Construction project continues...

After far too long away from the radio club, I finally made it along last night. It was a great evening and we cracked on with John leading the construction project, the SNARC version of "Nicky's TRF receiver". We got to view some mods that folks had made and check out John using the signal generator to check frequencies and make some pretty amazing sounds!



I am still in the process of building my radio receiver so carried on with that. I managed to complete the Af amplifier and test it out. As you can see I have attached the loudspeaker, battery lead and the volume control to the circuit and ground plane.


Above, you can see the chip in place, LM386 and the volume controller wired up. I shall carry on with this project throughout the evening and see where I get to.

QPR convention - Buildathon

Here I am at the Rishworth Radio Rally, in the process of the Buildathon in October (see earlier posting), constructing the 40mtr radio receiver ugly style.


As this was geared to beginners in construction, participants were given the circuit diagram as well as a scanned image of the finished circuit to copy from.


Under the guidance of the pro's i.e. John, my radio started to come together.


This is the finished article, wired up and tuned in!



Lovely stuff!

Rishworth Radio Convention

The radio convention yesterday was wonderful! Along with all the usual suspects around the market tables there were folks from further afield. Namely Rex Harper who delivered a fascinating lecture about PICaxes and their programming, see http://qrpme.com/. This really does seem like a rich area for electronics.

I participated in the Buildathon on the day, which involved constructing a 40metre radio receiver, ugly style under the guidance of pro's! (This project is publicised in Practical Wireless this month) :)

The build took about 3.5 hours in total and was working by the end of the session, receiving morse! I was well pleased.

Here is how it looks:



As I was browsing the isles of the market stalls in the rally I encountered a couple who were selling a book on crystal radio projects. Now I don't know if I have told you yet, but this is how I started getting into radio's. At least after breaking one or two when circuit bending and making music. I had encountered this easy radio to build on the internet. It uses only a crystal rock or a diode to rectify the signal of the electrical current, a tuning capaciter, and plenty of wire for ground, antenna and a coil. Oh and to hear you need a crystal ear piece.

So getting back to the rally. I had spent too long quite frankly looking through this book on crystal radio projects when the female of the couple said "you can have it for a pound" "oh, i guess i should buy it, I've spent so long looking at it!" Then the male counterpart joined in with questions about my job and then I suddenly developed into a "worthy cause". Very kind I think. And so for about £8 I ended up with a bundle of crystal radio parts to construct together and develop and share those skills.

So here is the crystal part.


This rock of galena is the detector. Using a piece of wire known as a "cat's whisker" to touch points on the crystal it is possible to pick up a radio signal.

Here is a suitable capacitor which is used to tune into the frequency of radio stations, this works along with the coil and crystal. Notice the fins that are carefully engineered not to touch each other as you turn the nob.


Then came these beauties


A real set of vintage headphones, 2000ohms (i think) that'll work wonders with a crystal set I am planning on building. They have a lovely leather strap and are in good working condition. The cord is fine for a vintage set of cans. Mmmm...


Once I am firmly on water I can get cracking with this project at my workstation. At the moment boxes lie upon boxes in the flat and there is no workstation to be seen - oh dear!

Antenna aid 3

Oi! tried to get on the club net but when using the new antenna no signals were picked up. Investigations will have to take place!

Antenna aid 2

The jubilee clip is fastened on underneath the ground plane holding the tube in place with the coax running down the tube to the rig. To get an idea of size, here is the radio antenna fixed up to the hand held hanging over the door.



That little blue thing on the wall is this...

Antenna aid

With thanks to Terry for his donation of the antenna, I am now aided and equipped when sending and receiving signals over the radio by boosting her transciever.


This is a ground-plane design with 4 copper legs and a point at the top connected together at the centre with a small square (corners bent) of aluminium. On the underneath is a female N type connection to attach a lead to the rig (radio).


Terry also helped me to put together my first lead.


This is combined of 'plenty' of Rg58, also known as coaxial cable (enough to run down a supporting tube and into car/house/boat to rig). The following image presents an exposed piece of coax (RG59 in this case which looks the same but has different properties such as impedence.) A - outer plastic insulation, B - braided copper, C - inner dielectric insulation, D - copper core.


A quick search on wikipedia provides great details about coax.

