160 meters - or Bust!

NOTE: I am pleased to offer a download of the slide deck I use for my talk on this project, which I've given to a couple of local ham clubs.  If you are interested in booking me to speak and you are not in New England we could set up a Skype.  Email me here to arrange...

Living on a classic suburban lot (100' x 70') I'm faced with the typical shortage of room to build antennas for the lower bands. While I was able to tune the 100-foot dipole on 80 meters well enough for 80 meter WAS, performance on 160 meters was sub-par. It's easy to see why since I was operating with a dipole only 25 feet above the ground - a fraction of a wavelength on 160 - which meant that most of my signal was going up, not out.

After exploring my options (including a sloper, inverted "U," several variations of an "L," some home-brew verticals with capacitive "top hats," as well as verticals sold by DxEngineering and MFJ) I decided to try an experiment suggested by Woody, WW1WW, to convert my 100-foot dipole, which was fed by twin-lead, and turn it into a vertical by twisting the leads together and feeding them into one side of a balun. The real work would then involve laying out radials, needed to act as a counterpoise. The small footprint of my property required a creative layout of the radials:
 

 


Aerial view of the QTH showing the four radials (white, orange, yellow, and green lines) and the location of the former dipole (dotted red line) now acting as capacitive "top hat"
 


View of the former dipole, now a vertical, with lines drawn showing the four original ground-based radials placed along the fence
 
 


The MFJ Balun secured - and grounded - to a ground rod.  RG-8x coax feeds into the shack and the MFJ tuner.



  So how did it work?
  An SWR under 1.5:1 on all 8 bands between 80 and 10 meters was possible with an MFJ-941E tuner. But even with the tuner getting a decent on most of 160 meters was impossible, as evidenced by this plot of SWR vs. f:

Plot of 160 meters adjusting the MFJ tuner for best SWR every 25 kHz (frequencies above band limit of 2 MHz displayed to show the dip.)


 Getting a 25' vertical to tune up on the lower end of 160 was going to require a loading coil.  Using EZNEC Woody modeled the antenna and calculated parameters for a base-loaded coil that would not only electrically extend the antenna but also eliminate the need for the balun.
 

38 special

I got a short piece of PVC, and cut two holes, one for a binding post with banana jack (to which I could attach radials) and another hole for an SO-239.
 
 

The coil is connected to the center of the SO-239 on the inside of the tube and the wire threads to the outside where it is wrapped 38 times around a 2" piece of PVC, then threaded back inside...
 

...so it could exit from the top of the pipe through a plastic cap.  The cap and all holes were originally sealed using my wife's hot glue gun (a QST "Hints and Kinks") but, frankly, the glue did not provide a waterproof or lasting seal, so had to redo with caulk.
 

The new coil, installed, with black tape wrapped around the 10ag wire.
 

Here is my first reading at the base of the antenna with an MFJ-259B - thanks to Erik (KE1V) for the loan




So let's look at the plots of SWR, Resistance (R), and Reactance (X).
 




Even though R was above 50 ohms across the band, I could still operate in the lower end of 160 without the use of the tuner (look at that SWR!) and through the spring static got some good reports on 160 (thank you 1900 Net.) Operation on 80, 40, and other HF bands was also possible with the MFJ-941E tuner.
 

Nurse... elevate me

Now it was time to tackle R, with its unacceptably high readings.  More radials were clearly going to be needed, but you've seen the size of my property.  Where could I lay them?  The answer was in N6LF Rudy's QEX articles on verticals and radials which detail how elevated radials can be as effective - and sometime more effective, than ground-based radials.  I ran a pair of radials approximately 3 1/2" off the ground, along the upper support of the fence, as seen below....  


The red lines show where the first two elevated radials being tested are attached to the fence

This annotated aerial shows the path of the elevated radials around the property:


The length of the longer radial is a bit less than 130 feet, or 1/4 wavelength at 160 meters.



