July 17, 2012

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Mid-Year Project Recap

A review of the 30 technical topics and 15 projects we've put in motion during the first half of this year
... and an update on the status of each!


We've covered a lot of ground in the thirty (30!) weekly CWTD sessions we've had thus far.  And coming back online now fresh from our "summer break", we'll be getting back into the swing of things by overviewing all the projects and technical topics accomplished to-date.  So if you missed a session or two, or if you'd like to ask a live question this time (instead of just listening to the podcasts), or if you'd like to get an update on that one "special project" ... this will be the session for you!

73, George N2APB  & Joe N2CX

Audio Recording ... (Listen to the MP3 podcast)

Discussion Notes:

<20:10:22> "W2AEW - Alan": I'm currently building a K5BCQ/K5JHF QRP power meter for a friend: Picture: https://twitter.com/#!/AlanAtTek/media/slideshow?url=pic.twitter.com%2FHJvmCreB
<20:12:26> "Charles WC5MC": http://www.wa0itp.com/qrpom.html
<20:12:38> "W2AEW - Alan": Link to their page: http://www.qsl.net/k/k5bcq/Kits/Kits.html
<20:14:37> "Frank N3PUU": http://www.arduino.cc/
<20:14:38> "Rich, K7SZ": http://www.wa0itp.com/qrpom.html
<20:14:41> "W2AEW - Alan": Radio Shack even carries the Arduino now!
<20:16:08> "Ray K2ULR": W1REX http://www.qrpme.com    
<20:16:25> "Lee KM4YY": Can you post URL for the White Board tonight. my email URL didn't work.
<20:16:40> "Frank N3PUU": the rasberry pi is looking interesting
<20:16:40> "W2AEW - Alan": http://dl.dropbox.com/u/43021514/CWTD/Jul%2017.html
<20:17:02> "Terry WB4JFI": Arduino-like Papilio boards. Learn FPGAs and soft-core processors
<20:17:34> "Terry WB4JFI": http://papilio.cc/
<20:17:39> "Charles WC5MC": Oh yeah I got a Pi now :)
<20:21:20> "Terry WB4JFI": Rick: I used to work at the Lafayette Radio in Falls Church, VA. Still remember 1/8" stereo plug was part# 99-62101.
<20:26:46> "Rick K3IND": George, can you recommen a good SoIC book?
<20:27:27> "Paul - wa0rse": That series was my favorite, Joe and George!!!
<20:28:08> "Paul - wa0rse": Is the sweeper input card for the 908 available? I can't remember...
<20:31:22> "W2AEW - Alan": link to my distortion video: http://www.youtube.com/watch?v=XHA4c82msqo
<20:41:01> "Paul - wa0rse": The two detectors (SIC and microwattmeter) are both unavailable, I think. What were your suggestions for those of us who want to do something with this now?
<20:42:01> "Paul - wa0rse": great! very generous!
<20:44:03> "Paul - wa0rse": the "keeping it simple" (detector diode and resistor) approach is one I habitually forget. Thanks for the reminder!
<20:47:27> "W2AEW - Alan": My favorite is the old 1930's classic 130' center-fed dipole, fed with 450ohm line. Works great on 80-10m
<20:52:40> "George - N2APB": I love using 450-ohm feeder with dipoles like this.
<21:11:34> "Terry WB4JFI": I second the X-Tronic 4000 rework station
<21:13:38> "Paul - wa0rse": I'm sorry I missed those but happy I attended this recap to bring my attention to these two podcasts!
<21:15:40> "W2AEW - Alan": You can even reference my youtube channel: http://www.youtube.com/w2aew
<21:16:38> "W2AEW - Alan": sounds good!
<21:28:47> "Pete - WB2QLL": Sometimes..."air terminals"
<21:29:15> "Terry WB4JFI": SSMPS = sometimes switching mode power supply
<21:29:30> "Paul - wa0rse": Otto Schmitt, of the Schmitt trigger, was my M.S. mentor. He built EVERYTHING using "sky wiring"!!!
<21:29:50> "W2AEW - Alan": Paul - nice!
<21:33:39> "Paul - wa0rse": Bye for now, everyone! 73's
<21:34:35> "W2AEW - Alan": can't wait to make a 10MHz GPS disciplined oscillator for my bench
<21:37:23> "W2AEW - Alan": Yay - can't wait!
<21:38:46> "W2AEW - Alan": that's incredible
<21:44:53> "W2AEW - Alan": Thanks Armand!
<21:46:46> "Terry WB4JFI": Great job George! Nice summary of the various sessions.
<21:52:49> "Lee KM4YY": Incredible resource for you fellow amateurs! Excellent job, George/Joe!
<21:53:50> "Frank N3PUU": yes, thanks George and Joe!
<21:54:31> "Charles WC5MC": Amazing amount of prep work that you make look easy. Good job
<21:56:52> "Ray K2ULR": N1RX
<21:59:32> "W2AEW - Alan": 73 all, thanks!


