JOHNSON COUNTY RADIO

AMATEURS CLUB, INC.

P.O. Box 93Shawnee Mission, KS 66201

FEEDBACKMARCH 2016

The JCRAC was well represented atthe WW1USA commemoration of

the Battle of Verdun.

Bill Brinker, WAØCBW explains"SWR and other Mysteries".

MARCH MEETINGS

March 11 – Military Auxiliary Radio

System (MARS) - Kent Dickinson,

KØWEW

March 25 – Remote Operations -

John Raydo, NØIZ

The Johnson County Radio Amateurs Club

normally meets on the 2nd and 4th Fridays

of each month at 7:30 PM at the Overland

Park Christian Church (north entrance),

7600 West 75th Street (75th and Conser),

west of the Fire Station.

Much of the membership travels to the

Pizza Shoppe at 8915 Santa Fe Drive for

pizza buffet and an informal continua-

tion/criticism/clarification of the topics

raised at the meeting ... or anything else.

Leave the church, turn right (west) on

75th. Turn left (south) on Antioch. Turnright (west) on Santa Fe. Pizza Shoppe isjust past the Sonic on your left.

The success of inter-club cooperation with WW1USA led to theestablishment of the MO-KAN Council of Clubs--shown at its first

meeting, above left and right--to co-ordinate activities in the metro area.IN THIS ISSUE

1 - February Photos

2 - President's Corner

3 - February Meeting Minutes

5 - Hambone Goes HF or Dude Saves the Day - Jaimie Charlton, ADØAB

8 - The Amateur: Harmonic Resonance and the HeterodyneHoax - Chip Buckner, ACØYF

11- Member Profile: Barb McKinney, KEØEGG

12 - Adapting Microphones to Yaesu Transceivers: If It's Not Broken, Then Fix It! - Tom Wheeler, NØGSG

Kathy Carter, RJ Wheeler and SteveCarter visited the club the nightbefore taking their license exams

Coloradans Aldis Strautins, NØTFJand John Raydo, NØIZ (decidedlyNOT a first timer) visited the club

- 1 -

-> FEEDBACK <-

A publication of the

Johnson County Radio Amateur Club, Inc.

Bill Gery, KA2FNK, President

Aaron Boots, AAØRN, Vice President

Ted Knapp, NØTEK, Secretary

Cal Lewandowski, KCØCL,Treasurer / FEEDBACK distribution

* * *

Chip Buckner, ACØYF, Editor

Charlie Van Way, NØCVW, Photography

Deb Buckner, KDØRYE, Contributing Editor

All email addresses are available at w0erh.org

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

Member Profiles

Deb Buckner, KDØRYE, has decided that the club is full ofinteresting people that she wants to get to know. So, she hasdecided to do just that. This issue of the FEEDBACK containsthe first of what she terms a "regular" (she's not quite ready tocommit to "monthly") feature on JCRAC club members.

For the first several installments, she has indicated that shewants to explore why and what about radio interests the otherwomen in the club. Turn to page 11 to read about our "egglady".

A Field Day "Try It" Table?

The club's Field Day site, near the observation tower atShawnee Mission Park, draws many passers-by. Some stopand look. Some of the stopper/lookers ask questions.

Might we establish a "try it" table that offers casual visitors alow-commitment way to get their hands on some of thetrappings of our hobby?

The CW people always have visitors. How about a key, a codepractice oscillator and a Morse Code chart where visitors maytap out their names? A second station might have a devicethat sends a 5 WPM code greeting that visitors, armed with apencil, paper and another Morse Code chart attempt todecode. A time-difference-of-arrival radio direction findingunit and a couple of foxes? An HT connected to a coat-hangarground plane antenna might impress visitors with thepossibility of low-cost entry to the hobby.

We're pretty good with "this is cool". What else can we do toimpress people with "I could do this"?

PRESIDENT’S CORNER

The Club's 145.29 repeater isnow a year old andperforming great. The

investment aswell as thematching fundsfrom personsunknown hasproven to be agood decision.The repeaterdoes not have

any of the heat issues thatplagued the old repeaterduring the summer months.

Thanks to all club membersthat volunteered at Ensor astour guides. The Club receiveda nice check from OlatheParks. Volunteering as a guideis really easy on a Saturday orSunday for a couple of hours.

Event planning for 2016 isunderway. Thanks to clubmembers that put in extratime to make WW1USAspecial events, shootouts,Field Day, auction and Ensorcamp fires a success. Whenyou can, please assist thesecoordinators with theirevents.

Also please remember thepublic service events as listedon Larry's List. Each yearthere are more events that arereaching out to the amateurradio community forassistance.

– Bill Gery – WA2FNK

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Johnson County Radio Amateurs Club - February 12, 2016

Attendance: Self introduction with name and call sign. 36 signed the check in sheet. This was followed by the Pledge of Allegiance.

The Minutes from the January 22, 2016 were accepted with 1 opposed vote.

The Treasurer’s report, as follows, was read and accepted unanimously.

Cash on Hand $ 123.35 Repeater Operating Reserve $ 701.44Checking Account $ 314.50 Memorial Fund $ 310.00Savings Account $ 9,878.94

Total $ 10,316.79 Active Members: 147

City of Olathe (Volunteering at Ensor) $720.00

CarMax Foundation (Nick Atkins KD0VXJ) $160.00

Amazon Smile Program $12.11

Old Business:• Repeater Update – All Repeaters are working well. • WW1USA – The Club is Sponsoring the May 7 – 8 Event at Liberty Memorial and Museum. This

event will take place outside.• Field Day 2016 – June 25-26 at the Observation Tower in Shawnee Mission Park. To gain additional

point Aaron Boots, AA0RN will set up and manage a Facebook (social media) account.• Harry Wilson, KA0JLN has asked for the Club’s help in selling some of his Ham Radio equipment.

After a short discussion a Motion was made to help Harry sell his equipment by First, offering to sell the equipment to any Club member. Second, putting unsold equipment on Larry’s List (Eddy Paul, KY0F offered to help). And third, take remaining equipment to the Club’s Auction in the Fall and not charge Harry consignment fee. The Motion was seconded and a unanimous vote followed.