Here are the plots of SWR, R, and X with the original 4 radials (shown in red) and after the addition of the 2 elevated radials (shown in blue).  Note the rise in SWR, but the improvement in Reactance and major improvement in Resistance:

Some other interesting things happen with the addition of the 2 elevated radials, like a steeper bend in the plot of X, which indicates an increase in Q.  But most important to our goal of improving system output is the lowering of R across the entire band, with as much as a 20+ ohm difference from the 4-radial configuration. Outstanding.  But can we do better?
 

8 is Enough?

Over the next month I experimented with several layouts of radials, including two on the top of the fence and another test with a "spider" of eight 16' radials (testing the theory that more radials, even short ones, will improve antenna performance.)  None improved (lowered) R, in fact both tests actually raised R across the entire band.)  In late August, 2011 I decided to try a couple of longer, ground-level radials:
 
 


Location of the additional 2 radials to the 160 meter ground system



The results, plotted in green below, show that SWR rose and X did not change appreciably from the levels measured with 4 (red) or 6 (blue) radials.  The plot for R shows that the extra 2 radials (8 radials) reduce R across the entire 160 meter band by about 5 ohms and into the 30 ohm range near the lower part of the band, which is precisely in the targeted area of the band.
 
 


 


 



By the fall of 2011 I felt like I got to the point of diminishing returns with the radials and decided to operate that winter with the system as is, and see how I did.  Which wasn't bad - in fact, it was pretty damn good, with 41 states and 9 countries contacted, a HUGE improvement over the dipole.




May 2012 Update

Really enjoyed the 160 vertical, but missed my 80/40/30 dipole, so I took Woody's suggestion and added a relay so I can switch the antenna back and forth between a dipole and a vertical, remotely from the shack.



Ciruit diagram
A circuit diagram of the remote antenna switch



Switch cover off
An annotated photo of the relay box showing how the twin lead on top of the box can now either act as the 160 vertical or as more feed line to the horizontal wires above, to then act as a dipole.  (The relay was one of several Potter & Brumfeild R808-E1-W2 latching 12v relays I purchased at the Deerfield Nearfest in May 2012.)



Relay box
              closed
The base of the antenna just after closing up the relay box, showing more of the  twin lead above the relay box, which will act either as the vertical on 160 or a feed for the dipole on 80.



shack control
In the shack, this MO-DPDT switch is wired to send 12v to the relay at the base of the antenna with opposite polarities, depending on the selection of 80 or 160. The polarity for 80 selects the twin lead (turning the vertical into an 80 meter dipole) while the polarity for 160 selects the base coil (so, with the two leads shorted turns the antenna into a vertical.)



June 2012 Update

Okay, so the switch worked and I went off to the higher bands to do some DXing.  Then, in mid-June, I decided, just for grins, to get on 160 and 80 to see how the relay is holding up.  Good thing I did, because something was clearly wrong - the SWR at 1820 was 2:1 (it had been 1.2:1) and only by running QRP could I prevent the SWR from spiking over 3:1.  My first thought was that the heat wave and high humidity was causing arcing between the switch's contacts.  Fellow hams at work all immediately suggested the same thing, but not until I opened up the box it did I see it was far worse than anyone could have imagined - except Woody, who said he thought all along this might happen with a relay enclosed in plastic. (Always glad to be Woody's guinea pig...)

Bad Relay
The relay, showing the effects of water (humidity?) inside its plastic case.


Just like Roy Scheider in Jaws, I was gonna need a bigger boat.  Or, in this case, a bigger relay, one with contacts wider apart (to prevent arcing even in humid weather) as well as a box that would protect it better from the elements. (When I opened the first box up, there was a small pool of rusty water at the bottom - not sure if that was all humidity or some leakage from rain)



New Relay
New relay

The new relay is an OMRON MGN2C-DC12 non-latching relay which, like the old relay, sits directly on top of the loading coil.  The larger box, with liberal application of caulk seems, as of January 2013, to be providing more reliable waterproofing.  (I also drilled a few small holes at the bottom of the box to provide an exit for moisture that builds up inside.) One change in the shack was required, as well - the MO-DPDT switch had to be replaced by a standard DPDT switch that provides 12v to the relay when operating as a dipole.


