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April 15-21, 2017:  QTH Big Island of Hawaii ..........  Grid:  BK29ik  .........  US County:  Hawaii

also KP4/AH6FX and AH6FX/W6

Updated:  February 12th, 2017

Elected president of the Nokesville Area Radio Club [NARC] on November 8th, 2016.

The picture above shows a portion of an 18 bay - 36 element Sterba array antenna; sometimes called a Sterba curtain antenna. It is tuned for 20 meters. The top elements were up between 65-70 feet at the pole, and the bottom elements are about 33 feet below. The 450 ohm ladder line reverses phasing going to each bay. The antenna was oriented about 355 degrees which takes it over the north pole from Virginia into relatively unpopulated zones with few ham radio operators. It was a great antenna and generated tremendous gain, but because of its orientation and narrow beam width, I only worked few stations. But the stations I did work gave great signal reports - often 20-30 db/S9 from my 125 watt transmitter. The Sterba was taken out of service in 2010.  In 2017, I hope to construct a smaller version of the Sterba array antenna oriented towards northern Africa and the Middle East.

Horizontal Loop Antenna:  Above the Sterba, you may be able to see a portion of a horizontal loop at the 75 foot level.  I conducted antenna maintenance in December 2016 and replaced pulleys on the poles supporting the loop and other antennas.  Also, the antenna wire of the loop was replaced because its insulation was cracking and falling off.  The new loop now runs about 890 feet long and is about 25 half-wavelengths [or 12.5 full wavelengths] long when used on 20 meters.  The large number of wavelengths helps increase antenna gain and increases effective radiated power.  On the receive side … the loop has a lot of capture area given its geometry and is quite good for receiving.  It tunes well the 80, 40, 30, 20, 17, 15, 10, and 6 meter bands.  The 160 meter band is tunable using my external Dentron MT-2000A antenna tuner [serial number 0003!].

Stacked Phased Loop Antenna:  In January 2017, the 75 foot high loop was phased with another loop at the 42 foot level on the same antenna poles.  The lower loop is also about 890 feet.  The difference between 75 feet and 42 feet = 33 feet [1/2 wave length for 20 meters] which is the length of the phasing line connecting the two loops.  450 ohm ladder line feeds the stacked loops in the lower corner apex, in a similar method used to feed the Sterba.  Each side of the ladder line requires soldering three wires together – the bottom loop wire, the phasing line, and the feedline.  

The phase line does not reverse phase, so maybe reversing the phase may be something to experiment with soon.  The most noticeable difference with the stacked phased loop antenna compared to a single loop is in the tuning.  The ladder line runs inside the shack to a DX Engineering DXE-BAL200-H10-AT 4:1 balun which runs to either of two Icom transceivers.  Each transceiver runs the stacked phased loop very well on 80 through 6 meters.  The internal antenna tuners seem to tune the antenna quicker with less grunting and groaning.  The stacked phased loop seems more broad-banded.  Performance on 80 and 40 meters is much better, and it does not fight the former band edges by flashing the tuner light red as it struggles to keep SWR in the tolerable range.  At this point, I am not sure how stacking and phasing the loop effected the angle of radiation and antenna effectiveness.  With the single loop at 75 feet, I was often able to work the big DXpeditions worldwide using only exciter power, which indicates a good low angle of radiation.  First indications are encouraging using the stacked phased loop, based on good reports from E51, VK8, V51, VP8, and RI1 [Antarctic] stations worked within the last few days.  YB stations from Indonesia on 40 meters are heard well around sunset, but the huge pile-ups prevent logging them.  Bottom line:  initial DX results are encouraging for the stacked phased loop.

