Sunday, April 24, 2016

More 160m thoughts ...

After looking at what a dipole will do on 160m I quickly came to the conclusion that the Vertical is what I need to put together.   First article I Googled ....

Which is the Best 160m Antenna ?

Topband antenna survey by ON4UNIn a nutshell: vertically-polarized antenna for transmitting, using separate antennas for receiving.

Per W8JI on qrz.com:

"Nearly all especially successful stations on 160 use a vertically polarized antenna of some type for transmitting. That's just a fact."
"The fact is....... an Inverted L with 20 or more radials at least 50 feet and hopefully 100 feet long will absolutely smoke any normal height loop antenna or dipole antenna at nearly any distance on 160 meters. The possible exception is between 20 and 200 miles."

"I have a full size 160 dipole at 300 feet, and it is never really much better than a 1/4 wave vertical at any distance in any direction. As a matter of fact, the dipole is 10-20 dB weaker than the vertical off the dipole ends. The dipole only beats the vertical broadside to the dipole, and then only rarely!! And this is with the dipole 300 feet above ground."

"As a matter of fact a low full wave loop has no gain, any horizontal wire has increased earth induced loss as it is made longer when close to earth."

http://forums.qrz.com/showthread.php?t=260716&highlight=beverage


Full article here .... http://www.w0btu.com/160_meters.html and a good link to the Beverage Antenna for RX   http://www.w0btu.com/Beverage_antennas.html

The Antenna I am going to build is an Inverted L like the one below but the horizontal part will be more vertical then horizontal!   Different 160m Antennas here ....http://topbandhams.com/tech-page/6-22-different-wire-antennas-for-the-160-meter-band













This is interesting I had no idea at all and hope this statement is true ....

 The “L” works good because a quarter wave antenna only radiates from the bottom 20%, the rest is only there for “loading” purposes, so as long as it's there, somewhere, it'll work fine. So, that means the “L” should begin to function as a Marconi with a height as little as 25 feet, with some skewing to the pattern. But, like I said, the higher the better.

6 Meter Dimensions

Ok ,  6m is a must do however I am not 100% on doing it with a simple vertical or even dipole.   Aurora and Tropo demand directional antennas with lots of gain.   I am just curious to see what I here and then maybe it would spark a greater desire to improve the antenna.  

Here are the 6m dimensions ....

Six Meter Wire Antennas


Six Meter CW/SSB

Center Frequency:  50.100 Mhz 147.86 Mhz 3rd Harmonic
Halfwave in space is:   9.82 feet  6.68 coax| 8.05 twinlead
Quarterwave in space is:  4.91 feet  3.34 coax| 4.03 twinlead

Quarterwave Vertical is:  4.67 feet  5.50 foot ground radials
Five Eights wave Vertical is: 12.04 feet  4.67 foot ground plane
Three Quarter wave Vertical: 14.49 feet  2.34 foot eighthwave

Halfwave Dipole/Vertical is:  9.34 feet  4.67 one side.
Halfwave Reflector is:   9.81 feet  8.92 for Director
Low Mount Halfwave is:   9.14 feet  4.57 one side.
Halfwave Folded Dipole is:  9.22 feet  4.61 one side.
Halfwave Inverted V is:   9.68 feet  4.84 one side.
Colinear Array is:  19.16 feet  9.58 one side.
Extended Double Zepp is: 24.07 feet 12.04 one side.

Fullwave Quad Loop is:  20.36 feet  5.09 one side.
Reflector|Director:  21.38|19.44  5.34| 4.86 one side.
Fullwave Delta Loop is:  20.36 feet  6.79 one side.
Reflector|Director:  21.38|19.44  7.13| 6.48 one side.

Waves 1:  19.16 |1.5:  28.98 |2:  38.80 |2.5:  48.62 |3:  58.44 |4 :  78.08
Waves 5:  97.72 |6.0: 117.37 |7: 137.01 |8.0: 156.65 |9: 176.29 |10: 195.93

Six Meter FM

Center Frequency:  52.525 Mhz 155.01 Mhz 3rd Harmonic
Halfwave in space is:   9.37 feet  6.37 coax| 7.68 twinlead
Quarterwave in space is:  4.68 feet  3.18 coax| 3.84 twinlead

Quarterwave Vertical is:  4.46 feet  5.25 foot ground radials
Five Eights wave Vertical is: 11.48 feet  4.46 foot ground plane
Three Quarter wave Vertical: 13.82 feet  2.23 foot eighthwave

Halfwave Dipole/Vertical is:  8.91 feet  4.46 one side.
Halfwave Reflector is:   9.36 feet  8.51 for Director
Low Mount Halfwave is:   8.72 feet  4.36 one side.
Halfwave Folded Dipole is:  8.80 feet  4.40 one side.
Halfwave Inverted V is:   9.23 feet  4.62 one side.
Colinear Array is:  18.28 feet  9.14 one side.
Extended Double Zepp is: 22.96 feet 11.48 one side.

