RF — Test and Measurement Homepage
FAQSite Update LogAbout...Design Apps
Topics 1998 - 2005 SWL Page RF Preamps QRPHB Software Popcorn DC Receiver Mainframe 40 M Popcorn Superhet Receiver Broadband Transformer Topics Diplexer Topics Ugly Construction Wee Willy 75 M DSB Transceiver W7ZOI JFET Biasing Tutorial EMRFD Review Tapped Cap Impedance Transformation More Active Antenna Experiments Fun with LEDs SWL Receiving Antenna Experiments
Topics 2010 - 2011 Low Noise Crystal Oscillators Crystal Parameter Checker Supplement Hobbyist Circuits 2010 RF Workbench Page 1 RF Workbench Page 2 AF Transistor Input Z Experiments RF Workbench Page 3 Misc RF Experiments 2011 Hobby and Fun 2011 QRP Modules 2011 Receiver Band-pass Filters RF Workbench Page 4 VFO-2011 VHF Butler Oscillator
Topics 2006 - 2009 Experiments with JFET Biasing TRF Receiver for WWV MF and HF SWL Receiving Antenna MF and HF Receive Antenna Splitter MF TRF Receiver Junk Box Low Pass NDB Filter More NDB Ideas and Circuits Low Pass Audio Filter Experiments TRF WWV Receiver for 5 MHz Complementary-Symmetry Amplifier Biasing Basics Low Power Audio Amp Experiments Two Bravo Receiver Experiments ICOM IC-7200 Review Electronic Hobbyist Circuits Output of a Diode Ring Mixer in an Oscilloscope
Topics 2012 - 2014 VHF to the Max ! HF Ragbag RF Workbench Page 5 VHF-FM Sundry Experiments 2012-13 VHF - Veronica RF Workbench Page 6 HF Embarcadero Caitlyn 310 : UHF Beginnings
Make it — then measure it!
1. How to you make your schematics?
RF — Test and Measurement
Frequently Asked Questions
I hand draw my schematics using the Paint Program that ships with all Microsoft Windows(tm) operating systems.
I strive to make schematics as clear and as small in file size as possible.The Windows Clipboard is used extensively to copy and paste the desired components from previous schematics to new schematics — very few new components are ever drawn; rather they are recycled from schematic to schematic. My system allows me to paste color 3D labels and small photographic bitmaps into schematics.
The raw 24bit bitmap drawings are compressed to 16bit png files. Prior to May 17, 2010, bitmaps were compressed as 8bit gif files. An example drafted circuit using the Windows 7 Paint program follows.
At least 25 people have sent or recommended software for making schematics. Thank you for this kind gesture, but I prefer my current method and after 15 years — make schematics quickly.
2. How come you don't supply parts lists? Other people do.
The answer is simple; lack of time. It takes considerable time and effort to put up a new web page and also to maintain a large web site. I save time by leaving the parts list up to the builder. In addition, this site is about experimentation and using what parts you have on hand.
3. Why didn't you answer my email?
I answer all legitimate emails as soon as possible. Our POP3 server gets an average of 2016 spam emails per month (December 2013 data), however, our software removes 99.27% of these and I never see them. Occasionally, legitimate emails are filtered in error and I apologize. I've received as many as 83 legitimate emails in a single day so can get behind. Please keep emailing — when readers stop emailing, I'll know the site has fallen totally obsolete [it may already be obsolete] and delete it.
Our mail server software logs and analyzes the network information of all spammers and may automatically filter and/or block their addresses or even their entire ISPs at the router level. Analysis indicates that 90% of our SPAM comes from just 3 countries and if you happen to live in one of these countries, the filtering will be especially sensitive.
This sounds dogmatic and unfriendly, however, until you've set up a domain and must handle ++ spam emails, endure and then develop router control software and other strategies to handle DDoS attacks and so forth, your completely naive about the 'dark side' of running a homebrew web server. Massive amounts of bandwidth might be otherwise wasted by allowing unwanted server use unless we actively counter these activities to keep the site running well for legitimate hobbyists. Not to mention all the wasted time. Further:
The 3 host web servers, the power, the server software, the security apps, the internet bandwidth etc.are owned or purchased by my family, and as you know, nothing is free. Despite many offers by companies to place ads on my pages, I've kept the site advertisment free and running pops.net costs us a few thousand dollars each year. We ask you to please respect our site for the sake of the experimenters who visit.