New Business:

• We recently received our first Amazon Smile check for $12.11. AmazonSmile is a website operated byAmazon that lets customers enjoy the same wide selection of products, low prices, and convenient shopping features as on Amazon.com. The difference is that when customers shop on AmazonSmile (smile.amazon.com), the AmazonSmile Foundation will donate 0.5% of the price of eligible purchases to the charitable organizations selected by customers.

• Rod Rodriguez, K6TBJ has Ararat Shrine Hambash tickets for sale at a discounted price.

Reports:

• 6 m – NR.

• 10 m SSB Roundtable – NR.

• 440 Wheat Shocker net – 17 participated on February 10 and 17 participated on February 3.

• 2m Wheat Shocker net – 23 participated on February 11 and 18 participated on February 4.

• HF Activity – India on 40m, DXpedition to Lesotho 7P8C, and South Georgia.

Announcements:• Welcome to all the 1st time visitors.• Brian Short, KC0BS gave a short description of TV25 with some new programs that will start in the

Spring.• Ham 101 Class Saturday March 19 Smithville Fire Station.• Hamclass.org will hold a Technician Class on Feb. 20 and 27. See Hamclass.org for details.• Watch Larry’s List for upcoming events.

Business meeting adjourned at 8:01 PM

Program: The Program for this meeting was presentation on Gonset Gear by Dennis Baker, KEØQM.

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Johnson County Radio Amateurs Club - February 26, 2016

Attendance: Self introduction with name and call sign. 60 signed the check in sheet. This was followed by the Pledge of Allegiance.

The Minutes from the February 26, 2016 were accepted with 1 opposed vote.

The Treasurer’s report, as follows, was read and accepted unanimously.

Cash on Hand $ 147.35 Repeater Operating Reserve $ 722.44

Checking Account $ 464.42 Memorial Fund $ 310.00

Savings Account $ 9,878.94

Total $ 10,490.17 Active Members: 154

Old Business:

• Repeater Update – All Repeaters are working well.

• WW1USA – The Club is Sponsoring the May 7 – 8 Event at Liberty Memorial and Museum. This event will take place outside.

• Field Day 2016 – June 25-26 at the Observation Tower in Shawnee Mission Park. Looking for someone to coordinate the dinner on Saturday. Also looking to see if anyone wants to set up a solar/experimental Station.

• Rod Rodriguez, K6TBJ has Ararat Shrine Hambash tickets for sale at a discounted price.

New Business:

• Brian Short, KC0BS suggested that we have a “Bring a Friend to the Meeting” night. More information to follow.

Reports:

• 6 m – NR.

• 10 m SSB Roundtable – NR.

• 440 Wheat Shocker net – 22 participated on February 24 and 19 participated on February 17.

• 2m Wheat Shocker net – 22 participated on February 25 and 19 participated on February 18.

• HF Activity – Antarctica and Poland on 40m CW. John Raydo, K0IZ and John Morse, N0EI reported making several interesting DX contacts.

Announcements:

• Welcome to all the 1st time visitors.

• Johnson County ARES SAR Drill Monday March 14.

• Ham 101 Class Saturday March 19 Smithville Fire Station.

• Watch Larry’s List for upcoming events.

Business meeting adjourned at 8:02 PM

Program: The Program for this meeting was presentation on SWR and other Mysteries by Bill Brinker, WA0CBW.

- 4 -

Hambone Goes HF--or Dude Saves the Day -- Jaimie Charlton, AD0AB

It’s a crisp, snowy February morn-ing when we find Hambone and hisuncle Elmer standing in thedriveway and sipping mugs ofsteaming chocolate as they studythe new SSB transceiver in thetrunk of Hambone’s car.

“Well, your installation looks prettygood,” observed Elmer. “You did agreat job mounting the remoteoperating head on the dash, it looksvery professional. Your cablinglooks good, too.”

“Thanks, Unck, it may look good,but it doesn’t work good. I thinkthe receiver is okay, but when Itransmit the car lights dim and I getsort of a buzzing noise on mysignal.

A guy at the club said that it mightbe some sort of RF feedback. Hesaid that RF getting into the car’selectrical system can cause all sortsof funny stuff.”

“Maybe, but it sounds like youmight have a weak battery, did youcheck it?”

“Yeah, I took the car over to Searsand they checked out the battery,alternator and charger and said itwas all okay.”

“Hmm, well, let’s have a look atyour antenna. I see you havegrounded your coax properly andputting that little auto tuner right atthe base of the whip is a great idea.”

“Yeah, you know that guy, Dill,who comes to the breakfast clubs?That’s the way his is and it worksgreat. So, I copied it–whip, tuner,everything.

I also bonded the major parts of thecar together to form a better groundplane. I remember what you saidabout HF mobile installationsneeding all the help they can get,”added Hambone.

“Oh, so you were listening afterall,” chided Elmer. “Since yourantenna and coax shielding allseems to be good, let’s look at thepower supply.

I see yourradio is alsogroundedthrough thecoax shield tothe car body.Does your car’s negative batteryterminal connect directly to thechassis or, is there something like acurrent sensing resistor between theterminal and the car body?” Notwaiting for an answer, Elmer driftedinto his lecture mode andcontinued.

“If the car’s electrical system has acurrent sensor in the negativebattery lead, you have shorted it outthrough the coax shield and thatwill cause some strange behavior inthe car’s electrical systems.”

“I checked that,” said Hambone.“This car’s fifteen years old anddoesn’t have any fancy stuff likethat. Its high-tech accessory is acassette player.

I did put fuses at both ends of thepower wires, I hope they aren’tcausing the problem.”

“No, they aren’t. Fuses are alwaysessential to prevent fires when youwire directly to the battery ter-minals. Be sure they are sized toprotect the wire. The radio has itsown fuses.

I still think the problem is related topower,” added Elmer. “Go and getyour multimeter and your PowerPole splitter and let’s see what’shappening. Oh, and while you’re atit, grab my portable short wavereceiver and some more hotchocolate. Mine’s gone cold.”

