My Latest Antenna

Despite the snowy conditions today, I finally got the 20m ground plane antenna up and adjusted. As suggested in the Handbook, it’s hanging from a tree branch. I think I adjusted it a little too short, though, as the low-SWR point seems to be about 14.150. Even so, the SWR is only about 1.3 at 14.050.

The antenna’s bandwidth seems to be quite wide. It’s less than 1.5:1 across the entire band. Who knows? I may even try to work a little SSB with it.

The jury’s still out on how well the thing is actually working. (We all know that low SWR does not equal good performance, don’t we?) The first contact was with a K0 in Missouri. I gave him a 589, while he only gave me a 559. After we said our 73s, though, a KB4 in NC called and we were both 599. I didn’t hear any DX on the band this afternoon. Its position so close to the tree has got to be having some effect on the radiation pattern, too, I’d guess.

I did the coax balun thing by looping the coax three times just below the feedpoint. I don’t know if that’s helping reduce the RFI or not. I didn’t have any problems with RFI on 20m before–just 40 and 10.

For my next trick, I’m thinking of building a 17m/10m dual-band dipole out of some 450-ohm coax I have laying around. It would be nice to be able to have the ability to get on at least two different HF bands. Also, I’ve never worked 17m, so that would be something cool to do.

Book Review: AC6V’s Dxing 101


226 pages, comb-bound
©2002 Rod Dinkins

$24.95 list price, QTB price $23.70 ORDER IT NOW!

226 Pages, comb-bound, 8-1/2 x 11
� Rod Dinkins, AC6V

While this book’s title might lead you to think it’s just about DX, it’s really about HF operation, in general. In Chapter 2, for example, Rod talks about equipment specifications. This is all good stuff to know even if you only plan to rag chew once in a while. Here’s an excerpt:

2-1. SENSITIVITY
Sensitivity is the capability of a receiver circuit to detect weak signals and the major factor in receiver sensitivity is the signal-to-noise considerations. Due to the resistance and temperature of various components, receiver noise is inherent in any receiver. In lab measurements, the amount of signal input required to produce a signal to noise ratio of 10 dB is generally used to specify the receiver sensitivity specification.

In modern transceivers, this is typically a few tenths of a microvolt to a few microvolts depending on the input frequency, mode, and bandwidth of the receiver. Another figure of merit used in determining sensitivity is the noise floor, which is another way to express the receiver noise. Typical values are �€“130 dBm to �€“140 dBm depending on the mode, filtering and preamplifiers used.

However atmospheric and man-made noise enters into the real environment so that the minimum required sensitivity is something quite different than the lab measurement. On the lower bands the noise can be quite heavy, an S-Meter reading of S7 of noise is not uncommon. So even though the receiver has excellent sensitivity, it is unusable in the presence of atmospheric and man-made noise. Using well-designed DSP units and low noise antennas (beverages and loops) are necessary, particularly on the lower bands. Increased sensitivity is gained at the expense of dynamic range, the latter being of greater importance in today�€™s crowed bands and the noise, both atmospheric and person-made noise.

Discerning weak signals generally requires a signal to noise ratio of 10 dB. The noise is a combination of atmospheric noise, receiver noise and circuit design. Note that many CW operators can typically copy code at a signal to noise ratio of almost 0 dB perhaps accounting for the superiority of CW over phone under minimal signal conditions.

2-2. DYNAMIC RANGE
Dynamic range is expressed in dB where the lower limit is the smallest discernable signal (receiver noise floor) and the upper limit is the point where intermodulation products become noticeable. It is an important specification as it gives a figure of merit for evaluating the strong signal handling characteristics of a receiver. Values of 103 dB are typical. The use of front-end attenuation and an AIP circuit can help reduce the effects of intermodulation. The receiver noise floor can be affected by receivers using synthesized tuning schemes. This has improved considerably with the new transceiver designs.

