Category: Antennas

Sending Sounds into Space

Sending Sounds into Space

Early in 2018 the club was contacted by artist Sian Hutchings who was in her first year of a masters degree in fine arts at Northumbria University, Newcastle and she wanted some help with a project that was going to come to a head with an event at the Baltic Centre for Contemporary Art in Gateshead on the 15th March.

The club is no stranger to working with artists having previously been involved with the Waygood group and an event called Scatter in the AV08 Festival involving artist Marco Pelijhan again at the Baltic Centre for Contemporary Art in 2008.

Anyway Sian’s project centered around the ‘Voyager Golden Record’ which were two phonograph records that were included aboard both Voyager spacecraft launched in 1977. The records contain sounds and images selected to portray the diversity of life and culture on Earth, and are intended for any intelligent extraterrestrial life form, or for future humans, who may find them. The records are considered as a sort of a time capsule.

Sian wanted to update the recordings stating that she considered the recordings didn’t reflect the way we live in the 21st century and weren’t a true reflection of modern society.

Sian planned to record an updated version of the golden record and transmit the recording herself so she contacted the RSGB to find out how she could do this. Sian was informed that she would have to complete the Foundation licence course in order to do this and due to her timescale it wasn’t a feasible thing to do. The RSGB did suggest that she contact a local amateur radio club to see if they could help and gave her our contact details, in due course Sian did contact us which resulted in Glen and I going into Newcastle to have a meeting with her at her studio.

At the meeting Sian outlined her idea to update the golden record and Glen and I told her how we could help which basically meant that we would be able to transmit her recordings, also we would be able to let her see the transmission via an SDR radio receiver but this would all be dependant on whereabouts in the Baltic we would be based in relation to siting antennas. A follow up meeting at the Baltic was arranged and I took a dual band 2m/70cm antenna to show Sian what we might use as Glen thought that 70cm might be a better frequency to use as trying to find another amateur on the band was as likely as finding teeth in a hen and it therefore hopefully wouldn’t cause any disruption to what Sian wanted to do, also it is a frequency that is suited to satellite (space) communication. We also took along a couple of radios to test the suitability of the location.

We were to be sited on the first floor and there weren’t a lot of options for feeding coax to the exterior and then onto the roof to feed antennas, it was decided to set up in the outside lobby area and fire the radio signal out of the glass windows running the full height of the building. This would be an easier option as we were right in the heart of the building and all other options quite frankly would have been a nightmare to sort out. 

Having completed the recce Glen and I had a better idea of what we could offer, Sian arranged workshops to record the sounds and on the allotted day Glen and I arrived at the Baltic in the afternoon and set up our station which consisted of my 70cm yagi antenna that was mounted on a microphone stand angled at about 45 degrees to the horizon, Glen’s Yaesu FT 817nd provided the transmit option along with a laptop which used a USB drive with the recordings provided by Sian from her workshops. I took along my SDRPlay RSP1 software defined radio to receive the transmitted signal and projected it onto the large screen in the cinema for a visual effect.

Sian was given a handheld transceiver to start each transmission using with the callsign that had been applied for GB8NOE, this related to our 2008 involvement at the Baltic and there is an 8 in 2018 (very tenuous I know). The letters related to the name of the group of artists also involved with Sian called the Noematic Collective.  

Sian transmitted four three minute recordings of sounds from her workshops and the people at the event were able to move between the theatre where I was projecting the image of the received signal from my SDR receiver and the corridor area where Glen was at the transmitting end of things.  There was an additional twist a vinyl recording was made of Sian’s recordings on an original recording machine from around 1930 I believe.

The event seemed to go well and Sian was very happy with the way that things went, the people attending also enjoyed it as well.

Check out our video page to see Sian’s video of the event.

 

 

 

 

73’s Graham M0GAE

 

 

 

 

 

A Tank For An Antenna

A Tank For An Antenna

ORIGIN

At one of the meetings of the Tynemouth Amateur Radio Club in the spring of 2006 somebody brought along some a few bits and bobs to pass on if any body could make use of them and at the end of the evening there was a green rod left.

I picked it up and was examining it when one of the members told me that it was a section of a Tank Antenna and I needed 4 sections to make an antenna for use on the Amateur bands. He told me to take it and to hold onto it as I would only need three more sections to be up and running.

A short while late I received a call from the same club member to say that he had a complete Tank Antenna and if I was interested in it I could have it for a donation to club funds.

I hot footed it around to his house and made a donation in exchange for it, the Tank antenna as previously outlined consisted of four rod sections, a top, middle and two bottom sections which measured about 4.9 metres when fitted together. The sections are constructed out of sprung steel (so I’m told), given a copper coating and painted green. They have a short broad thread on them and are pushed together and given a quick twist to join together.

MOUNTING

Having bought my Tank Antenna, I now had to figure out how I was going to mount it.

Another club member had a spare mount which he gave me. This consisted of a short metal tube that the Antenna fits into, a metal collett that tightens to secure the Antenna, and all this is mounted onto an insulator which is about three quarters of an inch in diameter and a couple of inches long.