Following his uncle’s instructions,

Hambone quickly returned with theitems. He connected the splitterbetween the power wires and hisradio. He then connected his meter,set for DC volts, directly to thesplitter’s free terminals. It readtwelve volts.

“Well,” observed, Elmer, “that’s theright voltage, now turn the radioon.”

When Hambone did so, the speakercame alive with noise and voices.The meter flickered slightly, but thereading remained at twelve volts.

“It sounds like the receiver andantenna are working fine and thevoltage is still right on the money.Now key the transmitter and speakinto the mike,” said Elmer as hetuned the portable radio to thetransmitter’s frequency.

“Stop! Stop!” shouted Elmer as aloud buzz with overtones ofHambone’s voice blasted from theshortwave radio’s speaker. “I seewhat you mean about the buzz. It’snot voice with a little buzz, it’s buzzwith a little voice. That is definitelynot good.”

“That’s what the guy told me. I didnotice if I turned the power waydown to say 10-15 watts, the prob-lem seems to go away. That’s whyI thought it was RF related.”

“There you go thinking again, youthought wrong. While you weremaking all that noise, I watched thevoltage at your radio and it droppeddown to 11 volts. That is the prob-lem,” stated Elmer as he took a longslurp of his hot chocolate.

“I guess that makes sense,” saidHambone. “It still buzzes when theengine is running, but I can runhigher power before it does. But Istill can’t run the full one-hundredwatts.” see HAMBONE on page 6

- 5 -

from HAMBONE on page 5

“I see you’ve run #12 wire directlyfrom your battery to the radio in thetrunk.”

“Yeah, Unck, I used a wire table andpicked wire size rated at thirty amps.The radio only draws about twentyamps peak, so I wanted to be safe.”

“True, thirty amps is the wire tableampacity, but that’s based on safetyconsiderations like temperature riseand insulation type, not voltage dropwhich is of interest to us.

From the looks of that slack you havecoiled up here, I bet you have abouttwenty-five feet of cable betweenyour transceiver and the battery.”

“Twenty-seven feet,” addedHambone.

“Because you’re going from thebattery to the trunk and back, youhave a total of fifty-four feet of #12wire in series with your transceiver.According to the wire table, thatamounts to about 0.08 ohms orresistance.

Ohm’s law says that resistance willgive you around 1.6 volts drop whenyou draw 20 amps on voice peaks.Add that to whatever drop you getfrom your battery and you are wellbelow the operating voltage of thetransceiver. That’s why it’s notworking properly. You’re starvingit!”

“Sh**t Unck, that doesn’t soundgood.”

“It isn’t, but it’s about as good asyou’re going to get. Even if you putin really big wire, you would stillhave the battery drop.”

“A lot of guys with higher powermobile installations put bigger bat-teries and alternators in their cars.Some install an extra battery andalternator just for their radioequipment.”

“That sounds expensive,” moanedHambone. “It took nearly all mymoney just to buy this used rig.

There’s no way I can buy a biggeralternator and battery.”

“I’ve never used one, but there’s athing called a battery booster orsomething like that. It’s sort of aregulated switching power supplythat steps low battery voltage up to13.8 volts. It’s intended for this kindof problem. I think they costsomething over $150.”

“That’s still too much for me.”

“Well,” mused Elmer. “You mightgrab that snow shovel and see if anyof the neighbors will pay you toshovel their driveways. The exercisemight even do you some good.”

Elmer’s last words were lost in thebody-thumping sounds emanatingfrom the rusty old car that slid intothe driveway.

“Hi guys, what’s happenin? Howabout my awesome new six-hundredwatt car kicker!” announced Joey.

Dude and his pal Joey had arrived.

Joey, about Hambone’s age,embodied everything Elmer disliked.A high school drop out with long redhair tied back in a ratty man bun,Joey wandered around town workinga variety of part-time unskilled jobs.Yet, he always seemed to haveenough money to buy the occasionalcool gadget and support his fugitive-from-the-bone-yard car that he aptlynamed ‘Rusty’. Joey’s mastery of thelatest colorful language wasunparalleled. Dude, not yet havingconvinced his parents to buy him acar, enjoyed hanging and ridingaround with Joey. Joey’s charmingpersonality and quick smile and thefact that both Hambone and Dudeliked him irked Elmer even more.

“Hi Joey,” greeted Hambone. “Rustysounds awesome. I’m feeling thebeat way over here.”

“Hi Mister Elmer,” said Joey,continuing, “Yeah Hammy, I’mtotally down with that boomer.Would you believe I found it allbroken up at that weekend flea

market? My main man, Dude, here,helped me bring it back to life andnow it’s totally awesome.

"Dude, fist bump!”

“That’s wonderful,” mumbled Elmerturning back to Hambone’s mobiletransmitter.

“What are you guys doing out here inthe cold?” asked Dude who noticedhis uncle’s less than enthusiasticresponse to Joey’s greeting.

“My new mobile rig’s got issues,”moaned Hambone. “Every time I tryto transmit at one-hundred watts thecar lights dim and the audio gets allbuzzy. Unck says that the car’spower is too weak. The best fixwould be a bigger alternator andbattery. Or maybe a battery boostermight work. But, I can’t afford eitherof those.”

“That sounds like Rusty’s problem,before Dude fixed it,” said Joey, ashe hitched his pants down to half-mast. “Whenever I tried to play mynew Def Lep tunes ol’ Rusty here sortof caved in on those awesome beats.But not now.”

With that Joey hit a switch and DefLeppard’s ‘Dangerous’ burst forthwith skull-crushing volume.

“Awesome! You da man, Dude! Fistbump!”

“Okay, Dude, what did you do?”asked Elmer. “I know there’s no newalternator and battery in that pile of…er, Rusty.”

“Simple, I just ran heavy wiredirectly from the battery to the trunkwhere the six-hundred watt amp andspeakers are. That made a reallygood connection.”

“Yeah, yeah, I did that too, so I knowthat’s not enough. What else did youdo?” said Hambone.