Chapter 4 is all about propagation. Again, this is stuff that all HF operators need to know whether you’re hot to work Pitcairn Island or Pitcairn, PA. Here’s another excerpt:

4-1. SOLAR FLUX , A INDEX , K INDEX
Propagation is tied to the number of sunspots on the surface of the sun, since the areas around sunspots emit large amounts of ionizing radiation – extreme ultraviolet radiation. Increased sunspots correlate closely with better worldwide radio propagation. When there are more sunspots, the sun emits radiation that charges particles in the earth’s ionosphere. Radio waves bounce off of (refract from) these charged particles, and the denser these clouds of ions, the better the HF propagation. The sunspot numbers are calculated by counting the spots on the visible solar surface and also by measuring their area.

Listening to WWV or checking propagation web sites will give the latest solar-terrestrial indices. It includes the 10.7cm solar flux index, Boulder A index and the Boulder K index. Solar Flux at 10.7cm is essentially a measurement of the thermal radiation of the sun, and contributes nothing to the ionization process. Solar flux is measured at several points on the earth, for example one is an observatory in Penticton, British Columbia using an antenna pointed toward the sun connected to a receiver tuned to 2.8 GHz, which is at a wavelength of 10.7 cm. The 12-month running average of 10.7cm solar flux correlates very well with the 12-month running average of the sunspot number �€“ called the smoothed sunspot number and abbreviated SSN. The higher the smoothed SFI number, the better. Typical daily SFI values have ranged from 67 (Jan 1997) to 370 (Jan 1991).

Other solar activity of concern to HF operators are solar flares and coronal holes, which can emit energetic protons and X-rays and cause a significant increase in the solar wind speed. Energetic protons can cause polar cap absorption events (PCAs). X-rays can cause blackouts on the daylight side of the Earth due to increased absorption in the D region. And a significant increase in solar wind speed can result in geomagnetic storms that generally depress MUFs.

The A Index is an averaged quantitative measure of geomagnetic activity derived from a series of physical measurements.

The Boulder A index in WWV announcements is linear in nature and ranges from 0 to 400, and is the 24-hour A index derived from the eight 3-hour K indices recorded at Boulder, Colorado. The K index is logarithmic in nature and ranges from 0 to 9, and is the result of a 3-hourly magnetometer measurement comparing the current geomagnetic field orientation and intensity to what it would have been under geomagnetically quiet conditions.

Suffice it to say that the geomagnetic activity, solar storms, X-Rays, flares, etc., can have an adverse effect on propagation. The Planetary A index relates to geomagnetic stability. Magnetometers around the world are used to generate a number called the Planetary K index. A one-point change in the K index is quite significant. K index readings below 3 generally mean good stable conditions, and above 3 can mean high absorption of radio waves. Each point change reflects a significant change in conditions. Generally the higher the latitude of the measuring station, the higher the K and A indices reported. This is because the effects of geomagnetic instability tend to concentrate toward the polar regions of the globe.

Oversimplification can be very misleading in the complex field of propagation, but in general for long distance HF, the rule of thumb is the higher the SFI and the lower the A and K indices, the better the conditions on the higher frequencies. The A index should be under 14, and the solar activity low to moderate. If the A-index drops under 7 for a few days in a row and the SFI is up, watch for some really exciting intercontinental conditions.

You can hear the SFI, A and K indices on WWV or WWVH or by calling 303-497-3235. Geophysical alerts are broadcast from WWV at 18 minutes after the hour and from WWVH at 45 minutes after the hour. Both stations operate in the high frequency (HF) portion of the radio spectrum. WWV and WWVH radiate 10,000 W on 5, 10, and 15 MHz. The radiated power is lower on the other frequencies: WWV radiates 2500 W on 2.5 and 20 MHz while WWVH radiates 5000 W on 2.5 MHz and does not broadcast on 20 MHz. Each frequency is broadcast from a separate transmitter. Although each frequency carries the same information, multiple frequencies are used because the quality of HF reception depends on many factors such as location, time of year, time of day, the frequency being used, and atmospheric and ionospheric propagation conditions. The variety of frequencies makes it likely that at least one frequency will be usable at all times.

