MY FIRST SDR

 Thank to YU1LM , I can finish my home project, SDR that I take and learn from your articles. As it is the first, I do it by making pcb from the schematic ( not from provided copy ).


 This is TX part of pcb placement

RX part

40M MOBILE ANTENNA ( Construction Detail Crossed PCB Core )

This another style of making Coil core for 40m mobile antenna, it is little bit complicate compared with PVC core, because you have to prepare a pair of teflon instead of PVC cap with accurate fabrication, and also 2 pcs of PCB for making core.

If you want to make it quickly, you just copy , follow its dimension and do as I show in photo .

Make cross cutting for PCB insertion

Top Teflon with Whip holder

Top View, the aluminium plate is for capacity hat

 

 

Matching Coil

Complete winding

PVC Cover

 Don't forget to remove copper layer at PCB. Cross and glue . One thing I still get problem is how to glue teflon to PVC, for the moment I use screw to fix it, and also for base connector, I drill the teflon and screw to hold the connector avoid of loosing .

40M MOBILE ANTENNA ( Construction Detail PVC Core )

Base Connector

Here I try to explain how to construct it step by step :
Prepare all the material :
- 2 meter Larson antenna ( set )
- PVC Pipe 1-1/4 inch 30 cm long ( Incl. the cap )
- Resin
- Copper Wire 1.5 mm dia.

Take 2 m antenna connector and whip holder . 
Make a hole just fit to the connector diameter at the PVC cap, and smaller hole just fit to whip holder size at the other PVC cap. 
Solder outer and inner connector with cable about 10 cm long. Now fix it to the hole and put thin glue around the connector to avoid of resin leakage.

Don't forget to prepare of another cap, otherwise you will do mixing of resin twice, and double works of pouring. One thing I forget to tell you, make inside cap surface rough enough, if neccessary you can add something like anchor mounted at the connector body by soldering some cm of copper wire.

Base Connector

After preparation  this job is OK, you can start pouring  resin on it.

If you are not familiar with resin work, ask chemical store to guide you how to do, especially for mixing. Don't repeat my bad experience , the resin never dry and leakage somewhere around  base connector. It is because of poor mixing and less activator.

Now you can see the connector from bottom side.

 

Whip Holder

It's the whip holder. You can see the whip going through the holder, I think it will be easy to adjust the whip up and down freely, to get wide range of resonance, but is a big mistake, I found it after some weeks I used it. The rain water come into inside and make SWR very high. So, now I change its style , I close the whip holder with strong solder, yes, the whip almost can't be adjusted, but it can make me relax.

Winding Style

Now, it's very easy job to do. Make a hole for starting of winding of 44 turns ( but you can make more turns for easy adjustment). You can start it 2 cm from top ( for cap insertion space ), wind the wire closely, tape strongly for holding it then make another 5 or 6 turns up to matching coil end.
The matching coil is 8 turns with one wire space and tapping point is 3 turns from ground side.

Ready to adjust

Now is ready for adjustment.
If you don't have antenna analyzer, you may use Grid Dip Meter and SWR meter, because it is very easy job.
Place this antenna to where the antenna will be installed. Make sure all the grounding system is already installed perfectly. First, bracket itself must be grounded ( with lead wire ), the doors must be connected to the car body. Don't do adjustment in garage , go to an open area for easy to get good result. If everything is OK, you can check with GDO by making loop wire at end fed to get frequency resonance. Keep all winding and whip just like that posistion. The adjustment is only at top winding
by adding or lessen the turn. If you are sure with frequency you choose, now connect to TRX and try with small power to check SWR. Slight tapping point slowly until you get the lowest SWR. Yes, now wrap it with heat shrink rubber and seal in some places like whip holder and edge of heat shrink. Good Luck.

MODIFIED FT 300C 80/40 M BAND

This is my modified FT 300 C that works on 80 and 40 meter band. An  External Oscillator is in the left side of FT 300 C, using FLL I build completely from IK3OIL schematic. The battery shown in the picture is additional preamp for Condenser Microphone using popular kit that you can get it in any electronic shop.To modify this transceiver is very simple, because we only cut the line X-tal amplifier ( tx/rx) then we joint both point of tx/rx input with external oscillator. The rest duty is rewind the coils ( RX/TX) bandpass or by changing the capacitor value. Another adjustment is phi-section coil and trimmer capacitor. I hope I can attach the detail schematic later, especially around the modification area.

40 M Mobile Antenna

 It is really very cheap antenna, and every body can build it. The whip is larsen antenna and the lower part is PVC 1-1/4" as core and body it self. I make three parts of winding. First, 44 turns close winding is in the upper part of PVC, and the center part is 4 turns with wide space winding then the lowest is for matching impedance has 8 turns with one wire spaced winding. The PVC length is 40 cm and I use heat shrink rubber to keep rigid and avoid of rain water. This antenna is quite good both for reception and transmission, but unfortunately, the bandwidth is only 20 khz and the lowest swr is 1.2: 1.I put this antenna at rear corner of the car. Up to now the longest distance is Pakistan, with FT 180A .

HF ANTENNA ANALYZER

      

This antenna analyzer is copied from VK5JST but offcourse, I change the impedance and swr display with vu meter.

60A SWITCHING POWER SUPPLY

Thank for James Arthur, I have finished from your basic schematic, and  I combine it with SMPS schematic I got from ARRL Handbook, now it becomes 60 A.

ANOTHER PROJECT

Both of these oscillator I built for any channelized radio purpose . PLL, the upper row, using common  design TC9122 but the display I take from IK3OIL using 7 segment because it is looked brightly for an old man like me especially in the darkness of  the night. Another advantage of this display is programmable offset so it can be used for any frequency of IF.

The second row is FLL, it is also from IK3OIL, but there is somewhere modification in oscillator region. Now I used it for FT 300 C oscillator for base station and PLL + FT180A I install in the car.

                                                                                                   

MY HOMEBREW

 

This is my second home made radio with 2 band operation 80,40m, the tubes are only for rf amplifier using a pair of 6146, the rest are transistor.  The filter I am using Collin 455 khz mechanical for side band filter.

  

This is my HF antenna 80M ( upper ) and 40M  ( lower ). All are shortened dipole type, 13m total length for 80m band and 9m for 40m band.