Amateur Radio

After some 60 years of just listening into the HAMs I finally bothered to pass just the first stage ( Foundation ) of the UK Amateur Radio Transmitting licence. I only want to chat to local HAMs on VHF or abroad using this PC on repeaters ( like mobile phones ) to avoid the massive interference on the Short wave bands. My VHF antenna does not look too ugly does it?, But I was advised to check the neighbours do not object.

 

Anything once wet might affect the tuning of the Antenna governed by its length as the 3 radials. Even being to close to a tall hedge can affect reception. Check out my site about Amateur Radio and recordings of abroad using Echolink.

 

If any are curious what HAMs talk about, you can listen into several UK Repeaters in the SE while using your PC anytime if you visit http://rilges.org.uk/liveaudio.asp Note by clicking on the bottom option you can listen in on ALL seven at once. In the unlikely event of more than one becoming active at the same time, just change to one only of course. I must point out GB3HE which was recently reactivated, even though limited at present to only 10 W, provides the widest coverage, being located at the highest point on the Ridge. This is a long strip of high ground to the North of Hastings, and is otherwise a curse to North as South communications. My call sign if you hear me is M3YXH

 

Congratulations on passing the foundation test Sigurd. Looking at the height of your antenna I'd guess that you could get a multi-band HF vertical into that space and if you can get onto the HF bands a whole new world will open up.
I've had loads of fun this evening working into Japan on 17 metres CW using just 5 Watts. Last week I was operating from our motor home on Skye using a fishing pole to hold up a 17m band GP antenna and worked into California and also had a contact with a pal (VP8CMH/MM) who was in antarctic waters south of the Falklands and I was just running flea power of 10 Watts.

73, Dave - GM0LVI

 

Thanks. Actually though I have listening in on the HAM bands for some 60 years, from the days I first built a 3 valve RX and now use a FRG7, I have never been very keen to transmit on HF, especially as most such QSOs only last a few seconds, such as contests due to massive QRM. I did try once to pass the old RAE, but failed probably because I could not recite the conditions in those days ‘ parrot fashion’ as seemed necessary. Today we only have to tick boxes of course.

Now at the age of 80 I am not in a fit condition to maintain the massive antennas really needed for SW such as in Hastings gales. But I get a lot of pleasure using VHF or Echolink with this PC, as you can see from the page on my site that includes some Echolink recordings, and PC links to local repeaters. But there is a possibility Ofcom might be putting pressure on those like me content to remain at the Foundation level, to ‘ progress ‘ and train for the full licence, something I neither need nor probably am capable of remembering all the info needed at my age.

 

@Sigord

Well done on passing the exam.
I never bothered as had a mate living only a few miles down the road that was an active HAM and would often go there to experiment with all sorts of antennae and other bits and bobs.

One antenna we did experiment with and had pretty good success with, is a sort of hybrid of the rhombic and folded dipole, sometimes also referred to as the full-wave antenna.
It's slightly directional and narrow band but the big advantage is that you can trade height for horizontal space, especially nice if one has a medium to large garden.

Basically what we did was put up some gum poles in a square around the perimeter of his garden and strung some 1.5mm diameter insulated wire between the poles.
The size of the square and hence the length of the antenna will determine your lowest operating frequency.
If you want to work the 160m band then you will need a large square but if you mainly stick to the higher bands you can safely reduce the dimensions.
The diagrams below give more detail.
The nice thing about this antenna, is that one only needs a small ladder and it lends itself to loads of experimentation and any "imperfections" can be matched out with an antenna tuner.

The other nice thing about this antenna is that it does not have to be too high thus you keep peace with the neighbours and it exhibits low wind resistance.
If you use wire with black insulation, the neighbours will probably mistake it for telephone cables and just ignore it.

The maximum power handling will depend on factors such as wire gauge, rating of the antenna tuner and so on.
We kept our experiments to low power (probably around 10w max) which makes it more fun to try and get those distant QSO's with as little power as possible, of course M.U.F. and other tropo conditions permitting.


