Automatic antenna tuners: the magic box that makes everything great! Before we get one and expect it to provide us with winning lottery numbers, the location of the Lost Dutchman mine, or the ability to talk to the International Space Station on your HT, let’s look at what it does.
The basic antenna tuners want to add inductance or capacitance to your antenna system, and why do we want to do that? For an antenna to be resonant and work the best, the physical length has to match the wavelength of the frequency we are transmitting.
If we put a random length of wire up in a tree as an antenna,
- it is going to be too long for some frequencies (poor match),
- it will be too short for some frequencies (poor match),
- and it will be just right (resonant) on certain frequencies (good match).
By adding inductance or capacitance, we are able to fool the transmitter into thinking the wire is the correct length and matches the transmitter, and when the transmitting frequency matches the length of the wire, we don’t use the tuner.
So, keep in mind, if you are using an antenna that is already resonant or tuned for the frequency that you intend to use, a tuner may actually make things worse. As the old saying goes, “if it’s not broken, don’t fix it!” If you’re having trouble tuning or transmitting on your antenna, try bypassing the tuner; you may find the antenna is matched and your transmitter is now happy. But, if you do find yourself using a random wire as an antenna (mine is 53 feet long…), you will certainly want an antenna tuner to do the magic and make the wire appear to change lengths to match your transmitter frequency.
Our July 23 ARES meeting will be on the air on 146.840- (MC1). Adam KF7LJH will be leading an SSTV practice exercise. Information on how to set up on your phone or a SignaLink will be sent prior to July 23. We are asking for you to check in via Winlink on the Winlink check in template form. More details will be sent prior to the date.
Be sure you have Saturday July 18 on your calendar for the mobile ARES exercise, “GPS Food Drive – Drive”. This should be a fun one and will get you out of the house and traveling to various checkpoints. Your food donations will go to those who need help feeding their families. You should already have the drill guide in your email. If not, send an email to leadership [at] multnomahares [dot] org and we can send you a copy. You will not want to miss this as we have several surprises for you along your way through the course.
The MCARES annual “Raffle” is coming soon! There are some great items this year. We have figured out a way to do this even though we are not currently meeting in person. Look for an email later in July. This year the raffle is raising funds to equip and build the “Spartan” trailer project.
We all really miss getting together in person and hope this COVID pandemic will get stamped out at some point. Stay safe!
We clocked 237 volunteer hours during the month of June, and we’re currently standing great with 108 active members!
Our June 25 ARES meeting will be online using Webex. Nate NA7EE will be talking about field stations. We hope you will join at 7:00PM. A link will be sent prior to the meeting, so watch your email.
The May and June Winlink drills from home were a great success. We appreciate our members who have participated and honed their skills. Remember to open your Winlink application every month to get the latest updates. Mark Saturday, July 18 on your calendars for the mobile ARES exercise. This should be a fun one and will get you out of the house and traveling to various checkpoints. I think we are all ready to get out of the house for a while! Watch your email for more details.
If you want to monitor you system’s performance, a good SWR (standing wave ratio) meter is a key piece of hardware. With a quick glance at the meter, you can see how your radio, coax and antenna are working. SWR meters come in many shapes, sizes, and styles.
Direct reading meters such as the MFJ-9213 can be identified by a FWD-REF switch and a common dial with a single needle. These meters require the user to set the switch to FWD (forward power) and then push the microphone PTT button and stay in the transmit mode while adjusting the meter to the SET or CAL line on the meter. Then release the PTT button, set the meter to REF, and key the microphone again while reading the SWR value on the meter.
Dual or cross needle meters such as the MFJ-860 require no adjustment. Push the microphone PTT button and one needle will show the power output, while the second needle will show the reflected power. The place on the meter where the needles cross indicates the SWR.
Digital meters such as the MFJ-845 require no adjustments and are the easiest to use. Just push the microphone PTT button and directly read the values from the digital display.
So what does this thing tell me? It will tell me if my transmitter is putting out the correct power. It will tell me how much of that power is being reflected back to the transmitter and it will tell me how well my antenna system is matched to the frequency I am using.
