All posts by Ed Deichler

I recently moved to FL after 30 years in NH and a member of NARC during the whole time. To all the newbees in the club, I say welcome to a renaissance in ham radio as the "old stuff" adapts to the 21st century's "connected" world. I was proud to be involved in the club in many capacities over the years, especially Field Day. Everyone will be hearing from me from time to time as the Tiny Elephant lumbers on!

Antennas: Where There is a Will…

The 2017-2018 contest season featuring the “big four” events (CQ WW SSB, CQ WW CW, ARRL DX CW and ARRL DX SSB) recently came to a close with a resounding thud. The Solar Flux Index seems to have flat-lined below 70 as we bottom out in the current sunspot cycle. This translates to little DX above 20 meters. For 40 meters and down to Top Band, however, no sunspots are good. I remember the fun I had during the last cycle bottom when I roamed Top Band as an avid bottom-feeder pulling in choice DX from the Pacific and Asiatic Russia. I had a pair of K9AY loops oriented in a cross configuration to enable me to select the four cardinal directions. The loops worked wonders at reducing the high noise levels on 160 meters. They also worked well on 80 meters during noisy conditions.

Alas, being in the land of CC&R and clandestine antennas (read: low, short wires and verticals), Top Band operation is non-existent. Yes, there are some diehards here who have a convoluted run of wire that is heavily loaded and fed with a tuner struggling to make a match. Working FL, GA, AL, Cuba and the Bahamas becomes the high point in a Top Band contest. If 160 meters is not practical, perhaps there is something to be done for 80 meters.

I think I may have found a way. About a month ago while the family and I were on a cruise, I noticed a three-masted sailing vessel at one of our ports of call. I was intrigued by the mess of ropes and sails on the ship and wondered how the sails were hoisted. Each sail is attached to a series of collars that ring the mast. As a sail is hoisted, the collars ride up the mast, much like a shower curtain that is pulled close. As my few brain cells coalesced on the concept, it occurred to me that I could do something similar with my PVC flagpole. In lieu of a sail, I thought of an extendable fiberglass mast like those usually found at hamfests. The base for the mast would be two or three feet away from the flagpole to hide it from direct view of the street. My thought is to erect a 40-foot mast using the sailing vessel approach to guy the mast against my flagpole. This approach would provide a support near the 22-foot top of my flagpole with a couple of guy ropes off the top of the mast. The mast to flagpole connection would be fixed at the 22-foot point with the mast.

So what kind of antenna will go on the mast? I did some modeling with EZNEC to see what an inverted V for 80 meters would look like. Each leg would be about 56 feet long if the anchor points are out 40 feet from the mast. First look at the antenna should reasonable performance – above 3900 kHz; not an area of the band I care to operate in. I added some inductive loading at the feedpoint to electrically lengthen the antenna. I was able to get good SWR performance for the lower 100 kHz which encompasses the CW and digital parts of the band.

(Note: The casual observer may notice that a 40-foot structure in a CC&R territory is begging for a visit from the local vigilantes. This problem is adequately mitigated by the fact that 80-meter propagation favors darkness so I would not raise the antenna until after sundown. I would have it down before most folks get through their first cup of coffee.)

Now that I have a sporting chance with something other than the fat coil plus 3-foot wire that I currently have with my 6BTV vertical for 80 meters, I needed to come up with a better receive antenna. While power-washing the moss and mildew off the side of my house I experienced another epiphany as well as a tired back. My house has vinyl siding, good for growing moss and mildew but it also non-conductive. I had been thinking of a K9AY loop but the loop needs a vertical support and has to be away from large objects such as a house. I looked at other receiving antennas such as the flag and pennant antennas, so called because of their physical resemblance to said shapes. These antennas have a length similar to the K9AY loop and function the same way, i.e. the intended receive direction is the feedpoint and the opposite leg is terminated in a non-inductive impedance. The antennas are mounted about 20 feet at the top point so that the lower leg allows clearance for people and critters.

