person like this.
  6. N3DT

    N3DT Ham Member QRZ Page

    I'm building a 30' 'mast' for my 6M beam that I built a while ago. 2 pieces of 2x4x12 bolted together and an old radio shack 10' tv mast. Total cost 0 since I had the stuff laying around. Of course I've got a place to guy and put it so if it comes down, I'm not worried about it. Left over U100 rotor too.
     
    AK5B likes this.
  7. WA8OLN

    WA8OLN Ham Member QRZ Page

    Must be very careful with push-up telescoping mast with alot of weight on it. Got the palm of my hand pinched in one once. Not fun but survived.
     
    WB5THT and AK5B like this.
  8. K6CLS

    K6CLS Ham Member QRZ Page

    consider a crank-up tilt-over tower. You can lower it to safety when you get one of those monster storms in 4-land. Also, better to do antenna maintenance with feet on the ground!
     
    AK5B likes this.
  9. W5LZ

    W5LZ Ham Member QRZ Page

    All of the above +
    A pole isn't as easy to raise/lower as you might think. With almost any beam antenna added to it it can get quite heavy.
    If it isn't planted very well (concrete) even a short pole will/can have a lot of "side" forces applied, and they -do- tend to bend. If you're gonna use a pole get a really heavy-duty one. Also guy the thing! You can use those guys for antennas too...
     
    WB5THT and AK5B like this.
  10. KB4MNG

    KB4MNG Ham Member QRZ Page

    Unless you are sporting a wire antenna or vertical in some type of configuration, you really can't compare a mast to a legitimate tower. apples and oranges.
     

Share This Page

ad: MyersEng-1