Nov 22, 2011 ... RF Power Measurements for QRPers:  


Nov 29, 2011 ... Technology Round-Robin:    

Joe N2CX -- Sweeper: Sweep frequency into a Device Under Test and measure/plot response on a log detector
Bruce N1RX -- Battery sleep timer
Carl W8KRF
Chuck WA6LTV -- Need a customized filter display, 1% accurate power meter
Dave AD7JT -- Overview of the keyer software for the NUE-PSK modem
Gerry N2GJ
Douglas ____ - ARISSAT TLM w/AMSAT
Ken VA3KMD -- Software in the Micro908
Milt W8NUE -- AQRP projects
Frank N3PUU -- Batter monitor, INA 219 "High Side Current & Shunt Monitor"

Dec 6, 2011 ... Best Kits 

<20:17:03>"George - N2APB1": ***** KIT TOPIC ... Arduino kits (N2CX)

<20:22:05>"Ray K2ULR": Reminder.. it's PTT.. not just hit the key

<20:23:22>"George - N2APB1": ***** KIT TOPIC ... Genesis G59 SDR kit, Arduino (WiFi radio project w/router), SDR 5W amp HF Projects & Filter Kit (W0ANM)

<20:25:37>"George - N2APB1": ***** KIT TOPIC ... Penny Whistle 20W amp, new 10m antenna in an antenna-restricted neighborhood (AD7JT)

<20:27:26>"George - N2APB1": ***** KIT TOPIC ... ATS-3, HRO-M(?), HRO-60 (AA3UR)

<20:28:07>"George - N2APB1": ***** KIT TOPIC ... QRP Kits PRF-3, Active Audio Filter (LM386 vs. LM380?) (WA2DJN)

<20:30:54>"George - N2APB1": ***** KIT TOPIC ... NorCal QRP Pwr Meter, Softrocks, NJQRP classic, AMSAT projects (analyze telemetry from ARISAT, spiraling in over next couple of months, upcoming FOX-1 sat  (KA2UPW)

<20:34:43>"George - N2APB1": ***** KIT TOPIC ... Arduino projects, Softrock Ensemble RXTX 17/20/30 (N3PUU)

<20:34:53>"Chris - w0anm": small wonder labs sw-40 great price, single band easy build

<20:35:13>"Frank N3PUU": thx Chris

<20:35:56>"Joe - N2CX": SW-40 a great choice but has VFO unlike SW-40 which is one freq!

<20:37:44>"Chris - w0anm": small wonders makes both rockmites and sw-40.  sw-40 does have vfo as rockmites are rockbound.  My sw-40 works much better that the rockmite.

<20:38:09>"Chris - w0anm": http://www.smallwonderlabs.com/

<20:38:20>"George - N2APB1": ***** KIT TOPIC ... SDR Cube, Rock-Mite (NJ2E)

<20:39:12>"George - N2APB1": ***** KIT TOPIC ... precision Freq Measurement, Parallax "Propeller" chip to control a Rubidium freq standard, Micro908 Antenna Analyzer, (N5VP)

<20:41:27>"George - N2APB1": ***** KIT TOPIC ...N2PK VNA with (helper kit), NUE-PSK modem and ICD2 programmer, (VA3KMD)

<20:45:58>"George - N2APB1": ***** KIT TOPIC ... G3XJP "PIC-A-STAR"!!!!! instrumentation kits, Si570 Sig Gen, SWL-40, Modular Spectrum Analyzer 8307-based log detector (W2HHV)

<20:46:23>"Joe - N2CX": Small wonder labs sells cabinet and external controls kits as well as SW40

<20:52:19>"George - N2APB1": ***** KIT TOPIC ... STM discovery board, Arduino Teensy++, AQRP Plug-in, EasyDSP from TI, Softrock Ensemble RXTX, AQRP's SDR2GO + Softrock, AQRP Digital Wattmeter, I2C graphics display & panadapter (W8NUE)

<20:53:38>"Joe - N2CX": Radio shack is selling some Arduino and Parallax kits!

<20:55:25>"George - N2APB1": ***** KIT TOPIC ... KX3, QRP Kits Tuner, [K2ULR)

<20:59:12>"George - N2APB1": ***** KIT TOPIC ... Benton Harbor Lunch Box(!), PICAXE (!!!), SCAF Audio Filter for the SB1400 Transceiver (K3IND)

<21:01:19>"George - N2APB1": ***** KIT TPOIC: Boatanchors: Collins R-390, Viking Invader 2000, National 183D, HRO-60, HRO-Jr (N2APB

<21:05:14>"George - N2APB1": ***** KIT TPOIC: Elecraft 2-Tone Generator, Directional Couplers [K2CK]

<21:10:18>"George - N2APB1": ***** KIT TOPIC ... Simple Sweeper a la Arduino, remotable Elecraft T1 Tuner, remote tuning the MFJ and Midnight Loops, portable operating desk, American Morse Keyer, wishlist of books(!): PDF/Kindle material, K8IQY "Magic Box T/R Switch" [N2CX]

<21:11:10>"Joe - N2CX": Hi Q

<21:21:56>"Douglas KA2UPW": http://w3nqn.com/details.html

<21:22:15>"Douglas KA2UPW": and http://w3nqn.com/build.html

<21:25:34>"George - N2APB1": ***** KIT TOPIC ... RTCC option with the NUE-PSK modem [K2CK)

<21:25:37>"Rick K3IND": Built a rtty filter w/88mh toroids in 1963 -- hooked to a Kleinschmidt!

<21:26:12>"Chris - w0anm": Rick, I did too, a rtty decoder with a model 19.. (late 70's)

<21:35:51>"George - N2APB1": Elecraft XG-2:  Measures sensitivity, selectivity, S-meter calibration ... good signal source

<21:36:38>"George - N2APB1": Audio amplifiers:  LM386 (popular, higher hiss, possibly less stable, lower power)

<21:38:17>"George - N2APB1": Audio Amps:  LM380 ... more power output, more stable, less hiss, more power required (+20ma)

<21:43:40>"Rick K3IND": George, Heath SB-1400 is repackaged Yaesu FT-747GX

<21:46:42>"Chris - w0anm": I've built an arduino HF amp controller for evaluation for a larger amp project.

