The AM Forum

I was wondering if any has had any dealings with Tennadyne? I have been trying to order a new T-8 log for about two months now and I get no return phone calls or e-mails. I spoke to that guy Roger once, it was the only time he called me back, to place an order with some upgrades I wanted and never heard back from him. Is this company still in business? or is this a reputable company? because I don't think I would now purchase from them or recommend them, or maybe they don't need the money?

Joe,
I have a very modified T12 from the old owner. Electrical very good but the old mechanical design sucked. Chuck told me he bought some custom T12s with better components. One Saturday we both worked Dean in Az. on 10 through 20 meters to compare performance of his stack. I think I doubled the weight. I know Roger uses a stronger boom than my ant. I had sleeves tig welded in the boom and added 1/4 inch fiberglass  plates around each element at the boom. My T12 has been up since '97. I thought the old owner was an AH.
I had the feeling I could have saved a lot of money if I built it myself from amuminum stock. The boom and element segments are too short because it ships in a 6 foot long box. I think you would get better VSWR performance with the T10 or T12. I ended up not using about 1/2 the element material and built my own.
The stock antenna has problems with the longest element ripping out of the boom due to heave ice load. Ask WA1IWQ who has a broken T10 at the top of his tower.
I am very happy with the electrical performance

Joe,

As you remember, you, Huzman, Todd and I stopped by Chas' house and checked them out a few months back.

For others' information:  Chuck recently bought four T-12's? and had them modified for better strength by the factory. He said to axe the guy for the extra $300 K1KW mods if interested. Chuck said the guy will know what you mean.

The mods are probably akin to what you did to yours Frank.

He also mentioned that the logs were mechanically redesigned since the new guy took over the company. Adding the additional mods put them over the top, according to Chas.

Joe, with your abilities, you would probably do better building your own. A few years back I built two big logs for 10-20M. One was on a 60' boom and weighed about 300 pounds. I used scrap aluminum from the scrap metal yards. If you catch the right yard, some will have stock from many many years hanging around. I cleaned out all the tubing they had for $1 a pound.

BTW, Chuck plans to mount four on a rotating tower. Now that oughta be some pattern.

T

The whole point of what I was saying is that it seems Tennadye does't care about selling products, after calling and leaving many messages and e-mails with no return calls, it seems to me like they are out of business. And Tom your right, I would just be better off building my own which I think I'm going to do anyway because of the fact that most af the commercial antenns are mechnically very poor design.

Joe,

In these times of deflation and impending depression, it would not surprise me to see many high profile ham operations drop out of the picture in the next six years.  It's been a relative cakewalk to this point.

I would try one last time and send him a copy (or link) of these postings.  I'll bet that will get his attention.  At this point it's still positive and he could erase all potential questions by a reply to you.

Yes, building your own will instantly free you of dependence on antenna manufacturers. You will have the confidence to build ALL of your Yagi-type antennas afterwards. It's really easy once you do the first one, OM.

Get a copy of YagiStress to easily model antennas mechanically in a simple Windows format.  There are plenty of log design programs around too - or just copy the Tennadyne electrical plan. Axe Chuck for a copy of his antenna stuff A-Z.

T

Joe,
I'd be glad to share my design changes so you could build it to stay in the air.
My T12 has been up since '97 with no issues. It has been iced a number of times and seen plenty of wind. I have a number of pictures. I think the T12 electrical design is very good with a 30 foot boom. The weight was around 100 pounds. I received a 57 pound box of crap from the first owner. I would have never let my kids play under it. All you really need is the right drill bits to drill the holes in the boom. Then the tig welded sleeves make it a lot stronger.   