Pops.net server rack in our warehouse.
While I appreciate that some people might want to email invite me onto their social networks, I do not have time to participate. All email traffic from or involving social networkssee this page for a listis deleted automatically by our POP3 server control software.
IneverI do give free parts to those in need though.buy or sell parts via email, nor exchange hyperlinks. Never. All email with the .info domain is blocked.
The number of people selling kits has jumped up by ~4 dB in the past 5 years. Increasingly, builders who need help with kits were emailing me for support. I rarely build kits and my knowledge regarding kit building is nearly 0. Please contact your kit seller for help.
You may wish to enquire with the kit seller about their online support polices and promptness prior to purchase. Additionally you might try the "support" email address provided and see if and how promptly they reply. Most of the popular kit sellers (AADE, Kits and Parts, etc.) provide excellent support to their customers. Like anything else online; buyer beware.
4. How come you didn't link to my web site  I linked to yours?
A big thanks to the folks who link to this web site! The QRP/SWL HomeBuilder site focus is content, not web links. Making a lot of links means spending time testing for and tracking down dead links  the so called "link rot". Time spent on the web site is time away from the electronics work bench. In addition, it is not logistically possible to reciprocate in kind, as hundreds of web sites and blogs have linked this site.
5. I see the word "popcorn" used a lot on this site what's this all about?
Popcorn connotes the essential theme of the web site; simple, frugal, without fuss and over use of technical jargon, or complex math and engineering techniques. The QRP/SWL HomeBuilder web site is referred to as the popcorn site by many. The site targets hobbyists. The emphasis is fun. The hope is that it will attract new people to electronic design, measurement and experimentation. Hopefully, this site stimulates interest in QRP homebrew electronics.
Soon after I began building electronic circuits, my teachers and the popular electronicrelated media of the day pushed me towards etched, printed circuit boards. I complied and this killed my passion for electronics. For me, habitually stuffing circuit boards lacks creativity and freedom.
Later, I discovered people were building guitar and bass amps using point to point wiring techniques with terminal strips and partial circuit boards. I became interested in building and repairing guitar amps and this passion continues today. In 1992, the discovery of 2 QST articles changed everythingfor me (complete reference provided):The Ugly Weekender: parts 1 and 2 by Roger Hayward, KA7EXM and Wes Hayward, W7ZOI; published in QST for August 1981 and June 1992. This was my first exposure toUgly Constructionand it was immediately adopted as the defacto standard bread boarding method in my electronics work shop. In fairness, etched circuit boards are a great tool, but not essential for the experimenter. After working with Ugly Construction over time, considerable progress was made in understanding RF circuits and one output was the launch of this web site in 1998.
Currently, little has changed, I continue to prefer scratchhomebrew rather than kithomebrew electronics. My interest in Short Wave radio and analog electronics has grown considerably. For me, electronic circuits hold a certain mystique which arouses my curiosity to learn, enjoy and share. As a lay person, this web site has facilitated meeting some awesome people through email from all continents and it has been a privilege to learn from them, my mentors, book and web authors and often enough; from my mistakes.
5. What do you mean by a 5K1 or 3K3 resistor value?
For E24 or 5% tolerance resistors 5K1 = 5.1K, 3K3 = 3.3K and so on. For E96 or 1% resistors 31.6K is written as 31.6K. All resistors are 1/4 watt unless otherwise specified.
6. How do you measure audio amp output power?
Please see Figure 4 on thisweb page.Any amp when cranked, outputs much greater power than when it is providing a clean sine wave. The quoted power for any audio power amp on this web site is the maximum average power it will give before the pure sine wave becomes distorted.
7. I noticed a new web page appears and then it is edited for 12 weeks. When is the web page completed?
When a new web page is added, it takes a week or so to find and change some of the grammar and spelling errors. Sometimes new ideas or feedback will cause me to further edit a web page at any point in time. This whole web site is a work in progress. The last date any given web page was edited is posted on the bottom of the web page.
8. Do you buy or sell stuff?
No and no.I receive numerous emails from people asking me to sell them stuff. I do not sell anything  no parts, books, coffee cups, ball caps, teeshirts, ad space — nothing. I do not buy parts in commercialquantity volumes and have no need to make contracts for obtaining any electronic components. Every week, Asian companies email to ask about buying their parts — please note, my answer isalwaysthe same: no thank you.
9. Questions and concerns about printing and printability
Each year, a few readers email to complain how poorly the web pages print. This is true and I apologize.
