The Hi/Lo Temperature Kit #1

Back for another 30 Kit Run

An assembled Hi/Lo Temperature Kit #1.

Closeup of the small microcontroller board with the temperature sensor (8 pin SOIC). The microcontroller is on the back of the board.

This is one of the easier to build kits. It simultaneously shows the Low, Actual, and High Temperature readings in degrees F or degrees C (so it's educational too). You reset it by momentarily turning the power OFF and back ON. The default is degrees F. If you want it to read in degrees C, short out jumper "J1" on the small board. The battery consists of 2-AA Alkaline cells and should last about one year. Use Alkaline cells because of the 1.5V rating. Rechargeable NiCad cells at 1.2V are really too low for proper LCD contrast. The temperature sensor is a MicroChip MCP9801 which is spec'ed at +/-1 degree C from -10C to +85C and +/-3 degrees C from -55C to +125C.

So what comes in today's Hi/Lo Temperature kit ? .....Bill of Material:

• 1 PC board
• 1 MC9S08QD4 programmed microcontroller
• 1 KTM-S1201 LCD 12x1 LCD
• 1 MCP9801 Temp Sensor
• 1 Battery Box 2-AA
• 1 2x5 header
• 1 8.2K resistor
• 1 0.1uf capacitor
• 1 DS foam tape

The price for of this Kit is $10 plus $2 postage in the USA and $5 postage for DX.

The Si570 Controller and Frequency Generator Kit #2

An assembled Si570 Controller. The LCD shows Memory location "36" and 14.060Mhz with the cursor in the 1Khz position.

You can see the Si570 chip soldered on the back.

New V4.x board with 4 mounting holes and a more convenient way to interface the I2C Bus to an externally mounted Si570.

This standalone unit (no attached PC required) has a frequency range of 3.5Mhz to 1417.5Mhz (yes, 1.4Ghz) depending on the Si570 part used. I have tested it up to 1200Mhz which is as high as my scope will go. Really an amazing, low jitter, and very low spur levels chip. You can go to the SiLabs website and look at the specifications. All setup and control is via the rotary encoder knob and it's push button. Power is battery (3V) or external power (5V-12V). It's compatible with all Si570 CMOS and LVDS versions, single ended or differential output, and any default frequency. This makes an ideal signal source for SoftRocks and many other projects. The Si570 Controller and Frequency Generator Kit includes a 12 digit LCD frequency display, a programmed MC9S08QG8 microcontroller, and a rotary encoder for tuning. It can ordered with a CMOS Si570 chip which is spec’d at 3.5Mhz to 160Mhz. Using other LVDS Si570 parts, the frequency range can be extended up to 1.417Ghz.

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ERATTA for V4.x Boards

Looks like SiLabs has changed the programming spec and disabled some math multipliers to facilitate their implementation of "Speed Grade". "A" Grade (1.4GHz) parts are not affected. I don't know how "B" parts are affected by the present Si570 Controller code. We use the "C" grade CMOS (160MHz) and LVDS (280MHz) parts. Using the existing Si570 Controller code does not appear to affect CMOS "C" level part operation, but the LVDS "C" level part is now limited to 260MHz with the existing Si570 Controller code (4 programming dots).

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Jack Smith, K8ZOA, of Clifton Laboratories has provided an excellent evaluation of the CMOS Si570 capabilities and the Si570 Controller kit at Clifton Laboratories

Sid Boyce, G3VBV, provided additional insite on how he used his Si570 Controller at G3VBV info

Features:

• Plus or minus Frequency Offset to compensate for Mixers, IF's, etc. The LCD will show the actual frequency.
• Frequency out integer Multiplier and Divisor for SoftRock (4x, etc). The LCD will show the actual frequency.
• Selectable encoder pulses per dial increment allows Variable Dial Speed.
• Dial Lock indicated by a flashing cursor. A momentary push of the PB sets/resets Dial Lock.
• Startup Memory location is selectable.
• 980 memory locations to save frequencies. The first 20 locations are Si570 Controller operational parameters.
• For best accuracy, the custom factory set registers in your Si570 chip are read and used.
• Can be powered for short periods with the 2-AA cells but the chip draws ~70ma so they won't last long and external power is advised. Use Alkaline cells because of the 1.5V rating. Rechargeable NiCad cells at 1.2V are really too low for proper LCD contrast.
• Hold knob PB in and rotate to change cursor location to selected digit, release, and tune
• Hold knob PB in for 3sec to save frequency to memory location shown. Memory will jump to next available location.
• Left most memory position provides for external BPF selection (1-8) provided via a 3 bit and Ground header (000-111) with 3V logic (memory "0xx" selects a BPF, "1xx" selects another BPF, etc).