Do any of the homebrew antennas you gentlemen are talking about have the elements welded to the boom?  I have thought about doing it that way but I wonder if the welded joints would stand up to the stress without cracking...6061 T6 tubing? Just curious   Steve

Steve,
The Tennadyne uses a pair of square booms that serve as the feed line.
Each element half plugs into a hole in the side of the boom. A 10-24 SS screw and lock nut mounted vertically hold the element into the boom. 1 friggen screw. I had sleeves tig welded into the boon in addition to the screw. Also added a horizontal screw through the element a foot or so out from the weld. The longest sleeve was about 3 feet long for the longest element half of 19 feet.
My longest elements are 3 telescoped tubes near the boom to make them stronger. Tennadyne had a 3 inch overlap and a sheet metal screw at the joint. Very JS. The longest element had a 7 segement joints with plenty of sag. POS.  I scrapped all that crap and built real elements. What a waste of money. The basic design was cool but JSed to death to make it cheap.
Knowing what I know now I would have bought 6- 12 foot long sections of square tube and some 1/4 inch fiberglass plate and built my own. The joints of the stock boom were joined with a hunk of aluminum angle, not square tube. I added square tube at the joints inside the boom. My boom is .062 wall thickness. Chuck told me the new guy upgraded it to 1/8 inch making the antenna heavier and a lot stronger.  The electrical performance kicks butt.
I did not change anything electrical because it worked so well. I built the antenna stock and worked plenty of DX at a height of 5 feet off the ground. Then I started doing my mods. 

I had a T-10 up for several years with no problems. Like most hams I did some tweaking of the mechanical structure (boom to mast mount). I sold it and purchased a T-8 which is still new in the box. I have several friends that have used them with no problems. If I ever get my tower back up the T-8 will be on it. I have had no dealings with the current Tennadyne owner so I can't answer to that. I do know that when I purchased the T-8 4-5 years back it was a good transaction. I have have had pretty much all of the typical trapped antennas, including the old Telrex beams and even several quads--none of them were perfect. I am a "little gun" so the expense of big arrays and top of the line antennas is out of the question. Based on the cost of aluminum, and the performance of the antenna, and assembly time I think the "kit" is a good deal.
Skip

Hi Steve,

Yes, most commercial ham beams are built like toys. Even the 60' boom 6el 20M mono bander "Big Bruiser" I bought from M2 used a small 1/4" thick aluminum mast to boom plate. It was a joke. After seeing how that first Yagi was made, I didn't even put it up - just used the aluminum to build my own from that point on.

On my 60' boom log I used a standard 4" telescoped to 3" round 3/16" boom.  I used flat fiberglass boom to element plates that u-bolted on the insulated elements.  I then used a pair of close-spaced  1"X 1" angle aluminum rails that ran the length of the boom to feed the elements.

It had side and overheard trussing.  On all elements I used double thickness sleeves where the elements mounted to the fiberglass plates to insure mechanical strength at the boom to element strees points.

No problems with winds or ice for about 8 years.  Finally tore the logs down and built up mono-band Yagis.
I did like the logs for performannce, but if I did it again, I would go with the three or four 24' boom smaller logs in a stack.

T

The homebrew 10-20M log shown below weighed 300 pounds on a 60' boom. It was turned by a prop pitch at the top of a 110' Rohn 45 tower.. I later added a 20M log at 60' - it was identical to the top one but missing 10-15M. I put it up myself, but it was way too much to handle. This is the log that snapped a tag line and slid all the way down the tramline and buried some of its elements in the ground.  I was taking it down anyway, but was a dangerous antenna to work with. The close spaced elements made it especially difficult to keep clear of guy wires and tower stuff...

There was a nice design for a HF log in QST few months ago.

My T12 is set up to swing it vertical if I ever need to service the elements.
I mounted the insulator block to a 3/8 inch plate with a 1/2 inch bolt through  it and the mast. I put it up vertical to clear the guy wires then my brother and I flipped it horizontal and added the 4 mast clamps. At close to 100 pounds we could handle it ok. Tom likes to drop element diameter 2 sizes at each joint. I did one size which makes the elements heavier or sag more. I think 2 sizes that Tom did makes more sense.
My mast is 2 inch OD and 1/2 inch ID with dual thrust bearings. I used a bunch of different diameter pipes to make the section of mast going through the bearings. I did a dual over head truss spread about 5 feet apart at the top.

I'm curious to see what these ants are all about - they escaped my radar... any links/pix?