While I am not able to raise a receiving antenna up 20 feet, why not slap in on the side of my house? I have an expanse of siding about 32 feet long by 8 feet high without windows where I could install a pennant antenna. The antenna vertical section would be about 8 feet at the top and about 0.5 feet above the ground at the bottom. The sloping parts of the pennant would run to the front corner of the house where the termination/junction point would be conveniently hidden by shrubs. The feedpoint, located halfway up the vertical section, would be hidden along the edge of one of my bedroom shutters. I can use yellow wire for the pennant to match my house color to add more stealth. If nothing else, I can always pass the pennant off as artwork on the side of my house. Many homes in The Villages has decorative metal artwork on the walls so I would fit right in.

So how would a “slap-on” pennant work? Back to EZNEC for some more modeling. I checked the antenna patterns for a frequency of 3.550 MHz and a termination resistance of 900 ohms. At an elevation angle of 35 degrees, I have a gain of -31.4 dB and a front-to-back (F/B) of 21.0 dB. I compared the performance of my pennant with a design by K6SE that has a 14-foot vertical section and is 6 to 20 feet above the ground. Total wire length is within a foot for both antennas. At 3.550 MHz, the K6SE pennant shows a gain of -26.6 dB and an F/B of 21.6 dB. Not bad.

To compare my pennant design to the K9AY loop, I ran patterns for 1.8 MHz since I had data for the K9AY loop for 160 meters. The K9AY loop sports a gain of -23 dB while my pennant manages a gain of -41.9 dB. It is likely that such a difference will also be the same for 80 meters. It is a good thing there are preamps available.

Now that I have the will, I just need to find the way to make it happen in time for the next contest season.

Ed, K2TE

FT8ful Encounter

Hamming with a multi-band vertical on a small lot means having to compromise on what to do when it comes to being heard. The current down-slide in the sunspot cycle doesn’t help either. The emergence of weak-signal digital modes such as JT65 and JT9 a few years ago from Joe Taylor, K1JT has been a welcome addition to my operating tools. If you are familiar with Joe’s work, JT65 and JT9 are Taylor-made (sorry Joe) for modest stations and simple antennas. The modes sport S/N levels of -20 dB or lower for Q5 copy, far better than an S1 CW signal. I have been happily working DX over the past several months using the WSJT-X program that integrates with its companion JTAlert logging application to link to DXLab Suites.

Anyone who has used these digital modes knows there is a downside to them. They are SLOOOW. A typical QSO takes 6 minutes to complete with nothing more than a report, acknowledgment, and goodbye. It is like watching paint chip and peel. To keep from falling asleep between exchanges, Steve Franke, K9AN has collaborated with Joe to rev up the process.

Say hello to the new FT8 mode which is the designation of the Franke-Taylor 8-FSK digital mode that Steve developed to integrate with the existing modes supported by WSJT-X. It is sort of like JT65 with a turbocharger. An FT8 receive and transmit cycle each takes 15 seconds to complete compared to 60 seconds for JT65. A transmit cycle switches to the receive mode after 13.5 seconds. When compared to JT65 that allows 12 seconds between cycles for the operator to select a station or a macro, 1.5 seconds doesn’t leave much time to do anything. Fortunately, the mode supports an auto-sequence QSO mode wherein the next macro is automatically selected during a QSO. The result: a QSO can be completed in 90 to 120 seconds.

I first started using FT8 in late July after seeing a number of spots for stations running the mode. I had to update my version of WSJT-X to the current release. Fortunately, JTAlert also has been updated to capture FT8 for logging. I jumped in to work stations on the new mode and promptly screwed up. I tried in vain to manually select a macro when working a station only to find the previous macro being repeated. After a few busted QSOs, I discovered the program automatically switched to the correct macro in the QSO sequence. This is definitely a cool feature to have.

It did not take me long to realize that I could call a DX station off-frequency to avoid competing with stronger stations calling. If he/she answered me, the program would automatically QSY me to the DX station’s frequency. Slick!

The mode is also tolerant of poor band conditions where signal strengths can change as much as 10 dB between transmit cycles. There have been a number of times where I have repeated a macro several times before getting a response and moving on to the next macro. Under such circumstances a QSO may take three minutes to complete, still better than JT65.

