Let's Build Something Reference Page


[Updated 10/28/2015*]

*Revised Booster Amp Schematic

See Project Page Link

Link to http://www.n6qw.com

Sneak Peak at the 2nd Generation LBS -- Think of it as a shrunk down LBS on Steroids. 9/01/2015 ~ This radio is now on 40M and in daily use at N6QW.



LBS 2nd Generation

Get your subscriptions for QRP Quarterly up to date. There is an article in the works to explore the LBS-II coming soon to mail box near you.


Newsflash (6/04/2015): We have received an input from a builder that there may be an inconsistency on the wiring connections to the AD9850. The input stated that one diagram shows AD9850 connections to digital pins 4,5,6,7 and the ino sketch shows the connection to 2,3,4,5. Either will work so long as what is in the sketch matches the hardware. So if any problems are expereinced in generating RF this is an item to check. Changing the code to match the pins is by far the easier solution.


Based on several inputs, the LBS Resource Page will be reorganized into three main subpages. These pages will essentially split the projet into a Basic Build, Intermediate Build and Advanced Build. Some first time homebrewers have expressed an input that having everything on one page is somewhat overwhelming. It may take a bit of time to do this; but hopefully, will address those concerns.

Ben KK6FUT & Pete N6QW ~ 6/2015

* LBS Basic Page



[The LBS Part II has compiled in V1.6.3]

NEW: See K6HX's input on the use of Sain Smart 20X4 LCD Display with V1.6.3 LINK This requires the install of a new Liquid Crystal_I2C Library which is explained in the link. If you load any software in V1.6.3 you most likely will need the new Library for any displays to function.

NEW: Part II is in distribution so check your mail boxes.


See New Projects on Projects Page

The user page is now a separate page and the build detail is also a separate page.

Listen to and see the SSB Receiver!


Final Receiver Tests 2/22/2015

Initial Transmitter Testing

17M LBS Tests

The LBS with A Yaesu FT-101 SSB Filter

20M LBS with a 9.0 MHz IF

Board Tour & On the Air with the LBS

Si5351 Calibration Routine (N0TKN)

Si5351 Calibration Instructions (N0TKN)

Sources for Commercial Crystal Filters

* INRAD 4 Pole 9.0 MHz SSB Filter Kit

* GQRP Club Kit 9.0 MHz SSB Filter

[NOTE: Must be a GQRP Member to Purchase]

Additional Resources for the Winding of the DBM's

[Also information on general construction practices provided courtesy of VE2TYQ]

User Project Page (Moved 3/25)


LBS Detailed Build Information (Moved 3/25)


Wiring Schematic for the Nokia 5110 Display

[Courtesy of Jack N0KSF]


LBS Frequently Asked Questions



Link to Photo of the Completed Part II Transceivers from KK6FUT and N6QW


Let's Build Something SSB Transceiver

The Lets Build Something Transceiver project currently has two transceivers on the air and we know of several that are in various stages of the build. It is imperative that the Part I Direct Conversion Receiver be built first as this accomplishes two things: 1) it builds critical units that will be used in Part II and 2) for the "newbie" builder promotes the development of the necessary skills needed to successfully complete Part II.

The authors have received numerous emails where because of the information published on this reference page, some builders forged ahead and built the Part II boards without completing Part I. The problems encountered were obvious -- Part I must be built and the Part II article has not been published as yet. Without the benefit of the Part II article it is a very difficult task to simply take schematics and expect a working project. The Part II article will appear in the next issue of QRP Quarterly. So step one is to join QRPARCI so that you will receive the next article.

This project is a springboard where many enhancements and expansion opportunities abound. The goal was to literally build all of the circuit elements from scratch. Performance improvements in the form of using surplus commercial crystal filters is readily accomplished. For instance two choices would be the filters out of the Heathkit HW/SB 100, 101 or 102. These are superb filters many of which can be found for $10 and operate at 3.395 MHz. The filters from the Yaesu FT-101 series are another candidate as they operate at 3.180 MHz. These are two particularly excellent choices for use on 17 Meters. [See the Yaesu Page here.]

Another variant which was used was the 9.0 MHz crystal filter available from the GQRP Club. The connections are the same as for the Yaesu FT-101 (500 Ohm Impedance). Three number changes in the software and the same software is useable with the GQRP Filter. Here is the sketch for the 9.0 MHz Filter.

