November Contests

Spend some quality time on the radio!

By the time you read this, October will be over and the California QSO party, the Oceania DX contests (both phone and CW versions), and the CQ Worldwide SSB DX contests will be part of contest history for 2019. I hope most of you gave at least a couple of these a try. We’re on the bottom of the sunspot cycle, so it could be “now or never” for DX contests for most of us.

Incidentally for those of you who haven’t already discovered them, the ARRL Propagation bulletins can be found archived here: http://www.arrl.org/w1aw-bulletins-archive-propagation

And while we’re on the topic, the best propagation forecasting software I’m aware of (and free, at that) can be found here:  http://www.voacap.com

Have a look at the site carefully so you don’t miss the point-to-point propagation predictions, the coverage area maps, and the Nordic-based HF propagation-monitoring cluster. Although the spots for the monitoring cluster are CW, they show where signals received at the monitoring cluster are originating from, in real-time, and the summary at the top of the page shows the number of spots per band, which gives a fair idea of which bands are open at the monitoring location.

November starts out fairly quietly as far as high-profile contests go, but

• CW: First full weekend in November (November 2-4, 2019).
• Phone: Third full weekend in November (November 16-18, 2019).

Contest Period: Begins 2100 UTC Saturday and runs through 0259 Monday. (all dates and times UTC).  This contest has a wonderfully challenging exchange that is great for testing (or proving) your skills. Full information can be found here: http://www.arrl.org/sweepstakes

Be sure you read the exchange requirements carefully!

Between the two versions of the Sweepstakes we have the RTTY version of the Worked All Europe DX Contest. This could be challenging without a good antenna and an amplifier. An interesting feature of this contest is the QTC Traffic bonus points. If you find RTTY boring, or consider yourself an RTTY expert, this is the contest for you. Figuring out how to get your contest logging program to send QTCs to other stations will get your brain cells revved up, and actually managing the process will keep you on your toes in the contest. 

If you aren’t up to sending the QTCs, note that they are optional, so you can still do the contest in a mindless, er, I mean simplified way.

And for microphone aficionados with better-equipped stations, there is a phone contest the  2nd full weekend of November  2019-11-09 0700 - 2019-11-10 1300 UTC  the JIDX Phone Contest. Even if you find yourself with an embarrassingly simple station, Japan is probably the easiest DX we can get from the west coast, and all it costs to try is some time at a radio, so you don’t have anything to lose by giving it a shot. You can find the rules here:  http://www.jidx.org/jidxrule-e.html

For CW operators, November wraps up (November 23-24) with a biggie, and well worth the wait: the CQ Worldwide DX contest. Multipliers by the dozen (CQ zones and countries, per band), and suitable for all stations, big or small. While contacts with our own county don’t count for points (just multipliers), from our location it’s easy to get contacts with the US, for two points each. Starts 00:00:00 UTC Saturday Ends 23:59:59 UTC Sunday The exchange is simple (RST plus CQ zone), so if you love to pound brass, this one is for you! You can find the rules here: https://www.cqww.com/rules.htm

As always, for regular mid-week contest practice, CW contesters have the CWops Weekly Mini-CWT test (http://www.cwops.org/cwt.html) and SSB enthusiasts have the Phone Fray (http://www.perluma.com/Phone_Fray_Contest_Rules.pdf). The SEPAR Tuesday night 2-m net is now starting at 19:15 (PT), which makes it easier to check into the SEPAR net and then jump over to the HF bands for the Phone Fray. The Phone Fray is an easy contest for anyone with HF SSB capabilities, so be sure to give it a shot. (We need some more local action, hint, hint).

As always, you can find a list of most of the latest contests from the (customizable) WA7BNM contest calendar (http://www.hornucopia.com/contestcal/index.html), and by checking the monthly ARRL “Contest Corral” lists (http://www.arrl.org/contest-calendar).

73 & GL in the contests!

------------------------------------

Great Tips…

On a weekend where there are multiple compatible contests running at once, here's a nice way to be able participate in a bunch of them, courtesy of the PVRC Newsletter:

N1MM Logger+ Hint for Multi-Contest Weekends

On many weekends there are more than one contest I might dink around in, like simultaneous QSO parties and the SAC or JA events. In N1MM you have always been able to start up multiple contest logs and go through the "Open Log in Database" menu entry to switch between them. But in version 1.0.5176 or later, N1MM+ now has a nice short cut: · With your cursor in the Entry window, hit ALT+F - that brings up "active" contest log list · Select the number in the list of the contest you want to switch to, type in that number and hit Enter · Voila - you are logging in the other contest.

