Amateur radio in the news: Purdue club

Geoffrey Stewart, son of Andy Stewart of Chelmsford, operates his ham radio. His call sign is KB1USE. COURTESY PHOTO

Ham radio: the original social network
Andy Stewart and his friends could be considered revolutionary. “The jokes that I hear are that ham radio was the original social network,” he said.

Purdue’s ham radio club turns 100.
During open house, members can spend their time however they want. Most of the time, members learn more about ham radio, make new contacts from around the world and fix radios. One time, a few members even made a credit card scanner just for fun.

Volunteers vital to Weather Service during severe storms
With the forecast calling for possible severe weather Thursday, the National Weather Service expects to call on its team of weather spotters. They include Roane County ham radio operator Phil Newman. For 16 years, Newman has communicated to fellow operators around the region and the world….

KB6NU places second for Michigan in the Florida QSO Party

I got this in the mail yesterday:

2012-fqp-certificate

My first thought was, “Boy, it sure took them a long time to send this to me.” I honestly don’t even remember working this contest.

Then, I saw the info sheet for this year’s contest. The 2013 Florida QSO Party takes place the weekend of April 27-28. They’re just trying to drum up business. I’ll have to try to get #1 this year. If you’re in Florida, listen for me.

Deciphering schematics like solving a puzzle

My brother, Mike, goes to estate sales. (He also blogs about estate sales, following a fine family tradition.) He finds all kinds of cool stuff at these sales, but for the past year or so, he’s been most keen on acquiring pinball machines. He now has a shuffle bowling machine and a Merry Go Round pinball machine.

Mike is an accountant, and because he had very little technical training, he asked if I would help him troubleshooting the electrical parts of the machine. Being a former pinball player myself, I said sure. It’s been a lot of fun. Deciphering the schematics—and, fortunately, the schematics for most of these machines are readily available—is like solving a puzzle.

The Merry Go Round machine is a good example. Below, is the schematic of the primary circuit of the machine. (Click on the image to get a larger version of it.)

Figuring out how this circuit is supposed to work was a lot of fun.

Figuring out how this circuit is supposed to work was a lot of fun. (Click on the image to get a larger version.)

Shortly after he bought this machine and got it down in his basement, he called me and said, “It doesn’t work. I plug it in and nothing. No lights. Nothing.” I told him to take a picture of the schematic with his camera and send it to me. I got an email with the image above minutes later. Now that we were literally working off the same page, we could figure out what was wrong.

One of the first things I noticed is that the component symbols are drawn a little differently than the symbols we use in electronics. This can be seen on the bottom line of the schematic. The switches almost look like capacitors.

Another difference is that both mechanical switches and relay contacts are drawn the same way. The switches are given a name, such as “ANTI-CHEAT SW,” while the relay contacts are labelled with a single letter. The relay coils are also labelled with a letter making it easy to determine what relay coil closes which contacts.

Once I figured that out, I started decoding the circuit logic. Unlike some machines, this one does not have an on-off switch. After staring at the schematic for several minutes, I figured out that the key was the COIN CHUTE switch. This switch is supposed to be activated when someone puts in a dime. Closing that switch allows current to flow through the K relay, which closes the K contacts. One of the K contacts applies power to the transformer primary.

I had my brother plug in the machine, then very carefully close the COIN CHUTE switch with a screwdriver. This was necessary because the coin mechanism wasn’t working right. Unfortunately, nothing happened when he did this.

Next, I had him check the switches on the very bottom of the schematic: ANTI-CHEAT SW, SHUTOFF SW, and the BOUNCE SW. As you can see, all of these have to be closed for power to get to the transformer primary. I told him to unplug the machine and then use his multimeter to measure the continuity between the switch terminals. After a discussion of what range to set his multimeter to, how the meter measures resistance, and why unplugging the machine was necessary, he did so.

At first, he reported that all three switches were closed. We were doing this over the phone, so I had to take his word for it, but that just didn’t seem right. If they were all closed, something should have happened.

I thought it might be possible that the K relay coil was open or maybe shorted, so I had him check its resistance. It measured about 400 ohms. I then had him measure the resistance of the E coil. That also measured about 400 ohms. Since the both measured about the same, I guessed that they were probably OK.

So, I had him check the switches again. This time, he found that the BOUNCE SW mechanism seemed stuck open. He fiddled around with it, and when he thought he’d gotten it closed, he plugged in the machine again and tried the COIN CHUTE switch again. Success! Lights came on and the motor started turning.

He’s got a lot more work to do before we can start playing the game. Bumpers need to be replaced and the scoring wheels need to be cleaned and lubricated, but we learned a lot about the machine with this exercise. It won’t be long before we’re playing pinball.

Upcoming amateur radio events

KB6NU teaching the Jan. 14, 2012 One-Day Tech Class

Me making a point (apparently about SWR) at a recent One-Day Tech Class

Here are some upcoming amateur radio events here in Ann Arbor, MI:

  1. VE Testing. ARROW, the club here in Ann Arbor, conducts an amateur radio license test session ever second Saturday of the month at the Washtenaw County Red Cross, 4624 Packard Rd., Ann Arbor (map).

