From my Twitter feed: FreeDV, W3EDP antenna, IARU on WRC-15

I haven’t been a big advocate of digital voice (DV), but I’m beginning to think it might be fun.

ke9v
Saw a little FreeDV love on Planet Ubuntu in the form of this post. Nice job by 9M2PJU.http://t.co/bdlzFMKVKU #hamr

 

Also, see My Favorite Cheap HF Antenna, The W3EDP on KG4GVL’s blog.

KG4GVL
Latest update on the W3EDP antenna. by: Brandon, the Random Man: More on the W3EDP http://t.co/niN6lzHAUO

 

Are more HF allocations in our future?

amradvictoria
IARU announces WRC-15 positionshttp://t.co/jFofmX02FF #hamradio

 

Amateur radio tip of the day: Low SWR isn’t the “be all and end all” it’s sometimes made out to be

Ham Radio Tip of the Day
————————————————————
Today’s tip is from Bob, KG6AF. For submitting this tip, Bob will get one of my e-books. Thanks, Bob!

Low SWR isn’t the “be all and end all” it’s sometimes made out to be. Just because you measure a low SWR, it doesn’t mean that your antenna is radiating efficiently. Conversely, a high SWR doesn’t mean that an antenna won’t radiate. Remember that a 50-ohm dummy load has a 1:1 SWR.

Most modern rigs will reduce or cut off transmit power if the SWR the transmitter sees is higher than 2:1, so you do have to make sure that the impedance the transmitter sees at the antenna connector is close to 50 ohms. To do that, we often use an antenna tuner. An antenna tuner will make the transmitter happy, but that doesn’t mean that the transmitter’s output power is being radiated by the antenna. There are many other factors that come into play.

Take the time to read reliable material on the subject. The ARRL Guide to Antenna Tuners, by Joel Hallas, W1ZR, is a good starting place. You can also find lots of solid information in the QST archives.

73!

Dan KB6NU

THIS WEEK’S WINNER!
Every week, I select one of this list’s subscribers to get one of my e-books. This week’s winner is Jared, N7SMI.

SUBSCRIBE
Tips like this one are sent out every day by e-mail. To subscribe to the list, simply click here and fill out the form. Every week, I’ll select a random subscriber and give them one of my books.

GOT A TIP?
Do  you have a tip that you’d like to share with other radio amateurs? E-mail it to me. If I use your tip, I’ll send you one of my books.

Tip of the Day: Add elements to make a single-band dipole a multi-band antenna

You can make a make a simple dipole antenna into a multi-band antenna by adding an additional set of elements for the band you want to operate. A couple of years ago, I added 30m elements to my 40m dipole and now it works on both 40m and 30m. The reason this works is that when operating 40m, the 30m elements present a relatively high impedance, while the 40m elements a relatively low impedance. RF current, like any kind of electrical current will take the path of least resistance.

As shown below, the 30m elements hang down below the 40m elements. If you space the elements close to one another, you may have to tweak the lengths of the elements for the best SWR. In my case, that wasn’t a problem.

fan-dipole

If two bands is good, why not four or five? Yes, you can do that. You can add as many bands as you have space and wire for.

SUBSCRIBE
Tips like this one are sent out every day by e-mail. To subscribe to the list, simply click here and fill out the form. Every week, I’ll select a random subscriber and give them one of my books.

GOT A TIP?
Do  you have a tip that you’d like to share with other radio amateurs? E-mail it to me. If I use your tip, I’ll send you one of my books.

From my inbox: 43 years of 73 magazine, SP DX contest, useless answer

I found these three items in my inbox this past week…Dan

73-apr-67-cover43 years of 73 on-line
Wayne Green has now released all back issues of 73 to the public domain. Although the last issue was published more than ten years ago, there’s still lots of good stuff to be found in them. You can download individual issues by going to archive.org. Indexes can be found on these web pages…

The first lists the contents of each issue. The second has direct links to the to the issues at archive.org.

The cover shown at right, a takeoff on MAD Magazine, is one of my favorite covers. Take a closer look at the soldering job Al Freddy is about to attempt. Click on the image to get a larger version if you can’t quite make it out.

