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