Fullwave Quad Loop is:  19.42 feet  4.85 one side.
Reflector|Director:  20.39|18.55  5.10| 4.64 one side.
Fullwave Delta Loop is:  19.42 feet  6.47 one side.
Reflector|Director:  20.39|18.55  6.80| 6.18 one side.

Waves 1:  18.28 |1.5:  27.64 |2:  37.01 |2.5:  46.38 |3:  55.74 |4 :  74.48
Waves 5:  93.21 |6.0: 111.95 |7: 130.68 |8.0: 149.41 |9: 168.15 |10: 186.88
Note: At Six meters the diameter of elements in terms of wavelength starts to become large, even with heavy wire like 10 gauge. With tubing elements, an additional shortening factor starts to become important. As elements get fat, the resonant frequency goes down for a given length. This is not a problem on the lower frequencies where even one inch tubing is still small diameter relative to wavelength, but at six meters and above it starts to become more and more significant.



30 Meter Vert / Dipole at the top of the hill

OK ,  yet another grand antenna plan this time repeating my 30 meter antenna lower on the hill.  Heading into the solar null I expect that 30 meters will continue to yield some DX from time to time so an investment in this antenna will pay off.  

http://westgreyham-ve3ldp.blogspot.ca/2015/08/on-30-meters.html


I want to compare two more or less 30 meter antennas ,  my existing one above and another to be built at the top of the hill.    I want to see if there are any "height advantages ".  I also would love to A/B a dipole vs vertical at the top of the hill

and the numbers ....

30 Meter Wire Antennas


This Band CW Only


Center Frequency:  10.120 Mhz  29.87 Mhz 3rd Harmonic
Halfwave in space is:  48.62 feet 33.06 coax|39.87 twinlead
Quarterwave in space is: 24.31 feet 16.53 coax|19.93 twinlead

Quarterwave Vertical is: 23.12 feet 27.23 foot ground radials
Five Eights wave Vertical is: 59.58 feet 23.12 foot ground plane
Three Quarter wave Vertical: 71.74 feet 11.56 foot eighthwave

Halfwave Dipole/Vertical is: 46.25 feet 23.12 one side.
Halfwave Reflector is:  48.56 feet 44.16 for Director
Low Mount Halfwave is:  45.26 feet 22.63 one side.
Halfwave Folded Dipole is: 45.65 feet 22.83 one side.
Halfwave Inverted V is:  47.92 feet 23.96 one side.
Colinear Array is:  94.86 feet 47.43 one side.
Extended Double Zepp is: 119.17 feet 59.58 one side.

Fullwave Quad Loop is:  100.79 feet 25.20 one side.
Reflector|Director:  105.83|96.25 26.46|24.06 one side.
Fullwave Delta Loop is:  100.79 feet 33.60 one side.
Reflector|Director:  105.83|96.25 35.28|32.08 one side.

Waves 1:  94.86 |1.5: 143.48 |2: 192.09 |2.5: 240.71 |3: 289.33 |4 : 386.56
Waves 5: 483.79 |6.0: 581.03 |7: 678.26 |8.0: 775.49 |9: 872.73 |10: 969.96




160 Meter Vertical + Antenna Dimensions

160 Meter Wire Antennas



Center Frequency:   1.840 Mhz   5.43 Mhz 3rd Harmonic
Halfwave in space is:  267.39 feet 181.83 coax|219.26 twinlead
Quarterwave in space is: 133.70 feet  90.91 coax|109.63 twinlead

Quarterwave Vertical is: 127.17 feet 149.74 foot ground radials
Five Eights wave Vertical is: 327.72 feet 127.17 foot ground plane
Three Quarter wave Vertical: 394.57 feet 63.59 foot eighthwave

Halfwave Dipole/Vertical is: 254.35 feet 127.17 one side.
Halfwave Reflector is:  267.07 feet 242.90 for Director
Low Mount Halfwave is:  248.91 feet 124.46 one side.
Halfwave Folded Dipole is: 251.09 feet 125.54 one side.
Halfwave Inverted V is:  263.59 feet 131.79 one side.
Colinear Array is:  521.74 feet 260.87 one side.
Extended Double Zepp is: 655.43 feet 327.72 one side.

