Another build....15/10/6/2 Fan Dipole / Vert

 Built this in my basement...

worked this guy from my basement ....

Folded it all up an lugged it up the hill for install.

Here it is mounted. 

2nd build this week ,  didn't like how the first fan turned so scrapped it and started again.   

The 15m element is attached to the rope.   The 10m and 6m segments hang below.  The 2m segment is a vertical dipole.  The antenna is completely built inside ready to go up the hill.  Installation time ... 10 min.   

I fussed over this thing with my NanoVNA and below is the results " In the Basement "  and then after it was installed "Up the Hill Outside".

15m in the basement

15m installed outside on top of the hill

10m in the basement 

10m installed outside on top of the hill

6m in the basement 

6m installed outside on top of the hill

2m in the basement 

2m installed outside on top of the hill  ,  see ***** below 

1-150MHz sweep inside

1-150 MHz sweep installed outside on top of the hill. 

******  the LDF4 run between the house and antenna is around 500' there is another 40ft of RG59 after that.   The IFL routes through a 4X1 switch that isn't spec above 6m so that is what I suspect is the problem with the 2m segment outside.   I have a direct IFL that I will switch to when the weather improves....probably May!  ******

  

Throw out the previous test ... 20m 1/4 Vert vs 20m Fan Dipole 24h WSPR

 The results of the previous test were inconsistent with what I was expecting.  Poking around I determined that the IFL was bad.    Its only a little over 100' but the RG214 has been buried for 20+ years and has been dug up and weed whacked a few times I am surprised it lasted that long.  

Replaced it with 40' of RG214 + 60' of smaller diameter hard line.   Probably less then a db loss across the HF spectrum ...more then acceptable. 

The results were more inline with what I was expecting.   The Vertical is just up behind the house with a tilted GP towards the W SW.  The Fan Dipole is at the top of the hill with  EU and AUS off the broad sides and nulls towards AS and somewhere mid S Atlantic.   The nulls off the end of the dipole are quite apparent and the low throw and tilted GP of the Vert stand out. 

The Fan is best towards EU and AU ,  the Vert is best towards AS.  The low throw of the Vert does give it a 360 degree DX advantage over the dipole.     Both antenna work very well and both have certain advantages  but overall we are talking a 3 db difference for the most part.  

Spots Map Green=both  Blue = Fan Dipole Red = Vertical 

Simultaneous Spots 

Top 10 DX Spots for each antenna ,  LDP Fan Dipole , IMI Vertical 

Added about a 1' chunk to the 80m segment of the 80/40/20 fan dipole.  Below is a comparison of the antenna before and after the addition.   Not allot of change ,  especially with the 80m band.  Next up adding a few feet to the 80m segment!          

    VSWR             VSWR After 1' added to        VSWR After 5' added to 80m  

  Original                     80m segment                     segment  2" removed 20m       

                                                

 80m 

Freq     

3.7             3:1                          3:1                                          3:1                                                            

3.75           1.5:1                       1.5:1                                       1.5:1

3.8             1:1                          1:1                                           1:1                     

3.85           1.5:1                       1.6:1                                        1.5:1

3.9             2.5:1                       2.3:1                                        2.2:1                       

40m

Freq         

7.0            1.2:1                    1.3:1                                            same

7.05          1.2:1                    1.3:1                 

7.1            1.5:1                    1.6:1 

7.15          1.6:1                    1.9:1

7.2            1.9:1                    2.2:1

20m

Freq     

14.0            2.2:1                3.1:1                                    >3 wont tune                        

14.05          1.7:1                2.3:1                                    3.2:1

14.1            1.2:1                1.6:1                                    2.1:1                         

14.15          1.2:1                1.6:1                                    1:1        

14.2            1.6:1                2.1:1                                    2.3:1 

Just had to sweep it with the Nano VNA

500 kHz to 60 mHz

80m

40m

20m

Sure looks like the 40m segment is a wee bit long.   80m is sure narrow band would really prefer it closer to 3.5 MHz  20m is anyones guess.   The IFL is 500' long and because of this I get allot of standing waves created on the IFL which makes it a little difficult to judge resonance.   One way of "tuning " the antenna is to add or remove IFL....doesn't make it resonant just makes it load better.