Wayne Green actually published the first article that I ever wrote, “Assembling Robots with a TRS-80.” I was 23 or 24 at the time. It was published in Byte, arguably the first widely-read magazine for computer hobbyists. The article was a short one on how to program in assembly language on the TRS-80. It displayed a robot-like thing on the screen using the blocky graphics available on the TRS-80.

 

SP DX Contest actually wants my log
A month ago, I made a few contacts in the SP DX Contest. It was only 20 contacts or so, and I had meant to submit the log, but I soon forgot about it. Well, this morning, I go this e-mail:

The first review of logs received for the SP DX Contest 2013 shows that your callsign KB6NU apears in many logs. However you propably have not submitted your log.

The SP DX Contest took place during the first weekend of April (2013.04.06-07). This year we are celebrating 80th Anniversary of the SP DX Contest as it was organized for the first time in 1933. We would like to make the log checking process as accurate as possible. It will also be a honour for us to list your callsing in the final results.

We would kindly ask to send your log to the SP DX Contest Committee, even if you made only a few contacts, even if perhaps you are a causal contester.

Well, how can I refuse? I’ll have to do this as soon as I can get down to the museum again.

 

Useless answer department
I’ve been doing writeups for the product pages on AmateurRadioSupplies.Com. (Yes, that’s a plug for them, but they’re paying me to do these writeups, and they’re even advertising here on KB6NU.Com.) For the past week, I’ve been working on coax descriptions.

In doing this, one question that came up is why does marine grade coax have a white jacket? I e-mailed a question to Marinco tech support, and got the following answer, “It’s hard to say but I think it is to distinguish it  as marine grade vs. house cable.”

Seriously? That’s all there is to it? Does anyone know the real answer?

From my inbox: CQ Burger King, BPL, solderless PL-259

Amateur radio plays a big part in this new Burger King ad.

 

FCC Denies ARRL BPL Petition. As this commentary from TV Technology notes, the FCC denied the ARRL’s that BPL systems include full time notching of amateur radio frequencies and an increase in the required notch depth from 25 dB to 35 dB. They also say, “While the Second MO&O isn’t good news for amateur radio operators, utilities seem to have lost their interest in using BPL to provide residential Internet access…and smart meters so it may have little real impact.” Let’s hope it stays that way.

Solderless PL-259. On the AMRAD mailing list, one ham writes:

Shakespeare has been in the marine antenna business since shortly before the discovery of oceans and they have a couple of bits of kit which you might consider for your ARES or Field Day bug-out box. They make a PL259 and a coax cable spice which go together with nothing but a knife sharp enough to cut the plastics and a pair of pliers. I wouldn’t try running the legal limit through these (the coax they fit wouldn’t like it either) but i have used the PL259 for up to 100-watt service and they have performed admirably.

They are kind of expensive at around $15 a pop, but they do look like quality parts and that they’d work pretty good in a pinch.

Putting up another antenna

When I got home from the Ann Arbor Hands-On Museum on Saturday, I called up my friend Mark, W8MP. I wanted to tell him about my contact with OG3077F, a Finn who has successfully worked all 3,077 U.S. counties. As it turned out, Mark has worked him several times. I should have suspected this. Mark seems to know everyone.

As we continued our conversation, he mentioned that one of his son’s friends had put up an antenna and that they were going over there to help him tune it up that afternoon, and he asked if I’d like to join them. Mark’s son, Brian, is KD8EEH, and his friend, Alec, is KD8RGP. To be honest, I was a little hesitant. I was kind of tired after walking home from the museum, but Mark twisted my arm a little, so I agreed to head over there.

On the phone, Mark suggested that I might want to bring over some coax and some other kinds of antenna-making stuff, so that if we needed to make modifications, we’d have the wherewithal to do it. So, I loaded my crate of antenna parts, my toolbox, my 100-ft. tape measure, and a spool of coax into my Mini.

When I got there, I found that Alec was way ahead of us. He actually had already set up a 20m dipole. One end was suspended from an old, now unused power pole at the back of Alec’s backyard. The other was suspended by a rope draped over a downspout.

