The Transceiver

The painting off aluminium plate is not easy, as you can see the colour drops. We will see if I can fix this later?

I have now run a few QSO with this transceiver on SSB. And this was the goal. It is not perfect but it works. In Rx the sensitivity is high enough with preamp on. On Tx it is from 10-15W out on all bands. I hope to test on 6m but for the moment is veary  quiet on this band.

As you can see from the display a lot has ben implemented in SW, RealTimeClock, Battery indicator, temperature, one VFO, vfo step size, Rx Rf gain or Atten, S-meter, Band select, mod set,  tune, power set 1- 15W and settings include touch screen calibration.

POWER and SWR  indication is not yet implemented in SW, hopefully ok in HW. Cw-keyer and CW decode is not implemented, same test has been made. I have separate code tested. Mic Compressor is not tested yet more qso and test is needed.

SD card is working. But not used to much. Can be used for settings and calibration. Touch screen is working but a bit slow, I hope to speed up it in a newer sw code?

The AF Filter CW/SSB has some strange behaviour so it is bypassed for now a MAX7400, I tested it before I do the schematic, murphy has been her.

As they say use the TRANSCIVER Make QSO, I haw new things to build (Digital versions, sty tuned)

73 de SM4HNG

 

TRX Board

This is a board from Dian Kurniawan (YD1OSC). BritX All Band HF Exciter with Audio BPF and 1 Watt TX preamplifier.  It is a design based on BITEX from Ashar Farhan.

I have take away the tx amplifier, I use my own design on the FrontEnd 02 board. Also take away the rx amplifier before mixer, then it works in/out to RF mixer.

Next mod is for CW I won’t sidton on audio if keying, so 12VTX to audio amplifier LM386 is taken from 12V to make it possible

I will son describe how I put all this together to a transceiver 1,8 – 52 MHz.

 

The Key

This is a key from Russia I bought in a ham market in Vårgårda 2019. Now mounted on a bit of  oak wood. Perfect for field operation. 

QRP Digital Board 01

                               KiCad

The Cad of this take some time, first try to put in CPU on the board didn’t  succeed , so the final is with the CPU module from . Same small mistakes is now fixed, and all function is verified. The result is a board with a lot of function.  Extra Dac for AGC , 8 i/o and one UART, 4 ADC channels this is for future use.  Tested and working is AREF analog reference for CPU module, RTC + EEPROM, VFO + BFO (Si5351), LP-Filter (CW/SSB), Input for CW key, MIC amplifier, MIC compressor, SD-CARD, TFT and Touch display, temp sensor, encoder and ton-generator for CW. Connection for the earlier done board PA, LP-Filter, Frontend 02. 

Next is a modified TRX board stay tuned!

QRP Frontend 02

QRP Frontend 02

Final test with the Arduino Mega controlling the i2C buss(select Filter and set attenuator Tx/Rx, turn Rx amplifier on/off.

QRP Frontend 02 is a BP filter board with RX preamplifier MAR-6 or a discreet PIN-diode attenuator, controlled by a dac. The same BP filter and the attenuator is used in Tx and is driving a amplifier SGA-3486Z as driver for the QRP PA earlier described. All BP filter is controlled from I2C bus. BP filter is from YU1LM i i think it is rely good result, no alignment.

I has started working on a front panel board, the latest before putting all this together to a QRP Transceiver. Stay tuned!

QRP LP filter and SWR board

QRP LP filter and SWR board

Here is the LP-Filter mounted on the earlier described PA.

QRP LP-SWR 01 is a LP filter board 1.8MHz - 52MHz and added SWR Meter, all relay for filter is controlled from I2C bus. The filter is design from GQRP Club Datasheet W3NQN, Filter PDF. I have rely problem to get low insertion loss, so I think it was the toroid was the problem. Now I know it is the capacitor I firs used has really bad Q value. I has change to SMD GC0 500V capacitor and they has much higher Q value than the hole mounted capacitor I bayed first. The SWR was presented in QRP-Quarterly January 2018, SWR Meter. I lock for different diodes then 1N60 and tried a few types and get god result with HSMS2800. Her is the result. 