               _-_-bear

Google is your friend

(http://www.tennadyne.com/images/tennlpdanavy.JPG)

Here's one working ground wave:

(http://www.wb7okx.com/oldpages/Log9.JPG)

Here's one doing a wind dance:

(http://www.tennadyne.com/images/windy.jpg)

Hang some balls and garland on this one and you're all set for the holidays:

(http://www.tennadyne.com/images/T12_copy2.jpg)

73s from SV land,
My name is Demetrius and my callsign is SV2GWY. I plan to make by myself a 6 element Log periodic for 10~20m. I wonder if anyone can help me giving me details for T6 :

Boom        length :
elements diammeter :
#1 element length :
#2 element length :
#3 element length :
#4 element length :
#5 element length :
#6 element length :
Spacing 1-2 :
Spacing 2-3 :
Spacing 3-4 :
Spacing 4-5 :
Spacing 5-6 :
 
          Thank you in advance,
 
                                             de SV2GWY / Demetrius

Hi Demitrius - there are several forum members that have home-brewed HF log periodics - Frank WA1GFZ and Tom K1JJ.  Hopefully they'll see your post.

There was a nice design for a HF log in QST few months ago. It even covered 6 Meters!

T12 longest element is 38 feet and they get 9% shorter as you go exept for the last small element which is a bit shorter that 9%.
The boom is 30 feet but I forgot the sequence. I think the first to second is 4.5 feet. I'll check at home to see if I have the demensions. The diameter to length ratio was way off but still worked. I changed it to make it much better.
I think it was around 100% and I got it down to around 30%.
The mechanical design of the stock antenna was junk but electrical was very good. I added close to 40 pounds to mine with some welding of sleeves into the boom at each element. Also added fiberglass plates between boom at each element. I would make the booms from 1/8 inch wall square tube 1 1/2 inch by 1 1/2 inch spaced 1/2 inch apart. The old owner used .062 wall. The new owner used 1/8 inch.

http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=16289

this does all the work for you

I finally got in contact with Roger at Tennadyne, I told him that I purchased a T-10 and would like to get some parts and upgrades, he promised me he could sell me what I needed and never came through...... after tons of e-mails, no returned calls and complete wasted time, I have given up on Tennadyne. Just poor service and empty promises. I would not recommend them to any one at this point.

Joe  WA2PJP

Joe,
So you bought that T10. Does it have the .062 wall boom?
I suggest you assemble it in the back yard. (once the roof is done) and put you hot rodder hat on. When you understand the electrical design you will be able to make it better. Put it up about 10 feet and work a few contacts.
Electrical performance is very good.

Hey Frank,

Yes got a great deal on  a T-10, new in the box for half the new price and it was the latest version with the heavier boom and choke support. I wanted to buy Extra clam shells and make up a larger center insulator for better support and add an overhead truss. I called that guy Roger, got ahold of him once, told him what I needed, said he would get right back to me and never did. Sent a number of e-mails to him along with countless phone calls, he told me when I did talk to him, that he never got any e-mails or phone calls from me.......he's got to be kinding !!!! That guy is a real flake and if I didn't get this antenna new for half the price......I would never order one from him or recommend that anyone else order from him.

Anyway, won't be doing any antenna work for a while, when I was roofing the rear shop, I trpped with a bundle of shingle on my shoulder going down slope and went off the egde of the roof, landed on my side and broke my hand. I'll be in a cast for 4 to 6 weeks.......Can't beleive it.......

Ouch!  Could have been a lot worse though, Joe - although walking around with a busted wing is no fun, I'm glad it wasn't a lot worse.

Good thing you were carrying 40lbs of shingles to break your fall!!

Get better soon, B.

Joe, Joe, Joe.
When are we gonna learn???