The display is a 12x1 serial LCD (3-3/4" x 7/8") and the programmed microcontroller is a Freescale MC9S08QG8. All the parts are supplied (except the batteries) and an instruction sheet is provided.

There are many output options available ranging from normal termination resistors to isolation transformers to LVDS/ LVTTL level converters. Some of thse devices have their own frequency limitations such as the MiniCircuits RF transformers are spec'ed to 800Mhz and the FIN1002 is spec'ed to 400Mhz. It's totally dependent on your application. The Si570 Controller board has footprint options for many alternatives. Also some of you bought Si570 parts from Tom Hoflich, KM5H, and may want to use those parts. Some of you have sample parts or parts from other sources. For that reason, the kit is offered with or without the Si570 part. The Si570 parts I supply are CMOS "C" speed which means they are spec'ed 3.5Mhz to 160Mhz by SiLabs (although they have been observed much faster than that).

So what comes in today's Si570 Controller kit ? ......Bill of Material:

• 1 PC board with 4 mounting holes
• 1 MC9S08QG8CPBE programmed Microcontroller
• 1 KTM-S1201 LCD 12x1 LCD
• 1 24(AA/LC)32 EEPROM
• 1 Battery Box 2-AA w/SW
• 1 2x5 header
• 1 Misc header M/F
• 1 56 ohm 1W resistor
• 2 2K resistor
• 2 51 ohm resistor
• 1 147 ohm resistor
• 6 0.1uf capacitor
• 6 0 ohm resistor
• 1 3.3V LDO Regulator
• 3 10uf capacitor
• 1 10uF axial lead electrolytic
• 1 Rotary Encoder w/PB and threaded shaft bushing
• 1 Knob
• 1 10 wire IDC flat cable
• 1 DS tape for battery
• 1 CMOS/LVDS Si570 chip if ordered
• 1 MiniCircuits TC1-1TG2+ RF Transformer if ordered
• 1 FIN-1002 lever converter if ordered

The price for of this Kit without Si570 is $25 plus $3 postage in the USA and $7 postage for DX.

The price for of this Kit with CMOS Si570 (160MHz) is $40 plus $3 postage in the USA and $7 postage for DX.

The price for of this Kit with LVDS Si570 (260MHz...see Eratta above) is $45 plus $3 postage in the USA and $7 postage for DX.

Options:

There are 2 optional parts available. None of thse are required for an operational kit, only if you want complete DC isolation or LVDS conversion from differential to single ended LVTTL.

Mini Circuits TC1-1TG2+ (easier to solder than the previous TC1-1T+) RF Transformer is $2 plus $2 postage in the USA and $2 postage for DX. No postage if ordered with a kit. You only need this part if you want complete DC isolation.

FIN-1002 LVDS to LVTTL Converter $1 plus $1 postage in the USA and $1 postage for DX. No postage if ordered with a kit. You only need this part if you are using a LVDS Si570 and you want to have an LVTTL single ended output vs the differential LVDS output.

The Morse Code Buddy Kit #4

A MCB with keyboard, headphones, and a set of homebrew Iambic paddles made from two sections of hacksaw blade. Those blades are hard to drill but have the right spring feel.

Closeup of the MCB. The large pads (on both sides of the keyboard connector) are for attaching two spring contacts which, when grounded to the keyboard connector shield become a small iambic paddle. Neat, huh ?

More detail on soldering relay contacts as a cheap iambic paddle ....sorta.

This is the MCB-II. The Beeper and Microcontroller locations are switched, making it much easier to change out the microcontroller for different functions.

