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From Shortwave Listener To Extra Class!
"How to go from shortwave listening to multiband antennas
 that tunes from 80 meters - 70 cm with an Extra class license"
..... all in one article!

By
Paul Coats, AE5JU,  Morgan City, LA
(See updates at end of article. Latest update, November, 2009)


Editor's note:
This is an article about how Paul, AE5JU went from a shortwave listener to an Extra class ham and his project of completing a multiband HF dipole that also includes VHF AND UHF as a bonus that evolved from his shortwave antenna!
The article contains lots of pictures, so if you have dialup, be patient.


-------------

Here is my story and I'm sticking to it!

I built a multiband dipole as my first "HF" antenna for the ham bands. 

Actually it is a modification of a dipole I had been using for SWL with an Icom R75. 

I just got "a ham license" a few weeks ago. That's me with that big proud grin below!


It is difficult to tell in the photo, but look at all those ("X's")

Yes, this is an Extra call sign, AE5JU . . . I took and passed all three tests in one sitting, after just 3 weeks of cramming.  My head still hurts!

I took the tests... all of them... at a hamfest 10-11-08 in Pineville, a 3 hr drive, early on a Saturday morning.  My wife drove while I reviewed study guides.

I passed 35/35 on the Tech, 33/35 on the General, and barely eeked by 38/50 on the Extra.  Well, I passed!  And I cheated... I'm not new to electronics.  I've been playing with soldering irons since I was about 8 yrs old.  I didn't start from scratch on this, just had to learn regs and such.

Enough of that!

I had gotten the Icom IC-R75 shortwave receiver early last spring and did what all newbies do. I stretched out a spool of hookup wire for a makeshift "random wire" antenna.  Performance was so-so.  I sought the advice of a friend from church who is a ham.  He advised me to build an 80 meters dipole, and for SWL only, it would do well.  He said, "Don't buy nuthin’. We (the ham club) are going to fix you up."

One ham club member cut the dipole center and end insulators from 1/4" plexiglass (seen below), mounted an SO-239 socket in the middle, holes for the wire to tie onto, and at the top to tie to a rope.  Another gave me some RG-8/U and a box of assorted fittings, and connectors.  I had to buy only the mast and brackets, rope, and some 14 ga insulated wire.


Center Insulator with S0-239


Center Insulator with SO-239 mounted and both sides soldered.
(See alternate center insulator using commercial insulator at bottom of article)

I use a lot of heat shrink tubing . . .  I love the stuff.  You can see in the picture above 
how I passed the wire end through the hole of the hanger, wrapped around itself 5 times, then heat shrink slipped over and shrunk in place to keep it from unwinding.  Then the wire end was doubled back over the wraps toward the center, and another piece of heat shrink slipped over and shrunk, securing it in place.


The ends tie to 6" plexi insulators seen below,


End Insulator

The mast is mounted to a wood privacy fence on the side of my lot.  I used regular TV type standoff brackets, with two 10' sections of TV mast tubing.  Through what was to be the top end, I packed the end of the tubing about 4" deep with epoxy putty to keep it from collapsing.  I drilled through that and inserted a piece of 3/8" all thread rod.  Put a nylon insert lock nut (aka "aircraft nut") on each side and snugged it up.  The epoxy putty kept it from egging on the end of the tube, and the nuts keep it tight.  Two more nuts held a little 2" marine type pulley in place.  I used some good 3/8" woven synthetic rope to go up over the pulley, and down to tie to the top of the plexi center insulator section.  I can raise and lower that when needed, for storms, repair, whatever.


Mast attached to fence

The ends of the ropes from the end insulators are tied off to eyebolts in the top rail of the wood fence shown in the picture below. I later replaced the white rope in the pictures with black "550 parachute cord" (aka paracord) as the black wire and black paracord are practically invisible against most backgrounds, showing only if you get under it viewing it against the blue sky.


Tie Off Eyebolt.