To date, I have worked some 200 stations on FT8, including 49 states, most of Europe and a handful of Far East DX stations. I run 40 watts to a 6BTV multi-band vertical and a 17-meter Moxon in the attic of my garage. QRP purists may be aghast as such a QRO level. However, remember that signal strength is about ERP. A monoband beam with 5 watts beats a quarter-wave vertical at the same power level every time. Remember that a vertical with 200 radials situated on rich Iowa loam (Ok, a salt marsh is better) has a gain several dB below a simple dipole and well below a monoband beam.

As a related note, the club here in The Villages kicked off a friendly competition the first of August to see who could work all 50 states. While most folks have parked themselves on 20 SSB, I decided to go after the states using FT8. The JTAlert logging application maintains a running list of stations heard that includes their states so I don’t have to blindly call hoping I have worked a new one. Like shooting fish in a barrel. It is only a matter of time before my elusive Montana station pops up.

To encourage you to try FT8, why not initiate a club competition to work all 50 states? The modest station requirements and free software make it easy for anyone to give it a try. Finally, if you use Logbook of the World, the ARRL has added FT8 as a recognized digital mode so you can get another neat endorsement.

Ed, K2TE

Little Pistol DXing

For many years, I enjoyed chasing DX from my NH station with two towers, multiple beams, an 80-meter 2-element quad and a 160-meter Inverted L.  I got spoiled with the AL-1200 hammer I used almost constantly whenever a DXpedition came on the air to bag it quickly.  The setup allowed me to bust a contest pileup in just two or three calls.  Ah, the good ol’ days.

I’ve been in FL now for 18 months in a covenant-restricted retirement community.  I was fortunate to find a place with a fair amount of open property that allowed me to put up a couple of low inverted Vees and a multi-band vertical.  The wire antennas drape off a pole on the back of the house, out of sight of most of my neighbors.  The vertical is enclosed in a PVC flagpole with just the 80-meter “stinger” poking out the top.  It may be an ugly flagpole but it falls within the covenant permissible guidelines and, more importantly, keeps the village aesthetic vigilantes off my back. I have about 32 radials fed from the base of the vertical in a ¾ pie-shaped field with lengths varying from 55 feet to 10 feet.  While this is far from the standard practice of at least 100 radials of 65 feet or more (assuming 80-meter capability), it is better than nothing.

As one might expect, DXing has been a far cry from what I was used to.  Hearing stations is a chore, even with a K3 over my old FT-1000MP.  I often find myself irritated at the juicy spot reports from New England that I cannot hear.  Part of the problem is geography; I am at a lower latitude and I line near Ohio longitudinally so gray-line effects are different.  One might think the high threat of thunderstorms down here also generates a lot of noise but it has been dry and quiet during the fall and winter months when DX is most active.

So what is an old DXer supposed to do?  Answer: Back to the future.  When I got my Novice license back in high school, I put up an end-fed long-wire antenna for 80 meters and a dipole for 40 meters, both of them much lower than 1/4-wavelength above ground.  The long-wire was fed with 300-ohm line.  Why?  Because that is what my Elmer and high school buddy told me to do.  I was clueless about matching, common-mode currents and RF in the shack.  I had a Hallicrafters S-38 reconditioned tube receiver that had a barn door-wide filter for CW.  You can understand why it was a thrill to work states west of the Mississippi.  If nothing else, I learned to appreciate a QSO and to be patient when trying to work someone.

My present station has the advantage of all the technological improvements in signal processing and automation that have mushroomed since the tube days.  Stations are still weak when I do hear them but I can work them if they aren’t too busy.  Contesting is actually better since many stations crank up the amplifier and plead for stations late in the contest.  Using an amplifier here is problematic.  My vertical is about eight feet from the shack so RF saturation would be likely.  Furthermore, I would need to run a 220 VAC line to the shack to avoid brownout when using 110 VAC with an amplifier.  The worse thing, however, would be EMP effects on the neighborhood breaker systems.  It seems building contractors have switched to breakers with a much lower RF tolerance than before.

