zondag 12 oktober 2014

Bitx20 V3 "Dead Bug Style" The S-meter

Last week I added a S-meter to my Bitx20.I used the design which was included in the purchased Bitx20 V3 PCB`s by  Sunil Lakhani.This S-meter,of course,is not a real acurate meter.Actualy it`s more a fun gadget driven by the audio output.But it looks very nice.I used an old S-meter from a Danita 27 MHz CB rig.For the old Kenwood look,I connected a 2Watt 150 ohm resistor in the power supply to the light bulb of the S-meter.Now I have a 4,5 Volts on the light bulb,whitout heating up the resistor.It gives a warm glow on the meter scale.If you take a look on the internet you will find a lot of designs for S-meters.They come in different shapes and sizes.RX/TX,so you can monitor your ALC in TX,and the ones with the AGC support.This AGC is also audio driven.I decided to keep it simple,because I already have heard the AGC on my Multiband Bitx which is very good.
This is the diagram I,ve used on my S-meter.

parts:

1X Potentiometer 100Kohm.
1X Potentiometer 470Kohm.
1X resistor 1Mohm 1/4 Watt
1X Capacitor 680Nf.
1X Transistor BC548

While I was testing my S-meter,I heard a round table conversation somewhere at the end of the band.A few German HAM`s on holiday in Spain where having there daily QSO.At the end of this conversation,I called myself in and a EA-station returned my call.We had a nice talk about the wheater and the fact that I used a homebrew transceiver.I made this QSO with 1,5 Watts and the other HAM was QRV on his sailboat with 400Watts.So,as you can see,It only takes a few parts and a drive to make a nice QSO whitout spending a lot of money.With this S-meter,I now think this Bitx20 V3 Dead Bug Style project is finished.Next........finish the Multiband Bitx.

woensdag 1 oktober 2014

Multiband Bitx: Sneak Preview of the case.

Picture of my Multiband Bitx project so far.In the front you see the VFO knob and display from the PA0KLT VFO and the push buttons.Just like my earlier builds.I used a VU-meter from an old Hitachi bandrecorder.Frontpanel is copper PCB board painted in white.

zaterdag 5 juli 2014

Bitx20 V3 "Dead Bug Style" New Bandpass Filter.

As I discribed in a earlier blog,the bandwith of my bandpass filter in the Bitx 20 was very small.Only 100KHz or so.I found this filter on the internet,and after I,ve build the filter I found out that this was the filter used in the Bitx20A from Hendricks QRP kits.Because I wanted to use the whole 20M band (14.000MHz-14.350MHz) I,decided to build the Original bandfilter which was designed in the Bitx20 V1 by Ashar Farhan.
The bandpass filter is located in the upper left corner of the drawing.Notice that the drawing above is the Bitx20 V1.My Bitx20 which I describe on this blog is the V3 build.Ok,let`s build.What do we need.A piece of PCB,3X 20pf variable capacitor,2X 10pf, 3X 47pf caps, 2X 2,2pf caps, and 3X Amidon T37-6 core and a few inches of magnet wire for winding the inductors.The diameter of the magnet wire is not that important.I used 0,30mm.The inductance of the T37-6 needs to be 2uH.Put 25 windings on the core and measure the value with a LC-meter.The one`s I made where exactly 2uH.Remember to use the whole core when you put on the windings.After you finished the windings,I put on some glue with a hot glue gun,so the windings would not move on the core.
After the toroids are finished,you must strip of the isolation of the wire and tin the wire ends.I started the build of the Bandpass filter to solder a Island on the PCB for the input and a Island for the output.These so called islands are copper double sided pcb from only a few mm`s.After you soldered the two islands on the filter pcb,always check that the Island pcb`s don`t make contact with the filter pcb.Before I put the parts on the PCB,I`ve measured them with the LC-meter.
If you follow the build of the Bitx20 by Ashar Farhan,you see that he used tap washer rings for the inductors.It is very important that the inductors can not "see" each other because of the magnetic field around the cores,so they won`t interfere.Therefore you need to put the cores on a 90 degree angle facing each other.When you use the Amidon cores like I did,these problems do almost not occur,but I did it anyway.On the picture bellow you see the complete Bitx20 Bandpass filter.
Because I don`t have a spectrum analyzer,I was not able to test it if the Bandpass filter was doing a good job on the frequency it was designed for.So I took out the earlier filter and put the new filter in my Bitx 20 V3.After I made the connections,I put the power and a antenna on the Bitx.And guess what.I didn`t hear anything,only noise.After a turn on one of the 20pf variable capacitors the stations where comming thru.I searched for a weak station and began to turn the three variable caps so that the incoming station was on his best.
Now it was time to adjust the filter on the transmit signal.I connected a 50 ohm dummy load and adjusted the caps for the most RF-power on the Diamond SX-200 meter.After a few whistles in the microphone the adjustment was done.Maximum power on the meter.In my case that is 1,5Watts on a 13,8Vdc.That is still no 5 or 6 Watts that is supposed to be on the Bitx20,but all of my Bitx20 builds are on that power.I will figure that out in a later stage.
After this adjustment I heard a station in Austria calling for CQ.With only this 1-1,5 Watt on a Endfed wire antenna the HAM gave me a 5-9 and good audio rapport.On the link bellow you can see and hear the new bandpass filter.