~ John K3TN

Digital Set Up And Its Ups And Downs

Hi, I am VA7FMR And I am relatively new to the Ham World. I got my licence in November 2015. You may remember my article about antennas and the problems and solutions to making a selection. I have progressed since then and have enjoyed making contacts around North America with my screwdriver Antenna installed on my patio rail.

This is the thing that I like about being a HAM operator, there are so many ways that you can have fun. For example, CAT control of your radio, or “Computer Assisted Tuning” of your radio. Now what could be more interesting than that. You just watch your frequency board in N1MM+ for example and Telnet puts up all of the new contacts that are on the air right now. Just click on one of the items listed on the board and the computer tunes your radio for you, contact made. If on the other hand, you turn your radio knob, the frequency board changes too. How neat is that? And what do you know, this leads us into the next exiting part of HAM radio, Digital Communication.

I was talking to one of our senior club members one Saturday morning and he asked me if I would like to join him at his radio shack to have a look at Digital Contesting. I came away from that morning thinking about all of the contacts we had made with just the push of a button. So again, just like my search for antennas when I first got my licence, I started searching for digital interfaces to hook up to my radio. Unfortunately, I did not learn a lesson from my antenna problems, I just went ahead looking for what I thought would be the best bang for my buck, big Mistake. Since I also have an interest in Morse Code, an advert caught my eye on a web site based in the UK. It boasted that not only did their little black box provide CAT control but it also, in one box, provided two more of what I wanted, digital and CW. I can not of course provide the Manufacturers name of this mistake but I can tell you that it took a long time to realize that this unit did not live up to its claims. I struggled for weeks trying to make this beast work. 

The instruction manual, if you could call a photocopy of 6 sheets stapled together a manual, told me that when the USB cable from the unit is plugged into the computer, 3 com ports are assigned to the unit. It is easy to find out which com ports are assigned by using Windows Settings and then Device Manager to look at the com port numbers. Mine were 3-4-5. The manual told me to run a piece of software on his web page and it would look at the interface and tell me which com port was the CAT control com port. The software told me that CAT was on COM 4. Off I go to N1MM+ logger and in the setup window I tell N1MM that CAT is com 4 and I go through the setup procedure and look to see CAT working, not on your life. My Band Map stubbornly refused to talk to my radio.

This was the start of a six week love and hate relationship between a black box and a very frustrated me. I went on the internet and found instructions that pretty much guaranteed to get you working. I had just replaced the four ink cartridges in my printer and I printed so many documents I ran out of ink in just the first two weeks. The paper and ink Manufacturers loved this black box but I disliked it with a passion. 

On a whim, I went back into the setup of N1MM+ and told it that I was sorry but could I try another com port for CAT Control and I input COM 5 and did the setup thingy again and give that man an orange, it worked. I had CAT control. How could this be? The black box manufacturer told me that CAT was com 4 but here was my black box working on com 5. well winners can't be losers can they? On I went to get started in digital communications. I downloaded MMTTY and FLDIGY. In many of the documents I had downloaded I was told to setup MMTTY as a stand alone entity first. So, that is what I did. Since I had been told by the black box provider that com 3 was digital and com 5 was CW, I started the MMTTY installation with com 3. When setting up MMTTY, there are about 15-20 things that can be changed, one of the downloads gave me a pretty good inclination of what to set and what not to set. Having done the deed I tried MMTTY and nothing happened, no digital for me. 

Now I think you can see where I am going. If CAT was wrong at the black box, could it not follow that the manufacturer was wrong with the other two com ports. Sure enough, after several more days chasing my tail, I got MMTTY to trigger the black box using COM 4 not 3 as the black box manufacturer had stated. It was now time to incorporate all of this junk into N1MM+, you guessed it, not a chance in hell. Although CAT control worked fine the black box did not want to talk about Digital to anyone but it's self. Throughout this debacle I had been in constant contact with John Brodie, now this guy has the patience of a very very patient man. He gave me lots of encouragement and when I felt like wrapping the black box around the refrigerator he came through with calm and patience. A few days into this saga, John had produced a Signalink USB device and suggested that I might like to try it. I wish that I had done as he asked day one. I was now at my Nieces house and had installed My 73' long wire antenna. 