The construction was actually quite ingenious. For the center insulator, Alec had drilled some holes in a small block of wood that provided both strain relief for the wires and a way to mount an SO-239 connector. I wish I’d taken a picture of it. The end insulators were made from some scrap plastic.

The Budwig HQ-1 center insulator is a great way to build a dipole

The Budwig HQ-1 center insulator is a great way to build a dipole

Ingenious though it was, I suggested that we might wan to rebuild the antenna with an HQ-1 center insulator (right) to make it more reliable. While we were at it, I also suggested that we use a set of HQ-2 insulators for the ends. Mark got the boys working on disassembling the current antenna and rebuilding it with the new insulators, and in a short time, it was back up in the air.

Because Alec had already routed the coax down to the basement, we all tromped down there to see how well it tuned. Yipes! It looked to be way long. So, we lowered it, shortened each side by six inches and tromped back down stairs. We were closer this time, but it still needed to be shorter, especially since we were tuning this for the phone portion of the band. We shortened it by another six inches, and bingo, this time we got a nice dip right around 14.25 MHz.

Flush with success, someone suggested that we might want to add 40m elements to the dipole. This sounded like a good idea to me, and I told them about the 30m/40m dipole that I have. After a little discussion about whether to use feet or meters to calculate antenna length (we decided on inches as my tape measure is ruled in feet and inches), Alec started scrounging around for some wire.

At first this looked like it was going to be a problem. There was one 28-ft. length, and a couple of other odd lengths, but it wasn’t clear that we were going to be able to make two, 33.5-ft. lengths from the pieces we had. We finally did figure it out, though, and the antenna was lowered, and Alec attached these elements to the center insulator.

As it turned out, there were some convenient supports for these elements that allowed this dipole to be oriented nearly perpendicular to the 20m dipole. On one end, the boys used a tree, and at the other end, the wire was draped over another a downspout on the opposite side of the house.

We again tromped downstairs to check the resonance. Again, we were quite long. We lowered the antenna and shortened it by six inches on each end, then measured again. This time, the resonant point was just below 7 MHz. This time, we shortened the antenna by nine inches on each side, and the resonant point was just about in the middle of the General Class portion of the 40m phone band.

Of course, the proof of the pudding is in the eating, so we told Alec to get on the radio and see if we could make any contacts. Tuning around, Alec found a few stations working the Missouri QSO Party. He called a couple of them, and worked them on the first call.

At that, we called our efforts a success, and went upstairs to eat some take-out curry that Alec’s parents had gotten for us. Over dinner, we all patted ourselves on the back. I’m sure that Alec is in for a lot of fun on 20m and 40m.

Ads of note from the April 2013 QST

I couldn’t sleep this morning, so rather than just lie in bed, looking at the ceiling, I got up and made myself a (very) early breakfast. Whilst eating my eggs and cantaloupe, I scanned the ads from the latest QST. Here’s what caught my eye:

The TT1A costs $129, and that doesn’t include the 200 V power supply. Yipes!

  • YouKits (page 128). YouKits is offering a new kit this month – the TT1A two-band, two-tube CW transmitter. It’s very cute, but according to the YouKit website, it costs $129 (plus $29 shipping), and even at that, you have to buy or build a 250V supply to power the thing. Call me crazy, but I think that’s a bit much for a 4W transmitter, don’t you? I think I’d rather spend that money on the Funk Amateur SDR kit (see below). TenTec is YouKits U.S. distributor, but I don’t find this kit on the TenTec website yet.
  • Mosley Electronics (page 132, 153). Mosley has been making quality antennas for many years. In the April 2013 QST, they are running a very small ad on pages 132 and 153. I guess they have such a good reputation that they really don’t need a big ad. You’d think that I’d be more familiar with their products (since I’ve been a ham for many years), but I’m not really. Their ad prompted me to go to the Mosley website, where I found out that they not only made beam antennas, but verticals and dipoles as well. In addition to information about their products, there is information about antennas in general. I particularly liked the short article on “SWR-itis.”
  • Funk Amateur (page 147). A lot of amateur radio operators are funky, but “funk” in this case is German for radio. This German company is offering two kits: the FiFi SDR kit, which is a 0.1 – 30 MHz SDR receiver for $169, and a voice keyer kit for $55. Both prices include shipping to the U.S. I’m going to contact them and see if they’re going to be at Dayton. If not, I might just pop for one or both of the kits.

