Sierra Echo International 11m DX Group :: View topic - The SE144 Portable 3 Ele Cubical Quad

43SE144 · Last edited by 43SE144 on Mon Oct 01, 2007 8:30 am; edited 13 times in total

Now that the portable 4 ele yagi is up at my brothers (43SE122 Kerry) place, we needed another portable antenna. With all the talk about Cubical Quads lately, I decided to build a portable model. The criteria was that it could be put together easily & taken apart to be packed away into a small package to fit on car or trailer roof racks.

So I grabbed a beer and started looking around the yard & under the house. I came across some 50mm square aluminum extrusion, it was left over from the back veranda make over. It's length is 3.14m, mmmm I thought, thats close enough to make into a 3 ele quad. So without using the quad formulas for the loop spacings, I threw caution to the wind and grabbed another beer & set up my portable antenna shop.

I grabbed my new digi camera (and another beer) to document the making of this quad, which I called ""The Portable 3 Ele Cubical Quad, Model SE144OZ"" This documentary is to be photoed over the next month or so, as I scrounge up bits & pieces for the quad & throw it together. (look for & find parts for the quad)

The following photos & notes are the first part of this epic quad building journey. As I said at the start, I'm using spacings that suit the length of the boom, not using the classic quad formula for spacings. One of two things are going to happen after it's finished. 1) it's going to be a lemon and not work or 2) oh my god, it works. So we won't know until we give it ago. The loops will be made with the quad formula.

This antenna might not work (I think the spacings are too small), but the main reason I'm doing it is to show people how to make up a cubical quad, although you would use the dimensions from the quad calculator. Thats why I'm photographing the manufacturing stages.
I also have a length of 50mm (2") dia PVC pipe that is 1.8m in length. I'll be making a 2 ele cubical quad from it, photographing the whole process, step by step. The 2 element quad will be erected here as my homebase antenna

Center Frequency of 27.455

These 3 pics are of my antenna shop.

_________________
43SE144, Pete.
Co-Founder & Oceania Co-Ordinator/Director
Sierra Echo International 11m DX Group

43SE144 · Last edited by 43SE144 on Sat Dec 01, 2007 4:57 am; edited 12 times in total

Material Listing
1) 1x Boom- 50mm square extruded aluminum, 3.14 meters
2) 1x Large U-Bolt
3) 12 x 20mm PVC electrical conduit @ approx 2m long
4) 6 x 16mm OD aluminum tubing @ approx 600mm long
5) 12x 20mm hose screw clamps.
5) quite a lot of electrical copper wire, the thicker the better.
6) a 1:1 Balun ( the balun is not really needed, the quad can be fed directly with the coax. If you have problem neighbors, the balun will help stop tvi problems. I have a habit of using baluns when making wire antennas, so since this antenna is for portable use, I'll be taking the balun off. Thanks to John 14SE058 for bringing up the subject.)
7) whatever else is needed when the time comes.

fig-00 working out the spacings for the spreader spiders.

fig-01 the 50mm square extruded aluminum @ 3.14m

fig-02 the 50mm square extruded aluminum @ 3.14m

fig-03 One long U-Bolt clamp with pipe bracket

fig-04 20mm PVC electrical Conduit (Bamboo is hard to get)

fig-05 20mm PVC electrical Conduit (for the spreaders)

fig-06 Find the center of the boom @ 1.57m & mark your center line. (c/l = center line)

fig-07 I decided (after a beer & some thinking) to mount the boom to mast section towards the back from the center line. That would give me nearly equal spacing of the elements.

fig-08 marking for drilling bracket holes. 1st hole is 10mm back from c/l, 2nd hole is width of the U-Bolt, here it is 75mm. So 2nd hole is 85mm back from c/l. (The dir to dri spacing is 15mm shorter than ref to dri. Otherwise, nothing to worry about.)

fig-09 measure forward 15mm from c/l. This is for the 1st spider of the PVC spreader. Remember that I'm using 16mm OD aluminum tubing, which the PVC will fit over quite nicely.

fig-10 the 2nd spider is on the same side as the mast bracket, it gives you room to tighten up the nuts on the U-Bolt. Measure forward 32mm and mark it. This is for the second spider. There is a 1mm spacing between the 2 spiders inside the boom. Make sure ALL the spiders on this side are marked forward of the other side. This is to keep the spacings even.

fig-11 Now for the Reflector. Measure back from the edge, 20mm. Mark it. (make sure you are using the side that does NOT have the clamp on it) Next, rotate boom 90 deg and measure in 37mm, mark it.

fig-12 With the Director, use the SAME procedure as the Reflector.