I was going to be here looking after dogs and house whilst the family were away on vacation. The antenna was working like a charm and the BARTG digital contest was due to start in two days. I removed the dreaded black box and installed the Signalink and left it like that until the next day, I had to recoup my own patience quotient and recharge overnight. The next day I had MMTTY talking nicely to the Signalink, incorporated it into N1MM+ and after a false start and a recheck of settings my Icom 7100 went into transmit and I were a digital man at long last. I worked the contest over two days, total about six hours or less and I logged 80 Qso's, including 8 Japanese stations, 1 Mexican station and a Hawaii station for good luck. The remainder were in Canada as far away as Ontario and the United States as far as Connecticut and Florida. I had a ball, I can not impress upon you how good it felt to log stations thousands of Kilometres away.

Well, was there a lesson learned here? There sure was but I should have learned it after my antenna fiasco. Do not go after the super fancy stuff and certainly never rely on a supplier off continent. I read on a public web page that the manufacturer of my unit thought that people who called for installation advice were stupid and inevitably hung up on the caller, what kind of after sale service is that? I can call anywhere in Canada for free on my Cell Phone so that is as far as I should have looked. After sale service is extremely important, particularly to newcomers to the hobby like me and some of you out there. KISS, Keep it simple stupid covers the above problem very well. 

Have I learned my lesson, I hope so.

~ Robert VA7FMR

GNU Radio

Build amazing, working Ham Radio projects on your computer!

Kevin McQuiggin VE7ZD came to a meeting to present GNUradio. 

What is GNUradio? It is an open-source free software package for all major platforms that represents common radio components as blocks, much like the block diagrams you studied for your basic exam. They are assembled and linked together to form receivers and transmitters, referred to as “flowgraphs” in GNUradio.

A filter in GNU Radio - But you do not need to know the math!

How does it work? Radio signals are always “analog” (electromagnetic waves), of course, so an analog “receiver” is still necessary. This is where a cheap $20 USB dongle comes into the picture. These receivers analyze the electro-magnetic spectrum and immediately digitize it. The “numbers” are then streamed to the digital radio processing chain. The math defines signals precisely: AM, FM, SSB, PSK, et cetera. Math can then process these digitized signals to substitute, with much greater accuracy than analog radios, the various blocks of the receiver including mixers, filters, amplifiers, et cetera, and you don’t need math skills.

As with much radio innovation in history, hams are at the forefront and your imagination can allow building general coverage all-mode receivers, Cell site emulators, Radar transceivers and Aviation applications, to name just a few.

Kevin demonstrated a basic FM broadcast receiver in class and showed a video of contacts he has made with Inmarsat, decoding that satellite's data. He followed up with a Saturday morning workshop that was well attended and everyone came away with a better understanding of the program.

An illustration of a GNUradio filter and an FM broadcast receiver

This is a remarkable program, the operation of which should be within the grasp of any ham with a Basic license.

Kevin has promised an article on GNU radio for an upcoming Communicator... stay tuned.

More On Propagation...

Back to Basics

From the Canadian Basic Question Bank

Back To Basics is a regular column in the SARC Communicator Newsletter, available on this blogsite.

B-007-003-002
What is the maximum distance along the Earth's surface that is normally covered in one hop using the F2 region?

A. 2000 km (1250 miles) 
B. 300 km (190 miles) 
C. 4000 km (2500 miles)
D. None, the F2 region does not support radio-wave propagation

There are at least a dozen questions in the Canadian Basic Question Bank that touch on propagation, this is just one of them. The science of RF propagation can take volumes to explain, let’s see if we can summarize the basics.

Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another, or into various parts of the atmosphere. As a form of electromagnetic radiation, like light waves, radio waves are affected by the phenomena of reflection, refraction, diffraction, absorption, polarization, and scattering.

Radio propagation is affected by the daily changes of water vapor in the troposphere and ionization in the upper atmosphere influenced by the Sun. Understanding the effects of varying conditions on radio propagation has many practical applications, from choosing frequencies for Amateur Radio contacts, to designing reliable mobile telephone systems, to radio navigation, to operation of radar systems.