Ultimate goal is to get the desired freq under 2:1 VSWR keeping in mind a 2:1  VSWR equates to a 1 db loss in TX Power.  

So the plans is ....#1 lengthen the 80 segment then test again #2 depending on the results after lengthening the 80m segment I may want to shorten the 40m a bit.   #3 look at 20m after wrapping up the first two steps.  

20m Fan Dipole vs 1/4 Vert

 Comparing  these two antennas it was alot closer results each having its own advantage.  

The 20m Fan Dipole is at the top of the hill runs from about 260 deg to 130 deg favouring EU and AUS,  40 and 220 deg broadside.   The 1/4 Vert with 8  radials is just behind the house on the side of the hill with a GP tilted towards 200 deg.  

The fan Dipole is LDP ,  the Vert is IMI.  The fan favours EU and the Vert favors in the direction of AUS.  

The reason being is that the vert is shadowed by a big hill looking toward EU and the ground plane is tilted towards AUS.   The fan Dipole has clear LOS both directions.    

Looking out greater then 3800 km ...simultaneous spots 

and less then 3800 km...simultaneous spots 

20m Fan Dipole vs 160m Inv L

 The 20m part of the fan was tangled up with another antenna when I did the initial testing.   Corrected the problem and did another test today.  Way back when I discovered that the 160m Inv L loaded on just about all bands with the exception of 80m.   The 160m antenna acts like a long wire at the higher frequencies.  The antennas are collocated at the top of the hill being fed with 500' of LDF4.   

VE3LDP is the Fan Dipole,  VA3IMI is the 160m inv L.  

No great surprise here!   The fan blows away the 160m Inv L by about 5 db.  

In the past I compared the 160m inv l to the 1/4 Vert just behind the house and the Inv L won.   Up next comparing my 1/4 vert to the Fan.   

20m Vertical vs 20m Fan Dipole - Simultaneous WSPRs

 When I tested the 40m Fan vs 1/4 Vert  the Fan came out nearly 5 db better.  I was expecting the dipole to be 3 db better broad side with a deep null off the ends but it really wasn't all that dynamic. 

 Overall the 20m 1/4 Vert with 8 radials did better then the 20m Fan Dipole by about 3 db. 

The graph below is simultaneous spots ,  LDP the Fan  subtract IMI the Vert

Spots Map both are Green Dots,  LDP the Fan is Blue and IMI the Vert is Red 

Its really interesting when you look at simultaneous spots more the 4,000 km away.

The KH6 is more or less off the end and the EU stations are broadside.  

40m Vertical VS 40m Fan Dipole - Simultaneous WSPRs

 Both antennas are at the top of the hill.  

The 40m vertical is 3-4 years old and has 8 radials.  The Fan Dipole is new 80 / 40 /20 meters.   

The vertical is ground mounted and the Fan Dipole is up about 35' in the middle.  Most importantly dipole faces Europe broadside 50 degrees and the South Pacific broadside 230 degrees,  ends face 140 deg and 310 deg.   

 The performance of the new Fan Dipole was so much better then the Vertical I have a suspicion that I may have some losses in the IFL.     

Used 2 WSPRlites running 100 mw.  LDP is the Fan and spots are Blue Dots, IMI is the Vertical and those spots are Red but I don't see any!   The Green dots are where both IMI and LDP receives reports from.

Simultaneous Spots 

The Fan Dipole overwhelmingly comes out as the better antenna by 4.5 db ....HUGE!   

Here are the top 10 DX spots for each antenna....

Fall Antenna Work

 Did a few Antenna projects spring and summer.  

 First was the 6m vertical with 8 radial placed at the top of the hill on the ground.    It really didn't work all that well compared to the 160m inverted L which loads perfectly on the low end of 6.  Next up was a 6m dipole at the top of the hill.  It loaded right up ,  1:1 VSWR and worked well sometimes better then the  160m inverted L.    Next up was a 6 wavelength end fed 6m long wire pointed more or less south.   It worked sort of but as it turned out I had a bad chuck of IFL.  Found that out when suddenly the perfect dipole no longer loaded!     

