Some Amateur Radio projects I've been working on over the years. This information is provided as-is and comes with no waranty.


FT-857 PSK interface

A simple interface for the FT-857 as a portable PSK31 interface, although it will work with most datamodes. It is also isolated and has adjustable levels.

Parts

 


Schematic



Pic


 


Tuscon Speech Processor


This processor is based on a design from when I was a CB Radio operator, aiming to get the best quality audio as the limit of 4w is quite constraining for DX. The design shown here is for use with a Cybernet chassis radio, although it can be re-wired for any mic configuration.

 

 


 

Parts List

Resistors

R1 - 330 Ohm 1/2 Watt
R2 - 1k Ohm
R3 - 220 Ohm
R4 - 1k Ohm
R5 - 10k Ohm
R6 - 1k Ohm
R7 - 47kOhm
R8 - 1M Ohm
R9 - 1k Ohm
R10 - 10k Ohm
R11 - 1k Ohm
R12 - 100k Ohm
R13 - 180k Ohm
R14 - 470k Ohm
R15 - 1k Ohm
R16 - 10k Ohm
R17 - 10k Ohm

RL1, RL2, RH1 - 1k Ohm

RH2 - 100 Ohm

VR1, VR2 - 10k Ohm

Capacitors

C1 - 0.01uF
C2 - 4.7uF
C3 - 4.7uF
C4 - 0.002uF
C5 - 4.7uF
C6 - 0.47uF 25v Electrolytic
C7 - 0.002uF
C8 - 150pF
C9 - 4.7uF

CF1 -0.1uF
CF2 - 22uF

Diodes

D1, D2 - 1N914
D3 - 1N4735A

IC

IC1 - LM324


 

Build Instructions

Obtain a piece of Stripboard - 26 Strips by 32 Holes or Bigger
Clear Copper from tracks as in this Diagram Below...

Place in the wire bridges first ...

Then the resistors...

Then the capacitors...

Then the other components ...

Finally the wires for audio in / out and power.

Finished .....

 

^ TOP


Ladder-fed Portable Dipole

Following the 20m Sota Dipole Experiment, and the good results obtained from this design, I set about making a portable dipole, around the same principle, but this time, ladder fed, and multi-band via the SGC-211 Auto-tuner.  It functions well on 80m to 10m.

Parts

1 x 150mm Length 20mm Conduit
1 x 20mm Conduit Clip
2 x 4mm Bolt - Flat Head
2 x 4mm Wing Nut
1 x 450 Ohm Ladder Line
2 x 8.5m Length 0.16/24 Stranded Wire

Assembled on the SOTA Pole and Tuned via SGC-211 - 5 9 again into Sweden using 35w - Inverted V layout, E/W Arrangement at the NLO Antenna Day.

Dipole fed with 300ohm ladder feed

This antenna has not had as much development as the SOTA Dipole, but has been used for some portable operation.

^ TOP


Notes about the ATAS-120A

 

I bought an ATAS-120A from Martin Lynch & Sons and it is the finest Mobile Antenna I have used .... But the Instructions that comes with it are rather short ... Here's the things that I now know about the antenna, but couldn't find anywhere else ...

1. Grounding of the mount.

Any user of ATAS will tell you to ground the mount PROPERLY. This antenna requires a good ground, or else you should have saved your cash and bought a reel of bell wire. If it is grounded to the vehicle properly, it will work excellently, not grounded and you may as well disconnect the PL-259.

I use a Maldol PRM-T trunk mount on an Alfa Romeo Giulietta. The Grub screws are lined up with 4 holes made in the foam of the trunk These have had their foam removed in the form of plugs, and the screws now bear down on to galvanized trunk metal. Earth Continuity was then checked to the WHOLE CAR BODY.

2. HF, HF/50 or ATAS ALL

Set your radio to control the ATAS Antenna via the menu's. This differs between radio's, but the FT-857 and 847 were pretty straight forward. The display will acknowledge the ATAS is armed, with a symbol on the LCD. The controls from here are simple, TUNE, UP, DOWN. On pressing TUNE for the first time, the Antenna will go into INIT, where the Processor will locate the antenna fully retracted, so it knows where to start from... it doesn't have the luxury of eye's to see where it is. From then on, HF / 50 will tune as command, quickly if the Frequency has been used before.

3. VHF/UHF does'nt supply Motor Current.

This made me think my ATAS was faulty, as the manual does'nt state anything about this. The Operation of the ATAS on the 857 should fully retract the ATAS when TUNE is pressed on VHF/UHF. In the event of no duplexer, as I was awaiting one on back order, I followed the instructions, and manually moved the PL-259. Plugging into VHF, and pressing TUNE just showes WAIT in the display, and no motor movement.... This is because, if you leave the Antenna in the HF port, and switch to VHF and press TUNE, it will work !!!!

4. Using a Duplexer avoids above !!!

I now use a Duplexer (Diamond MX-62) and all is well ... but don't expect DX VHF/UHF .. but is quite adequate for Repeater and short duplex work ... I use it for static mobile HF anyway.

5. When someone say's "The ATAS is an Expensive Antenna that does'nt work"

Say nothing, in the safe knowledge that if they had installed it properly, they would be having Pile-ups on HF from their Vehicle ... It's all in the preparation folks ..

^ TOP