What's on YOUR Bench?


A collection of personal projects in-progress by CWTD listeners ... Grounding system, DC power distribution box, boat anchor refurbishing, keyer project, 75m Small Transmitting Loop, NPOTA Adventures, burglar alarm, Bluetooth control, mic preamp/EQ, ... and more! 
See what your fellow experimenters are working on .. and who knows, maybe you'll get some ideas for a project that you've been thinking of!



Nigel Maund:

1) I have a set of K8IQY Designer Dream Boards (http://www.4sqrp.com/dreamboards.php), that I have had let sit idle for too long. So I started to populate them with the S7C "Simple Superhet" from EMRFD (http://www.arrl.org/shop/Experimental-Methods-in-RF-Design) pages 12-16.  First step was to recreate the Rick Campbell basic R1 direct conversion receiver circuitry (chapter 8 of EMRFD) then I created the LO and Front end filter, and now I am adding the active mixer.  I plan to also test out a dual MOSFET mixer, from the "Clackamas" a W1FB-inspired superhet minimal component design ( NT7S's entry to 2010 FDIM QRP Challenge).  So a bit of a research project to get back to the basics with analog design techniques.  See the EMRFD Yahoo Group (https://groups.yahoo.com/neo/groups/emrfd), and in the files section there's a file called the CompactSuperHet.pdf

2) 9850 DDS Daughtercard -- I bought a kit from the past at a hamfest last year - a DDS VFO AD9850, from NJQRP. It had never been opened from the brown bubble wrapped envelope.  I finally built it and so now I am going to try interface it to my Arduino.  It will then make its way to becoming part of an Antenna SWR sweeper circuit from ARRL's "Ham Radio for Arduino" projects book. With some modifications it will serve as a signal source for testing.

Chris, KQ2RP:

1. QRP Labs shack clock kit (built) that needs boxing up.
2. Kanga Acorn SDR II kit
3. Rebuilt G0FAH/ZS6BKW that needs to be hoisted into the trees.
4. Partially built 10-15-20m portable top-loaded vertical (modified from old Ham Radio magazine article)
5. Swan 350 to troubleshoot/re-cap.
6. 30m TVI issue with DirecTV box in upstairs bedroom (close to antenna)
7. 40m Chinese Pixie kit

Mike, WA8BXN:

1) One of my projects I call a keyer keyer. I uploaded a PDF to the files section describing it ... KeyerKeyer.pdf

There are plenty of keyers available and using an Arduino sort of processor is nothing new. My design has a few interesting aspects perhaps not often found in other keyer implementations. My primary need was for a keyer that had both dit and dah paddle outputs so it could be used with something that was designed only to be used with paddle input. In particular I wanted to use it with a Remoterig control unit that I use with a TS-480. The Remoterig box takes only paddle input to send over an internet connection to a similar Remoterig box where the body of the radio body is located. So my keyer is designed to key a keyer, hence the name “Keyer keyer”.


2) I am now the proud owner of an Elad FDM-DUO transceiver as recently reviewed in QST and a Hardrock 50 amplifier which I plan to use camping. Been playing around with PSK31, a watt or two works well when band conditions are decent, a bit more power will be available when they are not.  ... Specs


John, KG9DK:

1) I have a box for CWTD projects, waiting for the mother board to be release... no hurry I have plenty to do.

2) Have several Si5351 boards, I am currently building  some kits from QRPLABs... I have finished and it is working a WSPR transmitter.  took me a while to set up and don't ask me how to do it again... I will have to do a lot of reviewing of the documents.

3) Things I hope to get to is learn more about Programming the and using the Arduino products.  One can get by without knowing how to program, so far that is what I have done.

4) It looks like SDR is going to be the wave of the future, not sure where sure to jump in at.

Rick, K5FNI

  1. Homebrew Rig Runner: This one I just saw posted is definitely on my list ... https://sites.google.com/site/gw6itj/home/homebrew/homebrew-rig-runner

  2. Alignment and possible refurbishment of an elderly Standard C 6500 receiver [I'm seeking X-Ray board images and/or service manual to assist: I found the English schematic in the German manual online]

  3. Trying to figure out the best plan for me to get antenna egress from the shack through gypsum board, sheathing & Hardie Plank

  4. Bi-directional Bluetooth A2DP for shack use at workbench, away from actual station setup

  5. Microcontroller beefing up of Harbor Freight cheap burglar alarm to do what I want, when I want (not really ham, but certainly the "killer app" that gets me into programming microcontroller boards)

  6. Audio control for ham station, allowing use of one mic/headset for all rigs, balancing audio in and out

  7. Several minor tasks for ancient technology (refurb of Hallicrafter S-85; dial restring for Drake 2-B; refurb Collins R-388; refurb National HRO-500)

George, N2APB

1) Station Grounding -- Using a previous episode of CWTD as a reference, and N2CX as my usual Elmer, I installed 3/4" copper pipe along my operating bench, with each transceiver, tuner and amplifier strapped to it using copper braid. The copper pipe travels out through the basement wall to a 10-foot ground rod, which in turn has numerous ground radial wires connected and buried just beneath the surface. I found that this greatly improved my antenna tuning ability, and gave me the confidence to start using higher RF transmit power levels this winter/spring. I've been meaning to do this for many years and found that it was well worth the effort!