Also needed for the lead includes a male N-type connector to attach the lead to the ground-plane...


and a 50 Ohms BNC plug (one that you have to identify in the Foundation license exam). Apparently the only way to tell the difference in Ohms is by the thickness of the centre pin of the plug, but this takes a highly skillful eye to identify and not necessary in the exam (in my case just ask the stall holder).


And finally, as the Yaseu has a particular connection for the antenna, I purchased an S.... (will have to look this up as the name escapes the mind).


In brief, to make this lead the coax cable is stripped to the braiding on both ends, the plugs unscrewed and certain bolts threaded on. The brading is unravelled and then trimmed to the bolt edge. Measuring the centre pin in the housing helps to identify how much of the inner insulation to trim thus exposing the core. This core is then pushed inside the pin and soldered. Screw on the housing to the bolts. Do the same for the other end of the cable using the suitable plug. Test that there is no continuity between the centre pins and the housing one strand of the braid could do this, so check before fixing all together, and Bob's your Uncle.

Now the next thing is to take a tube which is used as a support


and from one end of the tube cut down about an inch in a cross formation.


Then using a Jubilee clip...


tighten the tube around the N type underneath the ground plane allowing the cut strips to overlap. This should provide a sturdy pole to fix upright. I am yet to find the best place to fix this new antenna.

Transceiver from her love!

From the best love there could possibly be I received this in celebration of passing the Foundation course:


So, there it is, I am beaming from cheek to cheek. With my callsign down, M6DOE, the female deer has a new found hobby. The Yaseu Vx-170 is still charging it's heart out, though I couldn't resist and scanned around and listened in on a Morse lesson between Mary and John earlier today, great stuff, she even picked up a thing or two! Hours of fun!

This is Mike Six Delta Oscar Echo over.

Radio project

The radio club nights of late have been occupied with the latest construction project, a radio receiver. Run by John. I have been taken through the first steps; understanding the circuit diagram, a lesson in solder (basically if your life depends upon it don't use lead-free solder, but wash you hands afterwards!) and then working in 'ugly fashion'.

What is this? I hear from the beyond the door... Well, it is a form of building a circuit with the use of copper plate and copper pads (insulated on one side with paper or fiber glass) and not being restricted by using a circuit board (PCB board with lines connecting parts up). The main copper plate is the earth and so any parts that need to be isolated from this are soldered on to the pads which are mounted on the plate. It apparently looks ugly, but I think it looks awesome!


The above image is the first evenings work. This flat board will have a vertical piece soldered at the front for switches and such like, so the copper plate was carefully positioned right at the edge of the wooden block. The plate was pre-drilled (thank you John) and so using a marker pen the holes, attaching the plate and capacitor, were marked down on the wooden block and drilled. Due to the nature of the wooden block forming a small mountain when drilling, Oi! first drilled with a small bit (not all the way through mind as this is purely to aid the working of screws) and then only slightly in with a larger drill bit to overcome the mound. There are four holes for the screws, one in each corner. Then three holes arranged at points of a triangle (for the tuning capaciter) and two for a brace for the capaciter. Just a note that the capaciter is absolutly brilliant! with very fine fins that glide between each other at the turning of the spindle. There are lovely cogs that gently spin as you do so and a tiny spring to prevent any bounce back as you tune back and forth.

With the use of a template for the copper pads, I was able to mark down in formation where on the copper plate they were best to go. So using a stanley knife and ruler a sheet of copper plate had been scored on both sides into 5mm strips. This was then snapped off using pliers and cut into small squares using some hard-core cutters (making sure not to let the pieces fly off). Using the good ol' super-dooper glue, these were fixed in place. Notice the longer strip for several connections and the small rectangle of holed board for the IC chip (more about that later).

So, there we are. I'm not sure if I can post the circuit diagram, best check in with John next week. Until then, over.

Foundation: review

With regards to the amateur radio foundation licence here is a recap of things you need to know. Firstly, it does get easier, this is from the point of view of someone who is self taught in electronics and inexperienced in working on the air. The club that I attend, ran the foundation course over 10 evenings with a good teacher who happily answered any daft questions. Then I spent the whole weekend with a refresh of all topics, mock exam and the final exam.

