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, Featured, General, Newsletter

When the Wind Blows

As most of my friends in NARS know, I have been using a Hustler 6BTV multi-band vertical for the past 2 and a half years. It is concealed inside a long piece of PVC pipe configured as a flagpole. An ugly flagpole but it still passes the deed restrictions and keeps the vigilantes off my back. I have a piece of rope about a third of the way up the pole that is intended to counter gusty winds that predominantly come from the North. This arrangement has served me well, allowing me to log over 200 countries.

A couple of months ago, I was out in the garage one afternoon watching an approaching storm. As is often the case, the rains came down in buckets. In less than a minute, the winds came screaming out of the West at near-hurricane force, driving the rain sideways. The winds subsided to almost dead calm almost as quickly as they ramped up. I stood there stunned at what apparently was a microburst. I peered apprehensively toward my flagpole and discovered it laying on my neighbor’s tree. Oh oh, this can’t be good, I thought. I looked around the neighborhood and noticed that a palm tree two doors down had been snapped in half. Good thing I did not have one on my property.

I went over to the leaning pole to try straightening it. The resistance I experienced told that the antenna inside was bent. I relaxed a little knowing that perhaps I could straighten it out. I tied a rope about halfway up the pole and proceeded to pull it back to vertical. I applied considerable force to pull the pole up. As I neared vertical, the pole suddenly swung around toward me and was now leaning close to the house. Yep, this definitely was not good. If it wasn’t broken before, I feared it was broken now.

The next day my son and I lowered the stricken antenna to ground. As I pulled off the pipe, I noticed the mounting base support pipe was bent. The pipe is about a foot or so in length and inserts in the first section of the antenna. The wall thickness of the pipe is an eighth of an inch. The pipe had been bent to about 30 degrees from vertical by the wind load on the PVC. Figure 1 shows the damaged support as well as the first section that was also slightly bent.

Antenna
Figure 1 – Bent Antenna Support & First Section

The rest of the antenna was intact with no signs of damage. Normally, I would have used a large vice to Armstrong the bent pieces back to vertical. However, being workshop-challenged in The Villages, that was not to be. I have always believed a garage is for vehicles.

The next step was to contact DX Engineering to order a new base support and first section. While I was waiting for the new hardware to arrive, I thought of how I could strengthen the base to mitigate wind damage in the future. I recalled an article from an amateur in Colorado who strengthened his beams by inserting sections of tubing as the element junction points for increased rigidity. I borrowed this approach on my 40-meter beam to withstand the wind and ice of New England. After 20+ years the beam is still up and still straight. (At least it was when I sold the place.)

I made a trip to the local big box store and found a 3-foot piece of tubing that fits snugly inside the base support pipe and protruded about halfway out. The idea here is that, once the first section is clamped in place, the added piece acts as a stiffener that will prevent the first section from bending. I used this same principle when I installed my mast on my tower by inserting another pipe inside the mast. It too has never failed. Many thanks to John, WS1E for the idea. Figure 2 shows the modified configuration.

Antenna
Figure 2 – Modified New Base Section

I reassembled the antenna and slid it back into the PVC pipe. My son and I hoisted the pole back in place on my base mount. For future protection, I added another piece of rope to tie down to the West. (Don’t tell the XYL!) A check of SWR across the bands showed that I was back in business.

Now that things are back to normal, I leave you with these words of wisdom for your next antenna project:

When the wind blows,

Gently, my antenna will rock,

When the wind howls,

Down it will come with a hard knock.

Ed, K2TE

Antennas, Featured, Homebrewing

Antennas: Where There is a Will…

3 Comments

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

Digital, Featured, General, Newsletter

FT8ful Encounter

1 Comment

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

Radio Amateurs Developing Skills Worldwide