“Simple, Bro, I put a five faradcapacitor directly across the amp’spower terminals.”

see HAMBONE on page 7

- 6 -

from HAMBONE on page 6

“Sure you did,” said Hambone, witha sarcastic tone in his voice. “A fivemic cap wouldn’t do anything.”

“Bro, I said a five farad capacitor. Itsupplies that extra current to give thatawesome kick without caving.”

“Let’s see that cap, it must beenormous and where did you get it?”

“It’s right there, that sub-sandwiched-sized chrome thing with the blueLEDs showing how charged up it is.Joey got it from a bud at the carstereo store for about fifty bucks.That’s a whole lot cheaper thanwhatever you and Unck were talkingabout.

You gotta get out of your shack moreand check out the car music scene.They have all kinds of cool stuff,”said Dude with a grin.

“Unck,” said Hambone, “How canthat work and would it work for me?”

“It works because music is mostlylow power with the occasional highpeak. Under normal conditions, thebattery supplies all the current thathis amp needs because it’s putting outmuch less than 600 watts. But whena big thump comes along and the full600 watts is needed, the capacitorsupplies the additional current. Anda five farad capacitor can supply a lotof current,” explained Elmer.

“I think it would solve your problem.Let’s say that on the average yourtransmitter draws only eight amps,but you hit voice peaks of 20 amps.Even though they only last about 50milliseconds, it’s those peaks thatgive you the distortion. Let’scalculate how much a capacitor willhelp.

With the engine running, you get 13volts at the transceiver. But whenyou hit a voice peak the voltagedrops below 12 volts and you are introuble. Look, here’s how it worksout,” said Elmer as he produced hisubiquitous yellow pad and #2 pencil.

Oh no, Unck, it’s too cold for all that.I agree it somehow works,” moanedHambone. “Besides, your pencil willfreeze and not write.”

“Don’t worry, Hambone, the pencilwon’t freeze and a little thinking willwarm you up.

Remember that the capacitor storesenergy in an electric field byaccumulating electrons. How muchcharge it has accumulated is shown inthe blue LED voltage display. Whenthat voltage is the same as yoursupply voltage, the capacitor is fullycharged. We use the unit called acoulomb when measuring chargebecause the charge on an electron isso small, it doesn’t amount to a fartin a whirlwind.”

“I think I’ve heard of that before, inphysics...”

“Probably, it takes6,240,000,000,000,000,000 electronsto equal one coulomb.”

“That’s a lot of electrons,” said Joeychiming in.

“Not that many,” continued Elmer.One amp of current flowing for onesecond will give you that many.

Here’s how it works out with a 5f capand 13 volts from the car battery:”

65135 =×== voltsfaradsCxVQ

Columbs

Q = coulombs stored in the capacitor

C = capacitance in farads

V = volts across the capacitorterminals and displayed by the blueLEDs

Seeing an opportunity to one-up hisolder brother, Dude interrupted, “It’ssimple, Hammy. Like Unck said, oneamp for one second equals onecoulomb. Using that formula andputting in 20 amps for the peakcurrent and 50 milliseconds for thelength of time the capacitor has tosupply that current, we can find how

many coulombs the capacitor has togive up to keep the transmitter going.Look here:”

TIQ ×=

15020 =×= msampsQDecrease

coulomb

Since the capacitor has to give up onecoulomb to supply the transmitterwith 20 amps for 50 milliseconds,that means it has 64 coulombs left init. Reworking Unck’s formula, wecan find the voltage left on thecapacitor, like this:”

voltsfarads

coulombs

C

QV 8.12

5

64===

Which is still plenty of voltage tokeep the transmitter going.”

“Dude, you’re really smart. Fistbump!” exclaimed Joey.

“Everybody knows that stuff. He justlikes to show off,” mumbledHambone.

“This is actually worst case,”continued Elmer. “Because your carvoltage is actually closer to 14 voltsand the battery is still supplying itseight amps, your voltage drop will beeven less. But remember, thecapacitor only works because voicehas lots of peaks and valleys. Itwon’t work for CW, AM, FM orRTTY transmission modes where thecurrent is drawn continuously. Thosemodes would use up all the ‘bonus’charge in the capacitor.”

“Wow!” exclaimed Hambone. “Let’sgo get a giant capacitor.”

As Elmer and Hambone prepared togo the car stereo store, Joey andDude took off in Rusty to thewindow-rattling beat of, you guessedit, ‘Let’s Go’ by DL.

-> FEEDBACK <-

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The "Amateur" in "Amateur Radio" -- Chip Buckner, ACØYF

Harmonic Resonance and the Heterodyne HoaxLast month, my plan was to buildTom Wheeler, NØGSG’s improvedcode practice oscillator. For wantof a MOSFET tran-sistor, I had to post-pone the project amonth. With thearrival of the MOS-FET, I began again.

What I am calling the "Mark 2"code practice oscillator lookedsubstantially more complicated thatthe first version. Fortunately, Tomdivided the project into severalmodules that could be built andtested separately. Section 1 is the"Automatic Power Switch". It callsfor a MEGA ohm resistor, which isten times the size of anything thatcame in my mail-order resistorassortment. Having twice failed tocollect the necessary parts, Idecided that there might be a lessonto learn here. I checked the wholeschematic and created a bill ofmaterials. It turns out that I needed4.7, 47 and 100 uF electrolyticcapacitors, which didn't match upwell with the 10's and 220's in mycollection. I've placed the neces-sary orders. Next month, perhaps?

Umm, the thing I intended to writeabout fell through. This could be ashort column. The advantage ofpervasive ignorance, however, isthat there are always plenty of newthings to learn.