Ripped down the 6m long wire a few weeks after putting it up its not all that practical! 

Tore down my 15/10/6 m fan dipole next to the house.   The antenna was fed with around 200' of RG6 and worked fairly well.   It was only up for a couple of years and seemed to not be as good as install.  When I took it down I found that a critter chewed through the Coax ... was surprised it worked at all!  

  Decommissioned the faulty chunk of IFL and revamped another chunk,  the original direct cable that went the 500' to the top.   About 150' from the top the original  IFL is joined.  It was well taped but somehow when I took it apart there was water in the female N-N barrel.  Blew it out ,  sprayed with contact cleaner the add two new chunks of LDF4 once again taking me to the tp of the will.     Luckly it worked and this direct run is feeding my new Fan dipole.  

Built an 80/40/20 Fan Dipole ,  its at the top of the hill it runs N NW to S SE roughly broadside to the EU and Calif and the South Pacific.  The dimensions and design were in the previous blog post.   Put it up and I really don't need to do any tuning...

80m 

Freq      VSWR 

3.7         3:1

3.75       1.5:1

3.8         1:1

3.85       1.5:1

3.9         2.5:1     

40m

Freq     VSWR

7.0        1.2:1

7.05      1.2:1

7.1        1.5:1

7.15      1.6:1

7.2        1.9:1

20m

Freq      VSWR

14.0        2.2:1

14.05      1.7:1

14.1        1.2:1

14.15      1.2:1

14.2        1.6:1

Did a bunch of cable sweeping with the Nano VNA learned a ton but thats the next blog post.   Have started to think in terms of return loss vs VSWR.  It paints a much better picture of how things are performing.   

Fan Dipole

 Planning on a fan dipole on the hill....

From this page http://www.hamuniverse.com/multidipole.html 

BUILD THIS MULTIBAND FAN DIPOLE
 FOR ALL BAND HF ANTENNA EXCITEMENT

(NEW UPDATED CONSTRUCTION TIPS FOR FASTER TUNING---SEE BELOW)

CONSTRUCTION UPDATES FOR EASIER TUNING WITH ADDITIONAL BUILDER FEEDBACK

Based on research done by the Stanford Research Institute (SRI) to construct a three-frequency multi-band dipole that would work without any need for cut and try techniques, we pass on this information in the hope that it will help you more easily get this type of antenna on the air quicker.

What they came up with was much improved method over the old cut and prune technique seen at the bottom of this page.

They found that the wires at the center feed point had to be separated by at least 5 1/2 inches vertically and the ends separated by 38 inches in the 2 to 18 MHz range. As in any fan dipole construction, all of the dipoles are connected in parallel but in the SRI method, the separation between them at the feed point must be maintained.
 
By this simple change they found that you could accurately cut the antenna element lengths for given frequencies and eliminate the need for pruning.

In the drawing above, the lowest frequency antenna is on top and is cut 4% short of the standard 1/2 wave length. (Length in feet= 0.96 times 468 divided by the operating frequency in MHz).
 
The middle frequency antenna (lower in frequency), is cut for an exact 1/2 wave length. (length in feet= 468 divided by the frequency in MHz)
 
The highest frequency antenna is at the bottom and cut for 1% longer than the 1/2 wavelength (length in feet= 1.01 times 468 divided by the frequency in MHz)

Compared to the construction effort of a standard multi-band dipole the only difference is the fabrication of a feed block or center insulator that is about 12 inches vertically by 3 inches wide, so make sure this is made of a good insulating material such as Lucite, Bakelite, fiberglass, or PVC.

The end 38 inches of separation can be maintained by separate halyards on each element or a spreader bar with a common halyard.
The bandwidth will be at least plus or minus 2% for a 1.5 to 1 SWR according to Stanford Research Institute.

Antenna in the Night

6m Dipole vs 160m Inv L RX

OK ,  here it is on RX .  RIP's first 3 CQs were RXing the 160m inv v the second 3 was RXing on the 6m dipole.

160m Inv L RX was 2 db better then the 6m Dipole from RIP

It was polarization

Tested the new 6m Vertical compared to the 160m Inv L that I have been using on 6m and found that the TX to RIP was way lower on the new 1/4 vert then the 160m Inv L.