However, reconfiguring the antenna system generated RF problems.  The addition of the lower loop and phasing line evidently disrupted my RF plain and generated unwanted coax feedline radiation which caused tremendous audio distortion problems when operating 40, 80, and 160 meters.  My windom antenna was the only antenna effected because it is my only antenna using a coax feedline.  I did the standard things to quickly rid the RF interference from my audio such as switching microphones, placing a string of ferrite beads on the antenna coax, and grounding the coax connector shield outside the shack on the house ground rod.  Some of those remedies worked with limited success, but they did not resolve my RF interference and audio problems.  The solution was installing a COMTEK line isolator [COM-LI-11140] between my transceiver and antenna switch.  The COMTEK stopped my feedline radiation problem and eliminated all RF interference in my audio.

Below shows the four antenna support poles plus pole extensions for the loop antenna which is at 75 feet. The center left pole is the main pole and is the apex for the loop with about 116 feet of 450 ohm ladder line feeding to the shack. 

If you magnify the picture and zoom in to the main pole ... you will see two of the four phasing subs and the lead-ins of two high gain single wire beams hanging at 66 feet.  The stack phased loops are not shown because this picture was taken before their construction.

Shortwave Listening Days - Breastfeeding for Ham Radio

Shortwave listening was my passion in my early radio days. My Father returned from an overseas trip to Asia in the early 1960s, and unpacked a Hallicrafters S-120 from his baggage. He and I raised the little whip antenna that came with the receiver and tuned around the bands. That is when the radio bug bit me! It was a thrill listening to radio stations all over the world broadcasting in different languages. We eventually put up an exterior longwire antenna which ran from our house to fence outside. The S-120 was a good beginner's general coverage receiver, but by now, I wanted a shortwave receiver which would allow me to accurately read frequencies so that I could retune stations at a later time. My parents bought me a Drake SW-4 shortwave receiver. The SW-4 was fantastic. It had a sensitive front end and excellent receive audio. It was crystal controlled and was primarily a shortwave band only receiver. By inserting other crystals, I could tune other HF frequencies to hunt down some of the exotic DX that lurked outside of the standard shortwave bands. My great friend Ed Shaw purchased what he thought was one surplus communications receiver. It turned out that Ed actually purchased "1 lot" of surplus receivers. It was a lot of 5 brand new Hammarlund SP-600 receivers still in the original packing material. Ed gave me one plus a small signal generator that allowed me to make precise frequency measurements. The SP-600 was the best receiver that I have ever used. Using longwire and dipole antennas, it was easy [when propagation conditions were right] to receive low power regional shortwave stations in countries such as Indonesia, China, North Korea, India, Turkey, and many other places. My best DX catch is the Pei Hai Fisheries station in Pei Hai, China. I forget its operating frequency, but it was perhaps outside the 49 meter shortwave band. Later I acquired an R-390 receiver, but the SP-600 proved to be a better receiver. I belonged to the North American Shortwave Association - NASWA for over a decade, and wrote the Listener's Notebook section of NASWA's monthly publication FRENDX for a couple of years. I also belonged to Numero Uno founded by world class DXer D
on Jensen. Other members of this small group of shortwave DX-aholics included Ed Shaw, Dan Ferguson (K4VOA), Dan Henderson, Larry Magne, Ralph Perry, Jerry Berg, Jerry Dexter, and several others.

Shortwave listening has served as an excellent training ground for many ham radio operators. Unfortunately, the shortwave radio services of most countries have been replaced by FM outlets and internet audio feeds, and the unique experiences of chasing rare, low powered DX on the shortwave bands are not like they used to be. It is always great rag-chewing with other ham radio operators worldwide who were once shortwave listeners too. One of my greatest shortwave DXer thrills on the ham bands was talking to ZD9BV, who was the radio engineer for the super rare Radio Tristan de Cunha which was super rare on the shortwave bands. I do not know of any shortwave DXers who worked Tristan in North America. I can say that I often checked 3290 KHz - but not a peep.