WØDEW to the Rescue

Larry (Larry's List) Staples,WØAIB’s, public birthday party atthe Ararat Shrine, DonWarkentien, WØDEW, accostedme, and insisted that heterodyneswere not difficult to understand.His explanation involved the "beat"one hears when violins tune to the

same pitch. Later that day, Tominvited me to his shack full of radiogear and test equipment to give mea practical demonstration.It turns out that heterodynes arepretty neat. The idea is that whenwaves A and B combine, you get“heterodynes”—that is, “bonuswaves”—at frequency A+B andfrequency A-B (or B-A). I remem-ber that from one of the licenseexams. When your receiver is set to"CW" mode, it generates a signalthat is 700 Hz "off" of the tunedfrequency. It combines the CWsignal it detects at/near the tunedfrequency with the receiver-gener-ated offset which creates waves atA+B and A-B, which--if you'retuned precisely on the signal, willbe 700 Hz. If you're not tuned righton top of the received signal, thereceiver-generated signal will besomething other than 700 Hz awayfrom the detected over-the-airsignal and you will hear somethingother than a 700 Hz coming throughyour speakers. (Single side bandworks the same way, but we'reworking with CW today.)

Tom tuned a receiver to a VHFfrequency. He then tuned a signalgenerator to the same frequency.Silence. The receiver made nosound. He moved the generatedsignal in 1 kHz increments. At 1kHz, the reciever generated a 1KHz tone. At 2 kHz, we gotanother tone an octave above thefirst tone. At this point, I took over,switching from 2 kHz to 3 kHz to 4kHz to 5 kHz.

People have long known that aplucked string generates a pitch.Pluck it once--get a pitch. Pluck itagain--get the same pitch. Change

the length of the string and you geta different pitch. Pythagoras (500BC) observed that there was a sim-ple mathematical relationship be-tween the lengths of string—the"string-length”—that made thenotes that musicians liked to playtogether. We radio people under-stand the relationship betweenstring-length and wavelength andfrequency. It so happens that goingfrom a 2 kHz tone to a 3 kHz toneto a 4 kHz tone to a 5 kHz toneplays a root note or “tonic”, movesup a “fifth”, up to the “octave” andthen up a “third”. This series oftones happens to be the series ofnotes that begins Richard Strauss’Also Sprach Zarathustra, whichpeople of a certain age will recog-nize as the music Stanley Kubrickused in the opening sequence in themovie “2001: A Space Odyssey”.1

At this point, I concede to Tom thatthere may be something to thisheterodyne business, but that I'mgoing to have to do some additionalexperimentation to wrap my headaround this.

Additional experimentation?If I am going to do additionalexperimentation, I need a signalgenerator that will generate wavesat a couple of known frequenciesand a spectrum analyzer that willtell me that I am getting waves itdetects that are different than thewaves the signal generator created.This is not the kind of stuff I havein my, uh … “lab”. I do, however,have this kind of stuff elsewhere inmy home.

A piano generates signals at knownaudio frequencies. The "A" above

see THE AMATEUR on 9

1 This is the kind of thing you have to put up with when you let a liberal arts guy edit your amateur radio club newsletter.

- 8 -

from THE AMATEUR on 8

middle-C sounds at 440 Hz. The“A” an octave lower sounds at 220Hz. If I were to strike those notestogether, I should generate waves/tones with frequencies of 220 and440 Hz, of course. If the combina-tion of waves generates a hetero-dyne, I should also get a heterodyneat 220 + 440 = 660 Hz, which isvery close to the note “E” at659.255 Hz.2 The musical intervalsbetween A-440, E-660 and A-880happen to be the same as theintervals between the first threenotes of Also Sprach Zarathustra,which is why I went into that dis-cussion in the first place. And Ihave an organic spectrum analyzerconnected to my ears that can tellthe difference between the first,second and third notes of thatmelody.

I sit at the piano. I strike E-660 totell myself what I am listening for.I locate the A-220 and A-440 andstrike them together to produce …the sounds of a piano playing A-220and A-440. No E-660.

Of course, having played octaveson a piano at other times in my life,I really didn’t expect to hear 660.But why don’t I hear it? Do I havea phase problem? Do I have aheterodyne, but at a signal strengthso low I can’t make it out over theloud 220/440? Or does hetero-dyning not work at audio?

I rule out phase. Tom’s signal gen-erator and his receiver were not

coordinating phase. I put any sortof audio-doesn’t-heterodyne to theside because Tom and Don bothinsist that heterodyning can be anaudio phenomenon and I have noreason to believe that they colludedto perpetrate a hoax on me. So,let’s test the idea that the heter-odyne is substantially weaker thanthe waves used to create it and thatI’m just not hearing it. Can I maskthe sound of A-220 and A-440 andamplify the E-660 heterodyne?

I think I can use natural resonanacethat occurs inside a piano to handlethe amplification. "Resonance",WIKI reports, "is a phenomenonthat occurs when a vibrating systemor external force drives anothersystem to oscillate with greateramplitude at a specific preferentialfrequency." If I create an E-660wave, it should cause the E-660string, "to oscillate with greateramplitude" at its "preferential fre-quency" of 660 Hz.

The other thing a piano does well isto mute the sounds we don't want tohear. Each string has a "damper".You press the key, the damper goesup and the string can vibrate. Yourelease the key, the damper dropsand stops the string from vibrating.

The other thing a piano does well isto mute the sounds we don't want tohear. Each string has a "damper".You press the key, the damper goesup and the string can vibrate. Yourelease the key, the damper dropsand stops the string from vibrating.

I depress the E key softly with myright index finger, so as not to makea sound. I then spread the thumband pinkie on my left and to octavedistance and smack and release theA keys. The two A’s sound brieflyand then … I hear the faint sound ofE-660! All right, let’s go the otherway. We need to use E-660 and A-440 to generate the differentialheterodyne (a term I might havejust made up) of A-220.

I sit at the piano and—no matterhow many times and how hard Ipound 660 and 440—nothing.

But I did hear E-660. So, what didI hear? Do I get higher pitches ra-ther than lower pitches because thehigher pitched strings are shorterand, having less mass, are easier tovibrate? Or, as I think is likely, amI getting harmonics of the under-lying notes? Let’s run some tests.