<21:46:48>"Joe - N2CX": ST microelectronics TDA2822M stereo power amp in DIP

<21:48:30>"Rick K3IND": round-tuits make great stocking stuffers!

<21:52:27>"Bill - KD5TFD": No panadapter  === no fun

<21:56:00>"Joe - N2CX": http://eksfiles.net/elmer-101-kit-building-materials/

<21:56:16>"Joe - N2CX": SW-40 is from Small Wonder Labs

<21:57:26>"Ray K2ULR": Hendricks is supposed to be kitting the SMK-1 again soon.

<22:00:27>"Bill - KD5TFD": http://hackaday.com/2010/10/12/arm-prototyping-on-the-cheap-with-stm32-discovery/

<22:01:18>"Ray K2ULR": http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATA_BRIEF/DM00037955.pdf

<22:06:14>"Bill - KD5TFD": Have a funcube .. bummer is the docs are mostly under NDA ... don't think it has bandwidth to really do broadcast FM

<22:07:13>"Douglas KA2UPW": http://www.funcubedongle.com/

<22:07:13>"Milt-W8NUE": STM32f4discovery board--$16.25 at Mouser


Dec 13, 2011 ... Favorite Parts & Kits Suppliers:  

<20:09:10>"George - N2APB1": http://www.makershed.com
<20:10:04>"George - N2APB1": Lady Ada ... http://www.ladyada.net
<20:10:48>"George - N2APB1": http://www.norcalqrp.org
<20:11:21>"George - N2APB1": http://kd1jv.qrpradio.com
<20:11:42>"George - N2APB1": http://www.qrpkits.com
<20:12:24>"George - N2APB1": Wilderness Radio ... http://fix.net/~jparker/wild.html
<20:13:19>"George - N2APB1": jackson Harbor Press ...  http://www.wb9kzy.com/ham.htm
<20:14:28>"Bruce - N1RX": http://www.kitsandparts.com/  toroids, etc
<20:16:27>"George - N2APB1": Diz W8DIZ runs Kits and Parts ... great supply of toroids.  Responsive and great prices
<20:17:35>"John - KE3S": Small Wonder Labs
<20:17:55>"George - N2APB1": PICAXE supplier ... Peter H. Anderson
<20:19:08>"Joe - N2CX": http://www.phanderson.com/ ... do not type panderson - that is a baaasd  site!
<20:20:24>"Bruce - N1RX": Rex, W1REX the tuna-tin man at QRPme also has small picaxe kits http://www.qrpme.com
<20:21:31>"Joe - N2CX": Diz has reasonable shipping charge for small orders
<20:22:24>"Bob - wb6kwt": www.vakits.com/
<20:22:47>"Bruce - N1RX": one tip to consolidate shipping is to keep and maintain a list of items you want or need. Then place an order when you get enough to justify an order. It's the same as a grocery list- only go when it's worth it. Stock up!
<20:23:25>"Bruce - N1RX": Or, BEG on qrp-l etc. People can be nice!
<20:24:15>"Joe - N2CX": When you order cheap parts say you need one or two - consider ordreing 10 - you will need them later!
<20:24:33>"Chris - w0anm": Arduino Kits --> http://moderndevices.com , also have LCD serial kits.
<20:25:38>"Joe - N2CX": Geo,  forgot to mention Tony Parks - kits sell out quickly - tips for finding out when they are available.
<20:25:49>"Milt-W8NUE": www.allelectronics.com
<20:26:04>"Bruce - N1RX": http://www.amqrp.org/misc/links.html
<20:26:19>"Milt-W8NUE": www.goldmine-elec.com
<20:26:31>"Frank N3PUU": kb9yig
<20:29:20>"George - N2APB1": GREAT set of llinks that I use on a regular, daily basis ... http://www.amqrp.org/misc/links.html
<20:29:38>"Chris - w0anm": Hard to find parts, some interesting stuff -->  http://electronicplus.com
<20:29:52>"Milt-W8NUE": Oceanstate Electronics  http://www.oselectronics.com/
<20:30:01>"George - N2APB1": http://www.dspradio.org
<20:30:04>"Bruce - N1RX": http://thepartsplace.k5nwa.com/
<20:30:23>"Joe - N2CX": Ocean states has a bad rap from some for sloooooow shipping.
<20:31:05>"Chris - w0anm": Not qrp, but some QRO vintage parts  -->  http://www.surplussales.com/
<20:31:38>"Milt-W8NUE": Softrock kit info  www.wb5rvz.com/sdr/
<20:32:16>"Bruce - N1RX": www.smallwonderlabs.com
<20:36:12>"Chris - w0anm": I built the emtech transciever for 40M nice rig.  Tuner is nice too.
<20:36:38>"Milt-W8NUE": The ZM-2 is a compact 5-1/16" x 2-5/8" x 1-5/8" and weighs only 8 oz. Great for backpacking.
<20:38:33>"George - N2APB1": http://www.steadynet.com/catalog/index.php?main_page=index&cPath=25   ... POLYVARICONS
<20:40:51>"Joe - N2CX": Dan's small parts is another relatively good site.  Kits are ok but plenty of parts takes only cash!
<20:41:40>"Joe - N2CX": Jameco is another big parts vendor that often has stuff that Digiey and Mouser do not.
<20:44:03>"Joe - N2CX": For LEDs try http://unclecytheledguy.com/
<20:44:43>"George - N2APB1": POLYPAKS!!!!  Man, those were the days!
<20:45:15>"Joe - N2CX": Bruce I used to love John Meshna!
<20:45:49>"Bruce - N1RX": Yes!
<20:45:59>"Ray K2ULR": Marlin P. Jones  <http://www.mpja.com/>
<20:46:16>"Joe - N2CX": Historical info - at one time Radio  Shack was associated with Allied Electronics
<20:47:26>"Bruce - N1RX": We have a local Radio Shack and snowmobile repair shop, all in one. He has parts that have literally been on the shelf since the 1970s!
<20:48:18>"Bruce - N1RX": Pulling parts for old boards is a time-honored tradition. I have a few cubic feet of computer boards etc on hand for use as donors.
<20:52:40>"George - N2APB1": http://www.harborfreight.com/
<20:52:53>"Rick K3IND": Whatever happened to Lafayette for parts?
<20:54:34>"Ray K2ULR": HF has a "spot weld remover" which makes very nice pads for Manhattan construction
<20:55:46>"Ray K2ULR": <http://www.harborfreight.com/3-8-eighth-inch-double-sided-rotary-spot-weld-cutter-95343.html>
<20:57:43>"Frank N3PUU": another place along the harbor freight line is Grizzly industrial
<20:59:47>"Joe - N2CX": Northern Hydraulics is another good tool source.
<21:03:08>"Milt-W8NUE": TI eZDSP C5535 site: http://www.ti.com/tool/tmdx5535ezdsp
<21:09:24>"Ted W2TAG": www.ldbepruchase.com  has C    hinese equipment at decent prices.
<21:10:53>"Milt-W8NUE": http://magazine-subscription-search.com/prd101588.php
<21:12:22>"Joe - N2CX": http://www.rsgb.org/news-radcom/radcom/?month=December&year=2011
<21:12:29>"Ted W2TAG": I baught a bench counter 0.1 hz to 2.4 GHz, a Precision bench type RF signal generator and a bench DMM from them.
<21:14:23>"Milt-W8NUE": may be of interest--just ordered one  L/C meter--- http://www.ebay.com/itm/NEW-LC100-A-Digital-LCD-High-Precision-Inductance-Capacitance-L-C-Meter-/270840165867  