Radio Propagation

One of the most important skills for any radio operator to acquire is the ability to determine or predict radio propagation conditions. As a shortwave DXer, propagation predictions often meant either getting up early in the morning around 0400 local time or so to catch that rare DX station - or sleeping in. Generally speaking, and depending on the season of the year - rare DX from Asia and the South Pacific islands on the tropical shortwave bands (60, 90, and 120 meter bands) could be heard on the east coast of North America (ECNA) from around 0400 to 0600 EST before beginning to fade out as the sun began to rise. The Armed Forces Radio and Television Network from Tokyo was sometime heard on 80 meters in the winter and served as a beacon of good DX conditions from the Pacific. WWVH the time station broadcasting from Hawaii on 5 KHz and 2.5 KHz {and other higher frequencies} was another good marker for propagation into the Pacific. DX from Africa on the 60 meter band could be heard on ECNA in the afternoon around 1600-1800 EST and again fading in around 2200 EST before fading out around 0100 to 0200 EST. Conditions for African DX seemed to be best during the fall, winter, and early spring. Central and South America had a number of powerhouse stations on the 60 and 90 meter shortwave bands, plus many lower powered stations on the 60, 90, and 120 meter shortwave bands. They were often heard fading-in around late afternoon and ran all night into the early morning hours Eastern Standard Time. They often faded-out after midnight only to fade back in around sunrise as the Asian and Pacific island stations faded out along the East Coast. Rare DX came from a number of low powered stations in Bolivia, Peru, Brazil, and the South Atlantic islands who were only heard in North America seasonally in the winter and spring; and then only when the propagation numbers were right. Europe for the most part was not DX because of the powerhouse stations transmitting throughout the continent. However, Liechtenstein and Monaco were exceptions with their low power stations that often were clobbered by QRM from the big guns. The USSR and China had their international services transmitted by mega-kilowatt powerhouse Radio Moscow and Radio Peking respectively. However, both the USSR and China operated vast networks of low powered regional stations. Many of these stations were rare DX in ECNA. Many of these regional stations operated outside of the standard shortwave bands, and were a thrill to receive. It was always a challenge to receive the regional stations on multiple frequencies at the same time. We called these parallel operations. For instance, as I recall the Fukien, China, regional station could be heard operating in parallel transmitting the same programming on several frequencies in the 3 - 4 - 5 - 6 - 7 and 9 KHz range outside of the regular shortwave bands. For me, receiving several regional North Korean stations in the 2 KHz range was fantastic.

So how does all of this stuff relate to radio propagation? I would regularly record the A-Index, solar flux, and magnetic storm information in my logbook. I also kept records of the dates, times, and solar conditions of certain DX loggings printed in FRENDX and Numbero Uno. Patterns would develop. Even in the days before Bill Gates invented Microsoft Excel and computers were affordable, DX-nerds would use accounting paper to keep track of propagation conditions that opened DX regions. Unknowingly, my parents threw away my shortwave DX logs when they moved several years ago. There went about 20 years of shortwave DX history! {cry cry cry!!!} However, I kept some of my propagation notes with my ham records that summarized the major indicators and signaled openings into DX regions. My information compared well to the data published by George Jacobs - the grand master of radio propagation, and other folks.

These are the propagation numbers and windows that we worked with. I am sure that the same propagation numbers will produce openings on the ham bands to the various DX regions.

I have about 75 years worth of historical radio propagation data stored on my computer. I have developed a test database to process the data to see what results are produced. This is going to be a long-term project and something to do when I have a lot of time to devote to the project. I will not say its going to be fun, but it might be interesting to see what the data produces.

More to Follow - site under construction

Ham Radio

I thoroughly enjoy many facets of the ham radio hobby. It all began as a shortwave DXer when I would turn on the receiver BFO to tune the SSB stations that were QRMing the shortwave stations that I was listening to. Listening to hams added a personal touch to shortwave listening. Instead of listening to foreign programming and music which I always enjoy, it was also interesting to listen to hams talk to other hams about "ham stuff" - antennas, receivers, transmitters, shacks, and stuff in general. One of my shortwave DX friends in Virginia - Shel was also a ham radio operator with a high standing on the DXCC Honor Roll. After a few years of coaxing, Shel, W4OEL, administered the novice exam. After a few weeks of FCC processing time, I became KA4ERX in 1978. After buying a HyGain 18AVT vertical from George Jacobs at the Gaithersburg, Maryland, hamfest - Shel then loaned me a Johnson Viking Ranger transmitter. I was good to go! My first CW QSO was with WA4ZKS in Silver Springs, Florida, on 40 meters CW. My first DX QSO was with JF3PII in Osaka, Japan, on 15 meters CW. That was it -- I was bitten by the ham radio bug and was infected with the hobby!!

