Cloud Chamber Finale

 

Today's aparatus (above).  Chamber is larger and I left the bottom sealed.  It sits directly atop a chunk of dry ice.  The spongeat the top is soaked in alcohol. 

This is a one minute clip.  It does seem a bit like watching paint dry, but you will see many atomic particles moving through the cloud. If you look to the right side of the screen you will see that the cloud has started to rain alcohol.  I will put additional clips on the Patreon site. 

Harry Cliff's wonderful book mentions the origins of the cloud chamber. 

Click for a better view. 

Click for a better view/

Here's an interesing site on cloud chambers: 

https://www.hep.phy.cam.ac.uk/scatter/cloud.html#:~:text=Operate%20the%20chamber%20in%20a,approximately%20parallel%20and%20horizontal%20beam.

And here's another one: 

https://scoollab.web.cern.ch/cloud-chamber#:~:text=The%20cloud%20chamber%20was%20one,dry%20ice%2C%20and%20Isopropyl%20alcohol.

I think that is all I will do on the cloud chambers.  This was a lot of fun, but I am running out of dry ice.  There is, however, a lot of room for improvement and experimentation here, and a project likes this puts you in touch with the earliest days of particle physics (as Harry Cliff explains above). Good luck on 1.22 nanometers! Please let us know how you do. 

Here is one more look at the "output" of my cloud chamber.  This is a ten minute video.   You can see many traces in this. Check it out: 

More Cloud Chamber traces. April 26, 2024 (youtube.com)

Thank you Charles Wilson.  And thank you C.L. Stong. 

First Ever Contact on 12 Meters: Homebrew, QRP, SSB, DX (Video)

I've recently finished most of the circuitry on the 17-12 meter dual band SSB transceiver. I have had contacts with it on 17 meters, but until yesterday morning (March 22, 2022) I had not had any contacts on 12 meters. This morning I talked to Paul EA5JZ in Valencia, Spain. I was running the 17-12 rig barefoot at about 5 watts with the final being one RD06HHT FET. The antenna was my 75 meter doublet fed with window line -- I had to modify the tuner to get it to work on 24.9 MHz. It was very cool to have my first 12 meter contact be QRP, HB and with Spain.

There is a LOT of soul in this new rig.  Here is a partial list of contributors: 

-- Overall BITX design:   Farhan VU2ESE

-- Termination Insensitive Amplifiers (TIA):  Wes Hayward W7ZOI and Bob Kopski K3NHI.  

-- TIA boards from Todd K7TFC

-- ASK-1 Mixer from Armand WA1UQO

-- VFO design parameters from Joe Carr K4IPV (SK) 

-- VFO stability ideas from Frank Harris K0IYE and Mike Murphy WU2D. 

-- HT-37 Tuning Capacitor bought from e-bay at suggestion of Pete Juliano N6QW. 

-- Pine board base of the rig:  Frank Jones (SK) W6AJF's preferred building technique. 

-- DTC Band-Pass filter circuits from Han Summers G0UPL. 

-- Low pass filter values from G-QRP web site. 

-- Idea of using RD06HHT instead of IRF-510 in the final:  Pete Juliano

-- Heat sink from Chris KD4PBJ

-- Trifilar Toroids used in many places from Farhan VU2ESE.

Thanks to all.  73  Bill  

The Bitsy -- Homebrew Double Sideband from Scotland

 

This is such a beautiful project:  it involves DSB, homebrew, troubleshooting, George Dobbs, SSDRA, J310s, a box kite,  and ham radio nostalgia.  I was struck by how similar the Bitsy looks to some of my own DSB creations (but the Bitsy is nicer).  I'm really pleased to find a DSB project coming out of the UK -- when I was there, DSB was kind of frowned upon by spectrum preservation zealots.  I say there is plenty of room for the very few homebrew DSB rigs that will ever grace the airwaves with their presence.   Thanks John.  Have fun with all your projects.  73  Bill 