But...... I can't talk now. I gotta climb this tower!  ::)

Joe,
I was wondering there was no update on FB, Bummer. I replaced a section of roof when I yanked out the skylight and decided pushing 60  and 1 disc operation is not a good age for roofing.
When you get ready to work on it let me know.
I used a pro welder to do my boom. He tacked each sleeve in 4 places rather than a full bead around each joint. He said a full bead will crack. This guy builds race car chassis so took his word. Mine has been up since '97.
I replaced all the plastic spacers with 1/4 inch exterior grade fiberglass. I sent you the pictures of my mods but I think you can get by without all the plates I added since your boom is heavier. I contacted Roger once and came away with the same opinion. I used the stock PVC plate at the center but bolted it to a 3/8 aluminum plate that holds the back stay and mounts to the mast with 4 clamps. I also have a 1/2 bolt through the plate and mast so I can swing it vertical  for service. Also locks it from twisting.

That radio stuff will ruin your life!

Get well soon.

"I trpped with a bundle of shingle on my shoulder going down slope and went off the egde of the roof, landed on my side and broke my hand. I'll be in a cast for 4 to 6 weeks.......Can't beleive it......."


Oh no, Joe!   Watch out for that HuzMan - he's trouble maker and it's all his fault... ;D

Yep, it's amazing how careful we all are climbing towers but screw up badly when on ladders and stairs. That must have really POed you off when you got up and relaized it was time to take a trip to ER.  Was that a little like the time you dropped the Harley in front of the nurses?  ;D

Since misery likes company, about two months ago I was on a ladder leaned up against a tree. The tree is round and the ladder is flat and of course the ladder swung around the tree and I hit the ground sideways on one leg. I came real close to a broken ankle. It swelled up and I couldn't walk on it for a week. It still hurts a little but is about 85% healed. I've never broken a bone in my life and feel quite lucky I sidestepped this one.

#2: My class E rig blew up the other day. Took me a good 8 hours of troubleshooting and replacing parts to get it going again... sigh

Hope you heal fast there, OM.

BTW, the heck wid that Log guy. You can do a better job reinforcing it yourself anyway.

T

Joe, BTW if you think Roger was a flake you should have had the pleasure of dealing with the first owner. What an AH insulting SOB.
The last time I talked to him I thanked him for the $750 box of scrap aluminum. Too bad because it is such a great electrical design. Then I built it right. By the time I was done I was kicking myself for buying the antenna when I could have homebrewed something much better.

- after all the frustration with the company, and falling off the roof - that sucks. Glad it wasn't worse though!

Joe,

Consider yourself damn lucky.  A former colleague of mine was building his home and fell off the roof while doing the sheeting and since then is crippled for life.

Take care,

I have a brand new T8 in the box - never opened. I plan to get it up in th enext few months, I hop ethat I have no problems considering the above comments.

As a minimum don't use the sheet metal screws at each element joint. Drill through and use SS hardware. Nylock nout or better yet find some Aircraft SS lock nuts. #4, #6, #8,#10 depending on diameter. I wouldn't let my kids play under the stock antenna
Second. Have each element end tack welded into the boom. Stock each element half is held in with a 10-24 screw.
Usual failure mode is the longest element rips out of the boom during a storm.
Hope you got the 1/8 inch thick wall booms

Frank, was it your experience - when the previous/first owner said the antennas are good for 5-7 years, the normal ham antenna lifetime, so don't worry about the poor construction? (Or something like that... ;D)


T

Yea, It was something like that. Hams change antennas all the time.
I told the bozo my quad was up for 19 years and wnated to add the new bansd so went LPDA. Then I thanked him for the box of scrap metal.
Splice square tube with angle bracket, come on.
Splice element sections with sheet metal screws
He took a great electrical design and JSed it.

Is the design patented??


klc

I don't think so. The coolest part of the electrical design are the square booms that act as the transmission line.  The square boom has a lower impedance than round booms. The lowest z of round booms is around 100 ohms but the 1 1/2 inch square tubes spaced 1/2 inch is around 60 ohms providing better match to the elements. The square boom is also easier to machine. So once you have the square tube is is just a matter of deciding on the LPDA design constants for the bands you want to cover. Once you find the element lengths and spacing is is then just a matter of how strong you want to build the elements. I did double wall for the longer elements with about 50% overlap. The electrical design of the T12 is very impressive one small vswr bump at 22 mHz otherwise flat.  The only thing I changed in the electrical design was a more balanced length to diameter ratio for the elements.