So what a desperate DXer supposed to do?  The easiest thing I can do is put down more radials.  As I mentioned, my radial field is far from ideal, even if I had moist, loamy soil instead of sand.  An ideal radial field would be a copper sheet surrounding the vertical.  In the climate here, it would turn green in a few weeks so it would look like a California painted lawn if it isn’t stolen first.  I decided to double the radial field I have to provide more return paths for the RF currents.  I have not modeled my antenna to see what kind of radiation pattern I have but it is a good bet that the so-called takeoff angle for bouncing off the ionosphere is 40 degrees or higher.  Conventional theory says that a takeoff angle should be 15 to 20 degrees, values usually achievable with yagis mounted 1/4-wavelengths or higher.  The hope is that I can pull-down my takeoff angle enough to where I fall into the usual DX footprints.

When I installed my original set of radials, it was a time-consuming effort to work each wire down through the thick St. Augustine grass here.  I finally got smart one day when trimming the walkways with my weed-whacker set up vertically.  I found that I can lay out the wire and walk along it with the weed-whacker cutting a narrow slice through the grass.  I then drop the wire down into the cut, add a few staples and close the grass around the cut.  The cut will be completely grown over in about a month.  (This technique will work in New England if you have a manicured lawn; the rocks in a natural lawn tend to mess things up.)  To date, I have added eight radials so it is still a work in progress.

For those of you with a modest station, take heart.  With today’s transceivers, propagation predictions, and worldwide spotting it is possible to achieve DXCC on several bands in less than a year.  I have been fortunate to work them all when I was a “big gun”.  As a “little pistol”, I’ve managed to work 176 countries with 144 confirmed.

The chase continues…

Ed (K2TE)

Moxons in the Attic (Part 3)

Well, another month has gone by on my two-band attic Moxon antenna project.  If you recall from last month, I was left with a perplexing matching problem with the 15M antenna while the 17M one works fine.  I had to figure out how to come up with a way to chase down what was causing the problem.  I guess this just proves that there is no such thing as a simple, straightforward antenna project.

So, with a can of suds as brain fuel, I sat down to methodically list what to do and rule out possible causes.  As a starting point, I connected a 1:1 balun to the 15M and a no-balun, connection to the 17M beam.  This time, I decided to do all measurements from the shack so that losses from the shack coax would be taken into account.  SWR checks on each antenna were consistent with earlier measurements, namely an SWR <2:1 on 17 and 15 meters using the 17M Moxon while rising to 4.4:1 – 6.0:1 across the band when switched to the 15M beam.

Ameritron RCS-4 Antenna Switch
Ameritron RCS-4 Remote Antenna Switch

The next step was to rule out any leakage inside the RCS-4 remote switch.  I decided to try this step because I was suspicious of the current design of the RCS-4.  I had used one for about 20 years in good ol’ NH weather without a problem.  The new unit, however, felt light.  The relays in the remote unit were too quiet for my liking, and an AC power pack replaced the internal power supply from the old unit.  I moved the 17M connection to the last position on the switch so that it was on a separate relay from the 15M antenna and measured.  No change.  I then disconnected the 15M antenna from the switch, leaving it open, and measured.  Again, no change.  I connected a jumper across the 15M connector to short the antenna elements together and measured both bands on the 17M antenna.  As observed earlier, the 17M beam works fine on both bands, indicating the 17M Moxon does not see the 15M one.

OK, so now what?  It was clear the 15M beam was being influenced by the 17M one.  I decided to check the phasing between the two beams wherein the center and shield sides of the coax were connected to the respective sides of each beam.  The casual observer will recall a demonstration by Dale, AF1T of what happens when stacked beams are fed in-phase or out-of-phase.  However, since I’m operating on two different bands, why do I want to do this?  The answer: electromagnetic behavior is complicated; just ask J. C. Maxwell.

To do this, I connected a center insulator that has an integrated PL-259 connector to the 15M beam.  I had used this connector in the past and it was already marked for the shield and center conductor sides.  I checked the balun connections that I had removed from the 15M beam, found the shield side on the first try, and marked it.  I installed the balun on the 17M beam which now represented the opposite of the previous antenna connections.  My rationale for doing this was that a direct, non-balun connection showed a good match on 17M.