As part of the licence you need to undertake some practical assessments. This is really fun. You have to set up a HF and VHF/UHF rig, tune into stations, read the signal strength, then send and receive a CQ call and morse. The morse is at a very very slow and steady pace, so from having not touched a key before, I passed.

All these practical achievements are recorded on a 'record of achievement card' which needs to be presented on the day of your exam. This along with some identification, like a passport. In the actual exam, you have 45minutes to answer 25 multiple choice questions on topics covered in the RSGB Foundation Licence handbook. You are given four sheets of information to use as reference, these include the Foundation licence parameters, the 2mtr and 20mtr band plans, frequency/wavelength conversion chart and the chart stating the uses of the VHF band.

The topics to address are;

• Nature of Amateur Radio
• Licence Conditions
• Feeders and antennas
• Propogation
• Technical Basics
• Transmitters and Recievers
• EMC (Electromagnetic Compatibility)
  
• Repeaters
• Operating Procedures
• Safety

Best to refer to the handbook for full details. I found it wasn't a matter of just understanding and reciting facts but actually to be able to apply this knowledge.

Hay-ho, it's all good.

Pass!

Papa Alpha Sierra Sierra. Whooo! That is what it said on my certificate for the Foundation License today. Sweet!

This weekend has been jam packed with going over the entire 10 week course aided by a slide-show detailing all the main points, then a mock exam and the final exam. I have to say that I really did enjoy myself and am very grateful to the gents who took the time to get her through it.

Celebrations are in order and she is now contemplating which hand held to spend good money on.

Foundation: Morse

-- --- .-. ... .

Known as CW, morse is a method of communication using a keyer (pictured above) to send tones (long and short) in sequences that spell out individual letters and numbers. The tones are known as dit and dah, dit for dot and dah for dash. For example a single dit is the letter E and a single dah is the letter T and so on. The following tree diagram is a method for working out, where to the left is the dit and right is dah. For example Y is dah, dit, dah dah.



The speeds people send and read morse are rediculous, however brilliant in that the sequences are very rhythmic.

For the Foundation, using a printed list of the letter codes you have to send and receive a short message. I am reassured that the speed is very slow, however this does seem to make receiving harder as the dits and dahs seem less pronounced. Better get keying!

Foundation: feeders + antennae

I nearly lost the will to continue last Wednesday, as it seems the more that I learn the less I understand. Things, I hope, will hopefully connect together as time goes on and the moment of darkness will end.

We started by looking at feeder leads and were handed round a variety of connectors and leads to learn their appropriate names; coax (positively charged inner bit surrounded by negatively charged outer), and a twin feeder (looks like a ladder) that is balanced. There are end types of note, BNC (the one that screws and clicks) and PL259 plug.

Then we looked at antennae; so, this is were the water muddies, the length of Ariel needs to match the wave length. But then there is something about half wave at which point I scratched her head till it bled.

Wavelength has the symbol of upside-down 'y' called lambda, lets just say that again because it rolls out so beautifully... lam-bd-A! Mmmm.

So then, there are different types of antennae; the dipole which sticks up vertically and receives horizontally, the yagi, like a TV aerial has the best focusing ability (but something to do with length needed can result in problems as you end up with one the size of a bus), 1/4 wave ground plane antenna which is like a horizontal cross (equallatteral one) at the end of a pole and radiates from the diameter of the end-points of the cross. Then there is 5/8 wave ground plate which has a coil then a long stick after. This latter one radiates ovally horizontally and vertically.

There is something about an Antenna Tuning Unit (ATU) which registers the standing waves flowing up/down the antenna and is useful to control the flow of SW, preventing the transmitter from burning out. Finally we learnt about Baluns which converts coax cable(naturally unbalanced) into balanced waves so it is suitable to use with say a dipole which is itself balanced.

dit-dah-dah-dit dit-dit-dit-dit dit dit-dah-dah

Foundation: Intro continued

I missed a week of notation and i've now caught up with the intro...
As we were gently broken into the Foundation course, the introduction ran into another evening under the moon-lit sails.