U-M ARC needs antenna ideas

W8UM

The University of Michigan Amateur Radio Club is celebrating their 100th anniversary this year. The recently reinvigorated club has a great station, W8UM, in the Electrical Engineering and Computer Science (EECS) Building on U-M’s North Campus.

The University of Michigan Amateur Radio Club is celebrating their 100th anniversary this year. To celebrate, they’re planning to operate a special event station from the Diag, an open space in the heart of the campus.

The problem they’re having are all the rules for such an event. For example, the event can’t be too noisy, even though it’s outside.

The biggest problem they’re having though is trying to come up with an antenna setup that the powers that be will approve. They can’t, for example, drive any stakes into the ground. Supposedly, that will damage the lawns. That rules out the 40m/20m inverted-V setup supported by the surplus fiberglass masts that we often use for these kind of temporary operations.

There’s also a rule that whatever structure is erected be no higher than eight feet tall. That also rules out the use of the fiberglass mast.

There are some trees near where they want to set up the station, but the grounds department have concerns about ropes in trees. That kind of rules out dipoles.

This morning, it occurred to me that we probably could use BuddiPoles and/or BuddiSticks. We could easily keep them under eight feet, and if operated vertically, they could be decent antennas. Using an insulated wire for the counterpoise should be safe enough.

I’d like to hear what you think, though. What kind of antennas have you used for this type of operation? Do they meet the restrictions these guys must meet?

Found my 20m noise source

About three months ago, I finally put up another 20m antenna—an end-fed, half-wave antenna. Right off the bat, I was flummoxed (I love that word) by the high noise level. It was nearly S9, obliterating all but the strongest signals.

I thought it had to be something to do with the antenna. I was not experiencing any noise on any of the other bands, after all.

As it turns out, though, the source of the noise is the laptop power supply. I had taken the laptop somewhere on Wednesday, and when I returned it to the shack that evening, I switched the rig over to 20m before connecting the power supply back to the laptop. No noise! When I plugged the power supply into the laptop, the noise jumped up to S9 again.

What’s really confusing about all this is that I don’t hear this noise on any other band. They’re all completely quiet. Like I’ve said before, sometimes 40m is so quiet that I wonder if the antenna is even connected.

At any rate, the last couple of days, I’ve been working 20m with the power supply disconnected, running the laptop off the battery, and the results have been quite good. This evening, for example, I worked several DX stations, including 6W/HA0NAR in Senegal.

Amateur Radio Videos: Velveeta, soldering PL259s, antenna polarization

Here’s a collection of ham radio-related videos that I’ve run across in the last week or so. I need to start doing videos. Anyone wan to help me out?

Velveeta? Really? Kraft is using ham radio to plug Velveeta cheese. It’s pretty cheezy (pun intended), but funny, too. Seriously, though, I hope not too many of you out there eat this stuff. If you need a recipe to make some “real” macaroni and cheese, I’ll post my recipe here.

PL-259 Connector Installation. Thanks to Alex, N3DER, for posting a link to this video on the Tacos mailing list. The video’s creator, Murray, W9EHQ, is very thorough and presents a very good technique for installing PL-259s onto coax. Lately, however, I’ve been using crimp-on PL-259s. Crimping the connectors is much easier than soldering them. Phil, M1GWZ, is also not sold on this technique. He notes, “I didn’t find the video entirely convincing. For a start, he remembered to put the plug cover on the cable before soldering the connector on. I’ve never seen anyone do that before.  :-)”

Yagi and Lightbulb Antenna – K0NR. Bob, K0NR, demonstrates polarization using a simple 2m dipole with a lightbulb connected between the two elements. I’ve done this demonstration down at the Hands-on Museum. It’s a really good way to show how polarization works.