Fullwave Quad Loop is:  554.35 feet 138.59 one side.
Reflector|Director:  582.07|529.40 145.52|132.35 one side.
Fullwave Delta Loop is:  554.35 feet 184.78 one side.
Reflector|Director:  582.07|529.40 194.02|176.47 one side.

Waves 1: 521.74 |1.5: 789.13 |2:1056.52 |2.5:1323.91 |3:1591.30 |4 :2126.09
Waves 5:2660.87 |6.0:3195.65 |7:3730.43 |8.0:4265.22 |9:4800.00 |10:5334.78

                   Note: 10 waves is well over a mile long.


No doubt a 160 meter dipole is not in the cards.  Getting this antenna up 0.5 Wavelength would
mean that it would have to be 245' off the ground.   Any attempt at a 160 Meter dipole would be
"Skywarmer " in other words radiation goes straight up!!!!   

Plane B ....

The Vertical

The numbers .....

Quarterwave Vertical is: 127.17 feet 149.74 foot ground radials


127' is a bit of a stretch when it comes to trees but I do have one advantage and that I some 
big ass trees on the side of a very steep hill.   I have read to that it doesn't have to be 100% V
Vertical and so its doable.    Planning on 8X radials each 150' .... its going to be fence wire.

So I need 1,200'of wire for the radials and I already have the 127' vertical wire ... lets get 
building!    




80m Dipole/Inverted V + Dimensions

OK now that I have bought all of the hardware its time to plan in detail the 80m  Inverted V or Dipole.   The antenna is going at the top of the hill because .....

1 )   Height advantage 100+ ft above the house.
2)    The Hill is steep and consist of Gravel so its a great insulator.  I expect the ground affect to be minimal and I should have no problem getting things elevated 60' or so.
3) Orientation will be more or less East / West so it will favor Europe and USA / South America with the null off the ends towards Australia and Africa.  It should give a 3db gain over the Vertical as long as I can get it up at least 1/2 Wavelength .  
4) I am going to try to possibly make this a 160/80/40 m antenna with the emphasis on 160m and 80m.  




Design considerations ....

#1 Priority is to make the antenna as efficient as possible with as low a take off angle as possible.   I am hoping the Balun will assist on achieving this goal.

Below is a VSWR chart Dipole vs Inverted V.    There is now doubt its going to be an inverted V so that should help drop the feed point impedance.














Just a little note on the Balun ....

One feature which should not be overlooked is the use of a current balun or RF choke at the feed point. This device encourages RF current to stay off of the outside of the transmission line. This unbalanced current causes the feed line to radiate, in addition to the antenna. This can create all sorts of problems. First, your antenna is now a combination of an inverted vee and a vertical running down the center of the vee. Since the transmission line is now part of the antenna, changes to its length will change the antenna length, which will change the antenna impedance, which will change the SWR on the feed line. Ideally, the SWR on a transmission line will be exclusively determined by the impedance of the antenna and the transmission line. The SWR should stay constant for different length transmisson lines. Actually, real transmission lines, due to loss, will lower the SWR (towards 1.0) with increasing length. If you have an antenna where changing the transmission line by a few feet causes a noticeable change in SWR, odds are that the feed line is part of the antenna, and that is rarely desired. Finally, the RF current on the outside of the transmission line may travel all of the way back to the radio shack, where it can cause additional trouble. 

And a cool way to do "strain relief " ...


























and now the numbers ....


80 Meter CW


Center Frequency:   3.600 Mhz 10.648 Mhz 3rd Harmonic
Halfwave in space is:  136.67 feet 91.57 coax|120.27 twinlead
Quarter wave in space is: 68.33 feet 45.78 coax|60.13 twinlead

Quarter wave Vertical is: 65.00 feet 76.53 foot ground radials
Five eights wave Vertical is: 169.47 feet 65.00 foot ground plane
Three Quarter wave Vertical: 201.67 feet 32.50 foot eighthwave

Halfwave wire dipole is: 130.00 feet 65.00 one side.
Halfwave Reflector is:  136.50 feet 124.15 for Director
Low Mount Halfwave is:  127.22 feet 63.61 one side.
Halfwave folded dipole is: 128.33 feet 64.17 one side.
Halfwave inverted V is:  134.72 feet 67.36 one side.

