Adrian G. Hanna GI0SMU
Welcome to my Grange

This is a view of the micro-shack where I have my own little world..... It must be a little world because
I can contact most of it from here.

I have two High Frequency Radio Transceivers, a very old (but faithful) YAESU 747 and an ICOM IC- 746 which is virtually a "shack in a box". There are two antenna tuners. (I don't know why we call them antenna tuners they are aerial tuners, an antenna is what sticks out of an insects head.) The one directly above my head is the NEVADA TM 1,000 with balun fitted internally. The black box on top of the Nevada (under the book) is the SGC Smartuner model SG-230. The Icom 746 has an automatic tuner fitted and it is pretty good, however I discovered that it is possible to connect either the TM 1,000 or the SG-230 in series with it for really fine tuning. You will also notice what appears to be a ZETAGI HP 1000 Transmatch well it is not a Zetagi Transmatch, it was, but I ripped the innards out and replaced them with a circuit of my own design.
Below the Transmatch you will notice a long squat blue rectangle this is my version of the Tona Tuner which enables me to accurately zero in on packet stations very quickly and accurately. The 747 is below that and below the 747 is my faithful SE Automatic Counter / Timer Model SM 205 this was a quality instrument in its day, as it still works perfectly it has a place in the shack.
To the right of the SM-205 you will see two switch boxes, these enable me to change over rapidly from one computer to another. The switches also enable me to switch between the Internet and Fax, to the Packet Modem, then through the Camera Interface to position four which is the Weather Station.
The black box under the Watson PSU is the IC-746 and to the right of that is the monitor for my small computer. There are two modest computers in the shack the main computer was built by Mossbank and the small computer is a special design also built by Mossbank. Neither computer are large machines or even fast they were built for reliability and endless number crunching as required by SETI (Search for Extraterrestrial Intelligence) which is what they do when I am not using them. You may ask why am I searching for extraterrestrial intelligence? The answer is very simple .... There is no evidence of it down here on Earth !!!

The strange dial sticking out of the right side of my head is a barometer for measuring air pressure, not inside my head but atmospheric pressure. The other strange object sitting on top of the switch boxes will be immediately recognisable by a few strange people who have difficulty with one of their trouser legs.

I retired from my profession during 1995 and began building kites to further my hobby of Amateur Radio, fortunately or unfortunately depending on your point of view the kite building began to take over my life and I inadvertently found myself working full time again. I now only build kites when I feel like it, It's only a hobby now and that's the way I intend it to stay.
There are three other VHF/UHF rigs, An Alinco DJ-G5 used for back packing and possible emergencies.. An Alinco DR-150E used in the car and a very simple Yaesu FT-23R which is exclusively used in the kitchen to monitor my favourite frequency S22, 145,550 Mhz. I am also a compulsive designer and builder, the debris in the shed is witness to that.

Voltage Distribution and Protection.

This is part of the of the voltage distribution system in my radio shack. I have a very old power supply which may give up the ghost at any time and I don't fully trust the modern switched mode power supply unit. Rather than take any chances I decided to build a little monitoring unit to see what was happening before it reaches the distribution board where power goes to my radios.

The little DC 100V 50A Voltmeter Ammeter costs only £3:29 + P&P which works out dirt cheap and much more economical than the analogue types of meter. The only problem is that it comes without instructions and searching the internet just leads to utter confusion as there are so many of these little devices all intended for different purposes.
After much head scratching I opted for this circuit. There are two plugs on the back of the unit, one plug has thick wires red and black, they are attached across the shunt to measure the current. The three thin wires are red, black and yellow. The red and black wires are the power supply for the unit itself and yellow is the sense wire to measure the voltage. As the negative line is attached internally there is no need to connect the thin black wire. The yellow is attached to the same point across the main conductor rails as the thin red wire. If the voltage on the main conductor rails is going to exceed 30 volts the unit will require an independent power supply as any higher than 30 volts will fry the unit. As my radio equipment is designed to work at roughly 12 to 14 volts I wired the unit as shown in the diagram and it should run happily in that configuration without the need for a battery.