zondag 29 juni 2014

Field test EndFed Wire Antenna lifted by a Kite!

Two weeks ago,Ramon (PE1OUW) asked me to join him and some other Ham`s on a field trip,where they would lift a wire antenna by means of a kite!I thought,yeah,why not ,interresting to see how a kite lifts a 20 meter wire antenna up in to the sky.So we went of to a location somewhere between the city of Purmerend and Amsterdam called Wijdewormer.On this location there`s plenty of space for the experiment and little to zero QRM.
After we arrived,Ramon prepaired the kite and the other Ham`s set-up the Kenwood TS-430 HF transceiver.This transceiver was set up in a case for field day`s.There is also a antenna tuner and a external speaker in the case.After the kite was in the air,we tried to lift up a 40 meter wire with a 1:9 Unun balun.Because there was not enough wind,the wire was lifted only half way.
Luckely,I brought my EndFed wire antenna with me.Because it consist of only half the lenght of wire (20 meters) in stead of the 40 meters with the 1:9,we managed to get the wire up in the air.So the kite was at 100 meters and the whole EndFed was up in the air like a vertical.Now we could start to make some calles.The first thing we noticed was the low QRM.As soon as we turned the radio on,a lot of stations could be heared.It wouldn`t take long before Ramon made his first QSO.We tested the EndFed wire on the band it`s supposed to work without the tuner.On 10,15,20 and 40 meters,the tuner was not needed.Very low SWR value`s.Only at the end of the 40 meter band at 7,199,5MHz the SWR was 1:2.Still no problem.
We also did some QSO`s on the 17 and 80 meter band.Now the external antenna tuner was needed.On the picture you see me making a QSO on 40 or 80 meters,I,m not sure,on the Dutch vacation round.


zondag 15 juni 2014

End Fed Wire Antenna for 10,15,20 and 40 meter band.

A few months ago I bought a FT140-43 toroid to make myself a homebrew End Fed wire antenna,without the need for a tuner.As you all probably know,I use this comercial antenna with a lot of good rapports with my Bitx projects.In the mean time,I changed my 3-bands wire,for a 5-bands wire.Now I can work on the 10,15,20,40 and even on the 80 meters band without the use of a tuner.OK,back to the homebrew.The plan is to make a End Fed wire antenna for 10,15,20 and 40 meter band.What do we need.The FT140-43 toroid,a single 150pf capacitor (mine is 1KV),exactly 20 meters of DX wire,and a piece of isolated 1mm copper wire.Put it all in a little box with a SO-239 UHF-connector.
You can find a lot of info on the internet about the build of this End Fed wire antenna.A popular site among Dutch HAM`s is Zendamateur.com.There`s a whole thread about the build of this antenna.In the thread you can also find the scematic of the construction.On the picture bellow you see the how the antenna is build.

Notice that the 150pf capacitor between the SO-239 is not displayed on the picture.
Because I use only one FT140-43,the maximum SSB power the antenna can handle is 100Watts.In FM you can use 30-40 Watts,depending on the SWR.If the SWR get`s too high,it`s time to reduce your power until the SWR get`s better.
Here is a picture of my EndFed wire antenna.Yesterday there was a field day of the YRC radio club on a nearby farm land.We connected the antenna on a 10 meter long fishing rod and hang out the 20 meters of cable.Just like I hoped,the SWR on all the bands (10,15,20 and 40 meters) was < 1.1,5.On 40 meters I made contact with the UK while there was a big pile-up.Big signal with the Yaesu FT897D (Thanks PA3KOE).We heared a Greek (SV) station on the 17 meter band.Now the tuner was needed and after a short tuning procedure we could work the HAM with a big 5-9.I think I can say,this antenna works great,it`s light to handle on a vacation,and you can build it for only €15,- Euro`s.
Thanks to all the members of the YRC Ijmond Radio Club to let me do the tests.

vrijdag 16 mei 2014

Bitx20 V3"Dead Bug Style" Making the call.