Dec 20, 2011 ... Best QRP References:  

<20:12:13>"George - N2APB": Familiar source is ARRL http://www.arrl.org
<20:12:27>"George - N2APB": ARRL Radio Amateur Handbook
<20:12:32>"George - N2APB": ARRL Antenna Book
<20:13:04>"George - N2APB": Several QRP books  (QRP Power, by Rich Arland, K7SZ)
<20:13:14>"George - N2APB": Antenna Compendium up to Vol 8
<20:13:27>"Rick K3IND": Question on "RF Design"...
<20:13:31>"George - N2APB": Experimental Methods in RF Design  ... Wes Hayward
<20:14:04>"Rick K3IND": mine has a lot of words missing...
<20:14:13>"George - N2APB": ON4UN's Low Band DXing  good reference for operating on 80/40/160m
<20:19:10>"Joe - N2CX": WB4JFI
<20:21:22>"George - N2APB": Excellent books from RSGB very high quality content … www.rsgb.shop   RSGB Radiocommunication Handbook, and several other books covering UHF/VHF, antennas, etc.
<20:22:27>"George - N2APB": GQRP has British and Australian books … http://www.gqrp.com.sales.htm
<20:23:23>"Ray K2ULR": I have a book to add.
<20:27:45>"George - N2APB": ARRL Digital Signal Processing
<20:28:07>"George - N2APB": Oppenheim & Schaffer ... good ref for DSP algorithms and theory
<20:28:33>"George - N2APB": Microchip has great tools and libraries for embedded programming
<20:29:07>"Joe - N2CX": ARRL has a closout sale on Digital Signal Processing Technology!
<20:29:33>"George - N2APB": Practical Digital Signal Processing for Engineers and Technicians, on www.Amazon.com   ... good as a used book.  Gets into college level math, good for engineers, well illustrated
<20:32:25>"George - N2APB": www.dspguide.com
<20:34:56>"Joe - N2CX": I was lucky enough to get that book as a doorprize at the TAPR CC!
<20:35:30>"George - N2APB": Understanding Digital Signal processing, Second Edition, by Richard G. Lyons ... #1 reference recommendation
<20:36:04>"George - N2APB": Radio Frequency Design, by Wes hayward, from the ARRL Bookstore ... great for RF design material
<20:37:53>"Joe - N2CX": Education is expensive no matter how you get it!
<20:39:16>"George - N2APB": QRP Tech ... Yahoo group dealing with technical topics, run by Chuck Adams, K7QO
<20:42:02>"Joe - N2CX": K7QO tech list groups.yahoo.com/group/qrp-tech
<20:43:25>"George - N2APB": Austin QRP Group, AQRP Yahoo Group ... join it! ... Active projects: Morse Buddy, Digital Wattmeter, I2C/SPI interface for LCD display, Temperature/Barameter Kits with RF link ... just doing it for fun!  Google for K5BCQ Kits
<20:44:29>"Jim - N2ADR": Digital Signal  Processing in Communication Systems,  Marvin E. Frerking
<20:48:30>"Joe - N2CX": $130.31 on Amazon!
<20:49:50>"George - N2APB": HalfPriceBooks in Austin, TX
<20:49:53>"Joe - N2CX": Half Price books i this area has nearly no tch books...
<20:53:28>"George - N2APB": Boatanchor Manual Archive … http://bama.edebris.com/manuals/   ... but it's down right now
<20:53:50>"George - N2APB": Wes Hayward W7ZOI … http://w7zoi.net
<20:54:15>"George - N2APB": Snow camping with Wes and son Roger
<20:54:42>"George - N2APB": Steve Yates AA5TB Homebrew, antennas, loops … http://aa5tb.com
<20:55:21>"George - N2APB": Successful antennas, antenna calculator for parameters of Mag Loops (STLs), hands-on info and usage of EFHW (end fed half wave antennas)
<20:55:39>"George - N2APB": Harry Lythall  Homebrew … http://www.sm0vpo.com
<20:55:50>"oh2nlt": Thank you for interesting meeting. Unfortunately I have to leave now.
<20:56:03>"George - N2APB": Hans Summers Homebrew … http://www.hanssummers.com
<21:02:19>"George - N2APB": Here's my customized links ... "my favorites!" ... http://www.amqrp.org/misc/links.html    (N2APB)
<21:04:10>"Joe - N2CX": http://www.amazon.com/Programming-16-Bit-PIC-Microcontrollers-Technology/dp/0750682922
<21:04:41>"George - N2APB": Basic programming information for 16-bit microcontrollers by Lucio Di Jasio "Prgramming 16-bit Microcontrllers in C"  (aka: Learning to fly the PIC24)  See Amazon.com link above.
<21:06:57>"George - N2APB": FPGA reference:  Rapid Prototyping of Digital Systems, using Altera Gate arrays ... Cypress line of gate arrays, Microchip provides the IDE (development system), by Hanlon, Paul and Furman (spelling?)
<21:14:11>"George - N2APB": DSP "Short Course" frm TA{R Digital Communications Conference 2010 ... http://www.tapr.org/pdf/DCC2010-DSPcourse-session4-KN6KB.pdf
<21:18:46>"George - N2APB": "Wirebook V" by Press Jones, N8UG ... available from The Wireman ... http://thewireman.com/products.html
<21:19:26>"Ray K2ULR": Simple Test Equipment for the QRPer by G3MFJ & G4WIF.
<21:20:24>"George - N2APB": http://k7og.net/?p=69   Simple Equipment for the QRPer
<21:24:19>"Joe - N2CX": Good for small club kit runs!
<21:24:33>"Ray K2ULR": http://www.myropcb.com/
<21:27:03>"George - N2APB": Reference site for Peter G3XJP ... His documents are very good reference material, describing basic fabrication and includes rationale for the development.  Example: PIC-A-STAR series of articles from RADCOM.  Antojer;  Automated antenna tuner: PIC-A-TUNE ... good insight to Q and losses.  see link to follow from Larry.
<21:28:09>"Larry-W2HHV": PicATUne and Pic-a-STAR II Projects by Peter, G3XJP at  http://uk.groups.yahoo.com/group/picaproject/files/