Exemple 80m and 10m.

Backside off the filter.

Part off shematic

I have a few PCB left, e-mail if you ar intrested xxx@gmail.com.

Signal generator for short wave 0.1 – 30 MHz

I have an old test set Schlumberger 4022 I don’t need longer. This was one reason to build this generator. The generator is a kit from QRP Labs   it uses Si5131 from Silicon Labs. I used 2 attenuator  Weinschel  0-63.75 dB. The insertion loss @ 0dB atten was around 7 dB so I need a Amplifier and one more attenuator to compensate for that. I adjusted the attenuator to get 10 dBm output. A high isolation switch on output to turn on/off RF, typical 75dB isolation. A rotary encoder and Arduino mini pro drive the attenuator and isolator directly and one I2c OLED display, really simple solution, sw 100 row of code.

RF Power Meter

It started with that the Anritsu power meter ML2438 brakes when i turn on the meter. The fault is in the power supply part. I lock around on internet and found this from Elektor.  link RF Power Meter

I ordered  the boards and build it. Get a problem with the software note a few liens in a forum and get a updated version in a few days. Added battery voltage reading on the display. It is really handy to only have one connection the RF port, that’s the reason I build in Lipo-battery 7,4V.

Data• RF power meter
• Bandwidth 1 MHz to 10 GHz
• Dynamic range 55 dB
• Compact: approx. 95 × 36 × 30 mm
It has 20 calibration points in frequency, so it is possibility to get accurate measuring result.

Fox receiver for 2019

Fox receiver

Prototyp

It starts in the spring this year, I help Bo SM5CJW to do some small receiver board he work with.  I save some boards for own use and later I get updated info from Bo. So I will give it a try.  I build the HF board and an LF board, the  Lo Si5351 i was familiar with earlier, it was also published in Swedish ham magazine QTC. After some change of mixer it works grate with excellent  sensitivity  and low noise level. Bo also have same example on different antennas, and I start to try with loop antennas . I really like the result. I build prototypes with both loop and ferrite antenna and as I see it the loop is the winner, 1 more shape on minimum signal, 2 more quiet, ferrite  has a small noise I didn’t  here in loop, 3 a little bit higher signal level.

I decide to try this receiver build together with my earlier built electronic compass. This was the hardest bit to put in 3.3V cpu together with an sensitivity receiver (around 0.5 uV) many filters and try and error to get all thing to work.

I start to merge the code to one cpu but I couldn’t  get it small enough, so way not run the Lo with Bos code on Attiny85 and do the rest with an Adafruit board Pro Trinket 3V. So this Fox receiver has 2 cpu!

Here is the result.

Sensitive receiver.

Excellent Front back or side decision.

Integrated compass direction  in display and calibration status .

Frequency information in display.

Battery voltage in display.

Signal strange meter in display.

Attenuator 0-80 dB info in display.

Look forward to test signal strange in practise, difference so far  95dB 1m from Fox compared to 3.5 km from fox.

I am relay glad I start this work has learn a lot.

Thanks to Bo SM5CJW for the receiver part.

QRP PA

QRP PA

QRP PA

See earlier work in December 2017. After that I made a PCB and have now mounted and tested the first board. It is inspired from K5BCQ and from  DK1HE QRP-PA.

Not as god as I hope, but working.

+10dBm iN,

OUT  @ 1.8 MHz  41,3 dBm

          @  7,1 MHz 43,3 dBm

          @ 28,4 MHz 41,0 dBm

          @ 52 MHz 39,2 dBm

RL < -15 1,8 – 52 MHz

Current 2,5 +/- 02A

I hope it will be in one more QRP transceiver  I have ides for, we will se!

There  is also an USB to serial board on the back panel.

I have some PCB over if you are interested e-mail.

Minima PA

Minima PA

I by  the Minima complete all mounted component in February, but i didn’t receive any so i by a new in April a kit 100W, after build it, i burn two transistor MRF 9120 so no idea to go on. Change to use IRF530 and skip 50MHz. And this works. After a try to made and measure on LP filter, all have high insertion loss  more then 1 dB. I decide to by one and to get ready with the PA. I found this on ebay

So a small board  with diode to fix the band select, and a regulator for the relays had to be done .