Hi Bill

In the early 80's I built and experimented with Direct Conversion Receivers and had a lot of fun with them. I came across a 40M DC cw transceiver by the late Rev. George Dobbs in a Practical Wireless magazine and decided to build it. Whether I was just lucky I'm not sure but it worked first time and I had several cw contacts with it. It was called “The PW Severn”. I then discovered DSB and looked into modifying the wee rig. I gave George a phone, no internet in those days, and explained what I was proposing to do and if there was any advice he could offer. His reply was ,  “it should work so try it and see, any problems get back to me”. It worked and I had a lot of fun with it. I used to take it portable and with a box kite to support a long wire and worked all over Europe.

It was after reading and learning about circuits and home brewing I wondered if I could design and build a DSB transceiver of my own. I had plenty of articles and most importantly a copy of Solid State Design, now well thumbed.

So the “Bitsy” was born. It is an 80M DSB transceiver. The PA produces about 2 watts. I took what I thought was the best for each module and built it using six circuit boards which I designed and etched myself. Nowadays I use the Manhattan method for one of circuits. It is much easier and quicker.

Like most home brew projects, the fun is in the building and the wee rig lived in a box for several years. Probably over 30. My doesn't time fly. I came across it again while looking through my boxes and decided to give it an airing. Expecting it to work on power up I was quite shocked when it produced nothing on both receive and transmit. After staring at it for a couple of minutes I unscrewed the lid and studied the wiring for a dry joint. Nothing so I switched on my Digital Multimeter and Oscilloscope. I soon found out that the output from the VFO was missing. The VFO uses one FET and two PNP Transistors for the buffers. The scope soon proved that the FET was faulty. I used an MPF102. These are hard to get so I replaced it with a J310. While I had the VFO out I also replaced the 9.1v zener diode, which provides a regulated voltage for the FET, with a 78L05 connecting the centre pin via a 580ohm resistor to earth. This gives me a 9.3v regulated supply for the oscillator. It is now back in full working condition.

With the Covid 19 epidemic I, like a lot of the Amateur Radio fraternity, am spending a lot of time in the shack and looking for new projects. I am buying back my old FT200 which was my first rig. An old friend and lapsed amateur has still got it and agreed to sell it back to me. It is still in a good condition for being nearly 50 years old and just needs some TLC. When it is finished it will take pride of place beside my restored Heathkit SB104A. And they say nostalgia is not what it used to be!!

John Forsyth

GM4OOU

More on GM3OXX

Sunset at Luce Bay Scotland, 3cm GM3DXJ, GM3OXX and GM8HEY dishes being set up. Photo GM8HEY (GM4JJJ). 322 km QSO to Wales. 10mW GUNNS WBFM.

Bill,

Thanks again.

I recall when George met up with the team from Wales in a car park in the Scottish highlands , they had also built 3cm gear and he found by direct comparison that their 3cm gear was more sensitive than his. He went straight home and redesigned and rebuilt his receiver. That gear then went on to break the World distance record on 3cm on a superrefraction path from Portpatrick to Cornwall with 10 mW WBFM. Smashing a record that the USA had held for 16 years from mountop to mountain top.

George was ambitious, he wanted that UK, EU and World distance record, he wanted to show the RSGB that Scottish hams could get the 3 countries and 20 counties award on 3cm. We  (G8BKE, GM3DXJ, myself and George) did it by travelling round Scotland in my Mini Clubman Estate with dishes and tripods and 3 hams packed in to one car, at the same time fitting in the EU distance record from Luce Bay in Wigtownshire to St David's Head in SW Wales at 322 km just to show them how.

No VHF Talkback, only a phone call from a telephone box earlier in the day to our Welsh counterparts to say we would be there about 6pm and to tune the 3cm band for us. Frequency uncertainty was in the 10's of MHz.  We arrived at the beach, set up 3 dishes, put on our transmitter test tones and then went back to receive, George asked us to make sure we had our test tones -off-  as his receiver was overloaded, it was the Barry Radio Guys he was hearing, they were so strong. Didn't matter where we pointed the dishes, we were in the sea level duct. Open waveguide still full quieting.