Several different types of propagation are used in practical radio transmission systems. Line-of-sight propagation means radio waves which travel in a straight line from the transmitting antenna to the receiving antenna. It does not necessarily require a cleared sight path; at lower frequencies radio waves can pass through building walls and foliage. Line of sight transmission is used in short to medium range radio transmission such as garage door openers, cell phones, cordless phones, handheld transceivers, wireless networks, FM radio and television broadcasting and radar, and satellite communication, such as satellite television. Line-of-sight transmission on the surface of the Earth is limited to the distance to the visual horizon, about 40 miles. It is the only propagation method possible at microwave frequencies and above. At microwave frequencies moisture in the atmosphere (rain fade) can degrade transmission.

At lower frequencies in the MF, LF, and VLF bands, due to diffraction radio waves, can bend over obstacles like hills, and travel beyond the horizon as surface waves which follow the contour of the Earth. These are called ground waves. AM broadcasting stations use ground waves to cover their listening areas. As the frequency gets lower the attenuation with distance decreases, so very low frequency (VLF) and extremely low frequency (ELF) ground waves can be used to communicate worldwide. VLF and ELF waves can penetrate significant distances through water and earth, and these frequencies are used for mine communication and military communication with submerged submarines.

At medium wave and shortwave frequencies (MF and HF bands) radio waves can reflect or refract from a layer of charged particles (ions) high in the atmosphere, called the ionosphere. So radio waves transmitted at an angle into the sky can be reflected back to Earth beyond the horizon, at great distances, even transcontinental distances. This is called skywave or "skip" propagation. It is used by amateur radio operators to talk to other countries, for diplomatic communications, and by international shortwave broadcasting stations. Skywave communication is variable, dependent on conditions in the upper atmosphere, and can be disrupted by events like solar flares, it is most reliable at night and in the winter. Due to its changing nature, since the advent of communication satellites in the 1960s many long range communication needs that previously used skywaves now use satellites.

Solar activity has a cycle of approximately 11 years. During this period, sunspot activity rises to a peak and gradually falls again to a low level. 

The current prediction for Sunspot Cycle 24 gave a smoothed sunspot number maximum of about 69 in the late Summer of 2013. The smoothed sunspot number reached 68.9 in August 2013, the official maximum. 

We are currently over 7.5 years into Cycle 24. The current predicted and observed size makes this the smallest sunspot cycle since Cycle 14 which had a maximum of 64.2 in February of 1906.

When sunspot activity increases, the reflecting capabilities of the F1 layer surrounding earth enable high frequency short-wave communications. The highest-reflecting layer, the F2 layer, which is approximately 200 miles (320 km) above earth, receives ultraviolet radiation from the sun, causing ionization of the gases within this layer. During the daytime when sunspot activity is at a maximum, the F2 layer can become intensely ionized due to radiation from the sun. When solar activity is sufficiently high, the MUF (Maximum Usable Frequency) rises, hence the ionization density is sufficient to reflect signals well into the 30 – 50 MHz VHF spectrum. Since the MUF progressively increases, F2 reception on lower frequencies can support potential low band amateur radio paths. A rising MUF will initially affect the 27 MHz CB band, and the amateur 28 MHz 10 meter band before reaching 45-55 MHz TV and the 6 Meter amateur band. The F2 MUF generally increases at a slower rate compared to the Es MUF.

Since the height of the F2 layer is some 200 miles (320 km), it follows that single-hop F2 signals will be received at thousands rather than hundreds of miles. A single-hop F2 signal will usually be around 2,000 miles (3,200 km) minimum. A maximum F2 single-hop can reach up to approximately 2,500 miles (4,000 km). Multi-hop F2 propagation has enabled low-band VHF reception to over 11,000 miles (17,700 km).

The correct answer to our question therefore is (C) 4,000 Km (2,500 miles) 

~ John VE7TI

Propagation Prediction

It’s All In The Layers

Someone told me they considered the “magic” of ham radio was the radio signal, but in my opinion the magic is really the radio wave skip propagation that allows world-wide communication without satellites.

You have probably heard another amateur operator mention at one time or another something about propagation being “terrible” or just the opposite, it was “excellent”.  What does this all really mean? I want to take a few minutes to revisit radio propagation outside of what can be found in the usual study guides and perhaps pique your interest in researching further on your own.