Fig-13 The holes for the U-Bolt mast clamp have been drilled.

Fig-14-15-16 The mast clamp in place.

Fig-17 The locating pilot holes have been drilled ready for the 16mm hole saw.

Fig-18 The 16mm holes have been cut. These are for the Driven Loop.

Fig-19 16mm holes cut on both ends, for the Reflector & Director loops

Fig-20,21 The 4m lengths of PVC conduit been cut into 2m pieces.

Fig-22 The aluminum spiders for the PVC spreaders @ 650mm in length.

Fig-23,24,25 Find & mark the center of the aluminum spiders for drilling the locking screw holes.

Fig-26,27,28,29,30 Mark out & drill the locking screw holes in the boom. Insert the aluminum spider, using a 25mm self tapping screw, secure the aluminum spiders to the boom. When it is time to pack up, just unscrew the screws & slide out the aluminum tubing to be packed away for transport.

Fig-31,32 With a hacksaw (metal saw) or a thin bladed saw, cut 4 slots @ 30mm long into one end of the 2m PVC conduit. Attach the 20mm hose clamp. When the clamp is tightened, the PVC is held securely to the aluminum. It is also easy to undo so the quad can be pulled apart for transport.

Fig-33 Three (3) of the spreaders attached to the boom.

Fig-34 43SE122 Kerry.

Fig-35,36,37,38 I'm using an old 240VAC extension power lead for my loop wire. With a sharp knife, I stripped of the outer protecting casing, leaving the 3 inner wires, green/yellow- earth, brown-active & blue- neutral. my 3 wires for the 3 loops.
Green/yellow- The Reflector Loop was cut 11.434m (+10mm for soldering) long, then with a marker pen, I marked of the lengths of 1 side of the loop, 2.858m. 10mm of each end was bared for soldering into a loop.
Brown- Driven Loop was cut 11.157m (+10mm) long, then with a marker pen, I marked of the lengths of 1 side of the loop, 2.789m. 10mm of each end was bared for attaching to the 1:1 balun.
Blue- Director Loop was cut 10.824m (+10mm) long, then with a marker pen, I marked of the lengths of 1 side of the loop, 2.706m. 10mm of each end was bared for soldering into a loop.

Fig-39 I put a small slot in the ends of the PVC spreaders, to hold the wire loop. The reason I marked off the loop sides with a marker pen is to make it easy to locate the corners of the loop onto the spreaders.
The spreaders are then slid out on the aluminum tube until the loops are extended. The aluminum tube between the spreader & the boom should be all equal in length.

Fig-40a,b,c,d The 1:1 balun on the driven loop.

Fig-41,42,43 The finished quad. Due to radio unfriendly neighbors, the quad could not be tuned in here at home. We are taking the 3 element quad up to the Log Dump to tune it in & to tidy it up. I put it together in the back yard just for the photo shoot. So we won't know until the end of this month if it will work or not.
I hope this little quad making epic has helped you with the construction of a quad.

Fig-44 After a hard days work, there is nothing like having a few beers & a BBQ. On the left is my brother Mark 43GVR140 & at the BBQ is my other brother Kerry 43SE122. The Kangaroo Team.

More photos & the test results will be posted here after the 3 days at the Log Dump.

CAN ANYBODY SPOT THE MISTAKE THAT I MADE WHEN PUTTING THE QUAD TOGETHER FOR THE PHOTO SHOOT ???
_________________
43SE144, Pete.
Co-Founder & Oceania Co-Ordinator/Director
Sierra Echo International 11m DX Group

14SE058 · Posted: Sun Aug 19, 2007 7:39 am Post subject: DX and FUN

Yes nice but the story don't tell how many beers were drunk to have this good ideas ! Very Happy

I was thinking about this PVC tubes because it's not easy to find fiberglass and it's expensive...

I would like to know if it's not too much flexible Question

If someone have a good link for fiberglass at a good price it's welcome...

73's

John - 14SE058
_________________
DX and FUN ! The best way for friendship...

43SE144 · Posted: Sun Aug 19, 2007 7:53 am Post subject: PVC

Hi John, I only had 6 250ml mini bottles of Tooheys New Beer.

As for the PVC conduit, I have used it many times. The wire around the PVC spreaders seen to act like guy wires, it keeps the PVC in place. The 2 reasons I use PVC is that I cannot find bamboo in the shops here and like you said, the fiber glass is very expensive.

Geoff, 43TR299, up in Darwin, has been using a 3 ele quad made from PVC for many years.