Dec 27, 2011 ... Homebrew Filter Design and Measurement Techniques - Part 1: Filter Selection

Softrock RXTX 6.3 LPF on the TXPA Board

<20:44:09>"George - N2APB": Great reference on LPF design (and other types) is in the ARRL Handbook.  I'm currently looking at the 2008 edition and this is in Chapter 12.  (Check the index for "Low Pass Filter" in the rear of the publication)
<20:54:51>"Fred - WA8PGE": here's a pretty nifty toroid calculator, tells you how much wire you need too..
<20:54:58>"Fred - WA8PGE": http://kitsandparts.com/tcalc.html
<20:55:38>"George - N2APB": That's indeed a great reference Fred.
<20:58:05>"George - N2APB": Q-Dope ... source for this?
<21:01:40>"Joe - N2CX": Qdope is a General Cement (?) product available from various electronic suppliers.  i think A good source might be Antique Radio in Arizona.
<21:03:31>"Paul - AK1P": Try < http://www.hmcelectronics.com/product/GC-Electronics/10-3702>
<21:04:05>"George - N2APB": AADE Filter Designer     <http://www.aade.com/filter32/download.htm>
<21:06:02>"George - N2APB": Tonne Software Elsie Student Version    <http://tonnesoftware.com/elsie.html> also in ARRL Handbook disc
<21:06:35>"George - N2APB": Tonne Software SCVFilter    <http://tonnesoftware.com/svcfilter.html>     also in ARRL Handbook disc
<21:23:31>"Larry-W2HHV": Topic suggestion: Test equipment most used for QRP breadboarding?  Which items should one buy versus build?

Jan 3, 2012 ... Homebrew Filter Design and Measurement Techniques - Part 2: The Project


Desired performance:

Suggested free tools & design programs:


The Sweeper Input Card (SIC) became a linchpin measurement device for us ... shown on left, and installed in the Micro908


Jan 10, 2012 ... Homebrew Filter Design and Measurement Techniques - Part 3: Measurement

Set-up #1 Set-up #2
A Micro908 Antenna Analyst in "VFO" mode is used to deliver a stable, adjustable DDS-based signal to the input of the LPF.  For measuring the filter output, the precision RF detector (the "Sweeper Input Card") is integrated into the Micro908 to read the log amp output and display the result on the LCD.  An HP8640B signal generator delivers a stable, 0 dBm RF signal to the input of the LPF.  For measuring the filter output this time, we're using the precision KA7EXM "Microwattmeter".