There's actually a number of active patents for log-periodic type antennas. Do a Google for "log periodic antenna patented"

The log periodic antenna was invented by Dwight E. Isbell, Raymond DuHamel and variants by Paul Mayes. The University of Illinois had patented the Isbell and Mayes-Carrel antennas and licensed the design as a package exclusively to JFD electronics in New York. JFD made tons of log periodic TV antennas.

Yes, using a pair of square tubes to double as a boom and feedline is clever.  I used a standard round boom with additional angle aluminum to form the feedline. In the end it was heavier than the square boom after adding the feedline insulator plates. If I do it again I will use the square boom technique.

It will be interesting to see how Chuck's installation works out. There's no reason why it shouldn't be very FB.

Considering the quality of the existing kit, I would opt to cruise the scrap yards and pick up all the element tubing and square boom material I could find. Then fill in the gaps from Texas Tower's nice selection. Using Frank's suggestions for construction and the basic Tennadyne electrical design anyone could build a very nice log indeed.  

The overall element length to diameter ratio can be worked out too. I was able to get my variation within about 1% or less element to element. That took some doing.  IE, you want ALL elements to show a constant tapered impedance curve in the cell. With random L/D elements, some elements (the lowest impedance ones) will hog power while others starve - NG for the pattern and swr curve.

T

Once Chuck and I worked Dean 10 through 20 meters at 100 watts to compare performance between my set up and his stacked pair. It was an interesting test. 
I think I got my L/D ratio about 30% end to end. I thought I had added enough weight so quit there. Stock antenna is closer to 100%.
!/8 inch wall boom allows more load so it could be dialed in better.

Geez, sounds like you have to have some idea what you are doing... leaves me out! :P

Clever but not new. I used antenna like this in the early 80's that were already at least 10 years old then.

The reality is that most amateur radio beam (yagis, logs, quad, etc) are substandard in their mechanical design - especially the ones for the lower bands. Hams couldn't afford ones built correctly and/or companies couldn't make any profit at a saleable price.

Can't remember the nomenclature now, but Collins made some monster logs used b the military and gov't agencies to work all over the world reliably. Part of the design included the tower, a rotating design IIRC. Many of them were destroyed in place when it came time to remove them, but a few survive and some have made it into the hands of amateurs. SERIOUS bucks to move and install, of course.

Gee HUZ that is true. We have a couple logs at work with square tube feed. Also have seen commercial VHF logs with square tube feed. Not a new idea.
Yes Todd we had a good time pulling my 100 pound log up the tower. Then there is the 200 pounder Tom dropped. So 50 or 60 pounds is a lot easier to deal with. BUUUT, Sheet metal screws at element joints, that is H.A. Then 7 segments  on a 19 foot element with 2 inch overlaps ???
I assembled the first element and looked at the sag, I was ripped and got on the phone.

"19 foot element with 2 inch overlaps 
I assembled the first element and looked at the sag, I was ripped and got on the phone. "


X3 the element diameter for a joint overlap is plenty - and even that's overkill.  What was the el diameter for that 2" overlap?


From the element sag, sounds like he used a direct slide-in taper. (example: 1" to 1 1/16")  I always use a buffer sleeve to make it 1" to 1 1/8".  This results in a straighter element and according to YagiStress, good for ~ 100 mph with 1/4" of ice.


BTW,  Al Gore invented the square log boom in 1968.

T

yes Tom, He started with 1 inch and the last segment was a 4 foot section of 1/4 inch. All elements ended in a 4 foot section of 1/4 inch. Seems like a lot of work to make a JS element. I did double wall with 50% overlap. So longest element started 1 1/8 for about 4 feet. Then I slid in a 8 foot section of 1 inch. Then a 7/8 8 footer to just beyond the first joint. I put a 10-32 screw and lock nut. Then I used a 8 foot section of 5/8 and finally 1/2 inch to get to 19 feet.
I wanted to use as much as the stock material as I could. I did look at 1/4 inch steps and it did look very strong but I would not been able to use most of the element metal provided.
I would go with 1/4 inch steps if I was starting over. It would be lighter than the elements I have now.