Key(s)Struck

220+440

440+660

440

440

880

220

220

220

220

220

Key(s)Held

E-660

A-220

A-880

E-1320

E-1320

A-440

E-660

A-880

C#-1100

440+600+880+11003

Tone(s)Heard

E-660

nothing

A-880

E-1320

nothing

A-440

E-660

A-880

(C#maybe)

440+660+880

It looks to me as if I am hearingwhole-number multiples of the fun-

see THE AMATEUR on 10

2 Musicians who are really into this stuff will know that there are a variety of musical tuning systems or “temperaments”. A

Pythagorean “E” would be at precisely 660 Hz. For reasons that do not belong in an amateur radio club newsletter, strict adherence to the Pythagorean temperament creates musical challenges. In J.S. Bach’s era, musicians introduced some compromises into the Pythagorean temperament to make music writable and playable in a variety of keys. In the modern—modern compared to Pythagoras,anyway—“equal” temperament, “E” is really tuned to something like 659.25515 Hz. I’m going to call it E-660 anyway, (a) because it’s really close to 660, (b) because it is cumbersome to keep writing 659.25515, (c) because no piano tuner can tune to 6+ significant digits and (d) because, even if a piano tuner could tune with that kind of accuracy, there is no chance that my piano is going to be in tune anyway. Incidentally, J.S. Bach was so delighted with the musically—if not mathematically—sensible temperament that enabled him to write in multiple keys that he composed a collection of preludes and fugues in all major and minor keys that he called the “Well-Tempered Clavier”.3 My hand wasn't large enough to reach all of these. I used a paperweight to hold down C#-1100.

- 9 -

from THE AMATEUR on 9

damental frequency. One explan-ation might be because the lowerpiano string generates overtones(for musicians) or harmonics (forengineers) that are being picked upby the higher string. Musicians likeovertones. They add interest andvariety to sound. They make clari-nets sound different from violins,which is the reason orchestrascontain both clarinets and violins.

at its "preferred" E-330 frequency.I had--for whatever reason--notexpected the E-330 string toresonate at 660 Hz.

It looks as though the thirdharmonic of A-220 (220 x 3 = 660)is causing E-330 to vibrate at twiceits "normal" frequency (330 x 2 =660). I tested other combinations tosee if I could get a string to resonateat a multiple of its "natural"frequency. It turns out that it isn'tvery hard to do.

"combine" or "mix" waves, they"multiply" them together. Thisraises two obvious questions. First,"whaddya mean MULTIPLYwaves?" Answer: I have no idea.4

Second, "why would RF engineerstwist and distort the meanings ofperfectly good words like 'mix','combine' and 'multiply'?" Ah, nowwe have moved on to MY hometurf. This one is easy. Answer:Nefarious5 purposes. I knownothing about RF engineering, buthave some experience with twistingwords for nefarious purposes. Trustme on this one. I'm a lawyer.

All of which suggests that maybeTom and Don did collude toperpetuate a hoax on me.

ODDS AND ENDS

-- MORSE CODE ON AN HT --

Tom Wheeler, NØGSG, observedthat an additional problem of usingthe PTT to key dots and dashes wasthat the HT has to switch betweentransmit and receive modes on eachkeypress/release, which when doneat any reasonable speed is hard onthe electronics.

Don Warkentien, WØDEW,informed me that HT's with numer-ic keypads--like your pushbuttontelephones--generate DTMF (dualtone multi-frequency) signals. Myexperiments indicate that each rowof buttons has a tone. Eachcolumn of buttons has a tone.When you push a button, yougenerate the row-tone and thecolumn-town. If you push twobuttons in the same row or column,you generate only the tone for theshared row or column, which can beused to key Morse code on an HT.

Key(s)Struck

A-220

A-220

A-220

A-220

Key(s)Held

B-247

C-262

Eb-311

E-330

Tone(s)Heard

nothing

nothing

nothing

E-660!

Key(s)Struck

A-220(x5)

A-440(x1)

E-660(x1)

Key(s)Held

C#-275(x4)

A-220(x2)

A-220(x3)

Tone(s)Heard

C#-1100!

A-440!

E-660!

I had been thinking about a piano asa signal generator. It is. But it isalso an audio frequency antennafarm. I've got all these audio fre-quency antennas in there thatvibrate/resonate at various fre-quencies. So, although my hetero-dyning experiment failed, I've gavemyself a practical demonstrationthat an oscillating sytem may reson-ate at more than one frequency. Onone level, I "knew" that 2m anten-nas worked at 70cm and that 15mantennas worked at 40m. I justdidn't expect to experience it--or tohave it so easily demonstrated--inthe audio frequency domain.

Why don’t I hear heterodynes?

The question remains, however,why I failed to hear heterodynes.

When normal people "combine" or"mix" things, we add them together.When normal people "combine" or"mix" waves, we "add" themtogether. When RF engineers

I ought to test my theory on a bunchof notes that are NOT multiples ofthe fundamental frequency.

Things started well, but when Iheard that E-660...? The pianodamper was supposed to kill thesound of E-660. Instead, E-660was sounding louder now thanwhen I had the damper raised. Thedamper was AMPLIFYING thesound!

Now wait a minute. This cannot behappening. E-660 cannot possiblybe vibrating, much less vibratinglouder than it did when I had thedamper disengaged. Of course, asthe (now snickering) engineersknow--and as I discovered when Ireleased E-330 key--the E-660string was not the one that wasvibrating. The E-660 sound wascoming from the E-330 string.When I struck A-220, it caused E-330 to vibrate at 660 Hz. I ex-pected the E-330 string to resonate

4 Well, I DIDN'T have any idea. Tom directed me to the "mixers" section of the ARRL Handbook. It turns out that you don't

multiply "waves", you multiply "voltages". Voltage is a number. I know how to multiply numbers together. Now WHY we multiplyvoltages or HOW/WHY someone decided that it would be a good thing to do or HOW/WHY a diode (as shown in the handbookdiagram) would multiply voltages are questions for further/future consideration.5 Really, really evil.

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Member Profile: Barb McKinney, KEØEGG -- Deb Buckner, KDØRYE

With the call sign KEØEGG,Barb McKinney knows she cannever get a vanity sign. Whatcould be better than being knownas "the Egg Lady" of ham radio?