(Click on photo for larger view)

(Click on photo for larger view)
The Results
Plot #1:  Full Sweep Plot #2:  Close-in at Roll-Off
Theoretical (from last week):
Theoretical (from last week):


Bonus project ... The Q-Meter:

Jan 17, 2012 ... What is the Best Antenna?   

















Jan24 ... Grounding 101

  • Cold water pipe
  • Electrical outlet ground :-((
  • All equipment
  • Braid or ground bar running at rear of table
  • #__ ga cable going to ground rod
  • Disconnect switch
  • Ground the (coax) shield at both ends
  • Coming into house
  • Spark Arrestor
  • Ground Rod(s)
  • Ground radials
  • Ground plate
  • Stainless steel
  • Buried radials
  • Elevated radials
  • Counterpoises
  • Tower grounding

Don Butler, N4UJW Hamuniverse.com ...
"You will also need to install a good station ground just outside the entry point of the coax. Get a good copper ground rod, 8 feet long and drive it into the ground just outside the entry point of a window or where it enters your shack. Keep in mind that the distance from the ground rod should be as short as possible from it to the equipment inside. It is never a good idea to have a long distance from the equipment to the ground rod ... remember: as short as possible. Now run very heavy (large conductor like # 8 size) if you can get it or as large as you can afford. The idea here is to have the least resistance to current flow as possible. The larger the wire the less resistance. The longer the wire, the more resistance is usually the case. Connect all of your equipment using whatever connectors needed to this single ground wire using short lengths if possible. Use the largest size wire that will fit the ground connections of your equipment.  It is also advisable to install a surge protector with several AC outlets on it for AC power connections for your station equipment.  Use metal water pipes as an alternate ground if you don't have access to a ground rod. Install a switch in the antenna coax that switches the antenna to ground if at all possible. This helps with lightning protection."

Pics from good W8JI website ( http://www.w8ji.com/ground_systems.htm  ) ...








Jan 31, 2012 ... Homebrew Battery Chargers: 

Simple NiCd NiMH chargers


Linear Technology battery charger IC application notes:

Here is a very simple NiMH float charger that I have been using once the charge is complete. Some interesting information on NiMH charging --> http://www.ka7oei.com/floaty_thingie.html

Commercial site for battery chargers ... http://www.batteryspace.com/batterychargers.aspx


Feb 14, 2012 ... Schematic Capture & PCB Layout:  

The familiar "napkin design" starting point ...

And on to making a nice schematic using PowerPoint and the N2APB-patented "micro-adjustment" technique ...

Download "perfect" PDF file of SIC schematic -- Notice how all the micro-alignments are perfectly lined up.

Download PowerPoint version of SIC schematic -- Use this as the starting point for making your own project's schematic

Here's the Circad PCB layout results ...    And the parts layout view (just showing the silkscreen) ...


And of course the completed SIC card ...


Feb 21, 2012 ... Circuit Simulation   ... Spice up your circuits!



April 24, 2012 ... Anatomy of a PICAXE SWR Controller:   The Growler 




The Growler

A low-cost, compact SWR bridge with LED bargraph display and varying audio tones to indicate measured results.  Morse code annunciation of specific SWR values.  Good up to 148 MHz.

The Growler is a descendant of the SWR bridge used in the Rainbow Tuner.  It keeps the multicolor LED bar graph display to give a visual SWR indication while adding audible outputs.  Its heart is a resistive bridge formed from surface mount power resistors.  Using surface mount devices and a compact layout provides operation through the 2 meter band as opposed to only HF coverage if leaded resistors were used as in the Rainbow Bridge.  The bridge resistors are sized to allow operation at full 5W QRP levels for periods of 15 seconds or less.  Simple diode detectors pick off forward and reverse RF and produce DC signals which are fed to PICAXE U1, analog to digital converter inputs.  The ratio of these is used to calculate SWR, which illuminates the LEDs.  A growling tone whose pitch is proportional to SWR is also controlled by U1 and sounded by the speaker.  When the RF signal ends, the speaker sends the SWR numerically in Morse Code.  Calculations based on the ratio of forward and reverse signals rather then their absolute numbers preserve measurement accuracy though the finite DC drop of the detector diodes results in increasingly optimistic SWR readings as RF power decreases below approximately one watt.

The Growler PCB


Growler Demo on YouTube

It's not perfect (was still being developed when the video was made), but you can see/hear the circuit in action! ... http://www.youtube.com/watch?v=2JJ9o1GDrGM

March 6 ... Rainbow Tuner SWR Bridge:







Rainbow Tuner schematic diagram



  1. EFHWA by N2CX - <http://www.njqrp.org/n2cxantennas/halfer/index.html>
  2. EFHA by AA5TB - <http://www.aa5tb.com/efha.html>



Mar 13, 2012 ... Intro to Digital Modes  


March 20, 2012 ... Simple & Accurate Power Measurement

Use of a 40 dB In-Line Power Tap ...

The Power Tap, directly from the W7ZOI article ...

So now, with the DL + Tap conveniently located next to the precision KA7EXM Power Meter, the two BNCs may be connected with a short length of coax to form a single measurement pair  ...


And actually measuring the SDR Cube's output power in Tune mode ... -9.9 dBm on the meter = 1.023W (see chart below)

Here's an excellent way to go for building an accurate, high dynamic range power meter, from the AQRP Club guys: K5BCQ, W8NUE, and K5JHF ...


Source:  The QRP Quarterly, Spring 2003   www.qrparci.org


April 3, 2012 ... Soldering 101 

A Clean Workbench is [not!] a must ...




The following is original work of N2APB as contributed to the ARRL Handbook, chapter 23 ...


