Discussion in 'Antennas, Feedlines, Towers & Rotors' started by AE7F, Dec 27, 2011.
Anyone ever tried to build one?
I have not but here are plans, if you want to try yourself.
TennaDyne (Roger Greenfield, WB8NDC) now located in Michigan still makes Log-Periodic antennas
Chuck Brainard, KA1PM was the founder of TennaDyne and sold the business to Roger in 2004.
Very cool, thanks. This is interesting:
Thanks. I have been looking at Tennadyne antennas for awhile (antenna comparisons.xls). You can see that I found the T6 to be a very, very nice antenna for the price and have been looking around for one.
Unless you have access to the materials for very discounted cost, it would be hard to beat the price of even a new Tennadyne.
Seamless aluminum 6061T6 alloy tubing is expensive, and the T6 uses a lot of it, including 24' of extruded square boom stock and about 160 feet of round tubing of various snug fitting diameters, plus several precision cut insulating blocks, thick machined PVC insulating blocks at the mast mounting point, etc. It would make an interesting project, but certainly not an inexpensive one.
Yeah, their pricing is good for the T6 but one does wonder what materials would cost for the aforementioned LP design.
The ARRL Antenna Handbook has detailed instructions also at least mine does. You could try that. You might also want to pick up a copy of the handbook, the older ones are somewhat better but I don't know if they have the LP plans in them.
Hope this helps
You might consider a wire type LPDA?
Maybe a 40ft boom and 12+ elements.
See Cebick W4RNL site for some big LPDA designs.
If it does not work well take it all down and use the boom as another antenna mast!!
The rear spreaders as the basis for a rotatable dipole etc.........
I would love to try one one day.Might need a bigger back yard though!
Using those costs, the aluminum tubing would run about $280. Then you'd have to cut it in three dozen places and drill it it 36 places to join the elements, and 12 more places in the booms to insert the elements. You'd still have to create mast to boom brackets, PVC insulating spacers, and the big PVC mast clamp insulators, plus add several dozen SS screws, bolts, etc.
It could probably be built for about $350 worth of parts, not considering shipping costs for the tubing.
Re my earlier post ,maybe something similar to this?
That is quite an antenna. It gives some additional thought to what is possible. There was a design that was featured in QST that used a spider type of support. Can't really remember when it was published and it has been awhile. The antenna was made from wire and it was a LPDA. At the time I was interested in that concept but I haven't had the room to put something like that up.
May be things will change, who knows?
LPDA... interesting.... found some stuff that looks cheap but might pack a punch...
You just made it sound not too bad!
Hardest part for me is that I can't see the aluminum tubing. If I could go pick sections off the shelf at the hardware store, knowing what I was getting, and that it would fit together.... If I find a local source for tubing watch out!
The T6 is a great price as is. But add shipping and suggested hardware and chokes/baluns and the DIY vs commercial price gap starts to grow.
I had a whole bookmark folder full of links to LPDA stuff.
Ill see if I can find the article about building a wire LPDA
I have an old Australian made LPDA under the house that was given to me by a generous Ham.
Just a little 6 element job ,needs some new centre insulators and tlc.
I like the Idea of having 1 directional antenna for say 7-30mhz,
Even with the compromises.
Just type "telerana" into your favourite search engine.
Thanks for posting the Telerana link; seeing photos made me realize that that is certainly an easily doable DIY 5-band single feedline antenna, isn't it? I believe this same or similar design wire LPDA is also in the ARRL Antenna Book (sans photos), too. Probably wouldn't be too costly to make; the fiberglass spreaders and the welded steel hub would be the only parts costing much.
With a 400-ohm characteristic impedance I wonder if a 9-1 balun would be better than the recommended 4-1 balun at the feedpoint?
Thanks again for further food for [antenna] thought.
The T6 is cheap to ship because it comes in a very short carton. That's why it's a whole lot of pieces to put together.
Mine shipped to Los Angeles and I think the shipping was about $25. The T8 comes in the same size carton, it's just more pieces.
You'd have to build a choke balun for any kind of LPDA whether you bought it or built it, so that's a draw. I just use the "RF choke" type current balun made of coax, as they recommend. It costs about $8 or so to build it. There isn't any extra hardware to buy, it comes with all the hardware you could need except for the balun and feedline.
I build VHF-UHF antennas pretty often but wouldn't try building an HF LPDA unless I had a big machine shop and a lot of time. To pull this off with hand tools would just be too much work, for me.
Appreciate the input. Always helps.
Drill press, chop saw, jig saw? Metal blades.... Shouldn't be too bad at all.
However, will probably just buy a T6 or try out some wire arrays in the meantime.
Yup, stumbled onto that link last night. Really cool. And *cheap*. Great way to try out the LP concept first...