Depending on the band your using you may not even use any form of “skip” or atmospheric benefits. An example of this would be line of sight or ground waves used by VHF. Typical repeater use will all but bypass what we often think of as radio propagation. It is true that the signals are “propagating” through the air but not necessarily skipping along the atmosphere to the benefit of either sender/receiver. Actual VHF propagation can still occur to our benefit and allow for distant radio communication in the form of tropospheric propagation and ducting.  This is when under just the right weather conditions a sandwich of moist hot air is trapped between two layers of cold dry air.

But how can we visualize VHF/UHF propagation or know when it’s happening? There is a tropospheric forecast available online http://www.dxinfocentre.com/tropo_wam.html  that visually shows predictions like weather charts show us hot and cold fronts and storms. 

A prediction is only as good as the data the science model shows. How can it really be used by a radio operator? By noticing a storm pattern or simply that the conditions are favourable could mean it’s time to experiment.

However to really visualize real time propagation reports on VHF we turn to APRS. Automatic Packet Reporting System is used by a variety of amateur radio operators to report their location and for messaging via packet radio. APRS equipped VHF radios send out beacon packets on a National frequency of 144.39 MHz and these packets include the sender’s GPS location. All APRS receivers are able to read the beacon packets can record the information. Some of the receivers are Internet enabled and catalogue all the beacons to popular websites like https://aprs.fi.  This information can then be used to show real time VHF propagation reports because we know both the sender and receiver’s precise location and can calculate exactly the distance between each station.

An example of this is the website http://aprs.mountainlake.k12.mn.us/ which adds visual aides to show the direction and distances between sites that have recently been heard.

Digital modes are far better at being received at long distances but the theory is that if packet radio is working, then voice will see a benefit as well. The contacts displayed that are yellow or red are a great distance for VHF and not necessarily line of site.  Without much elevation gain 2-way VHF is limited by the curvature of the earth. Only 6 feet above sea level antennas the distance about 3 miles. Most of the time for VHF use, one or more of the transmitters is well above 6 feet and aides in the transmission beyond the curvature of the earth.

The National VHF calling frequency of 146.520 Mhz FM or 144.200 Mhz SSB can be used during times with good VHF propagation and, if conditions are right,  make some very long distant contacts on 2m. The ARRL confirmed in 2015 that the VHF calling frequency could also be used for contests. http://www.arrl.org/news/use-of-146-52-mhz-fm-simplex-frequency-cleared-for-arrl-contests. This means that with the right conditions a contest on VHF could be great fun.

Larry Shaunce WD0AKX in Minnesota produced a video of VHF ducting https://www.youtube.com/watch?v=gBJQ0Ha9ORM

One of the first methods to help measure HF propagation is to listen on WWV. https://www.nist.gov/time-and-frequency-services/nist-radio-stations/wwv. This is a time and frequency checking station located near Fort Collins Colorado. It broadcasts the local time 24/7 up to 10,000 watts of power on 5, 10, 15 Mhz and 2500 watts on 2.5 and 20Mhz. One way of looking at it might be if you can’t hear this station clearly it could indicate issues running QRP or 100 watts on the nearest band. It can also be used simply to test your antenna and rig since it’s a strong signal running 24 hours a day.  http://tf.nist.gov/stations/iform.html

Unrelated to propagation, ARRL has a contest each year that contestants try to measure an exact frequency. FMT (Frequency Measuring Test) can also be used to determine propagation shifts.   WWV can be used as warm up for those wanting to begin entering the FMT contest world.

http://www.arrl.org/frequency-measuring-test

http://www.k5cm.com/

Beyond the use of WWV and FMT  there are the International Beacon Project . This consists of several key locations around the world each in perfect time synchronization. They rotate their signals and every few seconds a different location can be heard. All you must do is park your radio on the nearest band you wish to operate and listen.

The callsign of the station is sent by CW at 100watts, then long dashes after consisting of gradually less power, 10watts, 1watt, 100milliwatts.   You could somewhat predict how well propagation is on the band by listening for key stations in your region. Find it at URL: http://www.ncdxf.org/beacon/

Long term predictors of radio propagation is the use of tracking space weather specifically the sunspot activity. This is an entire subject in of itself that I personally would like to learn more about. 