George's words audible on the remote tape recording made in Wales, " You can pack up your gear now lads, that's the European Record!"

Happy Days!

-- David GM4JJJ

GM3OXX SK

Bill,

I expect you will have heard via the grapevine, George Burt GM3OXX is silent key. Bad news travels faster than light.

I knew George GM3OXX before I was even licensed in the 70's, as I heard his broad Scottish accent on 2m AM when he was portable on a local hill and was using 2m to set up 3cm contacts with QRPp WBFM. I climbed the hill and introduced myself and he graciously answered my questions. 

George didn't drive but despite that was able to climb all of the Munros (summits over 3000 feet) in Scotland and operated on 2m from all of them. He used hitch hiking and buses or bicycle to get to foot of the mountains. 

Fast forward a few years, I had my first ticket GM8HEY...

I spent a night in my grandfather's ridge tent on top of Snaefell (the highest mountain in the Isle of Man) (GD) with George. We had planned to take my car to the island by ferry, but had not realized that the TT motorcycle races were on and the Ferry was fully booked. We had to go as foot passengers and reduce the amount of gear. George carried his tripod and dish, 3cm and 2m gear and antennas plus rations etc, I carried this huge ancient canvas tent with wooden poles and pegs. We got to a campsite and we were told it was full, when we asked where the next site was the owner asked us where our motorbikes were, we explained we had come by foot, so he let us pitch our tent after all as we weren't bikers.

George originally had planned to climb the mountain by foot, but with this huge tent even though I was fifteen years younger than George I would never have made it, so reluctantly we took the mountain railway which goes nearly to the summit of Snaefell. 

The previous night it had snowed on the mountain, fortunately it was just freezing cold and windy when we camped right on the top. We had to use rocks to try and hold the old ridge tent down, it had no built in ground sheet. George's "rations" seemed to be a bar of chocolate and some tea that he boiled on a tiny stove powered by some little pebble sized block of flammable material. I have never been so cold and hungry after a night in a sleeping bag. We idled some of the time calling stations on 

2m with George's homebrew 2m battery powered transistorised transceiver.

Next morning it was too windy to set up the dish and tripod, so we assembled it -inside- the ridge tent and successfully operated from there on 3cm WBFM across to G, GW and GM. on 10mW QRP of course.

George went on to break UK and EU distance records on 3cm before packing microwaves in and going back to QRP on HF. 

George was as fit as a mountain goat in his youth, tragically he was struck down with a terrible condition in early middle age that robbed him of his strength and ability to even walk, let alone climb mountains, but you wouldn't have known it, he never complained, just the same old George "building wee boxes" as he put it to me on one of the last times I spoke to him. 

If you visited George's shack, you wouldn't find any commercial gear at all, everything he built himself, it was so beautifully made too, I marvelled at how compact and neat it was. 

There won't  be another George Mary Three  O Ocean  X X-Ray  X X-Ray on the bands.

Thanks for all the great times George, I am sure you won't be resting, you are probably designing that next "wee box".

-- David GM4JJJ

Pilgrim's Progress: A Peregrino Rig Concealed in a Book

On the G-QRP list guys have been talking about the Peregrino.  This is a nice little homebrew rig out of Spain.  Peregrino = Pilgrim and usually refers to people who are hiking along the Trail of Santiago that runs through the North of Spain to Santiago de Compostela.

I'm normally averse to chips, but this little rig uses two very understandable NE602s and an equally understandable LM386.  It has a homebrew crystal filter.  I like it.

GM4WZG came up with a really wonderful enclosure for his rig.  This reminded me of the time I put a QRSS transmitter inside a copy of "The DaVinci Code."

The Spanish guys have a nice site that describes the rig.  Google Translate should help, but even without it you can get most of the info you need from the schematic, chart, and foto gallery.  Check it out: http://ea3ghs.qrp.cat/peregrino.html

Enhorabuena!