These values are also available on all DX Packet Clusters (SH/WWV). Also you can find them on numerous pages on the internet, a good one is from WN6K at URL: http://members.cts.com/fort/w/wn6k/

Note that the K index reported on WWV is only updated every 3 hours and the A and SFI values are usually updated once a day at 21 UTC. The A index reported at 21 UTC is calculated from the last eight K index readings in Boulder, so it contains data that is 24 hours old when it is first posted.

For graphs that update every 5 minutes see http://www.sec.noaa.gov/today.html these show short term events long before they show in the WWV report. Also watch the K index graph at NOAA; it often differs from the WWV report, because the web page shows the estimated Kp (planetary K index) rather than just the reading from one site (Boulder) that is reported on WWV.

Classification of K-indices is as follows:

K0 = Inactive K5 = Minor storm
K1 = Very quiet K6 = Major storm
K2 = Quiet K7 = Severe storm
K3 = Unsettled K8 = Very severe storm
K4 = Active K9 = Extremely severe storm
As with the K-index, the higher the A-index, the more unstable propagation becomes. Classification of A-indices is as follows:

A0 – A7 = quiet
A8 – A15 = unsettled
A16 – A29 = active
A30 – A49 = minor storm
A50 – A99 = major storm
A100 – A400 = severe storm
There is, of course, plenty of information specific to DXers. Chapter 5 is all about DX operating procedures, including how to find DX, work pileups, and get awards. Chapter 7 is titled “”DX Secrets”” and has many practical operating tips, such as looking for DX on the 12m and 17m bands because they are generally less busy than 20m or 15m. There are also sections on working contests, QRP Dxing and CW DXing.

One unique feature of this book is that it’s continually being updated. AC6V prints the book on demand and is continually collecting equipment information and operating anecdotes. When you order it, he updates the book, and send you the absolute latest revision. The copy you buy today will be different than the copy your friend bought last year. This approach assures that you get the most up-to-date information available.

This book is really a great value, especially if you’re new to HF operation and DXing, but experienced DXers will find it valuable as well. Click here to see the complete table of contents.

Favorite Websites

I have a couple ham radio websites that I visit regularly:

They all are good for different things. AC6V.Com has probably the best set of links of any of them. I like the articles and forums on eHam. They also have submitted reviews of equipment, both old and new. HamWave just revamped their site and it’s now running some kind of content-management system. It’s relatively easy to submit articles and use the forums there.

What sites do you visit?

Book Review: The 2003 Handbook

The ARRL Handbook for Radio Communications 2003

1,216 pages, softcover, 80th Edition
© 2002 ARRL, ISBN 0872591921, $34.95 list price ORDER IT NOW!

It’s been a while since I bought a new Handbook, so I was excited when these arrived here at QTB.Com. This book is amazing in that it really does cover it all–from the basics of AC and DC circuit theory to more advances topics, such as satellite operation and moonbounce.

This year’s Handbook also has more comprehensive coverage of digital signal processing (DSP). Want to know what your fancy, new transceiver is doing to the signal. This chapter will give you some insight. The chapter on modulation sources has een updated to include coverage of digital voice modulation and the chapter on safety practices has also been improved.

One of the biggest strengths of the Handbook has always been its coverage of practical projects that hams can build. Just paging through it made me want to get out my soldering iron. There are hundreds of projects, from the very simple to the very complex. One of the simpler projects to catch my eye was the TiCK-2 Keyer. This keyer consists of an 8-pin microcontroller, a voltage regulator, and 2N2222 transistor, and a handful of resistors and capacitors.