Over the next few weekends I'll be doing more to the quad as I find the parts for it. With a bit of luck, this quad will cost me either $00.00 or maybe just a few $s.

*****************************************************************************
Cost update-
Aluminum Tubing- 2 lengths of 2m long 16mm dia = $16.20
PVC Conduit- 6 lengths of 4m long 20mm dia = $44.65
So the total cost of the 3 ele quad came to $60.85. Not bad for a high gain directional antenna.
The wire is from an old electrical extension cord.
_________________
43SE144, Pete.
Co-Founder & Oceania Co-Ordinator/Director
Sierra Echo International 11m DX Group

2xx182 · Posted: Sat Aug 25, 2007 6:10 am Post subject: re: 4 element quad

nice article pete. please when you get it finished i would like to see the full product posted in pictures on this web site with a full detail of how to on it . it is very interesting when you find a way to build a portable antenna as i get very interested in them as i like portable as well as qrp and that antenna will proove to be a winner if you get it to work on 11meters . but dont forget if you get your ham ticket to try it for those bands as well they are a fun band to work too with portable antennas . ive heard many a station portable even on a bycycle too we all can use a bit of light when it comes to experimenting with antennas some times other ideas make us want to build our own and share them with each other as well as trying to build what we see in magazine articles or on line well enough chat on this subject pete good to see the great articles posted on the forum 73,s and as always have a great time dxing with your new antenna 2xx182 dennis

43SE144 · Posted: Sat Aug 25, 2007 10:43 am Post subject: re: 4 element quad

Hi Dennis, that is exactly what I'm doing here. Each step of fabrication is been photographed & documented. It'll be finished in a few weekends. The center frequency is going to be 27.455, because with 555 is 10 up & our 43 div call is 10 down on 27.355. The bandwidth is depended on the dia of the wire, the larger the dia the more broadband it will be, I'm hoping around 50KHz of bandwidth.
Pete
_________________
43SE144, Pete.
Co-Founder & Oceania Co-Ordinator/Director
Sierra Echo International 11m DX Group

2xx182 · Posted: Mon Aug 27, 2007 10:36 am Post subject: re: 3 ele quad

thanks pete for getting back to me on that subject as i was wondering because i may build one myself it seems like you do know what you are doing as for building that 3ele quad i havent tried to build anything like that yet so it will be a challenge for me and you know we all like challenges til then pete best of luck on the antenna and i will look forward to seing the finish of it to come til then 73,s my friend 2xx182 dennis Idea

14SE058 · Posted: Mon Sep 03, 2007 7:06 pm Post subject: Near to copy Australia

Ok Pete we are on the good way, into a few days (when my little Bamby will be finished) we will have a QSO !

Ok I'm dreaming but well for me when I will contact for the first time Australia or Japan it will be the greatest day of the radio and specially if I'm able to make the real QSO...

So as I've said, I'm building a little Bamby and she will cost less than 10 Euros with the PVC tubes ! Which is really cheap it could be named the cheaper Bamby of the world !

I will do a few tests next and report them here on the SE's forum.

73's

@182 and @144

And all sure !

14SE058 John
_________________
DX and FUN ! The best way for friendship...

2xx182 · Posted: Mon Sep 10, 2007 3:16 am Post subject: re :3 element quad

nice job pete the antenna looks excellent hope you can get it tuned for 11 meters as well as getting the swr down to 1 to 1 i may consider making my own quad after all the pics you have shown it seems to look very easy to build but time consuming any way good luck with the tuning of the antenna and good dx from the log dump when you go on your dx pedition 73,s for now my friend and as always NICE JOB! Cool

2xx182 /---/--/---/

43SE144 · Posted: Mon Oct 15, 2007 8:50 am Post subject: SWR

After a couple of hours of tuning, the 3 Ele Portable Quad has a SWR of 1.2:1 on the center frequency. I can't wait to set it up at the Log Dump for the first tests.
_________________
43SE144, Pete.
Co-Founder & Oceania Co-Ordinator/Director
Sierra Echo International 11m DX Group

43SE144 · Posted: Sat Nov 17, 2007 8:56 am Post subject: The KTQ-3 is finished

The quad is finished & ready for work.

_________________
43SE144, Pete.
Co-Founder & Oceania Co-Ordinator/Director
Sierra Echo International 11m DX Group

43SE144 · Posted: Wed Nov 28, 2007 9:51 pm Post subject: It Works, It Really Works

A good success story, the 3 ele quad works extremely well.

_________________
43SE144, Pete.
Co-Founder & Oceania Co-Ordinator/Director
Sierra Echo International 11m DX Group