Licensed as a technician sinceApril 2015, Barb's road to radiohad an unfortunate beginning.Her husband, Keith, KEØAEP,suffered serious injuries in amotorcycle accident. Laid up formonths with a broken hip,shattered ribs and a collapsedlung, Keith began listening to ascanner to help pass the time.Barb became interested, too, butlooking at their old equipment,they decided to "see if we canupgrade." This led to severalvisits to Associated Radio. Keithhad been active with CB radio inthe 70s, and soon becameinterested in ham radio. Theybought their first radio andlistened in their truck where theyhad their only antenna.

Listening regularly, they beganto know the voices, DonWarkentien's WØDEW beingone of the first they came todistinguish. Keith said, "I think Iwant to do this!" With severalmonths still before his completerecovery, he studied for hislicense, passed and soon had aradio in the house as well. Theybegan to listen to the weeklynets, and Barb experienced thefrustration of knowing "I can'ttalk to these people!" Shedecided she needed to belicensed, too.

Barb studied two or three weeks,using the Gordon West book andaudio cds she played in the car toand from work. She found a lotof help from the QRZ practiceexams. She began completingbetween five and ten practiceexams each evening beforetaking and passing the real one.

"I want to understand all of it,"Barb said. "But some comeseasier than others." Sheacknowledges "we are so blessedto have so many brilliant peoplein this club" who can provideguidance.

Barb communicates using her"licensing gift", a dual bandIcom 2730, in her car. Sheenjoys the nets and just listeningwhile driving. At home, she andKeith have a Yaesu Fusion 400,while he also has a big Icom7410 HF transceiver, a mixer andspeakers. She and Keith enjoyclub meetings, and she recentlymade it to a breakfast with clubmembers as well.

Barb is studying for her generalexam and then wants to learnCW. This Christmas, shereceived a straight key, an audioteaching guide and an oscillator.But tax season is a busy time foran accountant. Right now, "workis getting in the way of myhobby."

She is also interested in learningmore about the YLRL (YoungLadies Radio League) andbecoming involved. There areadvantages to being a femalevoice in the world of ham radio."We are such a minority, peopleare happy to hear a femaleregularly."

-> FEEDBACK <-

Barb McKinney, KEØEGG and Deb Buckner, KDØRYE

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Adapting Microphones to Yaesu Transceivers:

If it's not Broken, then Fix It! -- Tom Wheeler, NØGSG

Introduction

Many of us are trying out the newdigital modes offered by the clubrepeaters, and the Yaesu FTM-100and FTM-400 are popular choices.These are great radios, but thesupplied microphones are clumsy,especially for base station use. Adesk microphone is a much betterchoice for fixed operation, butthere's just one problem: The Yaesuradios have a 6-pin RJ11-styleconnector and a really unique elec-trical interface. Getting a conven-tional desk microphone to workproperly takes a little doing, but it'snot hard to do.

Danger, Will Robinson!

First, a word of caution. If youconstruct an adapter for your ownradio, make sure you check itswiring thoroughly before pluggingit in. Modern transceivers are prettyunforgiving when it comes tomiswiring on microphone connect-ors, and in particular, miscon-nections to power pins on theseconnectors may cause a trip to theradio hospital for your unit! Ifyou're unsure, ask an Elmer forhelp.

Understanding the Interface

Most radios provide a simplemicrophone interface. The fol-lowing are typical pins andfunctions that need to be connected:

• Microphone signal--the low-level signal from the microphoneelement passes from the micro-phone into the radio on this wire.It's usually a shielded, miniaturecoaxial cable. The signal levels arejust a few millivolts, so shielding isabsolutely necessary. Caution must

be employed with the microphonesignal, some radios provide aDC"phantom" voltage on this lineto operate condensor microphones.(Yaesu generally does not.)

• Signal ground--theground return for themicrophone signal; it'susually the braided shieldfor the microphone wire.

• Push-to-Talk andLogic ground--a secondground is usuallyprovided for the push-to-talk switch and any othercontrol logic in the microphone.This reduces hum on transmit byisolating the sensitive analogground for the microphone element(that's only making a few tinymillivolts) and digital / controlgrounds (where many volts and afew mA of current may be flowing).

• Push-to-Talk--usually (in95% of cases), this is the magicwire that when grounded switchesthe radio to transmit, and whenopen-circuited puts the radio backinto receive.

• People like to do additionalthings with their microphones, somanufacturers also add a few moresignals:

• DC Power Supply--Some ofthe gadgetry (such as micro-processors--yes, some microphonesactually have one or more computerchips within them!) in a micro-phone needs DC power to operate.Some microphones also use what'sknown as an "electret condensor"microphone element, which alsorequires a small DC voltage tooperate. This DC power is also

sometimes used to power LEDs forbacklighting.

• Control Inputs--People liketo tune and control their radiosthrough the microphone, so these

range from simplearrangements like up anddown buttons for tuning,to more elaborate arrange-ments like 16-key touch-tone (DTMF) pads.

Every brand of radio has aunique twist on thesebasic interface signals. Tobuild adapter cables, then,

we must understand both the"pinouts" (what signal is on whatpin), but also what kind of signal isexpected on each pin by the radio.In general:• Kenwood radios tend toprovide dedicated pins for UP andDOWN buttons, as well as the PTTfunction. These are simplygrounded when activated.

• Icom is similar, but alsointegrates a microcontroller intomost of their microphones. ThePTT function is still a discrete pinthat's grounded for transmitting, butthe microcontroller in the micro-phone makes the radio transmit bysending a control code to the radiothrough a separate data wire that'spart of the microphone cable. Itdoesn't use the PTT pin! It's cool,but also complex and hard to adapt.

• Yaesu microphones use adedicated PTT pin, but instead of acomplex microcontroller in themicrophone, they use two analogsignals called SW1 and SW2 to

see MICROPHONE on 13

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from MICROPHONE on 12

send commands to the radio. Theresistances presented on SW1 andSW2 by the microphone tell theradio what to do. It's a simple andelegant solution, and quiteadaptable if you know the secret!