When it came to the higher HF bands such as 10Meters (28MHz) we even tried crazy things like resonating metal sliding door frames, balustrades and so on.
You will be surprised at what can be used as an antenna.
Don't be scared to experiment, just keep your power low and watch the SWR.

 

Dave I am the Club Secretary and Editor for http://www.radioclubs.net/herc/ could you please email me direct at [email protected] I am wondering if you would allow me to use your note on the antenna in our club News Letter?

 

Hi @Sigord

You are very welcome to use my previous post (text and drawings) in your publication.
I will email you shortly.

If you are looking for articles/projects to publish, I also built several active loop antennae which you may be interested in.
By active I mean that a FET is used to bring the high impedance of the resonant loop down to a low impedance (for the RX) so as not to swamp the tuned circuit and maintain a high Q and thus very narrow band which together with the directional properties of the loop, act to eliminate a lot of QRM and QRN.

Note that the circuit does not have gain, it actually has several dB's of loss which in practice is not a problem due to the relatively high field strengths commonly found on many of the HF HAM bands.

Below is a circuit diagram and construction details of the units I built years ago.
Please do double check them as I'm going by memory alone.
These units were very effective on the tropical bands allowing the reception of wanted stations when nearby interference would have made it virtually impossible to receive them without the filtering and directional properties of these loops.

The number of turns will depend on the frequency range required and if I remember correctly, the square wooden "loop" had all four sides in the region of 400mm in length and I used 4 or 5 turns of insulated wire.
The number of turns and resulting inductance (to resonate with the variable capacitor) can be worked out by applying the usual formulas commonly found on the internet and many HAM books.

The variable capacitors I used where good quality air spaced 12 - 365pF units.
These days they are pretty hard to find but every now again they do pop up at HAM flea markets.
Old defunct radios are also a good source for variable capacitors.






The variable capacitor, circuit and battery can be housed in a small enclosure if required.

 

Thanks very much Dave. Looking forward to your email. Send as many of your articles as you like anytime. Let us all know your Call sign. I am sure you would also like it shown a the foot of your articles. I will show you the latest club NL with one from the old HAM who writes a lot of our articles such Antennas, and on his vast collection of old QSL cards is G3BDQ and now 91

 

I used to be interested in amateur radio when I was a teenager. I even studied electronics at college, with a focus on radio. I bought myself a CB setup, which was about all the radio kit I could afford at the time (cost me a tenner for the rig and power pack, second hand, and another tenner for an antenna).

Unfortunately I lived about 10 miles from most of my mates, and there was a massive great hill and some steel works between me and them, which made it virtually impossible for me to communicate with them on the CB. This was especially frustrating because I actually fell in love with a girl having first spoken to her as a stranger on air, using my mate's setup just 3 miles from where she lived. We even met several times and became 'an item' for a while. Trouble was, when I was at home, we were out range from each other but more annoyingly, my mate who's rig I'd used when I first got speaking to her, was in range, and desperate. Still, all part of life's rich tapestry.

Not to worry though, being interested in the technology, and having some talent for it, I turned our loft into a probably illegal antenna array, and built an RF pre-amp and 27MHz narrow band filter. I even studied the topography of the land between me and all my mates, and this girl, and learned that if I made my antenna unidirectional, and pointed it a certain way, I could pick up reflected signals rather than trying in vain to go right through the big hill and the steel works. It was alas only a partial success. My efforts meant I could here my mates, and this girl, but they couldn't here me. Still, never mind.

I was also interested in HAM radio, but couldn't afford the kit or the license, so I never pursued that. There were two tricks that I read of that I was especially interested in though, if only for its technical ingenuity. 'Moon bounce', where you get a signal to other parts of the world by bouncing it off the moon, thus avoiding having thousands of miles of solid ground impeding your signal, and a phenomenon where RF signals at a certain frequency interact with chemicals in the atmosphere to become plasma, and plasma being somewhere between matter and energy, can actually bend under the influence of the earth's magnetic field as well as weather conditions, again giving a massive range (I think this happens with long wave but its more than 20 years since I studied this so my memory is very vague).