There are also some really simple antenna projects, if antennas are your thing. For example, there is a short piece on how to build a tree-mounted HF groundplane antenna. I think I’ve got the perfect tree in my backyard for a 20m ground plane. There’s also a cool project for building a 10m, 1-wavelength loop antenna.

If you’re new to rolling your own, there’s plenty of help here, too. The Handbook includes chapters on component data, construction techniques, and testing and repair. The appendices also have data that will help you get your projects built.

I know it’s cliche to say it, but the Handbook has something for every ham, from beginners to OMs. It really will help you get more out of ham radio.

——————————————————————————–

Contents

Introduction

What is Amateur Radio?
Activities
Wireless Technology for Everybody

Fundamental Theory

Mathematics for Amateur Radio
DC Theory and Resistive Components
AC Theory and Reactive Components
Digital Signal Theory and Components
Analog Signal Theory and Components
Practical Design and Projects

Safety Practices
Real-World Component Characteristics
Power Supplies and projects
Modulation Sources (What and How We Communicate)
RF Power Amplifiers and Projects
AC/RF Sources (Oscillators and Synthesizers)
Mixers, Modulators, and Demodulators
Filters and Projects
Receivers, Transmitters, Transceivers, and Projects
Digital Signal Processing
Transmission Lines
Antennas and Projects
Propagation
Station Setup and Accessory Projects
Repeaters, Satellites, EME and DFing
Construction Techniques

Component Data
Circuit Construction
Test Procedures and Projects
Troubleshooting and Repair
Operating Practices

Electromagnetic Interference (EMI)
Regulations
References

I Hate PL-259s!

I really hate PL-259s. Well, not PL-259s, per se, but soldering them onto coaxial cable. It took me four tries yesterday to finally get one connector on properly. I suppose I should look into getting crimp-on connectors, but the tools are expensive, the connectors themselves are more expensive, and I have a gut feeling that they don’t perform as well as soldered-on connectors. I guess I’ll just have to learn how to do it correctly.

Building the VA3TO EchoLink Board

My VA3TO kit arrived Thursday, and I began building it yesterday. The layout is very professionally done, and the instructions are well-written. I hope to finish building it today.

Next, I’ll have to reconfigure my computers. The computer that I want to use for the link is currently being used by my wife for Hotmail. I’ll have to move it downstairs to my shack and put a wireless Ethernet card in it. Another complication is that it’s currently running Linux, so I’ll have to make sure I have a Linux driver for the wireless NIC and then get the EchoLinux software to connect it to EchoLink.

Finally, I’ll have to make up the cables to connect my IC-22U to the board and then the board to the rig. That looks like another $15 and an hour or so of work. With any luck, I’ll have it on the air by next weekend.

J-Poles

My biking and ham radio buddy, Mark, came over Monday evening. We had three objectives:

  1. measure the SWR of J-pole I built a couple of months ago,
  2. measure the SWR of the 2m/440 antenna I just purchased from Purchase Radio, and
  3. build a 2m J-pole for Mark

To measure the SWR, Mark brought over his MFJ 259 Antenna Analyzer. In some ways, it’s much nicer than the Autek Analyzer that I have. For one thing the display is much more informative. The Autek display consists of simply a five-digit numeric display, capable of displaying only one parameter at a time. The MFJ is a full alpha-numeric display and displays the test frequency, the measured SWR, and some other information simultaneously.

The MFJ analyzer’s frequency range is also much greater. It covers the 2m and 440 MHz bands, while the Autek only goes up to 32 MHz. Mark doesn’t think it’s very accurate at 440, though.

The first thing we did was measure the SWR of the J-pole I’d built. I’ve been very happy with the antenna, so I was a little surprised that the first reading was slightly over 2.0. I did have it hanging very near to a fairly massive new barbecue grill we have, so surmising that the grill was detuning the antenna, I moved it away from the grill and the SWR did go down to about 1.5. Respectable in my opinion.

