Saturday, December 30, 2006

CQ2 VHF Receiver

This was a classic project! Back in 1969 there were very few Radio Amateurs transmitting on VHF (2 metres) along came this project in Practical Wireless which used a previously unknown device called an FET (Field Effect Transistor) these devices could work at very high frequencies (VHF) so I decided to have a go at this one!
After spending all my pocket money on a 2N3819 FET, the CQ2 began to take shape. I mounted the receiver on an aluminum front panel which was originally built to house an oscilloscope that I began to build when I was at school. (not a good idea!!) The metal chassis caused havoc with the tuned cicuit, so I rebuilt it on a piece of plywood! When the receiver was built I made a QUAD ANTENNA for 2m. The receiver was tuned by squeezing or lengthening the coil and fine tuning with the variable capacitor. Very tricky, as the receiver was a super-regen it was inclined to 'take-off' and blot out everyones television for miles around!

Here is the circuit...

The first results was listening to the gas board from their PMR transeivers, but after hours of twiddling I finally heard Chris Hartley from Bolton who worked 2m! Chris had a huge antenna system located in Bromley Cross and ran high power on 2m!

My very first attempt at VHF communications!

Why have I posted this...because my Grand Daughter, Melissa who is two years old decided to tear off the front cover of the original magazine (35 years old!!) After a big sort out with some magazines in my room. CQ2 Melissa!

Thursday, December 28, 2006

Pye Cambridge

What a wonderful hybrid transistor / valve PMR rig this was!

This super AM Tranceiver could be tweeked and modified to run AM and FM on 2m at about 5 Watts output. The rig was a hybrid, mainly transistors but used a QQVO-310 valve to supply the RF output. It had a built in invertor power supply to provide the high voltage needed for the valve PA.
Neil, G3ZPL used a dash mount Cambridge on AM to go mobile in his Hillman Imp back in 1972. Had some great fun with this rig and on one occasion while visiting 'The Wilton' Pub on Belmont Rd, Neil decided to try to use the Cambridge to interfere with the loud jukebox in the pub. We sat outside shouting into the microphone...never did know if it worked!!

Later, I managed to get hold of a bootmount Pye Cambridge with it's wires and remote control console and moutted it in my Austin A35. A few crystals and a bit of modding got me on the air mobile on 2m with a Halo antenna!
The bootmount Cambridge was great, so when I got a company car...a Ford Escort...I decided to modify the bootmount to make it dashmount. I did this by building a front panel for the box and adding an LED channel display. The channel display was the biggest job, it consisted of a matrix of about ninety diodes mounted on several layers of circuit boards. It worked a treat and displayed channel numbers to match the crystal frequencies. The whole unit was mounted under the dashboard held with a couple of big stetchy rubber clips. Some great contacts were made while driving around, later a quarter wave whip, (mag mount) was mounted onto the car roof.

Gosh...I spent so much time tweeking these beasties. They were so well made and the boxes were completely sealed so that even though the outside looked rough, the insides were like new!

Sunday, December 24, 2006

What about this then...

In the days of the 1970's as an apprentice TV and Radio Technician at Telefusion (about 1974) I worked in a small unit in Cobden Mill mending radios and cassette recorders and other small items. The miners were on strike and we had a three day week. Trouble was that you could mend transistor radios without mains power, so we bought a load of batteries and carried on working with our coats on! It was great fun really!

Around that time I worked with some more apprentices, Ian Harrison, Bhad Govan and Jim Hulton. Ian was quite keen on amateur radio and one evening we went to see a well known amateur radio voice on 80m who's callsign was G3MCR (more about this later)

One day I was repairing a cheap transistor radio that covered all the Short Wave bands including 160m and after replacing a component and re-aligning the radio using a Heathkit Signal Generator, I decided to have a listen on 160m. Guess what...there was Alf, G3HRV in Walkden about two miles up the road. After listening to his QSO with a room full of apprentices I thought it might be good idea to try and contact him using the Heathkit Signal Generator!!

A bit of a long shot, but by keying the aerial (a TV aerial that went all the way up the side of Cobden Mill) I thought it would be worth a try. I called Alf in CW and....he came back....i've never seen a room full of apprentices so astounded! We completed a QSO in CW with about a milliwatt of signal!