I remained a novice for a few years because I enjoyed CW and had no real desire to upgrade my license to get more operating privileges. I eventually upgraded the Johnson Ranger to a Kenwood TS-520SE which W4OEL highly recommended because of its superb CW tone and receiver sensitivity. I finally upgraded to General Class in 1983 and became KF4RY. What a great callsign for teletype - but I only operated CW and SSB at that time! Now I had phone privileges which really opened up the world for me. Now I was able to join some of the DX nets on 20 and 15 meters. I especially liked the 220 Net that was run by VK9NS Jim Smith on Norfolk Island. Jim always hammered into the US south in the early 1980s, and he was always a gentleman and operated a great net control station. He was always strong in Hawaii. I found that joining DX nets was a great way to work some pretty good DX. My favorite DX was in the Pacific and Asia, perhaps a reflection of my shortwave DX days. Another great thing related to dropping in on DX nets was that you do not have to run a great deal of power. My rule of thumb related to running wattage reflects my shortwave DX experience -- if you work them you work them. Working a station with a 3x3 signal is just like working a station with a 60db/S9 signal. The bottom line is you conduct two-way communications and you know who you worked, and that station knows your call sign too. If you are lucky - you trade QSL cards
to document the exchange and actually QSL (verify) the station.

For the first time - I was able to run over 100 watts from a new Kenwood TS-830S purchased in 1982. By getting under the hood and tweaking up the Kenwood, I was able to pump out a clean 110 watts now!! By accident, I came across Bob Heil's new external microphone equalizer which added a punch to my SSB signal. I received many on-the-air comments about the equalizer and how it improved my ability to punch my way through QRM or just simply work a DX station using relatively low power.

It goes without saying that Hawaii is a fantastic and marvelous place. From my time there in the early 1980s to the 1990s, I tremendously enjoy its exoticance and the wonderful people of Hawaii. In certain areas because of restricted space and other reasons there are antenna restrictions which prevent many Hawaiian hams from putting up HF antennas. Many Hawaiian hams on Oahu operated VHF and UHF, and use the great systems of repeaters, however many are able to put up very good antenna systems. A good example in those days was the contest station KH6XX which was located on the beach in the North Shore part of Oahu. A 2-meter buddy - Larry - KH6BUS, now a silent key, sponsored my membership in Honolulu's Emergency Amateur Radio Club. That was a great experience, and I met many great ham radio operations including the great DXer and physicist Nose - KH6IJ, now a silent key and also Lee - KH6BZF - Big Zipper Flipper. My neighbor Carl - AH6HP and I would piggy back working DX back to back. We would turn stations over to each other after working them. I remember Carl and I tried to launch a helium-filled balloon trailing a longwire. The balloon eventually got tangled in the trees, thus ending a great experience
! What wonderful people!

I was fortunate enough to put up HF antennas in Hawaii. I petitioned the neighborhood association and described how ham radio operators and particularly the Honolulu Emergency Amateur Radio Club were invaluable in assisting the community maintain communications after hurricanes and tropical storms. By that time, our neighborhood had recently survived Hurricane Iwa and several big tropical storms. Hurricane Iniki would hit in a few years. With neighborhood association approval, the 18AVT vertical and a G5RV went up. Later the G5RV was replaced by a small horizontal loop mounted about 15 feet off the ground. These antennas were great for working all throughout the Pacific and Asia. I also checked in more often to VK9NS - Jim's 220 DX Net.