Conclusion was RIP is Horizontal Polarization and my TX being a 1/4 Vertical was Vertical.  I always thought that the 160m Inv L was Vertically  polarized ....apparently its more horizontal!

So I through up a quick dipole beside the 160m Inv L .   Did 3 transmissions on the Inv L then 3 on the Dipole ,  results below.

First 3 is RIP RX on the 160m inv L,   9
Second 3 RIP is RX on the  new Dipole, 11

So it looks like the dipole is 2 db better then the inv V on TX to RIP

6m antenna test to VE3RIP

Did some FT8 to VE3RIP ( 26 km bearing 308 deg ) ...it LOS to his QTH

3 CQ's and he reported the following levels on each antenna ...

160m Inv L        1/4 Vert          Fan Dipole
  14                        11                    4
  15                        11                    4
  14                        11                    4

160ml and 1/4 Vert are Co Located ,  Fan Dipole is next to the house about 80' lower in elevation then the other two antennas.

RIP was using his Yagi,  horizontally polarized.   Modeling the 160m Inv L it calls it a horizontally polarized antenna and I am beginning to believe it!

So this is somewhat inconclusive,  it could just be the polarization or there could be attenuation  in the IFL  or it could be the fact that the GP is over 180 deg not 360.

One thing for sure ,  more work is to be done!

160m Inv L vs the 6m 1/4

Looks like the 6m 1/4 Vertical may be working well after all.    Initial testing had RX down 6-10 db from the new 1/4 Vert as compared to the 160m Inv V.   Today I had QSOs with VA3TX in Creemore.

VA3TX QTH is Creemore , bearing 70 deg and 58 km from my QTH.

First QSO was with the 160m Inverted L.  I received him at +12 and he reported receiving me at -7. 

Second QSO was with the new 1/4 Vertical.   I received him at +2 and he reported receiving me at -3.


So its a 10 db drop in RX for a 4 db gain in TX.   Need to repeat the test ,  need some other hams nearby to repeat the test to see if the data is repeatable. 

2nd QSO...1/4 Vert

NVIS vs Vertical Round 2

Round 2 of testing ,  9am to 10am thsi morning. 

DID NOT CHANGE anything ,  same amtenna ,  same height and same TX setup.

BLACK DOT -   My QTH
RED DOTS -  The 80m Vertical
BLUE DOT -  The 80m NVIS
GREEN DOTS - Both WSPRs received.

Only the dipole is heard < 200 km

Only the vertical is heard > 350 km with one exception.

Looking at simultaneous transmission reports under 


UNDER 300 km 

284 km away an the dipole and vertical were about the same.

Between 300 and 400 km
'

Between 300 and 400 km the dipole performed on average performed 3db better the the vertical.

Greater then 400 km

Over 400 km the vertical performed 7 db better then the dipole. 

NVIS vs Vertical

Built an 80m Inv V (  apex 30', ends 10' )  aka Near Vertical Incident Skywave Antenna...NVIS.

I also have and love an 80m Vertical   aka inverted L ( 30' Vertical , 30 ' Horizontal ) I call this my Vertical antenna.

The idea behind the NVIS is to have better signals in close for " local " use ...say under 500 km. 

I have compared both antennas doing simultaneous WSPRs ,  both  day and night.   The easiest way at a glance to see the results is the map below...


DAY TEST

 Noon to 1pm local -  Both stations were transmitting 200 mw or if you prefer +23 dbw  +/- 2 db.

BLACK DOT -   My QTH
RED DOTS -  The 80m Vertical
BLUE DOT -  The 80m NVIS
GREEN DOTS - Both WSPRs received.

There are a few variables but its obviously clear that the NVIS is doing what its suppose to do and teh vertical is also performing as expected.   Now keep in mind this was done between Noon and 1 pm so the D Layer is full tilt! 

Here is the data from stations receiving both the NVIS and Vertical transmissions at the same time.

Click on the image to make it large

NOTE VE3LDP is the NVIS
            VA3IMI is the Vertical

DIF is NVIS - Vertical

There is not much difference when you get under 300 km but going out 375 km the signals from the Vertical are 3 to 7 db better ... thats huge! 