So, what happened about the girl I met and fell in love with some might be wondering. Well, my desperate mate who was in range of her, took advantage of this and carefully engineered a story that I'd fallen for her best mate, who incidentally I didn't even fancy, and that I was a compulsive liar and womaniser. Playing to her insecurities, he filled her head with doubts about my integrity and intentions. It didn't help that she saw me with my sister (who she didn't know was my sister) one day when I was on my way to meet her. I didn't realise there was a problem at that time, and being a woman, she wouldn't tell me until much later, in the heat of an argument, why should gone cold on me. By then the damage was done, and it was all over. Still, my mate's plan didn't quite work, as he didn't win her either.

So what of my conniving mate? Well obviously when it came to light what he done, we had a massive fallout. There might have even been a light exchange of blows (poor lad), but we all calmed down, and realised that what's meant to be is meant to be, and we're still mates now, even though I didn't let him meet the girl that is now my wife for at least a year at first.

 

As I posted though I have been listening in on ALL bands both HAM, CB, and BC for over 60 years I only bothered to get just the Foundation license a few years after I became a widower, and rather housebound for someone to talk to locally on VHF. However I must point out once you get even only the Foundation license it entitles you to use Echolink by just emailing them a copy of your licence.

Though you can access Echolink from some local repeaters using a handheld transceiver, it is much simpler by just clicking on any repeater of HAM such as those showing at this moment below. The fact that you are limited to 10 W transmitting power with the Foundation license is irrelevant by using a PC, as you do not need a Transceiver or any antenna, and we seldom talk about equipment either over the air. Ask me if you need help with the simple training, and visit the RSGB site for details.

 

@clueless1

If you want to get started, then the simplest and cheapest way is to start listening to HAM VHF and UHF frequencies.
The reasons are that antennas at these frequencies are small and you can get scanner type radios which are available from ebay (plus others) and from HAM flea markets at good prices and these will cover the VHF (2m band) and UHF (70cm band).

As far as antennas go, you can re-use TV antennas.
In the old days, the UK used parts of the VHF and also UHF bands for TV services and for receiving only, these antennas still have adequate gain on the HAM bands but are directional.
If you can find an old VHF TV antenna in good condition (and price) then it can be connected to the scanner for the reception of the 2m band.
(Just make sure that the VHF antenna is for BAND III and not BAND I).

UHF TV antennas (especially the grid type) will work for the UHF HAM band but as I previously mentioned, these antennas are directional.
Note that UHF is still used in the UK for TV services so these antennas should be easy and cheap to obtain.

Alternatively, for frequencies above 300 Mhz or so, you can make your own omni-directional antenna very easily and cheaply which exhibits about a 10% bandwidth.
You can still use the antenna (with suitably dimensioned radials/elements) below 300MHz, but the dimensions get a bit big for the brazing rods to be self supporting so you will need to use bigger diameter radials/elements and also "beef" up the connection to the center pin of the BNC.

All though the antenna shown in the diagram below has no gain, they work very well and are easy to build from all sorts of materials.

To work out the radial/element lengths, see the formula below the diagram.

To connect any of the antennas to the receiver, don't use RG58 cable as it has far too much loss at VHF and UHF frequencies.
Rather use a satellite rated RG6 coax cable.
Although RG6 is rated at 75 ohms (instead of the standard 50 ohm), for receive only it makes little or no appreciable difference and the result is actually far superior to using RG58 cable.

RG6 cable is used for domestic satellite installations and the price per meter is very low.

 

Thanks Dave. I expect it could be used instead of the little ‘Rubber Duck’ antenna on my little VHF Handheld that cost a lot less than many Smart phones ---- and I can use it for hours without paying a penny !!