We are at the bottom after an 11 year cycle of “good” solar activity.

http://www.swpc.noaa.gov/products/solar-cycle-progression 

Recently I came across an article about the idea of the US Air Force wanting to spread plasma bombs in the sky to improve radio communication. Multiple research teams have been contracted to study this and the current thinking is that some form of small targeted plasma bombs in space could be used to improve radio communication. Perhaps some day we will all be looking at the targeted plasma propagation website? 

http://www.dailymail.co.uk/sciencetech/article-3753417/The-Air-Force-reveals-radical-plan-bomb-sky-improve-radio-reception.html

~ Jeremy VE7TMY

Double Your Range! A Counterpoise For Your Hand-held

A Communicator Reprise

September 2015

The counterpoise (sometimes referred to as a ‘Tiger-Tail’) is typically used in antenna systems for radio transmitters where a good earth ground connection cannot be constructed. In this application, it is simply a 19-inch length of common wire attached to the ground of your hand-held transceiver antenna terminal.

In the photo it is attached to a ring terminal with sufficient diameter to fit under the antenna. Alternatively, it can also be stripped of insulation and simply be wrapped around the antenna base, as long as it makes a good electrical contact.

It is very effective in extending the range of a portable transceiver in that it provides the 'missing' half of the dipole antenna for 2m or 70cm operation. In order to keep antennas short and manageable, radio manufacturers coil the antenna wire into a rubber covered spring—half the antenna. The transceiver body is the other half, but is not very effective from an RF perspective. Those little rubber antennas can have a very high SWR, power reflected back to your radio rather than radiating out. The counterpoise, left hanging straight down beside the radio on receive and transmit provides a much more efficient solution.

Try it with a weak station, you’ll surely notice the difference.

~ John VE7TI

The Power Gate: Keeping The Voltage On

A Communicator Reprise...

 November 2015

The commercial alternatives are good, but pricey. Here is an option for less than $10

In the September and October 2015 issues of the SARC Communicator [and on this blog], we featured circuits that will provide you with a reliable, robust power source. In September 2015 it was Hiu Yee VE7YXG’s simple Gel-Cell Battery Charger, and in October 2015 John Brodie VA7XB’s low cost Battery Monitor Project. This time we’ll round out this series with a device that will automatically switch your station to battery power if the AC fails, and switch it back when the power comes on. It is both inexpensive and simple, yet reliable, as there is only one part.

First, lets look at the commercial alternatives. There are a number of solutions on the market including one, quite expensive, at US$140, known as the West Mountain PwrGate. This device uses solid state devices to charge and automatically insert a backup battery if there is a power outage, and to switch back to the power supply if it is restored.

You will note that the PwrGate above is housed in a large heat sink. This device used Schottky diodes which can generate significant heat. Those fins are there to dissipate that heat. Heat is wasted energy, so we look at an alternative device that is more efficient.

The low-loss PWRGate is billed as being simple, safe, and reliable, and easily able to add backup battery power to your home station or go-kit. The Low Loss PWRgate uses MOSFET power transistors to switch the load between power sources with less than a 20 miliVolt drop, much smaller than systems that use Schottky diodes.  This keeps the power losses to a minimum and delivers full battery power to the load. The device is rated at 25 Amp total, with 3 power outlet ports, ARES standard Anderson Pole Connectors, 3 ozs, and US$49.95 plus shipping by USPS Priority mail. Note that there is no heat sink here, and it does not charge the battery. The distributor, Flint Hills Radio Inc. will also sell you a solar battery charge controller for US$ 39.95 plus shipping and a Smart Lead-Acid Battery Monitor and alarm for another US$ 29.95 plus shipping.

Makes our projects seem pretty reasonable doesn’t it?

So back to the low cost alternative. This device transfers up to 40 amperes at up to 14 volts DC continuously.  It is a safe way to connect both a 12 volt battery and a 13.8 volt power supply to a load, while electrically isolating both from each other.  Whenever your power supply is on, the supply feeds the load, and if you add Hiu’s charger, will also charge the battery, keeping it healthy and ready for use when the power supply is off, or loses AC power, all at a cost of about CA$ 10.00

I did some time in the seventies as a service technician while in my early twenties. One of the products I had some exposure to was alarm systems. In those days before PWRgate, a simple single pole double throw (SPDT) relay was used for the same purpose. The relay is the same as used in many automotive systems. In this application, if the magnetic relay coil is activated, when normal power is on, the contacts switch in the power supply. If the power supply loses voltage, as in a power failure, the magnetic coil is no longer activated and releases the contacts, which then switch in the battery backup. The coil, now deactivated does not rob the battery of any current. A very simple solution with no loss through excessive circuitry or heat. The coil uses a bit of current from the power supply to remain activated, but this is minimal.