A few weeks ago I changed my shack and put in a new floor,new wallpaper etc,etc.So all my gear,projects and rigs temporary had to move to the attic.When it was time to install my rigs in the new shack,I saw my Bitx20 "Dead Bug Style"and I realized that I never posted the results of all my hard work.So this is what I did.I plugged in a antenna and gave my Bitx20 some juice.The band was crowded and it was not difficult at all the get some stations thru.At one moment while I was listening,I heard DH7SA calling and I answered his call only with 500mWatt or so.This is what happend.

This QSO was made on the 16th of May using a HyEndFed antenna.

Multiband Bitx: The VFO

After the succsesfull reception tests I did with the Multiband Bitx on 20 Meters using the IK3OIL VFO,it was time to decide what kind of VFO I would use for my project.There where several options.The first one that came on my antenna HI,was the N3ZI DDS VFO.Another option is the VFO by DXkits.This VFO was specialy build for use with the Multiband Bitx.It`s a great VFO with build in band switching outputs for the low pass and bandfilter PCB.So this was an excellent choise for me.After a quick study of the manual and components ,I saw that this VFO was actually the PA0KLT design with the band switching outputs edit.Because I`d like to keep my hobby cheap,I decided to buy the PA0KLT A-kit VFO from SDR Kits.On the picture below you see the finished VFO and the Rotary switch.I also purchased the aluminum dial for the VFO.It`s heavy and it looks also great.
For me it was the first time that I had to solder SMD components.If you follow the manual that you can download from SDR Kits,you will find no problem at all to build this VFO.Because this VFO is not equiped with the band switching outputs that the DXkits VFO offers,I first will use a rotary switch which switches the voltage to the correct filter of the low and bandpass filter..After that stage I will make a PCB for the automaticly VFO controlled band switching using the HEF4028 BCD to Decimal Cmos decoder.

Screenshot of the excellent G6LBQ VFO by Andy.

All the parts for the band switching outputs.
On the picture above you see the VFO by Andy G6LBQ.More than half of all the components on the PCB are needed for the band switching outputs.I allready purchased a HEF4028 and the transistors BC547,BC640 and a few diodes.When my project works fine with the Rotary switch,I will make the right side of the PCB,because the PA0KLT VFO already controls these ouputs in the firmware.
Rotary Switch.
You can find a lot of information about this Multiband Bitx project on the Yahoo G6LBQ Group.On the next blog I hope that I`ve started the build of all the PCB`s in the case.
 

vrijdag 9 mei 2014

X-Phase II Noise Canceler

This week I started the build of the X-Phase II noise canceler.Because I have a lot of QRM on the HF-bands,especially on 160 meters.The biggest problem maker is standing one floor below in my living room.Yes,you`ve guest it right,it`s my Panasonic plasma television.Normaly I have a S7 QRM at night on 160M.When I turn on my plasma the signal becomes a S9+30dB.Here you can see what I mean.A local HAM by the name of Ramon (PE1OUW) who lives just accros the street had the answer.He had succsesfully build the X-Phase II V1.4 and showed me some footage of a test he did with this noise canceler.After I saw the results of this device,I wanted to own one of myself.So Ramon gave me some links and I started the build.You can find some information on the site of the German  DARC.More information can be found on this and on this site.So,first thing I had to do was the making of the PCB.It was 5 years since I made my last PCB,so hopefully all my materials where not over due and my equipment worked.
Here you see the stuff I made my PCB`s with.A face tanning lamp which I bought on a fair for €1,50 and a few containers for the developer and etch.A nice site for telling you how to make your own PCB,can be found here! After a few lousy attempts,I succsesfully made three PCB`s.
 
After that,it was time to finish the PCB with a protective photolack and I had to drill the holes for the parts.On the picture bellow you see the un drilled PCB.No proffesionel quality,but I think it will do the job.

After five years my Proxxon drill came to live.I used a 0,6mm drill for the standard holes and a 0,8mm for the potentiometer holes.
On the next picture you see that I started with the placing of the components.Because I don`t have all the parts on stock,this is where I had to stop and wait for the missing parts.