At first I had just the two 66' legs for SWL.  Great all the way down to 100 khz for beacons (ahh, what great programming!) from 100-300 khz.  The AM band comes in great.  160 meters is almost useless, but on rare occasions I pick up some hams on phone or CW. So, I got that all working well with the R75.


Raised

The guys at the ham club and Steve K9ZW, a ham friend in another state, kept asking when I was going to get a ham license.  Steve had gotten me the great deal on the NIB R75 from one of his ham friends.  Steve’s a VE, too.  And he has a popular ham blog that has quite a readership, reviews of new gear and other topical subjects.

http://k9zw.wordpress.com/

I had to take the original 80 meter dipole down temporarily due to
Hurricanes Gustav and Ike.  This seemed like a good time to make
some needed modifications.

Extra legs were added to make this a multi band dipole similar to the one shown here on Hamuniverse.

The original legs were for 80 meters, each leg cut to 66' (+ 2' folded back for tuning). I cut those for 3.55 mhz, not realizing at the time that was down in CW territory, and phone was higher.  I later trimmed those back to 60' each side for 3.90 mhz for the phone portion of the band.

40 meters segments were added, each leg cut to 33' (+ 2' folded back for tuning). 

20 meters segments were added, each leg cut to 16.5' (+ 1' folded back for tuning). 

All connections were soldered and well insulated with heat shrink tubing and sealed with Scotch Linerless Rubber Splice Tape 130C 3/4" wide.  This is the butyl rubber type tape that is soft and moldable, and commonly used for this purpose. Now the modified dipole looked like this:


Already I could tell that reception was better with the R75 on the 40 meter and 20 meter bands.

Due to the emergency situation created by Hurricane Gustav, I decided I really needed to go on and get a ham license which you read about earlier.  Steve sent me one of his "spare field radios", a Yaesu FT-897, complete with installed FP-30 110 vac power supply and LDG AT-897 tuner screwed on the side.  It was a complete package except for an antenna.

I had already modified my SWL dipole for three bands, adding to the original 60' legs for 80 meters, a pair of 33' legs for 40 meters (which work for 15 meters, too), and 16.5' legs for 20 meters.  I did not know at that time about the correction factors that make tuning faster in an update to the multiband antenna article here, or would have done it as suggested.


Wide view of multiband dipole, choke assembly and J Pole on top.

A few more notes:

I used plenty of "coax seal" (Scotch 130C) around the plugs/sockets of both antennas.

I also added an "Ugly Balun" consisting of 17 turns of LMR-200 wrapped around a piece of 4" PVC pipe.


Antenna shown with "Ugly Balun" and J Pole on top.
Notice the pulley arrangement.

I had just gotten in some LMR-200.  I ordered that as it is low loss coax, but is the same diameter as RG-58, to more easily wind a choke balun, aka "Ugly Balun", 17 turns on a piece of 4" pvc pipe.  Home Depot sells little cut off pieces of PVC pipe so you don't have to buy 10' or anything like that.  The wraps were held in place with Ty-Wraps through holes drilled in the pvc.

Steve wrote this about me...

http://k9zw.wordpress.com/2008/10/11/with-words-of-encouragement-newly-minted-ham-extra-class/

While at the hamfest I bought a B-Square Engineering 2m/70cm J-pole.  It is stainless steel construction.  Man, as much as I like DIY, I wouldn't fire up my torch to solder copper tubing at the price of the B-Square J-pole... just $40 in 2008 prices.  While the antenna was lowered to add the balun I decided to take the mast down and attach the J-pole at the same time. 

The J-pole is attached to the top of the mast with two stainless radiator hose clamps.  The RG-8/U I had previously attached to the dipole was moved over to the 2m antenna.  OK, it is a little lossy at 70 cm, and not great at 2m, but better than the LMR-200 at that frequency.

The LMR-200 is one continuous piece from the dipole center, around the pvc of the choke balun, and on down into my workshop/hamshack.

The wood fence is 143' long, the eyebolts for the longest segments are about 2' from each end, and parachute cord tied from eyebolts to the end insulators.  So that makes for a very shallow inverted Vee.