The FUSE in the circuit is a sacrificial device designed to blow whenever the Triac turns on cutting the power to the digital amp / voltmeter and everything else beyond. A single fuse from a packet of quick blow fuses rated for the radio equipment attached to the circuit is all that is needed. Once the voltage set by the 5k potentiometer is exceeded the LM431 Adjustable Precision Zener Shunt Regulator turns on triggering the Triac BTA41-600B). This causes an avalanche of current which blows the fuse cutting off the power to the equipment. Once you have fixed the problem insert another fuse and carry on until it happens again. The BTA41-600B is capable of conducting 40 amps more than enough to blow the fuse without getting hot as the action is virtually instantaneous, it can of course be fitted with a heatsink which also gives the triac a more stable mounting
The 50 amp current shunt is a brute of a device, far larger than the digital meter. It needs to be big and chunky as the current from the radio equipment is constantly running through it so it needs the thermal mass to keep cool.

THE TM-1000 AERIAL TUNING UNIT REVISITED

I lost the circuit diagram my TM-1000 some time ago and opened the case to try and figure out the circuitry and the diagram below is my best attempt. ...

The TM1000 antenna tuner has been round for many years, it is a very old design which has stood the test of time. It is not often that a really good piece of engineering comes along and does exactly what it says on the tin. The tin or chassis of this unit is a substantial piece of steel finished with a crackle paint job. All electrical parts are big and strong well up to the job. It will take 500 Watts all day long and easily handle 1000 Watts for short periods of time. It will also work very well as a QRP tuner as the internal losses are very low.

There are two versions one with and one without an internal balun. With the balun installed it is simply a matter of moving a jumper bar (link) to the output you need either balanced or unbalanced. The ferrite toroid transformer has a very substantial core with reasonably stout Enamelled Copper Wire (ECW) which looks to be about 1mm diameter.

The soldered joints are all very well made and should not fail under heavy operating conditions with wide temperature fluctuations. Any instrument which is constructed from metal will eventually tarnish and the bearings will eventually dry out. Where dissimilar metals come into contact there may be a small amount electrolysis this is not a problem at high power but will become apparent at very low power. On an old unit it is well worth checking that these connections are in good condition and a drop of oil on the bearings.

Do not be fooled into thinking that this is a simple piece of equipment the schematic circuit diagram would lead you to believe. Mechanically it is a work of sheer genius and must have taken years to develop. Circuits like this have been round since Marconi’s time and the mechanics have evolved over this time. This is not a piece of junk it is the Rolls Royce or Quad of the species. If you can pick one up grab it at any price and get to work.

The balun board is simplicity itself, switching between balanced and unbalanced is by moving the position of the jumper bar see # 01. Dust is another curse a soft brush is the best way to remove it from between the capacitor plates. The remainder can be removed with a vacuum cleaner. Hopefully anyone finding this blog will get in contact and swap ideas and perfect the circuit where it is not correct.


The front panel of the TM1000. To refine the tuning I added two large 360° calibrated escutcheon plates which helps when noting down the settings for a particular frequency.


The rear panel of the TM1000 is relatively uncluttered. If you look carefully between the balun output connectors you will see faint writing. This is the name of the chap (A Radio Amateur ) who built this unit together with his call sign and home address. I looked him up on QRZ and he apparently still lives at that location.


The inner workings of the TM100 .... what a testament to his craftsmanship.
Don't worry about the two pigtails touching one another, there is at least two inches separating them. The balun winding appears to be an auto transformer type but I can't be sure without first disassembling it. If you can give enlightenment I will print it here.

This page has provoked some questions which need answers which I am not qualified to give. However in the interests of the Amateur Radio fraternity I think one solution is to publish the questions here in the hope that soloutions may be found.

Roland wrote:
Hi Adrian
I just picked up a TM1000 ATU minus the toroid. Looking at your web page is that a 9:1 balun in there.
I want to put it back to it’s original condition and need any info I can get.


Hi Roley,
I think it's a 4:1 balun with roughly 24 turns on a large ferrite ring. (TOROID)
A large ring can be made using two stuck together. It is preferable to use the biggest toroid that you can find as small ones tend to get hot.