This was one of my most original contacts ever, and yes...I put it in the logbook!

Alf was a great guy, I went to see him a few times when I worked in Walkden. I would often listen to him talking on 160m with Ralph, G3WWZ.

Flying Spot Scanners

Watch out....there's a 5FP7 about!

I thought it might be interesting to post this on the email from John Stratham who went school at the same time as Neil G3ZPL.

While Googling during a quiet time at work, I came across your site which fired off some happy memories.
As a youngster at Bolton School I was always amazed by the skills of Neil Richardson G3ZPL who ran the
Radio Society. I clearly remember him working on TV using a photo-multiplier tube he'd aquired from somewhere. I have not heard anything of him since he left school and often wondered what became of him.

Hi John,

Thanks for your message, always nice to hear about someone who has happy memories!
When you were at Bolton School I was at Deane Grammar School where we also had a 'kind of' Radio Club at lunchtimes. Our Physics teacher Mr Bristow, was also a licenced radio amateur, but he never went on the air!

Neil and myself got our licences about the same time (1970/1) and used to talk for hours on 160m and later 2m and 70cm bands setting up cross-band contacts which allowed us to chat like being on the phone. One of the best projects that we did together was Amateur Television. Neil had a photo-multiplier tube and a 5FP7 flying spot scanner and this allowed still images to be transmitted over the 70cm band to my receivers. Neil worked out a really clever way of not having to send 'sync pulses' to lock the images...we used the BBC's 'sync pulses' by tapping them off another TV receiver. Dead clever! Neil had such innovative ideas, great times were had!

After leaving school, Neil went to Cambridge University and took a Degree in Engineering, then later completed a Phd in Engineering at Cambridge. Neil then got married to Christine (also from Cambridge) and then moved to Palo Alto in California and worked for a large company over there. He now travels around the world and is president of another company over there in Palo Alto. Neil and Christine have three children and as far as I know they are still in Palo Alto. Neil keeps in touch, but I don't think he has been to Bolton for quite a long time now.

As for me John...i'm a Primary School teacher in Bolton and love my job!

A lot of memories here! I remember the famous 5FP7, never got one myself, but I will never forget the smiley face that Neil painted on the front of the tube then transmitted via the photo-multipier tube. This was the first image that I received over 70cm, I thought it was hilarious...a big smiley face filling the screen! The 5FP7 was a long duration device, the screen would continue to glow long after it was turned off, so the smiley face would glow under the bed all night....scary!

I managed to obtain a couple of high quality photomultiplier tubes that came from the Winter Hill transmitter supplied by my Uncle who worked there. These devices provided the 'Test Card' from the ITV Transmitter. I never did get these devices working!

Friday, December 22, 2006


So much for the 6BW6...along came...Solid State Technology! Yes! Transistors!

By this time I was working as an Apprentice at Telefusion Ltd on the front line of Technology. So my next project was to improve the original Stereo amplifier and bring in Solid State Devices (Transistors) My friend Neil had just built a slimline amplifier based on an amplifier in Practical Wireless, the Partygram.

The Partygram was a Mono Amplifier that used two high power transistors (AD161 and AD162) in Push-Pull Mode to give an output of 10 watts rms. Two of these amplifiers built in the same box would give high quality stereo! I was dead impressed with Neil's Amp, so I set about building one myself. I managed to obtain most of the parts from work, but the most expensive item was the mains transformer. The drivers and pre-amps used BC108's and equivalent PNP devices. I built a case from aluminium and my Dad built a wooden surround, all the controls were mounted on the front. This was a superb project, we could have audio separates (Amplifier, Deck, Speakers) and was used at home and later when I got married right up until about 1980 with a pair of wall mounted Bush Denon Speakers (actually Warfedales)

Later, I used the case of the amp to house another amplifier, a FET 100 watt disco amp from Maplin which to this day is still fact I used it yesterday at school for the Christmas Disco!

I still have an original copy of Practical Wireless with the Partygram circuit and details, how sad am I?