Case Closed
Annotated look at the feeds to the new relay. I eliminated the banana jacks, instead threading both the 80 meter feed and 12v supply directly, through holes in the box that were heavily caulked.

There was an issue, in January 2013, of the contacts on the 80 meter side of the switch requiring some sanding, to remove a coating (dirt from evaporated moisture? ice?) that prevented operation on 80. Hmmmm... was the box not waterproofed well enough? Read on...


January 2016 Update

The result of three years of operation of the 160 Vertical/Multi-band Dipole went beyond my expectations, with the dipole helping me add a couple of dozen new DXCC entities in the log, and logging 48 states and 38 countries - some as far as 4500 miles - on 160 meters (see below for a log excerpt and map.)

Now, I don't get on the air much in warm weather, and 2015 was a pretty harsh winter, with something like 110 inches of snow in just a few weeks, so when the nice weather arrived I wasn't going to spend much time in the basement.  Now it was November of 2015 - and getting cold (shivers of dread) - so I thought it would be a good idea, before the snows arrived, to sweep up each band to ensure I could get on all the HF bands.

Yikes!  Immediately I saw serious problems on just about every band, save 10 meters; inability to tune-up, can tune up (using the IC-718 ultra-low power feature) but full power saw the SWR spike above 5:1 and, on 12 and 15 meters, having the tuner's indicator lamp glow like a supernova when I keyed up.  Hoping it was something simple I started the troubleshooting by disconnecting and reconnecting all the coax and twin-lead.  Nope, that didn't do it.  I opened up the case in which the switch is located, and gently sanded the relay connectors.  No dice.


Relay degrades
The result of three and a half years of New England weather on the relay

Opened up the IC-718 and cleaned the connections for the tuning section plate (which had been the cause of a similar problem on the upper HF bands.)  Drat, that didn't help, either.  Could the built-in balun in the MFJ-941 be bad?  I bypassed it with a spare stand-alone balun.  Shoot, that didn't make a difference.  One theory among my friends was that one leg of the dipole was loose up at the center connector, so I lowered the antenna and re-soldered both sides.  Negative.  My buddy Bob then suggested a Hail Mary - bypass the relay entirely to eliminate that as a suspect.  He suggested there might be cold solder joints.  I scoffed at that because I KNEW those connections were solid.  But... that WAS three years ago.  So I went back outside (I should point out all of the above had taken about six weeks,) opened up the box again.  This time, probing the soldered connection to the twin leads' jacks, I was horrified when the wire practically came off.  Flakes of metal floated to the bottom of the box.

Close-up of relay
Close-up of just a few of the connections that were redone after the discovery of serious oxidation.  Those two solder joints to the jack up top were so loose it is amazing that the antenna worked at all in either 160 Vertical or dipole configuration.


I regret not taking pictures of the connections BEFORE I made repairs.  Because there was a lot to repair.  Okay, those solder joints that WERE solid three years ago were total crap, now.  Re-did those solder connections at top, to the jacks.  Every place where a wire met a screw had oxidized, so I cut away the oxidized parts and then tinned the new ends.  I also cleaned each screw with Vinegar and steel wool (a great suggestion from Bob) before re-screwing the wires back into place.  Then I added a smear of Vaseline to each point of contact, to inhibit moisture build-up and a decay in conductivity.  Long story short is that in February 2017 when the SWR problem re-occurred it was because a wire had disconnected from one of the post leads at the top of the box.  Simple repair and in no time I was back on the air enjoying all bands on the antenna.  Life is good.  Too bad the bands aren't...