Some Thoughts on Noise and Receiver RF amplifiers from Scotland (and listening to sun noise on 2 meters!)

Bill,

Just listened to the latest SolderSmoke podcast where you asked why is it that an RF amplifier may be required on the higher bands but not on 40m and 80m for example.

At high frequencies the atmospheric and ionospheric noise levels are lower, so if noise figure of the receiver is reduced it will improve the signal to noise ratio you get from the receiver.  Adding gain -after- the mixer will not improve the noise figure of the receiver as it will be limited by the noise figure of the mixer. You need an RF amplifier which will itself have a lower noise figure than a mixer (certainly a passive mixer), to lower the total noise figure of the receiver to take advantage of the lower effective antenna noise temperature at higher frequencies.

This becomes very important at VHF and above, where antenna noise levels are much lower than at HF.

So, it isn't so much the overall gain of the receiver that is important with weak signal work, but the overall receiver noise figure which is determined to the largest degree by the first stage of the receiver.

There are spreadsheets available that will easily calculate the noise figure of cascaded receiver stages knowing the individual stage gains and noise figures.

One also has to be careful with the gain distribution throughout a receiver, if you have too much gain early on in an effort to improve the noise figure overall, you may overload the subsequent stages producing IMD with multiple strong signals. So there is a compromise to be met between noise figure and strong signal performance.

Going back to VHF and above if you have an antenna fed by coax with some appreciable loss then improving the receiver RF stage noise figure is not the best way to go because you are amplifying the signal after the loss the of the coax. What you need to do in those circumstances is to use a low noise masthead RF preamplifier which will give you gain and establish the noise figure of the receiver before the loss of the coax. Again there are spreadsheets to help with these calculations.

At VHF where an antenna is pointed at the horizon, the antenna sees the noise from the ground on the noise from the sky. As we elevate an antenna for EME or satellite working, then the effect of the ground noise should reduce (there will always be some due to side lobes) and then the receiver can benefit from even lower noise figure as the effective antenna noise temperature is now mostly determined by sky noise which at UHF is much lower than ground noise.

These last two days I have been able to see and hear the sun noise on my 2m receiver as the sun  set on my single 10 element yagi pointed at the horizon. Using WSJT's noise level scale I could see it  measure 12dB noise level and then once the sun set it dropped back to about 3dB noise indicated, most of that being local QRN from an antenna  sidelobe from my neighbour's house and his electronic devices which put out quite a bit of wideband noise on the band. (about 8dB above the lowest background level  I can normally detect).

To summarise, at LF where noise is high you don't gain anything by having a low noise figure receiver, and you actually lose out if you have too much gain early on as it will degrade strong signal handling.

At HF as manmade, atmospheric and galactic noise levels are lower, you can benefit from lower receiver noise figure and the way to lower your noise figure is to use lower noise amplifiers in the early stages of the receiver. Adding gain in later stages does not reduce the noise figure overall as the noise figure is largely determined by the first stage or stages.

At VHF using even lower noise figure devices in the RF stage will improve signal to noise.

Here is a practical test you can carry out. Switch between a dummy load and your antenna. If the background noise level increases when you switch to the antenna, then your receiver is sensitive enough, lower noise figure in the receiver isn't going to help.  If it doesn't increase then you have scope for improving the sensitivity of the receiver by reducing the noise figure of the receiver as you are no longer limited by antenna noise. 

Incidentally it is good to have a preamplifier that can be switched in an out of circuit so that you can reduce the noise figure when conditions allow ( low noise atmospheric noise levels for example), but switch it out if noise levels are high and signals are strong so that receiver overload and IMD don't occur. You can do something similar with an input attenuator to reduce strong signals where necessary.

I don't have a link here to the graph of manmade, atmospheric and cosmic noise levels versus frequency, but once you see one it becomes obvious why low noise figure receivers are not required at LF and MF generally.