The other two segments, 40 m and 20 m legs are tied to eyebolts further in toward the center mast, and form slightly sharper inverted Vees.



80m 40m 20m Legs

The white rope on the ends of the dipole elements in the photos has been replaced with black 550 parachute cord.  The black is nearly invisible against most backgrounds.  This is something to keep in mind if you have HOA Nazis lurking.


End view

The droop in the wires looks bad from an end view above, but it is really not that bad.  You just cannot pull the wire tight enough to get it perfectly straight.  There is a huge difference in pull between almost straight and a little sag.  Don't try to pull it straight.  Just get it acceptable.  There will be a lot less strain and less likely to break in windy conditions.

Not mentioned before, GROUND.  That metal building (my shop/ham shack) is on blocks on footings, and tied down on each corner to 6' long auger type anchors screwed into the ground.  With the moist soil conditions here on the coast, and the large amount of area of the auger end of the anchors, they make good grounds.  So my metal building is grounded on each corner, and I have additional ground wires from my transceiver and antenna tied to the nearest anchor as well.

There are lots of other ways to do this. 
So get busy, and have some real fun like I did, with the multiband dipole!
======================================================

So, how does it work?

I was listed in the FCC ULS database late Thursday afternoon of 10-16-08.  Friday morning (I work 14 on/14 off), I checked out everything one last time, no shorts in the coax.  I plugged it all up, read the manual again.  I turned power down to 5 w, found a freq that was not being used just below 3.900 mhz, listened for a few minutes, then keyed the mic, gave my call sign and asked if the frequency was in use, listened some more. Then I announced I would be doing a short antenna test.  (OK, most hams don’t seem to do all that, they just tune. But it seemed the polite thing to do, and being a new ham, it couldn’t hurt.) I switched to FM, keyed the mic with the meter set to read SWR.  Not bad, about 2:1, and no magic smoke came out of the radio.  Hit the tune button on the tuner and it dropped down to 1.1:1.  Wow!  And that tuner is noisy... sounded like my printer that just went out.

OK, that band will tune.

I changed bands up to 40 meters, found a freq around 7.2 mhz, same procedure, listened, gave my call, etc.  With the tuner bypassed SWR was a little higher, but it tuned right up.

20 meters, SWR started out at at 1.5:1 and went down from there as it tuned.

I was able to tune 17 m, 15 m, 12 m, 10 m, and 6 m.

2 meters with the J-pole:
The tuner only tunes the HF bands, not the VHF/UHF bands.  But 2m SWR was 1.1:1.  That’s good enough for me.  70 cm is a little high at 2.5:1, but it may be the extra 10' of coax coiled up inside the shop.  Later I’ll cut off the excess and see how it does.

So, there you have it, two antennas, and the FT-897 with LDG AT-897 tuner that will cover from 80 m - 70 cm.

So, how does it really work?

The next morning, around 09:00, I made my very first QSO with my good friend and Elmer, Steve K9ZW way up in Wisconsin from my home in southern Louisiana, a distance of 1,016 miles, on 20 meters with that dipole and 100 w. 

http://k9zw.wordpress.com/2008/10/24/working-paul-ae5ju-for-his-first-hf-qso/

Later I worked guys all over Louisiana and a guy in Florida on 80 meters.  I also worked a guy in Massachusetts on 17 meters.  He was pegging my meter, and me his.  I mean PEGGED.  Like you could hear the needle click on the stop pegged.

I also signed in on a net up in New Iberia (just south of Lafayette) 45 miles away on 2 meters with just 8 watts with that B-Square Engineering J-pole.

So far no luck on 6 meters or 10 meters.  Just no activity up there at this time, but those bands will tune up.

Final Lengths and Testing Updates 11-16-08

I spent the afternoon checking SWR at several places on each band, trimming length.