I already have an old led driver  LM3916 to monitor the power,  useful to monitor when struggling with the SDR parts!

Link to PA description Example Minima pa

Link to Filter

Result PA 1.8 – 30 MHz Output 45 – 75W ( drive max 5W) SWR 1.1 in 3.5 – 30 MHZ 1.2 @ 1.8MHz.

Hope to use it more in 2019!

Time for SDR

SDR

I am no retired from January 2018, time to do some more experience, i decide to try SDR technology. I will go for use Computer as a part. Then i found this Hobby PCB for reasonable price, see HobbyPCB.

After a lot of SW setup its run nicely with 4W out. 

I have now run around ten QSO by this unit in QRP.

 I wont to place the external sound card, also from Hobby PCB Startech 96KHz USB SoundCard and USB hub in one box, to get it more simple to use. 

Next is to get a PA to work together with tis equipment. I have already burn one simple with IRF530. So I will lock for a better one. I am definitely fast to this techniques, 96kHz of the band on the screen compared with turning one VFO. on the old station, it is like a new please in the Galaxy. I will sell my old transceivers.  I have already ordered a 2m transverter from Ukraine, hope it arrives this week. Hope to be on air in Mars VHF-Test     6 Mars. This is my next goal.

 Some fun things I like.

Calibrated S-Meter, continues controlled output-power, filter works grate, notch filter also.

Next goal is to get it running with WSJT-X sw for digital modes.

Stay tuned. SM4HNG

PA for 1296 MHz

Since i was finished with the transverter for 1296 MHz. I try to build a PA 45W this was not working. I start lock at ebay.com  an found a PA original from N9RIN. I by this and put it on a heatsink, it works grate. I run a few QSO with good reports. This pa was original set for class A bias 1.3A. My ide was to lower this to 400mA but when I try this I blow the transistor. It was a hard fight to get replacement for the PTF10021 infineon transistor. I bye 2 pcs from Alibaba, Kina this was not working. But on 18 December I received a pcs from Kynix.

 Perfect 23cm test was on the 19 December an now all was working even with lower bias 400mA, I measured 45.4 dBm out, not bad. The voltage to the PA is 28V so I tried to up converted it from 12V, there was a good article in Radcom nr2 2017, bayed from ebay.com, and add some filtering. Cant measuring any spurious on spectrum. A coax relay CX-140 used and a isolating extra relay Panasonic RK1-12. I has an already built RF pre-amplifier as I remember it is from  YU1AW, yu1aw. 

Now all is finished, before Christmas, hop on many more qso. next year.

PA and Driver for next QRP Transciver

I has built a driver for the PA. I started to lock at “Building a Transceiver” by EI9GQ and G4LFM. Side 118 it has a promising setup of RD06HHF1. The test showed god result. Next step was to put it together with the PA. I has little more to do with the optimize power transfer from driver to PA, but it will work just to optimize performance. In The plot from VNA it was 30dB atten from the output to VNA, its means gain in driver is close to 20dB.

PA For next QRP station

I by this PCB from K5BCQ a long time ago. Now I hade time to build and test the performance and it locks weary promising.  I measured max 42.7 dBm out.  But I think 42dBm 16W is more ok to not stretch the PA to much. The flatness is better then -0.7 dB from 1.8 – 52 MHz. It means that the work with the output transformers is grate.

I waiting for driver transistor to put in front of this module. I will put info here as son I has test the driver.

Link PA description K5BCQ

A BP filter for my next QRP Transceiver

I came across this YU1LM interesting side a time ago. Really interesting result. I build tree of this filter to check the performance, and get very close to the description but I don’t use so accurate values, that’s way I think it is worse loss in the passband. But I will go for this type.

 I has also tested pin diodes and other diode to use as switch, BAT18, BAP70-3, BAP51-02, BA592, BAP50-04 and 1N4148, I chose BAP70-03. I have read that some has problem with IM product when using diodes my test don’t show up worse with diode compared to without.