The Morse Code Buddy (MCB) allows you to receive and send practice code at speeds of 3-wpm to 40-wpm with a keyboard or iambic paddles, or just shirt pocket use for receiving practice code via the beeper or headphones. There are three versions of microcontroller, which is pluggable. The "C" version sends random 1x1, 1x2, 1x3, 2x1, 2x2, 2x3 calls (USA and DX) with 20 varying tones on a per call basis (sorry, no random noise in the background). It will send all alphabetic combinations. The "P" version sends random groups of all Morse Code letters, numbers, and characters. The "B" version will allow Beacon mode where a character string you define is repeated at an interval you define. Handy for calling CQ on a basically dead band or using for transmitter hunts. Hit any keyboard key on any of the versions and it reverts to iambic keyer mode.

It's also a 512 byte memory keyer, with adjustable tone, keyboard or iambic paddle input, Tx keying via a 2N7000, and it's powered by 3-AA Alkaline batteries (>100hrs). Do not use rechargeable NiCads. It's not required from a power standpoint and the 3.6V voltage is too low. The two large pads to the side of the keyboard connector can be used for isolated mounting or fabricate a set of paddles from the pads to the grounded shield of the keyboard connector (old relay contacts ?) and you have yourself a set of homebrew mini-paddles. Cool, huh ? ....check out the picture above.

The power options are many since the power requirement is 4-5VDC. You can use the battery box provided with 3-AA Alkaline batteries for portability, you can tap 5V off your rig if that is available, you can use an external 5V power supply, or you can tap 5V off a computer USB port you may have on the desk (all you need is a cable with the USB connector). If you use a cable for power it's a good idea to provide a strain relief using a plastic tie-wrap through one of the two holes at the keyboard connector end of the board.

This is a relatively easy kit to build. Some of the parts are an interference (tight) fit so they stay in place when you flip the board over for soldering.

Features:

• Stereo or Mono headphones, 3.5mm stereo jack
• Paddle input, 3.5mm stereo jack
• Keyboard input, 6pin Mini-DIN
• Keyboard arrow up/down is 1-wpm change, Page up/down is 5-wpm change
• Keyboard arrow left/right is 20Hz tone change
• Toggle the sidetone on/off
• Lock/unlock "key down" for tuneup or tuner adjustment
• Any paddle/keyboard input and MCB goes to Operational Mode, will go back to Practice Mode with "Alt/P"
• "Alt/F1-F12" stores memory, "F1-F12" plays memory in any sequence.
• The first two characters stored in location F10 "seed" the random number generator.
• Toggle Farnsworth Mode on/off
• Toggle the variable tone Practice Mode on/off ("C" version)
• Store and erase memory
• Keyboard speed/tone default modes
• Jumpers to select speed for shirt pocket use, all other parameters use last saved data.

So what comes in today's MCB kit ? .....Bill of Material:

• 1 PC board
• 1 MC9S08QD4 programmed Microcontroller
• 1 2N7000 FET
• 1 Beeper
• 1 8 pin socket
• 1 Battery Box 3-AA
• 1 2x5 header set
• 1 1x3 header
• 2 Stereo Jack
• 1 Keyboard connector
• 1 10K resistor
• 1 1K resistor
• 4 0.01uf capacitor
• 1 DS foam tape

The price for of this Kit is $15 plus $3 postage in the USA and $6 postage for DX.

Each kit is supplied with a "C","B", or "P" microcontroller (you specify). If you want more than one, please add $5 for each additional microcontroller to the above numbers.

Thanks to John Fisher, K5JHF, and Milt Cram, W8NUE, for the microcode and Ben Bibb, NO5K, for taking one heck of a lot of data in his lab.

There are three LCD display Modes; #1) shows which of the "six band groups" is supported by the three presently active polynomials. It also shows Forward Watts as "F XX.XXXX" and VSWR as "X.X" #2) shows Battery Voltage as "bat X.XXX" #3 shows the "six band groups" in more detail; "1" is 160m, "2" is 80m, "3" is 60m/40m/30m, "4" is 20m/17m/15m/12m, "5" is 10m, "6" is 6m. The Up/Down pushbuttons are used to step through the six groups.

Use Alkaline cells because of the 1.5V rating. Rechargeable NiCad cells at 1.2V are really too low for proper LCD contrast. Power consumption is about 1.25mA......not much.