Saturday, December 16, 2006

What's a 6BW6?

Well, here it is the famous 6BW6 valve!

What's a valve? you Digital Natives may ask... Click HERE!

This versatile little beast could produce around 10 watts at Audio Frequencies and great for my first attempt at a stereo amplifier.

Our 'record player' built by my Dad, sat in the corner of the front room with a speaker built in the front. It sounded nice!
Hi-Fi was the 'in thing' back in 1969 and records and LP's were now going STEREO so my Dad and I decided that we would build a stereo record player!
The original amplifier in the box came from an old radio that my Dad had used as an amplifier, not bad kit really, 6V6 valve amp provided a fair old sound. I decided at first to strip down the amp and use the chassis to build the new one...a bit of task really as it was my first project with valves! After a lot of drilling, filing and wiring the new stereo amp began to take shape, meanwhile, Dad was building the new wooden speaker cabinets...tall, slim and dark.
OK...I had a few teething problems with the amp, the pre-amp needed to be quite sensitive because we planned to have a deck with Magnetic Cartridges and this caused a lot of instability in the amp, so much so that the poor 6BW6 would glow red!!

Bought the record deck from Barry, G3WIS, a real piece of engineering, super heavy and stable complete with Magnetic Cartridge.

At last we were all ready to hear STEREO for the first time. To test the equipment we used a record that was made to demonstrate the effects of STEREO...I can still hear it now..."June is bursting out all over" and the train whizzing from one speaker to the other! I had just bought " Bridge over troubled water" and this sounded great on the new system.

Hi-Fi at last, thanks to a couple of 6BW6 valves!

Later, the 6BW6 along with the 5763 and EL84 valves gave me the power to build transmitters that could transmit Radio Frequencies 160m and 80m!

Sunday, December 10, 2006

Morse Code

This is the very same Morse Key in the photo taken by Dad of me when I was 17! It came originally from M. Dzubias in a big green box for about 50p! I still use it!

Today, Morse Code is simply 'past it's user date' , slow, inefficient and what the hell is it anyway? Children can 'text' on their mobile phones, but have never heard of Morse Code!
Well, here is my story from the days when Morse Code was the tried and tested way of communicating in even the most difficult environments, when radio operators on ships used Morse Code as part of their everyday life and Radio Amateurs had to learn it (like it or not) to gain a Class A licence.

In 1971 I passed my Radio Amateur Exam in May, my next target was to learn Morse Code at 12 Words Per Minute in order to pass my Morse Test to achieve my Class A licence.
George (G3ZQS) was an ex navy operator, he taught me everything I know about learning Morse. He would come around to my house in his slippers and teach me the G3ZQS way of learning morse. George was a real character, did so much to inspire me to go for it and also to bring so much pleasure to others learning the code. George made his own tapes, using the 'George method' I was able to learn Morse Code up to 20 WPM before taking my test. (A real acheivment for me at the age of 16!) George's methos involved grouping letters together with similar sounds and rhythms (Q - God save the Queen - dah dah dit dah)

It worked for me!

Soon I was on my way to the Liver Buildings in Liverpool with my Dad to take my Morse Test. I even had to get time off work for this. The day itself I can remember like yesterday, we got lost in Liverpool trying to find our way and asked a man near the Docks, gave us directions and explained how the Dockers were all on strike!
In the Liver Building we walked up several flights of stairs to the place where the test was to held. I was shown into a room with several different Morse Keys to choose from, I chose the shiny brass one, and asked to practice for a bit. Then I had to listen to a passage of text in Morse Code and write it down, following that I had to send a passage in Morse Code. I was allowed three errors! Scary stuff!

Well...I passed!

I could at last send for my Class A licence!

A word about George, G3ZQS:

  • Can listen to morse like we listen to words!
  • Can send Morse Code on a broken hacksaw blade at 60WPM!
  • Can send and receive Morse Code at 60 WPM after drinking several brown ales!
  • Can drive a big car with his slippers on!
A man of many talents!

So now, in the digital world where children, grown ups and digital natives send text messages daily, I have one advantage....

Text messaging is really Morse Code....and I can send it faster than they can text it!!