One very important detail about SWR meters is that they are frequency specific. Using an HF meter to test UHF frequencies will result in bad readings. So always make sure that you are using an SWR meter that matches the frequency you are transmitting on. There are many of the old CB meters out there – but remember they were made to monitor frequencies around 27 Mhz and do not work well on other frequencies.
For the month of May, we had 272 volunteer hours. We currently have 109 active members. Also, Eric N9WJQ has rejoined the Bravo team. Welcome back, Eric!
Becoming involved in amateur radio was a surprise to me. When I retired I looked around for a volunteer activity and subsequently joined the Laurelhurst Neighborhood Emergency Team. After a couple of years a colleague suggested we get our Technician license. I thought, “why not?”
Since then it has been a two-year journey of buying equipment and becoming familiar with the technology. I have an ICOM-7100 and a Kenwood D710 in my go-kit. Recently my Elmer, Dana K6BRR, helped me install a 40M Inverted-V antenna. Future projects include working with digital modes using VARA FM and HF. I also co-host a weekly simplex net to encourage amateur radio operators to get on the air and to do propagation testing within the neighborhood.
I am retired from the Boeing Company where I spent half my career in Washington, DC and half in Seattle. I have always enjoyed working on large programs so Boeing was a good match. I worked on Department of Defense contracts and a 10-year program to re-engineer the Commercial Airplanes business processes.
I share my passion for amateur radio with a passion for travel. Some of my more interesting travel adventures have included going through Checkpoint Charlie into East Berlin in the 60s, working in Venezuela, hiking in Lapland, and studying French in Provence. I also spend time gardening, quilting, and practicing yoga and Tai Chi.
It has been a great journey into amateur radio so far – thanks to the members of the MCARES and Portland NET ARO communities who have been so generous with their time and expertise.
I hope everyone finds themselves safe and healthy as they read this! June is almost upon us, which is normally our time to gather for field day where we share tight quarters, communally sup, and greet each other warmly. Unfortunately, epidemiological prudence demands a different tack. I am bummed, but I hope we all can make the most of the weekend of June 27 nonetheless.
Since we cannot meet in person, I am encouraging everyone to execute Field Day by operating field stations in their own backyards or physically-distanced location of their choosing. Given the number of MCARES operators, there should be contacts to be made locally even if VHF FM voice is your only operating mode. Since contacts count for points on each different band, this could also be a great excuse to expand into 6m operations if you’re interested. The sheer number of folks on the air can make the magic band seem alive for long distance contacts! In the spirit of the event, we should all strive to operate via auxiliary power (batteries or other) as well.
The gist of the operating on Field Day is a contest format with a standard exchange. Since there are usually so many stations operating, there is often great leeway granted to newer operators during Field Day. So don’t stress about the radio operations themselves; dive in and have fun. The best place to start is the ARRL’s Field Day page. A YouTube binge for Field Day videos is also a great way to start if you’re completely unfamiliar.
The rules are somewhat in-depth, so if you have questions after you review them, I encourage you to bring them to the June general membership meeting. Hopefully we can address everything at that time so everyone can operate with confidence. I hope to hear a lot of local “One-Echo-Oregon” stations on the air this Field Day!
Is your radio acting strangely? Coughing? Runny antenna? Watery display?
A quick way to check its overall health is with an amp meter. If power is going out, then your radio will be sucking power in! The amp meter is the thermometer of the radio world.
A quick review of your manual will tell you what your radio consumes when putting out full power. Most mobile radios will consume 20-22 amps. So don’t hesitate; if your radio seems sickly and you think it’s got the coronavirus, stick an amp meter in its mouth and key the mic and see if its temperature is normal. 22 amps on the meter? It’s not a virus!
If your 700 amp, klystron powered, 473 pound linear (another topic for another day!) power supply does not have a built in amp meter, you can certainly find one, like the one pictured here, on Ebay for around $10. A quick set of Anderson power pole connectors on each end and the doctor is ready to check radios!