===========================================
Hi Adrian,
I came across your web page regarding the above ATU, I acquired one recently, unfortunately, not in very good condition. It was damaged in transit, the bottom corner of the case is badly dented so I have striped the unit to repair the case and get it re-sprayed. I wonder if you could help with the following queries.
1) Could you supply a copy of the original manual, I will gladly reimburse any cost?.
2) Do you know the value of the small and large capacitor capacitance?
3) The turns counter dial on the roller- coaster is damaged beyond repair, do you know where I might obtain a replacement. Nevada were of no help they don’t know anything about this unit because of its’ age?
4) Have you had any problems with high resistance on the roller-coaster bearings, unless I am mistaken electrical contact is taken through the ball bearings of the end bearings. I once built an ATU using the same roller-coaster and I had to fabricate a different method of connection. The resistance through the bearings was several ohms, not good at high powers.
Sorry to bother you, I got your email address from QRZ.com.
Hope you can help.
73
Peter


Hi Peter,
I purchased the unit from Nevada over thirty years ago and the circuit diagram came with it, unfortunately over the years involving change of address it somehow got lost. When I say lost it is probably stored safely in one of my back issues of Practical Wireless ..... It consisted of a photocopied A4 folded. That's Q1 sorted.
Re Q2 I believe they are 500 pF's
Re Q3 http://www.minute-man.com/acatalog/Vernier_Dial_for_Potentiometers.html there is an image of the "Vernier Turns Counter" at that address.
use ....Vernier turns counter on Gooooogle.
Re 4 High resistance on bearings. ........
Depends on the wiring of your unit and its use.
If the unit is used frequently resistance is only measurable using the four point method and should be less than .001 1/000th Ohm. or a small fraction of a dB.
Do not remove the bearings add a rotating compression contact in addition.
QRZ has a lot to answer for.
Good luck with the refurbish. Kindest Regards
Adrian


Hi Adrian
It’s me again! Just an update and some queries. First of all I’ve ended up getting the ATU free of charge!! The guy sent me my money back because of the damage in transit, although that was clearly not his fault. He was claiming on the insurance so he must have been pretty sure the claim would be upheld. I told him to hang on until he received a cheque from the insurance company but his cheque with a full refund including the postage arrived next day. I must say it restores your faith in human nature. I managed to straighten out the case and have now had it stove enamelled. It was a funny sort of browny grey colour I asked for it to be painted dark grey, it is now a funny sort of bluey grey colour. Still, it now looks like new and you have to look very hard to find any trace of the previous damage.
Finding a suitable turns counter is going to be a problem. I packed the damaged one with grease and it is now a lot smoother so I think it will be useable in the short term. The ball bearing caged bearings on the rollercoaster, I decided I would clean them in a small ultrasonic cleaning tank, the resistance through the bearing is now worse!! but I am not connecting to earth and the other end I have a copper disc attached (by the convenient M6 thread in the end of the shaft) with a sprung silver contact bearing on it so that should overcome the “high” resistance.
Now the query, the large capacitor, looking at the photograph of your unit, is connected one end to one of the stators and the other connection to the other stator. There is no direct connection to the rotor, the two stators are insulated from each other and are coupled by the rotor, am I correct in this?
Sorry to bother you, hope you are still working the world. I understand 10m has been pretty lively recently but I can’t work that band at the moment, hopefully the ATU will assist in that SOON!!
Regards
73
Peter



The circuit may be as in the above diagram the lower earthy end of the inductor may not be connected as this will avoid circulating RF currents. We badly need to get this diagram perfected.

Hi Peter, Amateur Radio is a "Society of Friends" we all help each other.
I am doing a paint spray job at the moment on a model aircraft, I decided to use VW Lahasa Metallic which is a dark charcoal.
I rebuilt my 25 Amp Power supply and was pleased with the result of using that paint.
Anyway.... back to the subject....
There is the potential for circulating currents as shown on the top sketch.
Without the lower inductor connection the unit will still function.
Regarding the high resistance on the clean bearings ....
Nyogel or Servisol if they are still available should help, ..
however both should be used sparingly.
Try comparing the circuitry in your machine with the diagrams below I could have drawn it incorrectly, ... If so I will modify the diagram on the web page. Incidentally that page is very much out of date as the shack was abandoned after the lightening strike.
Kindest regards
Adrian.