73 from David GM4JJJ

Bill,

I found the article with graph of noise v frequency at last, in Ham Radio Magazine 1975!

A good read and as valid today as then.

http://www.r-390a.net/Receiver-Specifications-Explaned.pdf

I don't have a link here to the graph of manmade, atmospheric and cosmic noise levels versus frequency, but once you see one it becomes obvious why low noise figure receivers are not required at LF and MF generally.

73 from David GM4JJJ

Another Lightwave Communication Knack Story from the UK

Hi Bill,

I've been following your podcast since you started and enjoy every episode. I've been licensed here in Scotland since 1970 as GM8EUG.

I thought you/others might be interested in how I got into radio/electronics and how I feel I may have the 'Knack'. 

The above reference reminded me of some experiments I carried out in 1967 as a schoolboy. There were no ready sources of parts locally for me.. I lived  in a rural area so the nearest electronics parts shop was 50 miles away so it was all done by letter and mail order.

My first audio link was driven by a tube broadcast receiver with a 3 volt torch bulb connected instead of the loudspeaker. (I hadn't heard of impedance matching!)  This flickered nicely on speech/music peaks. The bulb was positioned at the focal point of a parabolic car headlamp reflector from a scrap car.  I now had a beam of light with audio on it.
Next step was the receive side...I didnt have access to a photo cell but had a Cadmium Sulphide photo resistor. Connecting a pair of low impedance headphone in series with this cell and a 1.5 volt battery gave me recognisable audio when the cell was in the beam...no amplifier needed!

Next step was greater range...this was achieved with a 6 inch shaving mirror to focus the beam onto the photo resistor. This gave me the length of the street (100 yards when it was dark outside )with the flickering beam shone out of my schoolboy bedroom window resulting in puzzled  looks from passers by.

Next problem was the frequency response.. all bass and no treble. Some research indicated that the photo resistor had a slow response so that was part of the problem but I had a hunch... How fast does a filament bulb react to audio? Biasing the bulb with a 1.5 volt cell so that it glowed  dimly with no audio improved the audio response greatly.

So what got me into radio...my father was a Chief Radio Officer in the Merchant Navy during WWII and my schoolboy bedtime reading (the only technical stuff I could find ) was his textbook ...the 1939 edition of the Admiralty Handbook of Wireless Telegraphy. Capacitors  were called condensers and they were measured in 'jars'!

That was the start of a career. I've now moved through testing international telephone exchanges, installing 2 way radio for the whole of Scotland for British Rail (paid for my hobby!) and finally 32 years in IBM writing manufacturing test software from the original IBM PC to Thinkpads.
Now retired I am active on WSPR and am writing Android apps to keep my brain in gear.

I just can't leave this stuff alone!

Hope this of interest/amusement.

73s

Neil Roberson GM8EUG

Moonbounce, Meteors and French Radar in Scotland

David GM4JJJ was the fellow who sent us the video of early Scottish moonbounce ops.  This morning he sent me a tale of woe involving some transverters and several BASTA! moments.  I will spare you all the painful details, but I really liked this paragraph about David's use of sigs from a French space surveillance radar:  

... While the transverter for 144 MHz was being tested out into my new homebuilt antenna I tried receiving the French space surveillance GRAVES RADAR on 143.050 MHz. It is easily detected here in Scotland via meteor scatter. It is also so strong that passing space hardware like the ISS reflect the RADAR and can also be detected, showing up on FFT displays with their rapid Doppler shift.  GRAVES is also easily detected by moonbounce, I could see it and hear it on my single 10 element yagi pointed at the horizon without a preamp. Even when the moon was at 15 degrees elevation here, and even higher in France the signal was strong enough to be picked up in one of the lobes of my antenna. You can actually see what the vertical pattern of the antenna looks like as the moon rises through the peaks and nulls of the antenna in conjunction with the constructive and destructive interference patterns caused by ground reflections and the direct path to the moon.