The "Doofus" SMT Hold-Down Device ...


KD5SSJ "SMT Soldering Tools & Process" (http://kd5ssj.com/solderpaste/smt-tools-and-process)


April 10, 2012 ... Oscilloscope Basics, by Alan Wolke W2AEW

June 19, 2012 ... Oscilloscope Applications:  

LOTS of videos on scope applications, and ham radio uses for scopes ...

  1. Monitoring your transmitter: https://www.youtube.com/watch?v=y4Zt_LJX1Tc

  2. Basics of 1X/10X Probes: https://www.youtube.com/watch?v=SX4HGNWBe5M

  3. AC/DC Coupling: https://www.youtube.com/watch?v=Hkq-fvb5-NI

  4. Triggering Controls: https://www.youtube.com/watch?v=OFGm-Pel4Hg

  5. Basics of Frequency measurement: https://www.youtube.com/watch?v=OQMnjaMSKn8

  6. Distortion measurements (or not!): https://www.youtube.com/watch?v=XHA4c82msqo

  7. Basics of Lissajous patterns: https://www.youtube.com/watch?v=t6nGiBzGLD8

  8. Simple Component Curve Tracer: https://www.youtube.com/watch?v=Gwo3pEH7hUE

  9. Delayed Timebase operation: https://www.youtube.com/watch?v=J-7MycqHPOs

  10. Three videos on viewing two signals clearly:

  11.   1) https://www.youtube.com/watch?v=LonFeZh2WL4

  12.   2) https://www.youtube.com/watch?v=hk0ZSRV8zIQ

  13.   3) https://www.youtube.com/watch?v=j4IxbF0oFRE

  14. Bandwidth Considerations: https://www.youtube.com/watch?v=oZ1Dv2dVGkU

  15. ALT, CHOP, etc. vertical controls: https://www.youtube.com/watch?v=zsy-pxpfB4o

  16. Poor Man's TDR - measure length and Z of coax: https://www.youtube.com/watch?v=Il_eju4D_TM

  17. Test an RF Power Detector: https://www.youtube.com/watch?v=vvqVTD-VEow

  18. Rear Panel I/O:

  19.     - create a "marker": https://www.youtube.com/watch?v=QCFBBiIm1h0

  20.     - Connect a counter, expand vertical scale: https://www.youtube.com/watch?v=tyA-4Qv8RDs

  21.     - Display video! https://www.youtube.com/watch?v=5FYF5uhCzAM

One, for example:   Monitoring your transmitter:  https://www.youtube.com/watch?v=y4Zt_LJX1Tc

This video shows a few ways that you can monitor your ham radio transmitter with an oscilloscope. Look at the RF carrier, the carrier envelope, the amplitude demodulated signal, as well as linearity "trapazoid" patterns (please see below). It shows a simple circuit I put together for a local ham radio club meeting and presentation.

I put this circuit together to show the radio club members examples of a sampler and a amplitude demodulator. Of course, since these were built onto the same "demonstrator" board with a common RF input, the linearity can not be measured with this since any non-linearity in the output would appear in both sensors. This is indicated by the notes in the video. In order to truly measure the non-linearity of an amplifier or a modulator/exciter, the X-input would normally be driven by the baseband signal, or the demodulated input to an amplifier, etc., and the RF output would be sensed with the sampler and applied to the Y input of the scope.




April 17, 2012 ... Erecting a Vertical Antenna


1) Choosing the site

2) Deciding on the mounting

3) Digging the hole

4) Cement base

5) Mounting antenna

6) Laying Radials

7) Feedline into the house

8) Tuning up!



Vertical Antennas

-Butternut HF6VX ($389)
-Hustler 5BTV ($189)
-Gap Eagle ($389)
-Cushcraft R8 ($539)

80m Scan


April 24th ... Magnetic Loop Design  


May 1, 2012   Harmonics and Spurs and Parasitics (“Oh My!”)

 “Mixing 101”


... And what it looks like in real life …


               Real Life Spectrum


SQM: Signal Quality Meter

Here’s a simple circuit that we designed as a group project at one of our Atlanticon QRP conferences several years ago.  The idea was to implement the simple approach mentioned above: “Measure all the energy and then take out the fundamental, and as a result leaving a measure of all the unwanted energy being generated.”

And all this is done with straightforward analog components … “we don’t need no stinkin’ computer!”

So the idea is to use this circuit to measure the spectrum energy above the fundamental signal being generated, and then make whatever adjustments possible to reduce this somewhat relative number … reduce the drive, use better shielding, better grounding, better filtering, et al.

The Signal Quality Meter, or ‘SQM’, is a user-friendly device that produces a graphical display of relative quality of an RF signal applied to its input. Using a modern analog integrated circuit and other familiar RF components, the SQM examines an input RF signal and identifies how much unwanted harmonic or other off-frequency components are attenuated.   It provides a simple and easy way to determine how “clean” the output of an oscillator, amplifier or properly attenuated transmitter really is.

Theory of Operation

An input signal in the HF range, as high as 4 Vpp down to 10 mVpp, is fed to the input.  The signal is attenuated and passed through a notch filter to attenuate the fundamental signal.  All other components (harmonics of the fundamental and undesirable higher frequency spurious signals) are allowed to pass on for measurements.  A logarithmic detector then senses this remaining energy in the spectrum and feeds a bargraph display to show the cumulative amount of remaining off-frequency signals.


May 15, 2012... R/C for Hams  

- Different "transport layers"




Remote ON-Off Keying



The Rookey "Decoder" Setup:
FM receiver, audio patch cable, Decoder board, ear buds,
and the 9V battery. (Battery not included in kit.)