Next, we measured the SWR of the dual-band antenna. This antenna is a 5/8 wavelength antenna that I had mounted on a mast. Its SWR measured about 1.5 near the ARROW 2m repeater frequency of 14.96- MHz. I was happy with that, so we moved on to the antenna construction.

We built the J-pole from plans I found on the Net. On their website, the Colorado District 24 ARES group has plans for making J-poles from 300 ohm twinlead, 450 ohm ladder line, and 1/2-in. copper pipe. The dimensions for each of these versions is slightly different, as the velocity factors are all different.

We opted to build ours with the ladder line because we each already had a hunk of it and it’s much easier to carve up some ladder line than solder up copper pipe. It’s not as sturdy, but it’s certainly sturdier than 300 ohm twinlead.

When I built mine, I did not have an SWR meter to tune the antenna with. So, I just built it to the recommended dimensions, and as mentioned earlier, it turned out to work pretty well. Since we had the analyzer when we built Mark’s we played around with the tuning stub, and it appears that he was able to get a slightly better match than I was.

Overall, it was mission accomplished.

Busy Weekend

I had a rather busy weekend with my real life–including raking up a mountain of leaves and visiting relatives–so I didn’t have much time for hamming.

I did make a few contacts on EchoLink, including one with a guy who lived in San Diego the same time I did. The funny thing about this contact is that we both were connected to a San Diego repeater via EchoLink, so we really didn’t need the repeater at all. It just provided a meeting ground for us. We were the only two talking, and our conversation was being transmitted by the repeater, even though neither of us actually needed the repeater to communicate.

I had a similar experience earlier in the week when I connected to a NW Ohio repeater. I talked with a guy who was also connected to the repeater via EchoLink. In this QSO, however,we were joined by a local ham, so the repeater was necessary.

EchoLink, again

Tuesday, I ordered the VA3TO board to set up a local link to EchoLink. It looked like it offered the best price/performance. In addition to EchoLink, the website noted that it would also support PSK31 operation, which is something I’m interested in trying.

We had an ARROW club meeting yesterday, and I floated the idea of setting up the link after the meeting. Everyone seemed to really like the idea. I don’t know how long it will take for the board to arrive, or how long it will take for me to put it together, but with any luck, I’ll have it up by the end of the month.

I really need to get back to my CW, too. I haven’t been on CW now for almost two weeks.

EchoLink

A couple of weeks ago, I was chatting with a guy on our local repeater, and he happened to mention that a friend of his had started using something called EchoLink. I just happened to be in my office, so I pulled up the website. How cool, I thought!

What EchoLink is is a way to connect to other amateurs over the Internet using VOIP (Voice Over Internet Protocol). Now VOIP is nothing new, and many chat programs use this technology. What makes EchoLink so cool is that amateur radio operators are using the technology to connect their VHF and UHF radios and repeaters to the Net. Via EchoLink, for example, I can make contacts through repeaters all over the world. Cool, eh?

The software is very easy to download, install, and use. The downloadable file is only about 1.5 Mbytes, which should be doable even on a dialup line. On my ADSL line, it took less than a minute. Once you’ve installed the software, all you have to do is point and click and you’re connected to the ham at the other end (once you have registered your callisgn with the server).

I did experience a couple of glitches. The first was my ADSL router. It has a built-in firewall that rejects accesses on all ports, except those I allow. Programming it to accept accesses on the ports that EchoLink uses cured that. The second was getting the microphone volume set properly. I’d never used a mike on this computer until now, so it was set way too high.

My first “QSO” was with Phil, a retired plumber in Connecticut. Just this afternoon, I worked my first DX when Wayne, an English ham called me. Both times, the audio was nice and clean, and we had nice chats.

The next step is to buy one of the audio card interface boards–the WB2REM board is inexpensive, as is the VA3TO board–and connect it up to my Icom IC-22U. That will open Ann Arbor up to the world and vice versa.