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Happy Pi Day! Scottish Moonbounce in 1965, Eddystone Dials

Somehow this seems appropriate for Pi Day (3-14).  I guess it is because the antenna is circular.
Thanks to David GM4JJJ for sending this to us.  There is no audio. Kind of fun to watch the lads struggle with the big antenna while wearing coats and ties! 
 
David writes:
 

Hi Bill,

    Just watched the video of the progressive receiver and immediately noticed the old Eddystone drive and dial. 

    My first general coverage receiver was an Eddystone 840C in about 1969 I guess, so it brought back fond memories. 

    I also had (much later) an Eddystone 770R VHF receiver, which I used to listen to transatlantic 50MHz on during the sunspot peak a couple of cycles ago now. That was before we were allowed to transmit on 6m over here. 

    Incidentally if you saw the recent film "The Imitation Game" about Alan Turing, you might have spotted the 770R in it, which was actually a mistake as the receiver was not produced until after the war. 

Now something to break your heart, and mine actually:

    This old rig which was given to me sometime in the 70's by another ham, was stored the attic of my previous house now used by my brother, and a couple of years ago I had to clear the attic of the "junk" that I had left when I moved out. I didn't have any more room to store quite a lot of things and I made the decision to take a few things that I never thought I, or anyone else, would need. They went to landfill. :-(

    As you can probably see there is an Eddystone drive and dial driving a VFO which originally had insulation material around it for thermal stability. I think it may have been mixed or multiplied up to 144MHz judging by the scale on the dial. Looking back now I should have tried to save it, but I just felt at the time it would just probably lie in my new attic until I departed and then someone else would have to throw it out.

    I don't know exactly who made it, I was given it by Andy GM3IQL(SK), but I vaguely recall him telling me that it was made by Fraser Shepherd GM3EGW(SK) who I did not know as he died tragically young, but was a brilliant constructor. It could equally possibly have been made by Jimmy Priddy GM3CIG, and I could contact him as he is still around in his 80's now. At least I had the sense to take some photos.
  Now a couple of semi related video material that I put up on YouTube.

http://youtu.be/dqTLVLmz5ro

This is a (silent 8mm) film made in the 1965s about the first moonbounce attempts from Scotland and Jimmy CIG made the film. My Elmer Harry GM3FYB(SK) is in it. 

Another one this time 1965 field day!

http://youtu.be/UjYyaS1Fkao

    Bill, I really enjoy SolderSmoke podcasts etc, I am returning to ham radio after about a decade, got the bug again....

    The KX3 is in the shack, and I have the parts here now to build a QRP WSPR beacon by Hans Summers also.

    I like QRP, having previously worked with George GM3OXX back in the 70's when we went out portable with wideband FM QRP 10GHz (3cm) gear using Gunn diode oscillators. Just a few mW and we could work several hundred miles with small 2 foot dish antennas in the right conditions over water by super refraction. The receivers were just mixers, no active RF amplifiers in those days.

I think the best I did was 322km with my 10mW from Scotland to Wales on 10GHz. A couple of decades I built up a real SSB transverter with surplus MOSFETs for 10GHz and with greater power (250mW) and SSB bandwidths I could work non line of sight paths on that band from home. 

    I also like QRO for such things as 2m EME (moonbounce) and am in the course of replacing my old 8877 W6PO design 1500W amp for 144MHz with an Italian manufactured LDMOS 1kW amp that is a fraction of the size and weight, who would have imagined a single solid state device would be able to do that at a price amateurs could afford?

   Anyway enough of my ramblings. 

   Hope you don't mind me taking up so much of your time, I will let you get back to whatever you have on your workbench!

73

David Anderson GM4JJJ

 

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

A Beautiful Workshop in Scotland

A nasty Coronal Mass Ejection hit our magnetic field at around 0600 UTC today.  The HF bands are now in poor shape.  What better time to visit a really impressive workshop in Scotland? 

Ian has an interesting site: http://www.ianjohnston.com/

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20