Extended double Zepp is: 349.87 feet 174.93 one side.

Fullwave quad loop is:  283.33 feet 70.83 one side.
Reflector|Director:  297.50|270.58 74.38|67.65 one side.
Fullwave delta loop is:  283.33 feet 94.44 one side.
Reflector|Director:  297.50|270.58 99.17|90.19 one side.

Waves 1: 266.67 |1.5: 403.33 |2: 540.00 |2.5: 676.67 |3: 813.33 |4 :1086.67
Waves 5:1360.00 |6.0:1633.33 |7:1906.67 |8.0:2180.00 |9:2453.33 |10:2726.67



 I am going to design this as an inverted V so the antenna  will be .... 

Halfwave inverted V is:  134.72 feet 67.36 one side.










Saturday, April 23, 2016

Antenna Considerations

Spring is here so its time to get going on some antenna projects!

 The 1/4 GP Verts with 8 tuned radials more or less worked like a charm this past winter.   I am particualry happy with the 17m and 30m verts but bit not 100% with the 40m and 20m ones.    I am going to try tweaking both in the spring and not do a darn thing with the other two.   The 5/8 Vert for 20m was a bomb do its coming down.  

 I am going to buys another 4:1 IFL switch and put it at the top of the hill at the end of my 500' run of heliax.   I am going to buy a ton more rope ,  a slingshot and a fishing real to get those wires  up there!!!!

 Now for the antenna wanna be....

1/4 Vert for 80m   .... one vert el of 20 meters  along with 8 radials.   For the elevation I have some very tall trees that should do the trick.   For the radial I am going to get some electric fence wire.   500' needed just for the radials!!!!    This should be a power house antenna for 80m DX.   I would love to put thsi one at the top of the hill but I am not sure how that would fit ... location TBD.

80m dipole .... top of hill for sure.   Get it up a minimum of 1/2 wave length or 120 ft is a bit of a challenge but this is where the top of the hill comes into play.  For a dipole to work as a decent DX antenna it needs to be up that high .  It should give around a 30 deg takeoff broadside with a 15 db null off the ends ... seems like allot.  Basically all the energy goes broadside.   Goo article here ...
http://www.qsl.net/aa3rl/ant2.html.

160m dipole ... top of hill.  OK there is no way to get this guy up 80 meters if I do do it probably will be a fan dipole off the 80 meter setup.  A more realistic setup would be the 160 vert.  

1/4 160m  vert ....ok I have the real-estate and I can almost achieve a 40 meter vertical element.   Radials ... no problem  8X40 = 360 meter or 1,200 feet ... once again fence wire!  

With the upcoming solar minimum theses would be some interesting antenna to play with.  

 What else ...

1/4 60m vert maybe in place of the 20m 5/8 that I am going to turf.  

1/4 30m vert at the top of the hill ,  I would really like to see if there is a "height advantage ".

6m vert dipole or 6m vert of 6m dipole at the top of the hill.... mainly to get away from vegetation that comes into play at these freqs.   This will be my first foray into the 6m world.  Ideally a high gain antenna with a rotor someday to play with Aurora or Tropo Scatter.  

Thursday, April 7, 2016

Juan da who or should I say why!!!!!

After not too great an effort to work VK0EK on 30m CW I decided to try for the other biggy Juan de Nova Island FT4JA .   Today I spent close to 3 hours calling these guys on 15m SSB.  They were calling on 21.300 and listening between 21.305 and 21.320.  You can fit a shit load of signals in the 15 Khz worth of spectrum.  Between 11am est and noon the signal was pretty weak fading out at times.   Between noon and 2pm est they were booming in and moving the S meter 2-3 units .... 100% loud copy.   Normally if I hear em I can work em on the 14avg with 100 watts.   That wasn't the case today ... just too too many folks calling and lots of big guns.   I sure wished they had have been CW...please , please please I am sure I would have worked them.

 As entertaining as it was I though to myself WHY ... WHY am I wasting my time.  Its not nearly as exotic a destination as Heard Island and it wasn't some  bazillion Ks away.   I am not chasing QSL cards couldn't give a rats ass about certificates or any kind of recognition.    I just get a kick out of making an antenna then using it to talk to folks around the globe ... thats all!