Homebrew Spiderbeam, not using the commercial kit...

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by AE7F, Jan 4, 2012.

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  1. AE7F

    AE7F Ham Member QRZ Page

    Here are some guying ideas that I've been kicking around:

    [​IMG]

    The row of examples along the top pertain to the guying of wire elements back to the spreaders and boom. The row of examples along the bottom pertain to guying the spreaders and boom to the standpipe.

    Anybody care to discuss pros and cons of each? My take:
    A - unknown. I don't know if anyone has done this. Rick from SB thinks this might put too much stress at one location on the spreaders. I think it would certainly add weight so instead, the ring would be made from plastic. Anyway, it would separate all of the guy points, which would help when tensioning individual lines.

    B - unknown. I would clamp a metal ring to the spreader and then the guy points would be around the metal ring. This would keep the guy points separate. The idea would be to get all of the guy lengths correct to the ring and then use a bungee to tie the ring to the spreader. Then you could adjust all wires at one time and also have some spring tension.

    C - This is how the guide suggests to perform the guying. This should work fine but requires expensive insulators. You still might have to untie and retension but you would do it at the insulator and not at the spreader.

    D - unknown. This is like C except using bungees to add spring tension.

    E - unknown. This would be a very useful way to guy the spreaders to the standpipe while separating the guy points. Get everything correct and then just slide the ring up or down the pole to lift or drop all 4 spreaders at one time. Secure with a bolt through the mast.

    F - This is how I am guying right now but it is very difficult to make adjustments to tension because the weight of the spreaders tend to make it hard to tie the knots in the correct places for tensioning. This also does not separate the guy points so it's hard to retension an individual line.

    G - This is how the guide recommends to perform guying back to the standpipe. Then you slide each line up or down the post to adjust guy tension.

    ...

    I am using methods C (without the insulators - just knots) and F. I don't think either method is correct for my high-wind QTH. It is very difficult to readjust tension using methods C and F.

    Regarding standpipe guying, I am considering replacing method F on my antenna with method E. I would drill several sets of holes in the standpipe. If the ropes stretch further, I can lift the ring and insert a bolt through a hole that is slightly higher than the last hole. Comments?

    Regarding wire element guying, I am considering replacing method C on my antenna with perhaps method B or A. If I went with A, I would actually install the bungies between the wires and the guy ring. Then when you slide the guy ring out towards the tip of the spreader, it tensions all wires at the same time but allows individually unique tension on each wire; each bungee can have different tension to compensate for differing wire lengths or adjusting. I love this idea but I'm sure the bungees won't last forever. You could tie a backup rope beside each bungee with more slack than the bungee; then if the bungee snaps, the wire will slacken but it will still remain connected.

    If I were to use method B, I would modify the method and again install the bungee cord between the wire element and the metal ring. This would work very similar as method A in the previous paragraph except that this method B uses a thin guy ring (like the ring on a hammock) and method A uses an actual mast guy ring plate (like a large flat washer with circumferential holes).

    The idea of individually yet properly tensioning all wire elements at the same by moving one device would be slick. Of course, if you guy everything perfectly and your knots hold properly and the rope has been prestretched and your antenna parts never shift around, you could just go per the manual and you're done.

    However, start adding up that you have dozens and dozens of knots to tie and with proper guy length on many segments and it becomes easy to see why you need a way to make adjustments - especially if you have a high wind QTH!

    Hmm... well anyway, I have 50ft of mil spec bungee cord on the way for experimentation.

    Comments?
     
  2. AK5B

    AK5B Ham Member QRZ Page

    I don't have much time to reply today so one thing I might mention briefly is Drawing B, which I like the best (first impression, at least).

    Instead of a metal ring I would use gray (conduit type) PVC round covers available at Home Depot to save weight. They're sturdy and can be drilled easily for a center hole as well as the guying holes. I have used two of them glued together to make sturdy mast guy rings and they hold up well in my experience. Maybe worth considering, Ben?

    73, Jeff
     
  3. AE7F

    AE7F Ham Member QRZ Page

    Yeah, thanks indeed for that idea.