    Preregistration is recommended but walkins are welcome. Contact Mark Goodwin – W8FSA (734-944-0730) mrkgoodwin@comcast.net, Beverley Stoner – K8ZJU (734-424-9446), or Ralph Katz – AA8RK (734-663-1288) aa8rk@arrl.net, for more information, and to register for the test.

  2. University of Michigan Amateur Radio Club’s 100th Anniversary Special Event Station. The University of Michigan Amateur Radio Club is celebrating its 100th anniversary by operating a special event station on Sunday, April 14 on the Diag on central campus. Setup is going to start around 1300Z. We’re hoping to start operating around 1400Z and continue until around 2200Z. If you’re in or near Ann Arbor, please come down and operate with us. If not, listen for us on the bands.
  3. One-Day Tech Class, Saturday, April 27. I’ll be conducting the next one-day Tech Class on Saturday, April 27, at the Ann Arbor Hands-On Museum. Go to wa2hom.org for more details.

From my Twitter feed: HF receivers, voltage reference, FDIM

ke9v
A History of HF Receivers | Smoke Curlshttp://t.co/A2uHc38mic #hamr

 

dangerousproto
Erl’s voltage referencehttp://t.co/X0MOESc8BO

I need to build one of these……Dan

 

qrparciFDIM 2013 (Dayton) – Full seminar schedule now online http://t.co/9eWdTI0FEx #hamr#qrp #hamvention

I’ll be attending FDIM. If you see me, say hi….Dan

I’m a TV star (well, on community TV, anyway)

Randy, N1NEZ, asked me to speak about amateur radio for his community TV show, “Exploring Hobbies.” This was a lot of fun. We did over a half hour on amateur radio, and we only touched on some things.

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.

WA2HOM Operating Report: Toad Suck, counties, Polish DX

I had a blast down at WA2HOM today.

One of my first contacts was with W5STR, the club station for the Small Town Amateur Radio Service (STARS), a club in Arkansas. The club was operating from a campground in Toad Suck, AK. Yes, you read that right–the place they were operating from is named Toad Suck, a place that a recent poll says has the “most unfortunate name” in the U.S.

As you may know, I’m a sucker (pun intended) for odd place names. That being the case, I had to find out how Toad Suck got its name. According to their website:

Long ago, steamboats traveled the Arkansas River when the water was at the right depth. When it wasn’t, the captains and their crew tied up to wait where the Toad Suck Lock and Dam now spans the river. While they waited, they refreshed themselves at the local tavern there, to the dismay of the folks living nearby, who said: “They suck on the bottle ’til they swell up like toads.” Hence, the name Toad Suck. The tavern is long gone, but the legend lives on.

I love it.

og3077f_back_1_

Next, I worked Heikki, OG3077F. On his QSL card, found on QRZ.Com and shown above, Heikki says, “I applied for this special callsign to commemorate my contacts with all 3,077 U.S. counties, all on CW, which took me 24 years to complete. I started chasing U.S. counties in 1987, which I met Bud, W0UBT, in Minnesota. He gave me the USA County Record Book, as a gift, and upon my return to Finland, I started to fill it up. Many thanks to all of my local and international county hunter riends for all of your support throughout all of these years.”

Finally, I worked 20 stations in the Polish DX contest. One of the stations I worked was SP9ATE, whose QSL card will be a nice addition to my collection of QSLs from stations whose callsigns spell words. I almost worked SP9GEM, but after many attempts to get him to copy my callsign, he gave up and went on to the next QSO.

From my Twitter feed: scholarships, testing power supplies, MT63

Lots of cool things in my Twitter feed this morning…….Dan

k9hi
Apr. 15 deadline is fast approaching for FAR scholarship applications. Seehttp://t.co/8eCHFvTM1x #hamr

dangerousproto
How to measure stability when testing power supplies http://t.co/WkzW6ZXMKD

hamradiopodcast
VOA Radiogram features MT63http://t.co/gslMp6qukr

ARLB008 FCC Seeks to Reassess RF Exposure Limits

fcc-sealI find the topic of RF exposure very interesting. It seems to me that back in the 1960s and 1970s, when I was just getting into radio, we never even thought about exposure. Now, people go crazy over it. Here in Ann Arbor, for example, the power company is installing “smart” power meters that send data via a cellular system back to a system that monitors power consumption. These devices are  low power at a low duty cycle, yet consumers are getting all bent out of shape about it…Dan

SB QST @ ARL $ARLB008
ARLB008 FCC Seeks to Reassess RF Exposure Limits

ZCZC AG08
QST de W1AW
ARRL Bulletin 8 ARLB008
From ARRL Headquarters
Newington CT April 4, 2013
To all radio amateurs

SB QST ARL ARLB008
ARLB008 FCC Seeks to Reassess RF Exposure Limits

On March 27, the FCC released a First Report and Order, Further Notice of Proposed Rulemaking and a Notice of Inquiry (ET Docket Nos. 13-84 and 03-137). The documents seek to reassess the FCC’s RF exposure limits and policies, as well as to propose changes to the FCC’s rules regarding human exposure to RF electromagnetic fields. These proposed changes would affect the Amateur Radio Service (Part 97) rules. The First Report and Order can be found on the web in PDF format.