Often the filters can be found but are missing the matching crystals, which also means a chance to bargain since without the matching USB/LSB/CW crystals the filters are kind of useless. But that is no longer an issue since the Si5351 can generate the needed crystal frequencies. The Bilateral matching transformer design would need a turns ratio adjustment to go from 50 Ohms to 2K Ohms for the Heathkit and the Yeasu would need a 50 to 500 Ohm match. Placing the VFO on the correct frequency to accommodate the filters and/or different bands is but a couple of lines of changing numbers in the Arduino Sketch. It's software not hardware!

Another improvement would be to use the SBL-1 Double balanced mixers in place of the homebrew mixers built for project. Some of the emails we received about problems with building the DBMs relate to not watching the three you tube videos on how to build the DBM's. It is difficult at best to build DBM's that match units built to exacting specifications on a manufacturing line. That said those built for the LBS are "Good Enough".

When one of the authors mentions he is using a homebrew transceiver, the most frequent question is "Which Kit Is It?" There is no kit and like the early days of radio this is a home built radio transceiver!

A real side benefit of the LBS is that it is a platform for experimentation such as was done with the installation of the various filters.

In case there are any concerns -- 5 Watts works! Stations in Washington, Idaho, Oregon, and Montana have been worked from Southern California running 5 Watts and which proves this is a viable transceiver project.






The QRP Quarterly Article is in distribution and there already are some requests for additional information. The article will not be reprinted here but we will supply some info that was requested. But the Radio Gods have spoken and Part I is a free sample in digital form from QRPARCI LINK HERE

Evidently the Sidebar drawing on how to cut the PC Board while mentioned was not included in the publication. (Click on the link.)

Figure 1 shows the Band Pass Filter ahead of the RF amplifier yet a close examination of Figure 8 in the article shows the antenna connected into the RF Amplifier followed by the Band Pass Filter and then on to the Double Balanced Mixer. The preferred method is as shown in Figure 9 with the antenna into the Rx RF amplifier and then onto the Double balanced mixer. A revised Fig 1, is in the listing below.


Advanced Warning: For the final SSB build we will be suggesting the use of the Si5351 Clock Generator Board available from Adafruit Industires (and others) in lieu of the AD9850 DDS. The advantage of this approach opens up many possibilities including eliminating hardware BFO circuits and the separate USB/LSB crystals and a greater frequency range. The Si5351 can operate from 8 KHz to 160 MHz. We will include hardware designs and sketches for both approaches; but by far it is like the difference between driving a VW Beetle or a Maserati. Other Si5351 options (and inclusive sketches) will cover the use of the Nokia 5110 TFT 84X48 Black and White display or the 128 X 128 TFT Color Display. The cost of these displays are in many cases less than the cost of a 16X2 backlit LCD.


This is the code as used in the LBS Part II SSB transceiver. The Arduino used can be an UNO, Nano or Pro-Mini. The Display is a standard 16X2 and the VFO/BFO is generated by the Si5351 available from Adafruit Industries. Copy these and paste them in the same folder in the Arduino Directory. Other libraries as specified such as Wire and the LCD Crystal must also be present in the Arduino Library sub-folder. When they are placed in the Arduino Directory folder they must have the same names as inthe main sketch.

* LBS PtII si5351.ino

* LBS PtII USB LSB Select (Toggle Switch Select on D9 and the code values for USB LSB frequencies will have to be determined as described in the Part II article as each filter may be slightly different. The code values in this sketch will get you close but for "spot on" frequencies the process in Part II must be used.)

* LBS 17M Version (Requires new BPF and LPF)

* Jsi5351.cpp

* Jsi5351.h


* AD9850_Arduino_Sketch Copy and paste into the IDE. Uses the 16X2 LCD for display.

New AD9850 Code Revisons (Courtesy VE2YTQ, Yves)

[Improves the Radix transistion and cursor changes.]

New AD9850 Signal Generator for testing Part II. Use the same Arduino wiring diagram as shown in Part I.

* Si5351for The LBS Copy and paste into the IDE. Uses the Nokia 5110 TFT for display. Note you need the Rotary Library, the Adafruit Graphics Libraries and the Si53515 Libraries.






* Si5351_Arduino_Sketch2 Copy and paste into the IDE. Uses the 128X128 TFT Color Display.

* Si5351_Arduino_Sketch3 Copy and paste into the IDE. Uses the 240x320 TFT Color Display. Note you must have all of the libraries and use the CD4050 Logic Level Shifter to make this play. The Fout = 4X and you also need a SN74AC74 divide by 4 following the Si5351. This gives a quadrature output suitable for SDR with less phase noise. See this link for more detail.

Links to various TFT displays are shown below including the Nokia 5110, the 128X128 and the 240X320

Link to Photo 1 ----------------------------- Link to Photo 2 ________--__Link to Photo 3 e


Follow the link Below for the Build Detail.

LBS Build Detail