Some people prefer pdf files for easy printing. I have resisted going to pdf format for 3 main reasons:
1.The web site audience is international and many are using web translators. PDF files are 8bit graphic image files and do not translate. 2.More and more readers are using mobile computer devices and pdf files are a pain for them. 3.We should all print less often to save resources
As an experimenter, I dislike crammed, smallsize schematics and feel they should be drawn formaximumclarity. Therefore, my schematics tend to have a lot of white space and color contrast. I try to make them no wider than 700 pixels, although sometimes it's impossible to do this. Big schematics arenotprinter friendly. The only practical solution is to click on and open them in a separate browser window for easier sizing and printing.
I also feature big photos which burn up a lot of printer paper. Project photos are important to me; they provide a more intimate glimpse into the bench work and promote the real purpose of the site — building stuff.
A potential printing solution for Microsoft Explorer 8 users;Click
10. I have noticed in your CMOS logic photographs, you don't always ground unused input gates. Isn't this bad?
Proper CMOS logic practice mandates the grounding of all unused input gates. In prototypes and experiments, I don't always do this as I generally want to reuse the IC in other experiments. This is a cost saving measure. When you build a lot of stuff, it can get expensive and recycling parts makes sense. In keeper circuits or critical prototypes, unused input gates are directly soldered to the copper clad board. This also anchors the IC very well.
11. What is the proper URL of the home page?
http://www.qrp.pops.net
The following pre2006 URL was decommissioned August 6, 2010: http://www.qrp.pops.net/default.htm
12. What are the QRPHB Design Centers and Professor Ivanenko character about?
This web site is about design and not just providing circuits to copy; I'm hopeful that the QRPHB Design Center concept initiated in 2011 will invigorate the site. Design Centers are the presentation of simple, but useful algorithms for amateur builders to advance their skills on the bench.
Professor Vasily Ivanenko ( ), afictitiousretired Russian physics professor wants to share his knowledge and give back to society. He signifies each Design Center. Professor Ivanenko was drawn for me by Rod Adams in 1996 using the Paint program that ships with Windows (the same app I make my schematics with). Rod did all of the other original bitmap art for this website including the coil guy and junk box pictures. This character was inspired by one of my favorite photographers: Irving Penn —this photograph, which is all over the web.
A new character; Dr. Natasha Petrovna appeared in late Summer 2012.
The professors are just a good bit of fun — add intrigue, characters on whom to focus and a means of identifying Design Centers. Electronics with just math and physics bores us all. Adding splash, color, clear photographs and characters such as the coil guy or the Professors boosts the site's appeal and provides a creative outlet for me.
13. Why did you kill your blog?
Time mostly.Myblog wastedyoursand my time. I carefully analyzed my personal yield from blogs in 2012 to 2013 — for the most part, blogs just entertain + share trivia, or rehash someone elses idea(s), or 'innocently' attract you in hope to sell stuff — and sometimes, just fulfill the author's need for attention. I don't seek, nor have time for entertainment or spectacle within my RF hobby and I certainly don't wish to wasteyour time. Each to his own, I suppose.
My analysis showed that unfortunately, blogs rarely boosted my understanding of electronic design or measurement practices. My ardent focus is to learn + improve and then pay some of this knowledge forward on a web site. Of course, everything in context — many exceptional people blog. For example, Dave AA7EE, or Jason, NT7S.
Most of the RF design and measurement people I follow keep old fashion web sites and provide generous email support. Design and measurement web sites, plus reputable and/or peerreviewed industry and hobbist books, journals and multimedia work best for me.
Further, great elmers don't just publicly hangout on blogs, or web server groups, or publish Utube videos — some just check their emails and when asked — give wonderful support without fanfare. Hats off to these humble folks. Thank you!
14. What oscilloscope should I buy?
Yikes — a tough question I get nearly every month. Please do your research. My best answer is buy the best 'scope you can afford. Are you a casual experimenter, or sit in your lab a lot? I prefer DSO's , however, made due with a old boat anchor CRT for my first 10 years. The Rigol 1052/1152 seem popular entrylevel choices due to their cost versus performance ratio. On the other hand,view this videoto see how much Rigol DSO technology has changed.
I owned and sold my 1052 to a builder in Michigan — a worthy choice like many other 'scopes. IMHO, the FFT and math functions on the 1052 and 1152 suffer due to low memory depth and clock jitter.