The mWattmeter uses a (very familiar) 12x1 digital readout, covers the HF bands from 160m to 6m, will measure 0.25mW (actually a little lower) to 25W (that's a 50dB dynamic range), has automatic range switching of 3 ranges, uses a total of 18 second order polynomials for curve fitting, uses matched Schottky diodes which are forward biased at 5uA, uses an 18bit differential input ADC (vs the usual 10bit or 12bit ADC), that allows temperature compensation by utilizing the differential ADC inputs, Battery operation (2-AA Alkaline, 1-AAA Alkaline for bias) or external 5V-12V power, draws 1.25mA so batteries should last even if it's accidentally left on, has a battery voltage indication, will store selections automatically and power up in the last state used, has a 6-pin BDM connector for reprogramming with a USB Multilink or USB Spyder, provides 2 BNC connectors.

Most of the recent low power wattmeters have used log-amps like the AD8307, AD8310, LT5537, etc. (and there are many more, largely driven by the cell phone and RF tag industry). In addition to the obvious log curve linearization, one key advantage of the log-amps over diode detection is that they provide range "compression" resulting in a very wide dynamic range (80dBm to 100dBm). The main drawbacks are cost (in my opinion), unuseable packaging (ever hand solder an 8 pin CSP ?), and we don't really need that much dynamic range (maybe 45dBm to 50dBm).

After considerable diode specification searching (special thanks to the Crystal Radio group for some really great links), I came to the conclusion that there are basically two alternatives left for a non log-amp wattmeter, 1) use a good pair of matched germanium diodes or 2) use a good Schottky diode pair and forward bias them slightly (5uA is good). After purchasing some germanium diodes (1N60, 1N34A, 1N270, 1N277) and testing them for stability and consistency it was determined that germanium diodes have neither. The "best" germanium diodes out of this batch were those labeled "ITT 1N277". The 1N270 diodes marked "1N270" or with color bands were very good also. 1N34A diode quality (several batches) depended heavily on the supplier. Some were really bad (forward resistance varied 5x+), some were "just so-so". I was really looking for low end accuracy and settled on the HP HSMS-2815, a matched pair of low barrier Schottky diodes. The matched pair comes in handy for balancing the bias levels into the differential ADC inputs and offers temperature compensation using the ADC differential inputs.

The next step was to decide on the directional coupler values based on our constraints of <1mW to 25W and max input to the ADC of 2V. I don't want to use resistor voltage dividers with their inherent tolerance variations. The fewer the components in the bridge frontend, the better. Using 25W as max and 2V as max, we need a coupling factor of about 1:250 or greater. Since the transformers give us a 1/(N*N) coupling factor, N must be 16 or more turns (1:256). From the ARRL Antenna Handbook.. The low frequency limit of the directional coupler is determined by the inductive reactance of the transformer secondary windings. The inductive reactance should be greater than 3x line characteristic impedance to reduce loss at the lower frequencies where the circulating current will be significant. The result is heat which we don't want. For 50 ohm line that is 150 ohms and that works out to be 13uH for 1.8MHz. That is why so many designs using small powdered iron cores "cook" them at the lower frequencies. A material #2 (red) T-68 or T-80 core with 30 turns, only has an inductance of about 5uH.

If we select type 61 Ferrite material on a FT-37 size core, 16 turns measures ~15.4uH ....close, but OK! We also want the lowest possible series inductive reactance of the single turn on the transformer. For the FT-37-61 that now measures 0.06uH.....GREAT! Note that type 43 material has a permeability 20x that of type 61 material and is not acceptable. For higher frequencies, we want to reduce the length of the transformer windings to "well below a significant fraction of a wavelength". We use a little more than one foot..... OK. We also want to reduce the turn-to-turn capacitance which can be achieved to some degree with insulated wire. Teflon insulated #30 wire is great but "slick" and a little difficult to wind. Kynar insulated #30 wire is easier to work with and has a slightly smaller diameter. I decided against using a "binocular" Ferrite core (although the board layout is wired to accept one) because the small ones are too difficult to wind with more than 10-12 turns and the larger ones have too much single turn inductance. I don't think we'll have a heat problem with FT-37-61 cores but there is always the FT-50-61 core or multiple FT-37-61 cores. The board layout will accept either one.