April 2016 Update

The fun never stops.  Just a few months after fixing the above, the problem returned but now it was on 160 meters, with the vertical.  This time, I discovered another weak link in the antenna system: the banana jack I had cleverly installed in the PVC to easily connect and disconnect
(for testing and maintenance) the 160 antenna's ground radials:

Broken Banana plug

The base of the banana jack simply rusted through and disconnected from the radials.  Which more than explained the 5:1 SWR.  All the radials are now (temporarily) connected directly to the SO-239 jack while I think up a way to waterproof the connection as best I can (given that it will be buried under snow for about three months every year.)

Also saw a return of SWR spikes (See above, the Janauary 2016 Update,) but only when using the dipole on 40 and 80 (no such problem on my 40 meter dipole, narrowing once again the problem to the antenna switch,) so I went back and re-soldered and re-screwed connections inside the box, eventually getting the problem to disappear.  The question, of course, is for how long...



September 2017 Update

Someone PLEASE make the fun stop ;(   As I explain on my QTH page, in 2017 I discovered that the tree in which I had hung one side of the 100' dipole had been girdled (that's when varmints nibble away the bark, preventing the tree from getting water and nutrients, effectively killing it) so I had to have the tree removed, and then installed this 40' aluminum mast from ChannelMaster, which holds up the north side of the dipole/top cap for the 160 vertical.


ChannelMaster




January 2018

After two snowstorms and a deep-freeze (temps below zero for a few days) we caught a break mid-January with a few glorious days in the 60s!  I used one of those days to go back out to the base of the antenna and pretty much do what I did in January of 2016, which was to clean up all the connections (inside: sand the relay contacts and screws for the twin-lead, outside: sand the exposed twin lead that connects to the top of the box because they, too, had developed a coating that was preventing a good connection to the relay.)  All is well, once again.  This fall I will make it a point to get ahead of this.




March 2018

The weather people are saying "March is the new February," and I can attest to the fury of the March 8th storm.  Because it started as rain and THEN turned to snow, it weighted down everything outside, including the 40' ChannelMaster mast which, when I woke up the next morning was bent beyond help.  ***sign*** guess I'm restricted to 20 meters and above until I can decide on a replacement, likely a 50' Rohn which, because I can have the tube sections intersected with each other (especially up top) could be strong enough to withstand another onslaught.  (Notice I said "could" and not "should")




April 2018

My new, very kind neighbors next door gave me permission to hang one side of my dipole/vertical from their tree which is just over the fence on their property. After a few flings of a one ounce fishing weight with my sling shot (purchased a ham flew market) I was quickly back in business. Here's an annotated aerial of the property with the new alignment of the dipole/top cap (blue is a 20 meter dipole and green is my ten meter dipole):


WB2HTO antennas


As luck with have it, the center of the dipole ended up directly over the outdoor switch box, which elimiated the need for me to move it and all the support cabling and power line. Back on the air with both long dipole and 160 vertical, and picked up a few more long-distance countries (Iceland and the Slovak Republic) on 160...




January 2019

Took advantage of what for passes in a New England winter for a pleasant day and took out my sling shot, a 5oz weight and some fishing line and pulled.  Hard.  Got the antenna raised 16' higher.  As you can see below, the vertical AND higher dipole are performing beyond my wildest hopes...


Lengthened Vertical
Antenna
Two views of the antenna (l: back of the house, r: from the front) now 16' higher...


Extending the height of the antenna meant making an adjustment to the base coil.  22' more vertical meant fewer turns of the coil, which I accomplished by shorting out the top 11 turns, leaving 21 turns. This allows me to run the vertical direct (rather than using the Versa-Tuner) and I get a 1:1 SWR.
 




Countries Contacted on 160
Holy crap! New Zealand and Antarctica on 160! 


ZL1AS
(This exchange almost doubled my previous distance record on 160)

RN1ANL

I also have all the Lower 48 states and over 65 countries.  Yes, I count the Orkney Islands separately from Scotland (go to www.joeandnemo.com to learn why).  Countries marked in red were collected after the extending of the vertical in January 2019.