The fully-populated Rookey pc board makes a Decoder

Rookey pc board populated to make an Encoder

The Rookey Kit consists of the audio Decoder pc board and all on-board components, a small FM receiver, audio patch cord, ear buds and an 9V battery clip. The microcontroller IC supplied with the Decoder board is preprogrammed with the BASIC software program that decodes the incoming audio pulses to illuminate any one of the four LEDs.

An extra (blank) Rookey pc board is also supplied in the Rookey Kit and is easily modified for use as a mating Encoder board to generate the coded audio signals that would be sent (with a user-supplied FM transmitter) over the "transport medium" of the FM band. Alternatively, the Encoder's audio pulses could be sent to the Rookey using IR, Bluetooth, hf/vfh ham band or ultrasonic transceivers. You could even just connect the Rookey Encoder and Decoder board pair with a long run of ordinary twisted pair wires to deliver multi-function control to the end-point.

The Rookey Encoder and Decoder boards use the simple and reprogrammable PICAXE microcontroller, thus allowing you to easily customize the project by changing the codes and adding other features to suite your remote control project ideas. All encoder/decoder software is freely available on this web page.

Additional software is available for the Rookey boards, provided by PICAXE-enthusiast David Gwillim, KB2TQX. Dave's programs allow the Rookey board to function as a Randon Morse Generator, Iambic Keyer, Koch Method Generator and a temperature controller. This source code is also freely available here.


May 22, 2012 ... Antenna Tuning Units


         Actually, "Antenna Matching Units" ...

         Why do we need them?

     Modern rigs  designed for 50 ohms

     Many antennas/feedlines are not

     Non-resonant wires

     Open-wire feedline

     Multiband operation


Fig 15.25 end-fed wire impedance plot


Z-Match Tuner

     Fairly simple construction

     Easy to tune

     Tunes wide impedance range

     Balanced or unbalanced




May 29, 2012 ... Feedline Frenzy  

[From Wikipedia]Coaxial cable, or coax, has an inner conductor surrounded by a flexible, tubular insulating layer, surrounded by a tubular conducting shield. The term coaxial comes from the inner conductor and the outer shield sharing the same geometric axis. Coaxial cable was invented by English engineer and mathematician Oliver Heaviside, who patented the design in 1880.[1] Coaxial cable differs from other shielded cable used for carrying lower-frequency signals, such as audio signals, in that the dimensions of the cable are controlled to give a precise, constant conductor spacing, which is needed for it to function efficiently as a radio frequency transmission line.

RG-59 flexible coaxial cable composed of:

A: outer plastic sheath
B: woven copper shield
C: inner dielectric insulator
D: copper core

        Coaxial Cable Loss in db per 100ft.


Coax Data Charts ... from N0HR page ... http://www.n0hr.com/hamradio/104/10/ham_radio0.htm

Coax data - attenuation, velocity factor, impedance, OD for various types of coax.

                            Coax Data

                    Attenuation - db/100 feet
Belden #   Impedance 100 MHz  400 MHz  1000 MHz    OD   V Factor

9880           50   1.3       2.8       4.5       .390      .82
   This is Thicknet Ethernet cable.  Most is marked "Style 1478" and
   has a #12 solid center conductor and 4 shields (2 braid/2 foil).      

                    Attenuation - db/100 feet
Belden #   Impedance 100 MHz  400 MHz  1000 MHz    OD   V Factor
9913           50   1.3       2.8       4.5       .405      .82
9914           50                       9         .403      .66
8 /U           50   1.8       4.7       6.9       .405      .66
8 A/U          50                       9         .405      .66
8 /X           50   3.7       8         12.8      .242      .78
58 A/U         50   4.9       11.5      20        .195      .66
58 C/U         50   4.9       11.5      20        .195      .66
174 /U         50   8.9       17.5      28.2      .101      .66
188 A/U        50   9.8       15.8      25        .11       .66
213 /U         50   2.2       4.7       8         .405      .66
214 /U         50   2.2       4.7       8         .425      .66

Coaxial Cable Power Ratings
Maximum input power rating - Watts at (MHz)

RG/U CABLE 1.0 10 50 100 200 400 900 1000 3000 5000
8 MINI,8X 4000 1500 800 550 360 250
150 65 50
8,8A,10A,213 11000 3500 1500 975 685 450
230 115 70
3500 1500 975 685 450
230 115 70
174 1000 350 160 80 80 60
35 15 10



THE PROJECT:  Remote Controlled Antenna Switch


Weatherproof enclosure


Pix of box,  overall about 6" x 6" x 4" ...



June 5, 2012 ... Retro SWR  

The old Heathkit SWR bridges ... recall the nostalgia days of building simple kits?!








Wiring the "Retro SWR Meter" ... Ugly-Style!




June 12 ... QRO Power Supplies:   A Homebrew, 13.6V, 10A Linear Power Supply 


My implementation ... "DC Power Cube", shown above-left

IN-PROGRESS PROJECT:   Remote Controlled Antenna Switch  ... (Continued from previous week's session)




June 26, 2012 GPS Applications in QRP Communications  ... by Joe Jesson, KC2VGL

The uM-FPU from Micromega can directly parse NMEA strings ... http://www.micromegacorp.com/umfpu-v3.html 

Jupiter-T GPS Receiver Module






GPS Disciplined Oscillator, by G3RUH ... http://www.jrmiller.demon.co.uk/projects/ministd/frqstd.htm  



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