Returning to the mainland in the 1990s, we eventually settled on some rural property in northern Virginia. Another loop antenna went up in the trees. Later it was replaced by a larger loop described above which hangs from four 75 foot telephone poles. Antenna experiments are fun. My most memorable antenna project was the Sterba Curtain or Sterba Array also described above. Lazy H's and Bazooka antennas have also been tried, but my favorite antenna remains the big horizontal loop because of the increased gain it generates plus all of the capture space that enhances reception. It is also a very quite antenna. It remains amazing. The antenna performed as well as you could expect when we had the major solar storms in early 2012. My plan is to play with a rhombic sometime.

I have been very fortunate to operate from various countries. I have operated as a /J37 in 1983 from Grenada. That was the first time I was "DX" and I still recall being amazed at how the frequency roared with calling stations. A noteworthy and fond memory of that trip was visiting J37AH - Don's hill top QTH that overlooked the Grand Anse School of Medicine in Grenada. I operated as HL9AH from South Korea several times in the 1980s and 1990s. The memorable thing about operating there was the tremendous signal strength of several Russian and other Asian stations - hugely different compared to how heard in Hawaii. I had the weird call of KA2DJ when operating from Japan also in the late 1980s. I was always amused by how many DX stations told me that I had a loud signal from New York!

We are thinking about retiring back to Hawaii in a few years -- but have to settle for an occasional visit now and then --- a very occasional visit indeed!

OK -- that's the scoop on AH6FX/W4 in Nokesville, Virginia. I hope that my ham radio bio was not too boring. I look forward to reading yours on QRZ.com.

Thanks for dropping by and I look forward to working you on the bands.

73 and Aloha from Virginia,



More to Follow - site under construction


Click here to access the NOAASpace Weather Prediction Center web-page showing various data including an aurora map:   http://www.swpc.noaa.gov/

VOACAP 1: Click this link for VOPCAP Propagation Map of Current Conditions. Fill out data for your location, and then click the "Run the Prediction" button to see the current band conditions. http://www.voacap.com/coverage.html

VOACAP Tips and Techniques:

1. Fill out the form appearing on the right when the webpage appears.

2. Be sure to select SSB vice CW � it makes a big difference.

3. The predictions are surprisingly accurate. I use it almost every time I fire up the rig. My technique is to open up several tabs in my browser, each displaying the prediction for a different band.

3a. Lately I have been opening up tabs for 20-10 meters. VOACAP is wonderfully color-coded to show the hot and not-so-hot regions.

3b. I click on each tab sequentially to see band openings. It is like a propagation slide show using browser tabs.

4. Be sure to refresh each map on the hour by clicking the back arrow on the browser.

4a. It takes you back to the form where you simply hit "run the prediction" again to refresh.


VOACAP 2:  VOACAP Online - http://www.voacap.com/prediction.htmlThis is another extremely interesting VOACAP variation.  It is a 3-for-1 propagation prediction tool, and is quickly becoming my favorite VOACAP version. 

The user data entry page is similar to the “basic” VOACAP 1 above but a “whiz wheel” or circular chart provides a snap shot of general band predictions (80-10 meter) throughout a 24-hour cycle from your shack [the red map pin] to the DX location, where ever you place the blue pin on the map

VOACAP Online is a great interactive propagation prediction tool that allows you to get new propagation pictures on the fly.  Moving the blue pin around the globe allows you to select a DX location to investigate.  Within seconds, you can get the DX picture in central Africa and then change it to Indonesia just by moving the map pin, for example.

Moving your mouse over the whiz wheel produces the percentage of success by band, by time.  It is a very good way to look at the hourly propagation picture for an entire day in one snap shot. 

By pressing the “Run Prediction” button, we get two more useful propagation pictures - the circuit reliability and the signal strength on the receiving end … in our shack.  From this picture, we get a  good correspondence of circuit reliability to signal strength.

The black line across the graph estimates MUF.


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