We were told about the must's and must not's when it comes to identifying oneself. Upon getting on the airwaves, find a spot by requesting if anyone is using the bandwidth. Then we use what is known as CQ, seek you - ha! This is a call out to other hams to make contact. Upon each CQ call you must provide your id using the same mode of communication e.g. voice, morse, CW. This also applies to handing over, changing frequency and dare I say, talking for longer than 15 minutes - on the air waves really there is not an awful lot to say, particularly with regard to the Q code (a series of abbreviations) mentioning the weather, old boys and the signal strength. Tis true there is no coding for the female of the species. I shall make one up, LFB. There.

There were more tedious rules about not using your own codes, sticking to those known. Morse. Mmm. Oh and addresses, for your license. As I frequent to myself... I do not have a permenat address for correspondance, I told you, I live on a boat... One thing you need to know for the exam is that to change address contact Ofcom. There are certain bands we can use and some we cant. There is a chart notifying of this so I wont go into details.

BTW (I apologise if these code words upset!), if I haven't mentioned the gang and I are working through the Foundation booklet available from RSGB Radio Society Great Britain.

Roger.

Foundation: Technical details

This session involved some tidbits of mathematics, trudging up some forgotten science plus clarifying some basics in electronics.

Current measured in Amps (A), symbol: I
Resistance measured in Ohms (upside-down horse-shoe shape), symbol: R
Power measured in Watts (W), symbol: P
Voltage measured in Volts (V), symbol: V

Electrons which carry the charge flow from positive to negative in a circuit. The energy loss measured from the circuit is known as potential difference. This allows us to calculate the voltage. The more voltage there is then essentially the more power there is.


We now have to know some details regarding lengths such as 1cm= 0.01 of a meter and 1mm=0.001 of a meter. This is to enable us to do some calculations in the exam. Three important amounts are:
Milli = 1/1000 or 0.001m
Kilo = 1000 or K
Mega = 1million or M

Have a look at a simple circuit to understand the symbols for battery, light bulb, switch and resistor.

Now, this is where I got a little stuck in mud. Fundamental point to note is that Current is the rate of flow and Voltage is the pressure. We will have to calculate either Power, resistance, current or voltage and so have to use the triangle symbols to help.

Cover the symbol you want and multiply or divide the alternate two symbols for your answer.

There was a brief mention of Alternating Current (AC) and Direct Current which are quite self explanatory.

Next was the mention of Waves(upside-down y) and Frequency (f). Best to view a waveform for this one! The cycles in a wave are known as frequency per second and are denoted at Hertz or Hz. We need to know the ranges in frequency and so here they are:

300KHz - 3MHz = MF medium frequency
3MHz - 30MHz = HF high frequency
30MHz - 300MHz = VHF very high frequency
300MHz - 3000MHz = UHF ultra high frequency

For sonic applications; the shorter the wave length, the higher the frequency.

In the exam we will be given several documents,one of which is a chart stating (in binary) length vs. frequency. Knowing how to read this means we can work out who uses the different ranges e.g. emergency services.

what what eh?

Foundation: intro

The course in HAM radio the foundation stage began last night. To clarify HAM radio is non-commercial communication between other members and stations. At the foundation stage we are limited to 10w which on fine days in sun spots can transmit and receive signals world wide. At this stage we can only build accessories and receivers not transmitting equipment due to the wattage restrictions. The course is kindly delivered voluntarily where I attend and the only cost will be £20 for the exam. Once passed I can apply to Ofcom for her license and call-sign.

In the UK call-signs (which is like a number plate which every HAM user has to identify themselves) begin with either the letters G or M. Those that pass the foundation stage have a call-sign beginning with either M3 or now as they have all gone, M6. Full license holders begin with the letters G, M1 or M0. Oi! forgets now about intermediate...

At Foundation stage you can only transmit in the country you are studying. However if you are to go in the UK for example, from England to Wales you have to enter something which is called a regional identifier, in the case as above you would enter the letter 'W' into your call sign. So MW6... There are different letters for Scotland (M), Isle of Man (D) etc.

The next thing we need to know is the phonetic alphabet. There are different versions such as countries, Mexico for the letter M. But we are using the NATO phonetic alphabet, Alpha, Bravo, Charlie, Delta etc. Apparently a good way of learning this is when strolling out and about to observe number plates and recite the letters in the form of the phonetic alphabet.

And after all this fun and laughter, I took along the Phantastron which certainly whet the appetite of some of the boys, from memories back in the days when...