Milt Cram, W8NUE, ran simulations and mathmatical analysis on the design and so have I. Data indicates low insertion loss and accurate SWR representations for 10 to 250 ohm resistive termination impedances. Complex impedances are more difficult to measure accurately.....tell me about it.

After all the above is said and done, MANY experiments run, MANY diodes purchased, and MANY prototype boards built (most which are now "drink coasters"), we narrowed in on an acceptable design. Two boards... a Directional Coupler board with all the RF and only the detect signals coming off the board and an ADC/Microcontroller board with no RF (that was the intent anyway). The best results for 160m to 6m were seen with two dual FT-37-61 cores with a 23 turn winding of #26 wire and a 1 turn winding of #18 wire.

Since all diodes are non-linear how do we compensate for that in order to calculate accurate Forward and Reflected power ? Well......Why not use the floating point math power of the modern microcontroller and a "few" 2nd or 3rd order polynomials to perform curve fitting ? Sounds interesting to me and I ended up with 18 polynomials. After enlisting the aid of John Fisher, K5JHF, and Milt Cram, W8NUE, to work their firmware magic, and Ben Bibb, NO5K, to make some accurate measurements in his well equipped lab, we're off to the races.

So what comes in today's mWattmeter kit ? .....Bill of Material:

• 1 Microcontroller/LCD PC board
• 1 MCP3422 18-bit ADC
• 1 MC9S08QG8CPBE programmed Microcontroller
• 1 KTM-S1201 LCD 12x1 LCD
• 2 2K resistor
• 3 0.1uF capacitor
• 1 10uf capacitor
• 1 47uF capacitor
• 3 PB switches
• 1 Battery Box 2-AA w/SW
• 1 2x5 and misc header
• 1 10pin IDC connector
• 1 10 wire IDC cable
• 2 5 wire IDC cable
• 1 MCP1703 3.3V LDO Regulator
• 1 DS tape for battery
• 1 1mW to 25W Coupler PC board
• 2 HSMS-2815 Schottky diode matched pairs
• 4 FT-37-61 Toroid Cores
• 1 misc bare/enameled #26 wire
• 2 BNC Connectors
• 6 150ohm resistor
• 2 10nF capacitor
• 4 270K resistor
• 3 0.1uF capacitor

The price for of this Digital QRP mWattmeter kit #9 is $55 plus $4 postage in the USA and $7 postage for DX.

• Check the orientation of the 2K pullup resistors, R7 and R8, it's easy to rotate them 90 degrees across the pads and the I2C bus won't be operational.
• Depending on the enclosure you pick, close proximity to the Coupler board may be affect readings. Don't make it too small.

Now for the most ambitious and complex kit of them all .... a SDR Hardwarwe/Firmware Development Platform which nets a pretty nice Software Defined Radio Transceiver and does --NOT-- require an external computer. This makes it highly portable .....hence "SDR2GO". The idea here is to also not duplicate existing hardware which you may already have by using existing I/Q frontends, like the various SoftRock Rx/Tx units, UHFSDR, SR63ng, etc.

SDR2GO Builder's Notes

SDR2GO dsPIC33 HEX Code V1.9.0

Be sure to check out kit #17 which provides an optional Graphics Interface for the SDR2GO

Yes, Virginia, there really is a SDR2GO. This unit takes the place of the computer and uses an existing I/Q frontend such as a SoftRock RxTx, SoftRock Ensemble RxTx, UHFSDR, and others. It is the work of mainly four hams; Charley Hill, W5BAA, who started this (and thus, deserves most of the blame/credit), John Fisher, K5JHF, Milt Cram, W8NUE, and myself Kees Talen, K5BCQ.