The closets reception reports was the one and only blue dot 116 km from me and this station only heard the NVIS antenna. 

In conclusion the signals in close really were not all that much different then on either antenna.  There was a clear advantage for the vertical  beyond 300 km. 



NIGHT TEST 

I was surprised  a little but the test was not totally conclusive but close enough.   

BLACK DOT -   My QTH
RED DOTS -  The 80m Vertical
BLUE DOT -  The 80m NVIS
GREEN DOTS - Both WSPRs received.

The blue dots through the Midwest are QTHs more or less broadside to the 80 Dipole... makes since as its a 3 db gain in that direction as compared to the vertical. 

Here are the simultaneous spots ...

Dipole performed better  but make note all the simultaneous spots were from 3 resporters in the US West.   The vertical was heard in close < 500 km  and then far off > 3000 km.  The dipole was more broadside but once you got +/- 45 degrees from SW the vertical was the antenna. 

No doubt a little more testing is to be down.    There was still pretty good performance off the dipole in spite of it being 30' up at the apex. 


NEXT up..lower the APEX and test again. 

6m Vert vs 160m Inv L

  My 160m inverted L works very good on 6m .   Built a 1/4 Very with 8 radials,  just like the inverted L and placed it next to the big antenna. 

Here is my first FT8 contact ...

Initially I was receiving WXK off the new 1/4 Vert ,  3 consecutive transmissions @ -8 db.   When he wasn't hearing me I switched to the 160m inv L ,  he came up 10 db and heard me reporting a -10.   His transmissions received on the 160m inv L were  2, 4, 2.

Wow ,  10 db difference ...HUGE.  The 160m inv L acts more like a long wire  on 6m.  When its modeled there is a distinct lobe in line with the long horizontal element.   The 160m inv L aims S  SE ....WXK was 169 deg in AZ.   The 160m inv L runs 135 deg ish. 

 I was expecting better 6m receive on the 160m inv  but better transmit.   There is one thing that I am slightly suspicious of and thats cable loss.   Its 500' to the top of the hill ,  mostly LDF4 with the last 100' being another chunks of smaller diameter hard line.  Swept the cable run a few days ago and the loss was less then 3 db!

 Further testing is required before writing this one off.   There is a 6m net on Tuesday eve that may provide some answers.

6m 1/4 Vert with 8 radials...constructed.

Working mids from home ,   its a NOC job so I am not always super busy.  Made a 6m 1/4 Vert with 8 radials while I was monitoring things overnight.   Used the dimensions in the previous post.


Here is the antenna before I sealed it all up with silicon.

I have made 160m through 17m antennas just like this and they all have been extremely successful and very inexpensive to make.   Being that they are all in a forest having the horizontal elements laying on the ground is a very good thing ...for obvious reasons!    I have never had a vertical element taken out by a tree!

With time on my hands I modeled the antenna using MMANA

Here is the antenna with the radials spread evenly...a true isotropic radiator with no gain! 

Cut it a little short ...depending on how it tests I may add a bit to the vertical element.


So I played around with the 8 radials moving them all +/- 90 degrees from the X Axis...

Well now ,  quite the surprise suddenly its a directional antenna with 1.5 db gain over the isotropic as well as a front to back of 2.4 db.   Where I live there is very little to the N NE ,  not going for Europe on 6m.  My target is NA so I figured I would aim the antenna S SW it should put a wee bit more signal in the direction of 95% of my 6m activity.  Looking at the Smith Chart in the direction of E SE and N NW its about the same as having the radials spread evenly.

On another note if interest.....

This antenna is going at the top of the hill,  500ft of LDF4 figure somewhere around 3 db or a little less attenuation.  Also at the top of the hill my 160m inverted L.  I have been using this antenna on 6m because it works very well and it even loads without an antenna tuner and around 50.260 its an even match.   Its great for sporadic E,  LOS up to 350 km regularly and I have even logged a few MSK144 meteor scatter contacts.    It will be super interesting to compare the new antenna to the 160m inverted L. 

And here is the antenna installed at the top of the hill...I am pleased now to see how it works!