In the 201-page document, the FCC noted that “[p]eriodic review of the government’s rules and regulations to ensure they have kept pace with current knowledge and changing needs is an important characteristic of good government, and we here will advance the process of providing a comprehensive review and modification, where appropriate, of this Commission’s various rules pertaining to the implementation of the National Environmental Policy Act (NEPA) requirements for environmental reviews, specifically those reviews related to health and safety of radiofrequency (RF) emissions from radio transmitters. Our actions herein are intended to ensure that our measures are compliant with our environmental responsibilities and requirements and that the public is appropriately protected from any potential adverse effects from RF exposure as provided by our rules, while avoiding any unnecessary burden in complying with these rules.”

The document is divided into three parts: a First Report and Order (First R&O) and a Further Notice of Proposed Rulemaking (FNPRM) in ET Docket No. 03-137, and a Notice of Inquiry (Inquiry) in a new docket, ET Docket No. 13-84. In the R&O, the FCC looks at several technical and semantic issues — initiated in 2003 — to be revised and updated; in the FNPRM, the FCC proposes to further update and revise its procedures and treat all services equally.

In the Inquiry, the FCC seeks comments to determine whether its RF exposure limits and policies need to be reassessed. “Since consideration of the limits themselves is explicitly outside of the scope of ET Docket 03-137, we propose with the Inquiry to open a new docket to consider those limits in light of more recent developments,” the FCC said. “The Inquiry is intended to open discussion on both the currency of our RF exposure limits and possible policy approaches regarding RF exposure. We look forward to developing a complete record to determine whether the current rules and policies should remain unchanged, or should be relaxed or tightened.”

According to the FCC, mitigation matters are “post-evaluation procedures to ensure exposure limits are not exceeded, such as labels, signs, barriers, enforcement and occupational issues.” In its Notice of Inquiry, the FCC included clarifications related to the application of occupational exposure limits for devices and at fixed transmitter sites. The FCC noted that it “should be helpful to licensees to codify our earlier adopted policy with regard the use of occupational/controlled limits at Amateur Radio stations.”

This policy was first established in the RF Report and Order of 1996, but it was not incorporated in the rules at that time. It allows amateur stations to be evaluated “with respect to occupational/controlled exposure limits, as long as appropriate training and information has been provided to the amateur licensee and members of his or her immediate household. Other nearby persons who are not members of the amateur licensee’s household must be evaluated with respect to the general population/uncontrolled exposure limits.” The FCC will codify this policy by adding a paragraph as a new sub-section in Section 1.1310 — radiofrequency radiation exposure limits — to its rules.

The FCC pointed out that one goal of the general exemptions from routine RF exposure evaluation proposed “is to avoid specific exemptions for particular services and ensure a consistent set of rules without exceptions.” With this in mind, the FCC is proposing to delete the special exemptions from evaluation in the Amateur Radio Service in Section 97.13(c) of its rules.

“We appreciate that Amateur Radio operators are knowledgeable about the appropriate use of their equipment, such that separation distances are likely to be maintained to ensure compliance with our exposure limits,” the FCC said. “However, since the existing amateur exemptions are based only on transmitter power and do not consider separation distance or antenna gain, exempt transmitting antennas that are unusually close to people could potentially lead to non-compliant exposure levels.” The FCC said that a separation distance of at least 24 feet would meet its proposed exemption criteria, “considering a currently exempt 50 W transmitter at VHF in accord with Section 97.13(c) and assuming an antenna gain of 6 dBd.”

The FCC noted that existing classification of amateur exposure as occupational “is consistent with use of our proposed general exemption criteria based on general population exposure limits because awareness of exposure greater than the general population limits is required in all occupational settings, including amateur households. Application of the general exemptions proposed here to Amateur Radio installations would preclude the possibility of overexposure and require further evaluation only when necessary, giving guidance for both fixed and mobile transmitting antennas.”

The FCC invited comments on how this would affect the amateur community: “Parties that support maintaining the current exemption based on power alone are requested to explain how it provides adequate assurance that the public is protected against exposure to RF energy in excess of our limits and the extent of the burden imposed by this proposal. We encourage interested parties to comment on the relative costs and benefits of the proposed changes in this section, as well as those of alternative approaches.”

“The ARRL has an RF Safety Committee, consisting of experts in the field,” explained ARRL Chief Executive Officer David Sumner, K1ZZ; “The committee members, as well as Board members and staff are reviewing the lengthy document and will formulate a response.”

Comments will be accepted until 90 days after the R&O, FNPRM and Notice of Inquiry are published in the Federal Register (this can take up to six weeks after its release by the FCC). Reply comments will be accepted until 150 days after publication in the Federal Register.
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