These relays are commonly available at auto supply dealers but I ordered mine through eBay and received two, with sockets and mounting brackets, for US$ 3 shipped. They are rated for 12-14 Volts DC and 40 Amps, more than enough to handle the current that most transceivers would draw. Wiring is fairly straight forward and I used three sets of Anderson PowerPole connectors. One for the battery, one for the power supply and one set for the load, being my transceiver. A numbered connection diagram was stamped on the top of the relay I received. The relay coil is wired in parallel with the power supply. If the power supply is on, the relay keeps it feeding the supply circuit. If the power supply goes off current is diverted from the battery.

Once I figured out the contact layout, the actual construction took me only about half an hour, definitely something that can be tackled even by a beginner. Pair this with Hiu’s charger and John’s low voltage alarm and you’re good to go uninterrupted if the power goes out.

~  John VE7TI

HF Antennas In A Restricted Space

A Communicator Reprise

June 2016

I want to share my experience with those of you who have recently passed their test and are looking for that perfect HF antenna that will suit their “New Shack” at their home location. My thoughts were focused on an antenna that would cover as many of the Ham bands as possible, that could be hidden on my apartment patio deck. I did, as most of you will, a lot of reading on the subject and eventually chose a Current Loop Antenna that was the rave in the UK and it set me back about $350 with shipping and tax. I set it up on my patio and I started to tune through the Ham bands and hardly heard a thing, I mean that, apart from static and a couple of stations, one in Alaska talking to a fellow in California, I heard nothing. I was beginning to think that there was something wrong with my radio, a brand new Icom 7100 and John Brodie very kindly invited me to his home and we attached my radio to his antenna. The radio immediately jumped to life with more stations than I could count. I tried several CQ calls and was rewarded with a reply from South Carolina some 2600 miles away, on 70 watts. What a thrill that was. Now knowing that my radio was in perfect shape, I again started to search for the perfect antenna.

Having proved that my radio was fine, I took the current loop antenna apart and put it where the proverbial squirrel stores his winter supplies and started looking for another antenna. I found an antenna called “The Tarheel Antenna” this is a motorized multi band antenna with excellent ratings, it is a mobile Antenna that I could mount to my patio railing and also mount it on my vehicle for away from home outings. Well, although I could hear more stations compared to the Current loop, they were so far below the noise level that they were not useful at all. Having spent another $700 plus on the Tarheel I still did not have a working antenna. All of the successful Hams will tell you that your success is based on Antenna, Antenna, Antenna.

I have reached the conclusion that my location is in a null zone created by the apartment blocks in which I live. The HF Spectrum is a fickle thing sent to try us. Imagine, if you will, a letter L reversed, the bottom leg runs North South and the vertical leg runs East West, the vertical leg being south of the bottom leg. I live on the East side of the bottom leg on the second floor, rite in the corner created by the bottom leg and the vertical leg. My location is protected by both of the apartment blocks.

My mistake was trying to buy the antenna that would cover the most HAM bands as possible, right up front, before checking to see if there were any signals at all. My advise to you and the whole reason for this small article, is to choose an antenna that covers one band, lets say the 20 meter band. Try to buy the cheapest antenna you can find, within reason, try to stay away from the Chinese antennas, they are usually of very poor quality. 

Put up the antenna at night if you are like me and live in an apartment, if you live in a house you will have a lot more room to play with than apartment dwellers. If you can hear contacts that are well above the noise level, have fun and start to build your log book. If like me, you hear little or nothing, you have just saved yourself a ton of money. Buying antennas can be very expensive as I have found to my sorrow.

I have not, however given up. There are lots of opportunities as a mobile station with my Tarheel antenna and setting up, as in the Field Day event, in a park with a long wire antenna. In my opinion, the whole idea of being a HAM is to have as much fun as possible with what you have and I certainly intend to do so.

~ Robert VA7FMR


Since this article was published, Robert has solved his apartment antenna issues. Check out the November-December 2019 issue of 'The Communicator for his solution. It will be posted here November 1st. - Ed.