Stevie B wrote:
Hi Adrian,
I got a Nevada TM1000 Atu with the balun removed and would like to find out where you got the 360 degree calibrated plates for it. Also looking for circuit diagram and advice on to service it as it squeaks like a mouse when tuning the coil. Do I just clean the wheel slide and use a light oil or Vaseline ? Many thanks for your help.
Steve


Hi Steve,
The calibrated plates came from a Military machine of some description.
I say that with tongue in cheek as I am not sure.
Many years ago there was an electronics scrap merchant who specialised in purchasing / flogging old military equipment .... The infamous “TV McDonald” who let me root through his stock and I found the plates in their original grease proof paper, purchased them from him for 20P, the pair.
My vernier also squeaks and it is the slow motion drive I believe is the cause.
The drive unit is susceptible to this ..... Years ago Maplin sold similar vernier slow motion drive units and they all squeak eventually. Don’t oil the vernier as it uses a friction clutch arrangement. What I have noticed is that the squeak diminished if used frequently. Clock oil is the only oil to use on the other parts as it does not evaporate and become sticky. Good Luck
Adrian
Google the following:-
vernier slow motion
and
http://oneguyfrombarlick.co.uk/viewtopic.php?f=105&t=13459

Hi Adrian
Thanks for your e-mail and answers to my queries I just wondered what tuning procedure if any, was recommended in the original instructions.I have copies of two articles “Getting the Most Out of Your T-Network Antenna Tuner” QST January 1995 and “A General Purpose Antenna Tuning Unit” RadCom January 1987 both very interesting. More than willing to send you copies of these copies if you are interested. With regard to the circuit diagram you traced I am sure I have read some where not to earth the bottom end of the coil because as the earthed slider moves up the windings it effectively creates a shorted turn which degrades the Q of the coil. When I built the ATU some years ago now I didn’t earth the bottom of the coil and it seemed to work OK, but I never did any comparative performance measurements. Incidentally, I overcame the high resistance of the bearing in exactly the way you suggested. I think one of the bearings is OK resistance wise on the Nevada ATU so I will use that on the “business” end of the coil. I have looked on ebay for turns counters, they are very expensive (around £50) and they won’t fit, I’m talking about the ones with the rectangular escutchion face.Looking at the plastic gear teeth on the Nevada turns counter a bit of judicious use of a needle file might just do the trick.
Anyway, thanks again, I will try not to bother you any further on this subject Regards
Peter


When using a tuner such as the TM1000 there is an infinite number of settings and there is no point in relying on memory, notes must be made. Eventually you will have so many notes that you will need to use a computer spreadsheet. Excel is as good as any but there are many other spreadsheets out there and available for free. The spreadsheet enables you to sort out the settings into order of frequency which speeds up searching through lists.

I had a search on the internet and I found this US Patent which looks exactly like the TM1000 circuit schematic.
I have re-drawn it using the UK parts I understand, the only difference is that the twin gang Tune capacitor is not split by the rollercoaster inductor, only the lower half of the tune capacitor goes to earth.
We still have the potential for circulating RF on the earthy side of the inductor.


The printed circuit board has now been made more obvious.
We may be getting closer to the original circuirt schematic which would be a good thing as this machine can tune a barn door.

Note the Nevada TM1000 predates this US patent by several decades.
Data de publicação   29 maio 2007   The patent reads:-
Resumo
In a T network tuner, a variable shunt capacitor is provided between the signal input and ground that is ganged to the variable input matching capacitor. The operation is mechanically arranged such that, as one decreases the capacitance of the variable input matching capacitor, one increases the capacitance of the shunt capacitor to assist in high frequency matching, both to increase the maximum matchable load resistance and to decrease the minimum matchable load resistance. The variable shunt capacitor therefore assists at the high frequency ranges to bring the antenna impedances down to the transmitter output impedance, thus to establish an extended matching range tuner capable working between 160 and 10 meters.

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Two simple Lightening Detector Circuits.
My home was struck by lightning on 8th June 2003 and cost my insurance company several thousand pounds to replace my computers and radio equipment. Lightning is a terrible force of nature and a warning of its approach will give you time to disconnect everything, hopefully in time before a strike hits. I have also recently taken up hill walking which represents another chance of possibly being struck so I decided to do something about it. The circuit I am now using is my version of http://www.techlib.com/electronics/lightning.html which I have updated to more readily available transistors 2N3906 and 2N3904. All I need from this unit is for a buzzer to sound each time there is a discharge and to turn itself off immediately to await the next discharge. The original SCR version would not reliably turn off when using a DC supply but this more complicated version is be very economical powered by two AA cells, or with the addition of a 78L05 a miniature 12v lighter battery.

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