Here's what I started with:

120' total (60' each leg) for 75 meters

66' total (33' each leg) for 40 meters

33' total (16.5' each leg) for 20 meters

-----------------------------------------------------

75 meters 60' each leg

SWR @ 60' 3.665mhz = 1.1
3.800mhz = 1.9
3.995mhz = 5

This showed that it was too long, resonance down around the lower end of the phone band. I wanted to get that higher, nearer to 3.9 mhz. I took 26" off each end = 57.83' each leg

SWR @ 57.83' 3.665mhz = 2.6
3.780mhz = 1.3
3.850mhz = 1.1
3.995mhz = 1.2

This is VERY close to the 96% adjustment for the lowest band segments from the Multiband Dipole page at HamUniverse.com.

-------------------------------------------------------

40 meters 33' each leg

SWR @ 33' 7.165mhz = 2.0
7.218mhz = 2.4
7.290mhz = 3.0

I took 8" off each end = 32.33' each leg

SWR @ 32.33' 7.165mhz = 1.1
7.225mhz = 1.1
7.292mhz = 1.3

Again, this ended up VERY close to corrections from the Hamuniverse page. I could probably have taken off another 1/2" or so, gotten the upper end down a fraction, but why? That is close enough for me.

--------------------------------------------------------

20 meters 16.5' each leg

SWR @ 16.5' 14.155mhz = 1.2
14.275mhz = 1.3
 4.345mhz = 1.6

It is easy to see this section was a little too long.

I took off 1" each end = 16.4' each leg

SWR @ 16.4' 14.155mhz = 1.4
14.175mhz = 1.3
14.190mhz = 1.1
14.275mhz = 1.1
14.345mhz = 1.1

I went back and confirmed that 75 meters and 40 meters were still the same as before, had not changed as a result of tuning the 40 m and 20 m legs.

-------------------------------------------------------
After trimming 75m, 40m, 20m segments, these figures were obtained on higher bands.

17m 18.120mhz = 3.5
18.160mhz = 3.5

15m 21.205mhz = 3.0

12m 24.960mhz = 5.0

10m 29.000mhz = 2.0

6m 52.800mhz = 2.0

15 meters had been somewhat lower, around 1.2:1, before I tuned the 80m and 40m segments, but not too bad now. It is easy to see that shortening the 40 meters segments shifted the resonance for 15 meters up out of the band. But the tuner easily handles it. And 17 meters is about what it was before.

Additional notes:

All SWR readings above were obtained with the tuner bypassed, that is, the coax in from the antenna was plugged directly into the radio’s HF antenna socket. These bands all tune down to 1.1 using the tuner.

I don't think I'm going to do any better than this. Everyone tells me to leave it alone now!

Had I used the Stanford Research corrections as per the Hamuniverse Multiband Dipole page, I would have already been finished.

Update - November, 2009 - ALTERNATE CENTER INSULATOR USING COMMERCIAL INSULATOR:

After the antenna had been up for a while, I fired up the radio to check in on the HiFivers Net and the antenna wouldn't tune.  Impedance was very low.  I found out the exposed side of the SO-239 connector (in the original construction article above), the center insulator on the dipole was dirty.
I had failed to use a "hood" to seal the exposed side.  Other corrosion on the connector, too.

Water had gotten into the SO-239 socket also.  I made a new center hanger by bolting a Jetstream JTCE1 Dipole Center Insulator to a piece of plastic kitchen cutting board.  The holes for attachment of the wire legs were chamfered by lightly touching the holes with a larger diameter bit.  The V shaped notch on bottom is to allow easier wrapping of the coax connection with Coax Seal or Scotch 130C butyl rubber tape.
I already had a new hanger fabricated from a Jetstream JTCE1 Dipole Center Insulator and a piece of plastic kitchen cutting board.  See photos below:


Jetstream Dipole center insulator


Jetstream Center Insulator mounted on plactic cutting board backing

 
The notch on the bottom of the backing piece is to make it easier to wrap the coax connector with coax sealing tape (Scotch 130C).
 
It took only minutes to replace my original center insulator with this new, more weather resistant one.

73 Paul - AE5JU




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