2) Mic Preamp/EQ -- I have a nice Astatic microphone that I intend on using with my boat anchor rigs, but it doesn't have the preamp in the base as is common for this class of "D-104" mics. And because of this, the frequency response is lacking bass and is hard to adjust for consistent quality use in both DX and ragchew conditions. After doing a little research, and recalling that W2AEW featured a nifty preamp in one of his many and invaluable YouTube installments, I expanded that straightforward design to give me some nice control of the lows and highs, in addition to overall level control. (As Alan explains so well, it's all about impedance matching and placing an adjustable filter in between the buffer and gain stages.) So add a visual indicator of bass and treble adjust, and a little AGC from a WB6VMI article in QST some years back ... and voila, I will (hopefully) have a pretty nifty preamp for using and customizing just about any mic here in the shack! If the prototyping proves successful, I think a pcb would be in order, fitting into a black die-cast enclosure the same size as our Midnight SNA project.


Pat, W0BM

  1. I have the pieces/parts for the GPSDO, waiting for the final installment. 

  2. I’ve got the SNA constructed, and now need to learn how to use it, along with using the additional firmware for the GPS Display Terminal. Plus need to build the return loss bridge for the SNA.

  3. One Item I’d be interested in from CWTD is a discussion on a distribution amplifier scheme and considerations for the GPSDO.  I have several instruments that can be driven from a standard 10 MHz source, and  I’d like to provide a buffered signal for up to 5 units. (currently HP 5335a frequency counter, 8656b signal generator, a buffered output for experimentation plus future expansion).

    Here's some references on Distribution Amps Pat ...

    1. Tutorial_Distribution_Amplifier_Architectures_STEINMETZ_rev1

    2. 10 MHz Video Distribution Amplifier (DL8JT)

    3. OH2NLT Distribution Amp

  4. And, I really want a shot at the sw30+


Rick, K3IND

1) Have you ever considered completing your PSOC Controller project, perhaps using an RTL-SDR dongle as the front end? Maybe you could provide the pre-programmed PSoC and listners could attach the controls and display?

N2APB:  Resurrecting the PSOC project and taking it the next step would be a good project.  AD7JT and I just got one of the latest versions of the PSOC experimenter’s board, so perhaps we could use that as the basis for going forward … http://www.cypress.com/documentation/development-kitsboards/cy8ckit-059-psoc-5lp-prototyping-kit.  If we are reading the specs right, the 5LP could replace the entire MSNA platform with a single chip and adding an Si5351A from Adafruit (https://www.adafruit.com/product/2045 ) could extend the frequency range to 160 MHz (YTBP = Yet To Be Proved) (I ordered a couple).  One question though is how long will the Cypress prototyping kit be available; it is priced at or below the cost of the PSoC chip alone (I ordered a couple).

I'm actually getting a little excited about this.  The prototyping "kit" looks perfect to handle the 100-pin PSoC chip (we could cut off the programming section and sell it separately, it looks to be usable as a USB to I2C and/or UART adaptor).  I also like their way to implement a USB type A connector.  The device comes with a 32-bit ARM M3 implementation which includes 256 KB of program memory and some peripherals plus a collection of analog and digital cells you can configure with their IDE.  The IDE is free including the C compiler.  The only negative I can see is Cypress only uses UPS for shipping and the shipping cost is nearly the same as the kit cost (that's why I ordered 2 kits).

And there’s a PSOC-based SDR project that I found  … http://pa0rwe.nl/?page_id=32

Anyone have other radio-related PSOC project references?


1) Top of the list is the Micro908B. I had it working three years ago with the uM-FPU math co-processor and a new vector-based computation algorithm.

2) I've developed a new concept for RF ground and a new device to implement it for QRP users.

3) I've also designed a tri-band 6m/2m/70 cm antenna.

4) I put the SDR-CUBE into a different case and am still trying to sort out the connections of the DB25 connector to the softrock transceiver and the new band capabilities.


(More coming!  ... We've only just begun :-)


Page updated May 13, 2016