    I like guying option B as well but I will probably try another variation of B:

    At the end of each wire element, I will tie the sporting line, which will extend the wire/rope segment back to the tie off point at the spreader. I would then substitute maybe 12" of bungee as a replacement to some of the guy rope. The bungee connects the rope/wire segments to the guy ring. Then I would use regular rope to secure the guy ring back to the spreader.

    This is a true way to allow each wire segment to have individually correct tension. In other words, pull/slide the guy ring towards the tip of the spreader to properly tension all elements at the same time. I love this concept.

    Granted, if your antenna never shifts around, you wouldn't need this. I like the way some have built their hex beams. Cut the guys to a specified length and add S hooks. Now just pull the guys back to the center post and connect. The bent fiberglass adds proper tension and the guy determines the tension. The S hook means no slipping.

    This is another reason to go with MaxGain spreaders. They are sturdy enough that one can use S hooks.
     
  4. AK5B

    AK5B Ham Member QRZ Page

    I'm sure you're referring to the standard MGS Type 1 spreaders---I look forward to trying out the 1L lightweight versions someday, with my fingerrs crossed that they'd be sufficiently sturdy. Perhaps a tad moreso than something like the Cabelas poles which seem to be working fine for you thus far.

    Ben, that reminds me; did you paint the poles before you installed them?

    UV can wreak real damage on FG over time and your Utah is anything but overcast most of the time. If not, maybe if/when you lower the big beam for maintainance. Really helps make everything last longer. Btw, we decided on Las Cruces instead of Albuquerque at the last minute so we'll be in a very UV-rich environment to say the least (and we'll have 50-60mph winds in the spring like you, too). Once I get back on the air there my signals might get blown all over the place (wind effect propagation?).

    Those pvc round plates I mentioned should work a treat for guying the spreaders. You should only need one per spreader as two glued together would be overkill. Good luck with working it all out but I think you've found a proper solution to the wobbly spreaders/loose elements annoyance.

    73, Jeff (back to moving chores now, what a collossal pain!)
     
  5. AE7F

    AE7F Ham Member QRZ Page

    Yeah, I was referring to the heavier spreaders. However, the crappie poles seem to work fine and they are very thin. At least they hold up to wind quote well.

    I did not paint anything because this is mostly an experiment to see how well the design holds up as-is. If it holds up an entire season or longer, I'd consider it a pretty successful trial. When it breaks, I want to use some different materials and methods.

    I just got the mil spec bungee cord today. It looks pretty nice. I will try it out next time I work on the antenna.

    On another note, I have found that how you tie the support ropes off makes a difference. Most problems are because of the difficulty of applying correct rope tension before knotting (I will experiment with the bungee cords, which I hope will solve more problems than they will cause). However, one way that worked really well for tensioning the ropes (remember, I'm not using SB insulators) is to tie a bowline loop on the end of one rope; then join another segment of rope to this one by passing the rope through the bowline loop; pull the ropes away from each other to apply tension; then hold the bowline loop in one hand and knot the other rope to itself; now you have a span of rope consisting of two segments, properly tensioned due to the loop on one segment. This is way easier and more effective than trying to apply tension to one entire segment of rope (i.e., pulling a spreader support rope back to the center post and knotting it).

    Those with experience building wire beams probably already know all of the best tips and tricks. Feel free to post the best methods of knotting and types of knots.

    Anyway, next time the antenna is on the ground, I will make a ton of improvements and eventually come back and post them here.
     
  6. AE7F

    AE7F Ham Member QRZ Page

    For anyone who is interested, there is a way to add 40m to the spiderbeam. The spiderbeam guys (and others) came up with a way to add a 40m dipole. I may try this next time the beam is down for maintenance.
     
  7. AE7F

    AE7F Ham Member QRZ Page

  8. KC8VWM

    KC8VWM Ham Member QRZ Page

  9. G4AON

    G4AON XML Subscriber QRZ Page

    Way back in this thread the subject of mounting a Spiderbeam on a tilt over mast/tower came up. Any of you guys see or tried a "HexLock" which is designed to overcome this problem with a Hex or Spiderbeam?

    http://www.nn4zz.com/HexLock.html

    Neat idea.

    73 Dave, G4AON
     
  10. AK5B

    AK5B Ham Member QRZ Page

    I agree; brilliant idea and product!
     
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