Country Callsign Grid Mode Miles
New Zealand
ZL4AS RE43vt FT8 9488
Antarctica RN1ANL JB59 FT8 8792
European Russia
RT6T LN05xb FT8 5125
Crete SV9CVY KM25ka FT8 4915
Ukraine UX1UA KO50em FT8 4470
Serbia YU1EL KN03ev FT8 4353
Belarus EU1WW KO34 FT8 4187
Bosnia-Herzegovina E77DX JN84ix CW 4182
Hungary HA7TM JN97 FT8 4171
Slovenia S51V JN86cm CW 4105
Croatia 9A1A JN75vn CW 4101
Lithuania LY7Z KO15we CW 4086
Slovak Republic OM2XW JN88ss CW 4079
Austria OE8SKQ JN76jn CW 4045
Czech Republic OL7M JO80cf CW 3977
Poland SP3DOI JO81vp FT8 3972
Finland OH1XX KP10ok CW 3886
Aaland Island OH0Z JP90we CW 3773
Italy IK4ADE JN54oe FT8 3758
Sweden SM3NRY JO99ah CW 3758
Switzerland HB3YAT JN46bt JT65 3758
Denmark OZ3AEV JO65gq JT65 3672
Spain EA3NE JN11an JT65 3652
Germany DL8GP JN39lh JT65 3634
Peru OA4AZP FI20ge JT65 3630
France F6ECI JN05sa JT65 3524
Morocco CN2CO IM64 FT8 3512
Belgium ON4GPE JO21nb FT8 3511
France F6GCP JN16gq FT8 3497
Belgium ON8DM JO01 FT8 3422
Norway LA7QIA JO29ta FT8 3335
Portugal CT7ANG IM67 FT8 3334
Canary Islands EA8AT IL38 FT8 3289
England G3BJ IO82om CW 3157
Scotland MM0SJH IO89jb SSB 3042
Scotland (Orkney Is)
MM0EAX IO89ka FT8 3031
Northern Ireland MI/3Z0X IO64pp FT8 2951
Ireland EI4KF IO54ue CW 2908
Iceland TF3DT IP04rr FT8 2547
Venezuela YV1KK FJ66wp CW 2512
Mexico XE1GRR DL80ho JT65 2418
Costa Rica
TI7W EK80aa CW 2379
Trinidad & Tobago 9Y4/VE3EY FK90ik CW 2308
Azores CU2CE HM58xl SSB 2270
Madeira Is. CT3MD HM58qm FT8 2239
Nicaragua H7/RM0F EK72is CW 2237
Colombia HK1T FK20ox SSB 2203
Grenada J38XX FK92aa CW 2190
Barbados 8P9AE GK03fe CW 2154
Saint Vincent J88HL FK93jg CW 2119
Curacao Is. PJ2T FK52kg CW 2105
Bonaire Island
PJ4A FK52me CW 2103
Honduras
HR1LW EK84JB FT8 2090
Aruba P49X FK52al FT8 2076
Saint Lucia J68GU FK94mb FT8 2070
Martinique FM5CD FK94kq CW 2025
Belize V31YN EK58 FT8 1965
Montserrat VP2MSN FK86vq CW 1872
St. Kitts & Nevis Island
V47KA FK87pg FT8 1816
US Virgin Is. NP2J FK77ps CW 1762
Puerto Rico KP4KE FK68kl CW 1687
Cayman Islands
ZF2CW EK99 LSB 1680
Dominican Rep. HI3K FK49ps SSB 1581
Turks & Caicos Is. VP5CW FL41aa CW 1495
Bahamas C6ANA FL24aa SSB 1315
Cuba CO8LY FK29bx JT65 920
Bermuda VP9/WW3S FM72ph CW 792
Jamaica 6Y5WJ EN82jl CW 619
Canada VA3WU FN03jc FT8 414
USA K1DG FN42ht CW 38