 I use 2 generators and a hybrid combiner a generator G1 in passband -12 dBm and G2 to different frequencies to test for IM -70 - +17dBm. If there is IM product it is worse without filter, so I can’t blame the diodes for that.

dokument http://yu1lm.qrpradio.com/INPUT%20HF-6m%20BP-LP%20FILTERS%20FOR%20SDR%20TRANSCEIVERS%20-%20YU1LM.pdf

The Measurment.

Stay tuned I working on PA for QRP. 

de SM4HNG

Si5351

Small wonderful VFO and BFO

I get this PCB from SM5CJW nearly a year ago. 5 Component, 2 resistor I2C pullup  1 decoupling 100nF, the Si chip and Xtal 25 MHz. Work grate directly.

Earlier i use Adafruit  module, and NT7S sw for Arduino.

Stay tuned I working on a QRP Transceiver.

My DS15001

I order this before the summer. Last weekend it was time to solder the kit. After turning on the Oscilloscope I see the test signal a short time then the screen was dark. The adj is connected to encoder did not work in both direction. After google about this, I was shore the small pcb. was mounted upside down with the encoder. The behaviour was different but don’t work. After checking the schematics and measuring around the encoder it was shore the PCB was broken in one track to the encoder. After a strap all run nicely. I fixed a 9V NiCad Battery and a box for that.

Here is the troubleshooting Trouble

A video about the Osciloscope Video

Electronic

Electronic Compass

In the winter i spent time to test a sensor BNO055. This was a success it works from start, has built in tilt compensating and calibration. Only a few rows of code. It has two register  to read the current calibration state for system all sensors and magnetic sensors all values  > 0, gives correct directions.

Above photo, first digit is magnetic sensor status second is system status 0 – 3. My next try vas to integrated with Fox receiver and it also works., no effect of metal box.

I also try a sensor LMS303, but this this I can’t get to work.  I has cod to make tilt compensation and calibration. It doesn’t  give me 180 deg. Difference from N to S direction and also W – E so I lev it for now.

The BNO055 has been on two competitions, and the first direction after start was tree spot on and the other 2 just a few degrees off, it was a 80m fox-run.

See adafruit BNO055

POWER METER

This power meter is now finished. A port is LTC5532 and port B and C is classic AD8307. I make my own PCB for this, today you can by AD8307 from Ebay sold for a few dollar.

I connected a LCD display and Encoder. Draw 5V from Arduino Uno to all tree PM boards. Output from A to A0, B to A1 and C to A2.

Then little sw doing the work.

LTC5532 can’t find a formula so I use my generator for input and read levels by ADC and put a table on my serial port than past in to the code, like this.

if(u0>3.4604)

  P1 = 8.0;

else if(u0>3.3822)

  P1 = 7.8;

else if(u0>3.3040)

  P1 = 7.6;

…………..

else

  P1= -21.2;

Then port A is working.

Port B and C. use my generator put in 0dBm and -40dBm read the level in V0 – V40/40 = x V/dB around 23 – 37 mV/db, put it in the code.

if(port==1)   //Cal Port B

{

   for(int i=0; i<10; i++)

     a1 = a1 + analogRead(A1);

   u1= a1/10;

   u1 = 5.0 * u1 /1023;

   pmSet.cal1 = u1;

}

 

To get stabile values I average 10 times.

P2 = (u1 - pmSet.cal1)/0.0242  + pmSet.atten[1] + freqComp[1][pmSet.freq[1]];

pmSet.cal1 = u1 att 0dBm input, calibrated in menu.

pmSet.atten = attenuation infront off power meter 0 – many dB integer values, set in menu.

freqComp[1][pmSet.freq[1]] = freq compensation set in code, measurd by generator @ 0dBm on varying frequencys (16 pcs.).

double freqComp[3][16] = {{0,0,0,0.3,0,-0.2,-0.1,-0.4,0.1,2.9,1.4,4.0,3.8,6.7,12.5,10.4},…….

Unit can be set dBm or W, in menu. Convert to W

if(pmSet.unit == 1) //Unit W

{

  P2 = pow(10,(P2-30)/10); 

}

Jumping over to new project, magnetic compass and PA 1296 MHz, stay tuned.