Even if you only work at HF, a bandwidth 5X higher than your main frequencies of interest works better for showing harmonics. Again, I advise people to simply buy the best 'scope they can afford since it will form the heart of your test bench.
15. I'm a beginner — what toroids should I buy?
Opinions will vary, but here's what I recommend. Buy any quantity you wish, but sometimes minimum quantities apply and shipping to some countries costs dearly, so I tend to order enough parts to last me for awhile.
RF — Test and Measurement
QRP — Log: Updates To Permanent Content
Oct 5, 2014  The end of QRPHB?As I wrote before, we're losing an average of 10% Expect the Qrp site to go down each day for 14 hours. of the outgoing packets and this peaks as high as 40% when many people are accessing the site. See an example graph below.
On Oct 2, 1 of our ISP's techs came and tested our WAN  "it's better than most" he said. Hopefully they can do something to boost the performance on their side. Wave bought out all the local competition and we're stuck with them [this is happening everywhere].Clickfor 1 of the many links writing about the emerging internet cable company monopoly.
You'd think that in 2014 we could properly host a web site like we've done since 1998? To boot, Stuart is paying for a high bandwidth business account and getting less than 1% of the promised bandwidth. We chatted today and will wait patiently for Wave to improve our outflow  but only for so long.
If Wave can't or won't boost performance, I am leaning towards taking this web site down as opposed to moving it  it's been a good run. QRPHB creates a lot of work and I could get way more done without the web site hassles. So, 2014 might be it for me. If so, thanks for coming here all these years and best of luck with your experiments!
 Sep. 19 Wave Broadband, our Internet provider suffered major problems recently and I shut the site down for 4 days rather than have it limp along pathetically. Well the Wave sagacontinues: the site loads slowly and pictures are missing etc.
Our email server remains working even when the main site is down. You can always email me if the site is not working for you  or if you have a comment or question.
Vistor volume rose this Summer so we added a better router that provides bit by bit data performance collection and new features to help throughput. At minimum user bandwidth, a unique visitor hits the site every ~0.7 minutes. I'll start formal bench experiments on October 3  to kick off the sites' 16th season.
August 31, 2014 —Kit to upgrade my HP frequency counter to 3 GHz added as Section 5 onCaitlyn 310 — UHF Beginnings.
August 18, 2014 —QRPPOS Data on theSundry Web Page. Look at the end of Section 8: Popcorn AF Amps For Receivers — Reprise. This new, alldiscrete AF stage will go into the Funster Line receiver and ranks as 1 of my best in terms of power and headroom.
August 12, 2014 —Funster Line: a QRP 40M band CW transreceiver added to HF Embarcadero web page as Menu item 4.Click herefor Funster. Only the transmitter is presented for now.
June 18, 2014 —I tweaked the page now calledAbout...on the top level menu. Also, on this web page, I added a new essay for 2014 just under the essay for 2010. I'm off the bench until Fall, but hope to add a little content on rainy days or such. I'm about 2 years behind in presenting some of my experiments.
May 22 and 26, 2014 —New Supplemental Web Pagefor VHFFM launched. This page and another supplement will house some new receivers over time. The new supplement is linked on the original VHFFM web page in section number 4.
May 5, 2014 —Section 7: NE612 Mixer Diddy added toVHF Veronica
April 14, 2014 —Completion of Return Loss Bridge Experiments [ added Bridge #4 ] onCaitlyn 310.
April 7, 2014 —Return loss and VCO experiments added toCaitlyn 310.
March 7, 2014 —Section 3 added toVHFFM. A DC Converter for VCOs.March 25Poor Hams ScalarQRPPOSDATA for March 2014 Network Analyzer (PHSNA) added to Section 1 ofSundry.
February 14, 2014 —Caitlyn 310 — New repository web page for my venture into UHF.Click. Surprisingly, the site averages ~ 3000 unique visitors every 24 hours.Clickfor the Feb 25 tally
January 15, 2014 —The FAQ was often missed and therefore moved to the top level menu + editted/augmented.
January 4, 2014 —A followon version of the K3NHI QEX power meter added toRF Workbench 5as section 6.
December 15, 2013 —I added Section 3 toHF Embarcadero. VXO and VCXO Notes. I significantly updated theVFO2011web page on Dec 17, 2013.
November 7, 2013 —Section 6 added toVHF — Véronique. 1 photo added to the end of the Ugly Construction page. Severe Fall weather