Measurements from the shack on the 15M beam now showed an average SWR of ~3.3:1 across the band, better than before but not great.  Measurements on the 17M beam when tuned to 15M, however, were clearly worse with an average SWR of 4:1.  Measurements on 17M were also degraded with the SWR above 2:1.  Clearly, the antennas were not happy with this arrangement.  I decided to disconnect the 15M beam from the RCS-4 switch based on the noticeable change observed on the 17M beam, and remembering that the 17M beam did work before on 15 meters.  When I tuned the 17M beam across 15 meters, the SWR jumped to 8:1.  I was now suspicious of what effect the balun was having on antenna behavior.  Why should the performance be significantly worse with a balun when compared to the simple split feed of the center insulator?

I pulled the insulator and the balun off the antennas to check the connections again.  I was surprised to find that the center insulator showed an open-circuit for the center conductor side.  Even more surprising was the fact that the balun showed the same thing, meaning NO CONNECTION to one side of each antenna.  I looked at the lugs for each device where the center conductor was and noticed that they were loose.  Furthermore, the PVC plastic around each lug had been melted from my efforts to remove old wire and solder from the lugs.  Murphy, you struck again!

In desperation, I took a hacksaw to the top of the center insulator connector to check the center wire inside.  I found it to be intact so I then removed the eye-bolt and replaced the lug with a new one.  The connection to the PL-259 center conductor now worked.  I could re-use the “topless” insulator since it would be in the attic and not exposed to rain.  I scrutinized the same lug on the balun and figured the melted PVC plastic, as in the case of the center insulator, must have formed an insulation between the lug and the eye-bolt to the balun center conductor.  I scrounged around the junk box and found another PL-259-equipped center insulator I could use.

I trudged back up to the attic and reinstalled the center insulators on each beam and scrambled back to the shack to measure things.  This time, SWR for the 17M Moxon was flat across the 17M band vice over 2:1 before.  Performance on 15 meters for the 17M beam was now down to 2.2:1 which was certainly better than 8:1.  The 15M Moxon, however, still showed slightly greater than 3:1, indicating some interaction was still going on, or still a mismatch.  Now what?

As I pondered what could be happening, I remembered something about RF chokes around the coax jacket to prevent common-mode interference.  I recalled my education about rejecting common-mode interference from a presentation by Chuck, W1HIS, aka, Doctor “Ferrite”.  Chuck is the de facto High Priest of Common-Mode Exorcism to prevent RF from entering the shack via feed lines and anything else that comes into the shack.  (By day, Chuck is an MIT professor emeritus.  The Dr. Ferrite title has been bestowed upon him for his prolific use of ferrite chokes throughout his house.  He hates RF noise.)

Admonishing my transgression, I grabbed a couple of ferrite cores from my junk box and scurried up to the attic.  I wrapped as many turns as possible of the RG-8X coax line from the shack until there was no more slack on the attic floor.  I also wrapped a few turns of the coax from the 15M Moxon around a core.  Sadly, there was no change when I checked each beam from the shack.  Well, at least I was relieved that I did not appear to have RF sneaking back into the shack and playing tricks on me.

OK, what next?  As I pondered what to do it occurred to me that the antennas were fed in-phase wherein the shield side of each antenna was the same.  The logical next step was to feed them out-of-phase.  I removed the center insulator for the 17M Moxon and reversed the leads so that the coax center conductor was now under the shield side of the 15M Moxon.  A sweep of the 17 and 15-meter bands while feeding the 17M Moxon showed an SWR under 2:1 for each band.  Switching to the 15M Moxon and sweeping the band still showed the perplexing behavior of SWR greater than 3:1.  I did a sweep of several MHz above and below the 15-meter band to determine if the 15M Moxon might be resonant elsewhere but it was not.

Well, at this point it looks like I can operate two bands with the 17M Moxon so it is not a total loss.  I am back to where I started in terms of performance of the antennas except the flaky balun is gone for 15 meters.  I checked how the EZNEC pattern looks when operating at 21 MHz with the 17M antenna and it does not look much different from 18 MHz.  On the bright side, I can always use the tuner in the K3 to make the 15M Moxon play right for the band, giving me some flexibility if I can hear a station better on one antenna than the other.  Like I said, the electromagnetic behavior is a complicated phenomenon.

Ed, K2TE