RAN Technology

"B" Bench update


Technical 0 Comments 02/03/2020 

Making my work area suit me rather than vice versa

Posted By: Robert Nickels (ranickels)

 

Like most of those reading this, I've upgraded and added to my test equipment inventory over the years, starting with the Heathkit VTVM I built when I was 15 or so.   There's no "right" piece of equipment, just personal preferences, and while I'd be the first to say my work habits are anything but "right" they are what they are, and I'm old enough to realize that my workbench layout will have to conform to my preferences, rather than the other way round.

I recently decided to make some changes to my "B" bench, which either stands for "boatanchor" or because it's the second-best equipped.   My primary bench is used mostly for design and building and SMT assembly and it's undergoing some changes too, but the "B" bench is where a newly acquired piece of gear is most apt to land for an initial check-out and where restoration of most gear will take place.  

It's an 8 ft. wide stand-up (my preference) bench where the needed variac and power related stuff occupies the right hand end area.   I'd had peg hooks for tools but found I was very poor at actually putting things back, so I decided to try the four plastic bins instead.   Tools are organized loosely from the most frequency used in the left-most bin.    A Weller soldering station is to the left (I'm a southpaw) and the Haako desolder and 150 watt gun are underneath.    I do not like having to look "up" to see a meter, so I'm anxious to try the Fluke 37 which I recently acquired which is front-and-center on the bench and will be nicer to read and use than a handheld.    The very good HP 3466A DMM is atop my bench receiver, the Heathkit SW-7800 when morr precision is needed.   The SW-7800 is not Heathkit's best effort but works well in this role because it has digital readout, an attenuator, and USB/LSB/AM/Wide AM modes.   It's used only for audio monitoring of whatever RF emitter I may be working on at any time.  There's also a B&K "Flip-o-Matic" VTVM, mainly because I think it's cool.

There is just nothing better than an analog scope for looking at analog signas, IMHO.   The Tek 475 is a mil-spec upgrade of the basic 250 MHz scope  and replaces a Tek DSO which I'll get more use out of as a portable.    Other gear:
 

B&K Function Generator.   I like that it has enough output to test speakers yet is very simple to use.

To the right of the Heathkit, top to bottom:  Elenco signal generator/counter   I'll bring over a signal from my main HP sig gen for alignments, etc but it's nice to have an RF source with a knob handy.  Boonton 8210 Modulation Analyzer.  This is a new addition and since I work on AM transmitters a lot it will see some use.   Racal-Dana 1992 universal counter timer.  I've needed a better counter and this 1.3 GHz counter fills the bill nicely.

Next:  HP-410C   I don't need a VTVM often but this is the industry standard and the RF probe also covers the range I'm interested in.   The Waters dummy-load wattmeter has switchable ranges from 10 to 1000 watts.  For  more accurate measurement I'll use the scope for low power or a Bird.

Those with sharp eyes will note the Supreme "Audolyzer" on the top shelf.   This instrument from the late 1930s is very handy when repairing AM radios because it can act as a tunable RF voltmeter to check RF and IF stages and as a signal tracer.  It was scrounged from a dumpster at a hamfest because no one knew or appreciated what it was.   The box with the red chicken-head knobs on top is a speaker substitute box known as a " Coastwise Ferret 721".    Panel jacks allow selection of voice coil or it's built-in transformer - these were popular items in the day when a serviceman would bring the chassis of a radio into the shop for repair but would leave the heavy cabinet containing the speaker and its transformer in the customers home.

Lastly there's a B&K transistor tester, an HP DC power supply, a Fluke DMM and a big honkin' semi-regulated Motorola DC power supply that is basically a battery substitute for mobile radios.   I don't use it often but it's nice because it has a variac to make up for voltage drop.

Every shop and every person's needs are different, and I have a bunch of other gear I'll bring in when needed but this set pretty much does what I need for boatanchor tube and solid-state repair and restoration.   My FT-817 is often used as a  low-power signal source and as a receiver, very handy piece of test equipment when not being used on the air.    The same is true for a simple RTL-SDR but that will be another story!

 

 

 

Click on the image title or on the image itself to open the full-sized image in a separate window.