The major features are listed below:

• I/Q Signal Demodulation
• I/Q Signal Modulation
• Headphone Output
• Microphone/Line Audio Input
• PTT Input
• PTT Output for control of SoftRock/UHFSDR receive/tramsmit operation
• Effective Receive AGC
• Si570 Frequency Control
• Backlit 16x2 LCD Frequency and Status Display
• Design will support positive/negative bias LCDs and pin 1/2 variations
• Main Rotary Encoder for frequency control and Si570 parameter definition
• Keyboard Port for Si570 parameter definition and real time frequency control
• Secondary Rotary Encoder for setting DSP parameters
• USB/LSB selection switch input
• Microphone/Line selection switch input
• Output Audio/IQ Amplitude adjust selection switch input
• IQ Phase adjust/Default IQ parameter selection switch input
• EEPROM storage for Si570 control and DSP parameters
• Onboard mounting of the Si570 as an option
• Physical access for I2C interface for mounting Si570 on I/Q frontend
• Three bit data interface for controlling a switcheable BPF
• Physical access to dsPIC SPI interface for future use
• Physical access for programming the dsPIC
• Physical access for programming the SH32
• Five Volt Power input
• Board size identical to a SoftRock V6.3 RxTx or the "NG" footprint
• Board layout and device pads designed to accomodate hand soldering

The SDR2GO uses a dsPIC33JF128GP804 microcontroller for the DSP functions and a MC9S08SH32CWL for Si570 tuning, keyboard interface, alphanumeric display control.

Some New Additions (from The Si570 Controller Kit #2):

• Backlit 16x2 LCD
• Keyboard Interface in addition to a Rotary Encoder
• Scanning capability
• Additional feedback to user
• Offsets selectable on a memory location basis instead of one offset for the controller
• 12 characters of your custom alphanumeric text may be displayed
• The frequency is shown in KHz with 1Hz resolution

The unit is really a platform for firmware development (come and join in) and general SDR experimentation. As such, there is quite a bit of flexibiliy designed in (some of which, bit me) and there are several available interfaces for future expansion.

All that said, it makes a real nice low power CW/SSB rig "as is".

For our first trials, 30 V1.x kits were built and they are out there being used and refined (including trying to come up with good documentation). To be honest, this is NOT an easy kit to build because it has parts such as a 32 pin QFN CODEC TLV320AIC3204 (best part for our needs that we could find and only available in that package). It also has a 44 pin QFP and a SOT-6 package.

So what comes in today's SDR2GO kit ? .....Bill of Material:

• 1 2-1/2" x 3-1/4" PC board
• 1 TLV320AIC3204IRHBT CODEC
• 1 dsPIC33FJ128GP804IPT programmed DSP Microcontroller
• 1 MC9S08SH32CWL programmed Si570/KBD Microcontroler
• 1 16x2 Yel-Green Backlit LCD
• 1 Bezel for LCD
• 1 24(AA/LC)128-I/SN EEPROM
• 1 24(AA/LC)32AT-I/SN EEPROM
• 1 SN74LVC1G3157DBVR FET Switch
• 1 MCP1703-3302E/DB 3.3V Regulator
• 2 Rotary Encoder w/PB switch
• 1 Kbd Conn
• 3 2N7000 FET
• 1 12MHz Crystal
• 1 10K Potentiometer
• 2 1N4148 Diodes (for charge pump)
• 2 LED green (power)
• 1 Push Button (reset)
• 13 Misc Headers
• 2 Stereo Jacks (HP & Mic)
• 3 10pin IDC
• 1ft IDC cable
• 4 Resistor 0 ohm
• 1 Resistor 100 ohm
• 2 Resistor 2K
• 2 Resistor 2.7K
• 2 Resistor 3.3K
• 13 Resistor 4.7K
• 5 Resistor 8.2K
• 2 Capacitor 22pF
• 17 Capacitor 0.1uF
• 13 Capacitor 10uF
• 2 Capacitor 47uF
• 1 Inductor 47uH
• 1 CMOS Si570 chip (160MHz) if ordered
• 1 LVDS Si570 chip (260MHz....see Eratta in Si570 Controller section) if ordered
• 1 MiniCircuits TC1-1TG2+ RF Transformer if ordered
• 1 FIN-1002 lever converter if ordered

The price for the SDR2GO Kit #10 is $73 plus $4.00 postage in the USA and $7 postage for DX.

Optional parts: CMOS Si570 chip $15, LVDS Si570 chip $20, MiniCircuits TC1-1TG2+ RF Transformer $2, FIN-1002 lever converter for LVDS $1.