Secrets of the Yaesu MH48 Microphone

Figure 1 is a marked-up version ofthe MH48 hand microphone that issupplied with many of the newYaesu units, including the FTM400and FTM100. Don't be intimidated,as it's just a few switches andresistors that do the work!

In Figure 1 the power supply wirehas been highlighted in red, and redboxes have been placed around twovery important sets of resistors. Theresistors in these two red boxesform the bottoms of two distinctvoltage dividers, as shown in Figure2 (on the following page)..

The "top" resistors for these twovoltage dividers are not within themicrophone, but are instead locatedinside the radio. They are around100 k ohms each and are connectedbetween an internal +3.3V sourceand each of two analog-to-digitalconverter inputs on the radio's CPU.

These two voltage dividers areconnected to Pins 1 and 2 of themicrophone connector, and are thesignals "SW2" and "SW1,"respectively. The CPU can thereforedetermine what voltages are onthese pins.

The action is pretty straightforward.Referring back to Figure 1, supposethat the user presses the UP button,which is switch S5003 towards theleft of the diagram. Through the topdiode of D5005, the SW2 signal iseffectively grounded, and through

see MICROPHONE on 14

Figure 1: Yaesu MH48 Hand Microphone Schematic Diagram

- 13 -

from MICROPHONE on 13

the bottom diode of D5005, thebottom of R5008, a 27k resistor, isgrounded. So as a result, the CPU inthe radio sees ground on its SW2input, and a 27k resistor to groundon its SW1 input.The CPU softwareinterprets this as an UP buttoncommand and executes theappropriate command routine tobump the frequency or channel up,or start and stop a scan command.

Similar action happens when theDOWN button is pressed.Strangely, the SW2 input is againgrounded, but this time through thetop of D5007. However, the SW1input now sees a total of 27k and39k to ground, as the bottom ofR5009, the 39k resistor, is nowgrounded instead of R5008.

The CPU now sees a differentcondition. It sees ground on SW2,but (27k + 39k) or 66k on SW1. Itnow understands that the DOWNbutton has been pressed and takesthe appropriate action.

The keypad works in a similar way.The Yaesu keypad is not a normalkeyboard matrix, though. Each keyhas two switches that closesimultaneously when pressed! (Thedetail of what's inside each switchposition is shown on the schematicof Figure 1 within the green box).

As an example, when the [1] key ispressed, positive voltage from the+5V supply is applied to the basesof NPN logic transistors Q5005("KR0") and Q5004 ("KC0").Q5005 turns on and effectivelyshorts the SW1 signal to ground,while Q5004 connects the 27kresistor R5004 to ground on SW2.Again, the CPU sees this as aunique condition and understandsthat the [1] key has been pressed.

Figure 2: Simplified SW1-SW2 Control Circuit

Figure 3: Adapting the Yaesu MH48 to a Kenwood 8-Pin Interface

This is a pretty slick control system.There's essentially nothing in themicrophone but a few resistors andswitches, yet more than 20 differentcommands can be reliably sent tothe radio. And it's quite easy toadapt, as Figure 3 demonstrates.

In Figure 3, a small amount of thecircuitry from the MH48 has simplybeen cloned to emulate the UP andDOWN signals the CPU needs. Ona Kenwood base microphone, the

UP and DOWN controls are simplyswitches to ground. Pressing eitherthe UP or DOWN switch will causethe signal SW2 to be near groundpotential, just like with an MH48,as either D1 or D3 will conduct.

Pressing UP connects only R1, the27k resistor, to ground through D4,while pressing DOWN connectsboth R1 and R2 in series to groundthrough D3. It's that simple!

see MICROPHONE on 15

- 14 -

CPU

Microphone Equivalent Circuit

ADC Input #1

ADC Input #2

RadioR5004 ~ R5007

R5008 ~ R5011

100k

100k

SW2

SW1

+3.3 V

SW2 SW1

GND

PTT

MIC AUDIO

5V

UP

DOWN

SIGNAL

GND

MIC

AUDIO

PTT

GND

PTT

DOWN5V DC

NC

UP

P1

To Yaesu Radio

1 2 3 4 5 6

D1

1N5711

D2

1N5711

D3

1N5711

D4

1N5711

R2

39 k 1%

R1

27 k 1%

J1

To Kenwood Mic

5

6

7

8

43

2

1

from MICROPHONE on 14

both R1 and R2 in series to groundthrough D3. It's that simple!

All the diodes in this circuit must beSchottky types. The CPU in theradio expects correct voltages onthe SW1 and SW2 signals as thevarious resistors in the microphoneare switched in and out, and thevoltage drops of the diodes (about0.3V) are incorporated into theCPU's programming. The MH48 it-self uses Schottky types, type1SS321 dual-diode units, though,any generic Schottky diode willwork.

Construction

This is a non-critical interface tobuild. Just be careful, and doublecheck your work before pluggingthis into your precious radio! Yourauthor was exceedingly lazy andhad all the parts in surface-mountform, so he simply used CircuitScribe ink (which is solderable) todraw the interface onto the back ofa business card, as shown in Figure3. Total construction time using thismethod was 15 minutes.

The Figure 3 circuit was simplyplaced in the base of a Kenwood-compatible base station micro-phone. You'll note that half of thebusiness card was used--so thatfolding it over provided a freeinsulator to prevent short circuits. Itmight actually be better to put theentire interface and connectors in aseparate plastic box. There areprobably too many components inthe circuit to attempt building itdirectly into a connector shell.

Figure 3: The Lazy Way of Building It

Conclusion

If you really want to ditch that handmicrophone (which by the way is aquality unit), it's not hard to adaptyour Yaesu radio to desktopoperation. In an evening of time,you can easily build an interfacethat will do that for you, and

increase your operating conven-ience--and with a little ingenuity,you can easily add otherfunctionality if you need it.

-> FEEDBACK <-

The JCRAC has earned $12.11 from Amazon.com through its Amazon Smile program. If you are going tomake a purchase anyway, consider visting http://smile.amazon.com/ch/48-1071476 to direct 1/2% of your

purchase to the JCRAC. It costs you nothing.

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