    Jay Miller KK5IM recently wrote an article in Electric Radio magazine about fulfilling his dream of building a homebrew "AM Kilowatt" transmitter (375 watts output by today's standards).     His crystal-controlled exciter that drive the 813 was based on his Novice transmitter, which was built by his grand-uncle back in the 1960s when Novice class hams were l...  READ MORE
- Robert Nickels (ranickels),  07/09/2020 
  

Bias control of Class E amplfiers

Previously undocumented phenomenon
Category: Technical
Micro SDR innovator Guido PE1NNZ has implemented polar modulation using an Arduino MCU and a class E PA.   For more informartion on this fascinating project, join the discussion group at https://groups.io/g/ucxInitially, Guido's design implemented the polar or EER modulation scheme using modifications to the QCX CW transceiver hardware in the traditional way as described by Leonard K...  READ MORE
- Robert Nickels (ranickels),  06/20/2020 
    I'm always intrigued by the odd and unusual ham gear that I remember seeing in catalogs as a kid but have seldom seen after hundreds of hamfests and uncountable for sale listings.   One such is the Lysco mobile transmitter which was produced by the Lysco Manufacturing Company of 1401 Clinton St. Hoboken NJ between 1949 and 1953.   Despite being a very cute and co...  READ MORE
- Robert Nickels (ranickels),  06/06/2020 
  

Class E Notes

the result of experiments with high efficiency class E amplifiers
Category: Technical
 There is a lot of misunderstanding about how a Class E amplifier works.    Including my own ;-)   As the result of studying the literature and experimenting, I thought I'd share what I have learned.Below is an example of a test amplifier I used to optimize my 2 watt wspr transmitter boards.   It can be visualized as two circuits - the amplifier itself a...  READ MORE
- Robert Nickels (ranickels),  06/06/2020 
   Seeing this article on Hackaday about how a guy in China made a crystal set using the diode in a chip credit card for the detector reminded me of the Postcard Radio.  It was a project in the WWII-era "Boys Fun Book" that I had as a kid and although I remember it well I had no reason to build one because who would want to mail a radio to someone else?     I did ma...  READ MORE
- Robert Nickels (ranickels),  06/04/2020 
   What can I say, I like oddball radios!    There was already a different version of this CAI SSB-125 on my shelf but it had the remote control head, and this one was cheap, well under $100 including shipping, and I'm easily amused.   VIDEO DEMO HERECommunications Associates Inc. was a supplier of commercial, military, and marine radios based in Huntington Station, ...  READ MORE
- Robert Nickels (ranickels),  05/14/2020 
   The HW-16 had to be pushed aside while waiting for parts, creating an opening just big enough for the homebrew receiver I got recently via eBay for $18.50 - plus 2X that to ship it here.   I like saving and restoring old homebrew gear just out of respect for the amount of time and effort our forefathers put into making things from scratch, and this receiver intrigued me, as the IF transf...  READ MORE
- Robert Nickels (ranickels),  04/28/2020 
    The Multi Elmac Company of Hazel Park and later, Oak Park MI is best know amongst hams for it's great mobile transmitters and receivers which were probably the most popular rigs of their type and are still often used on AM today.   The Multi Elmac Net pays tribute to these little rigs by and typically a half-dozen or more are heard on the net weekly.But the company's origin...  READ MORE
- Robert Nickels (ranickels),  04/22/2020 
  

Wireless on a Train

a lesser-known radio "first"
Category: Historic
WHEN Frederick Wally stepped out of a little cubby-hole in one corner of the forward day coach on the Lackawanna Limited, west-bound, as it neared North Scranton, Pennsylvania, Tuesday, November 25, 1913, and pinned a sheet of paper on the wall, the passengers in the front seats, who had been casually wondering what caused the strange, crackling sounds that had been coming from the cubby-hole, pri...  READ MORE
- Robert Nickels (ranickels),  04/14/2020 
    The  Dentron MLX-MINII thought it would be cool to use the Dentron MLX-MINI on the Saturday Vintage Sideband Net but it's a little marginal since the rule is "no tubes, go home!".   However hybrid rigs are allowed, and Special Dispensation is given for rigs with Red LEDs.    So I thought the MLX was double-qualifed - even more so after I realized t...  READ MORE
- Robert Nickels (ranickels),  04/04/2020 

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