For several weeks I pondered on how I was going to mount the Antenna with or without the mount that I’d been given. While looking at mounting options in my garden one thing that really struck me was that it has a low impact visually.

I now had to decide how I was going to mount it. Looking on the internet you will see vertical antennas on the market that are mounted close to ground level so that was an option. There is a lot said about Stealth Antennas and I thought that it might be a good antenna to mount at the top of the fence and couple it to an auto ATU.

In June 2006 a couple of us from the radio club decided to go out for the day and play radio, it was planned to go to a farm that we have been lucky to gain permission to use for our various field days.

With this planned it made me work a bit quicker to sort out a way of mounting the Antenna.

Looking at the insulator there is a hole underneath and I wondered if it would sit on top of a section of fishing Pole. It would but there would be too much flex and it would probably fall to the ground. The insulator would fit inside a Swaged pole and also inside a section of fishing pole.

I had a couple of spare sections off a fishing pole that was broken as a result of my son using the pole to retrieve his Frisbee out of a tree, he took it apart and put it back together again the wrong way around and trying to sort it out damaged a few sections of the pole, so I now had two spare sections.

I decided to mount the antenna at ground level and cut one of the poles down and fitted the mount inside. I had a Ground Spike from another manufactured Portable Antenna, so I decided to use that, and the Pole fits nicely inside the tube attached to the ground spike.

The Antenna was now mounted and supported.

RADIALS

The next thing that the Antenna needed was Radials.

The Antenna is about 4.9 metres long, so you don’t have to think too hard to work out that it was around a quarter of 20 Metres. Thinking back to a talk given by the Chairman of the club at the time on ground planes and radials I remembered various points discussed and using these principles I made up 12 radials. In the talk given to the club it was mentioned that a good number of radials to use was 120. I couldn’t manage 120 so I decided on 12.

I mounted the radials on a bolt that was connected to a short earthing strap and that would then be attached to the Spike or Pole. I have a SOTA beam which comes with a length of coax with a BNC connector on one end and lengths of wire soldered to the centre core and outer braid of the coax cable with crocodile clips attached to clip onto the antenna. I had made up another similar length of coax with a PL 259 plug on the end, so I used this and connected the centre core of the coax to the metal collet on the antenna mount and the outer braid to the earthing strap which was connected to the radials.

I made the radials slightly longer than the antenna with the intention of folding them back until I got the SWR right and I would then cut them to length. I attached automotive connectors onto the radials in order to thread them onto the bolt.

      

OPERATION

On the 8th June2006 along with the other two members of the club Tony and Glen we went to the Farm to play with our Radios and Antennas.

The three of us have Yaesu FT 817’s and we were going to have a QRP day.

I took along the Antenna, my 817, an SWR meter, an ATU and a small amplifier because on my previous attempt at portable QRP operating I didn’t have any success with SSB with the antenna that I used on that day and I had people who were using higher power bleeding over the top of me (Glen).

To power this entire set up I also took along a Leisure Battery, over the top I know but I wasn’t going to take any chances and if I wasn’t successful with the QRP I was going to use the amplifier, so the extra power would be handy.

I set the Antenna up, connected it to the radio and switched on. Immediately I was receiving good clear strong signals.

I hooked up my SWR meter and checked the SWR and it appeared to be spot on, the needle only moved a fraction on the meter.

I called Tony and Glen over and checked the SWR again to show them how good it was (I expected to be fiddling on with the radials for some time to get the SWR right).

When the needle hardly moved Glen said,

It’s broken”.

I kept the SWR meter connected to the radio, but I could have actually removed it.

I made only made 12 contacts but at a fairly leisurely pace, it was also a social event with plenty of chat.

My first contact came after a couple of CQ calls and was with Ian G3PHD in Tilbury, Essex who gave me a 5 & 7. I had one 59 report, a couple of 57 and a lot of 55 reports which when you actually take time to understand the RST system of reporting 5 by 5 reports are perfectly satisfactory. On this first outing I contacted a German station DQ2006S who gave me a 55 report and he obviously found it hard to believe I was running only 5 watts, he kept asking me to confirm I was QRP I confirmed it and he came back to tell me that he was running 500 watts.

As a fun club event on the 15th of July that year a few of us organised a QRP Barbecue come QRP competition. The basic idea was that we would have a day out at the farm, do some operating and have a barbecue. The competition side of events was that Glen erected a wire dipole for 40 metres and I took along the Tank antenna for 20 metres and we both took our 817’s. Competitors would have a 15-minute slot on each antenna and the person with the most contacts was the winner. There was an adjudicator sitting with each competitor to verify the number of contacts.

It was a great day out with fantastic weather, good food (if I do say so myself), good company and overall it was good fun.

DEVELOPMENT

Since that first outing and success with my antenna I have made another coax lead with automotive connectors on to tidy up the connection between the coax and the antenna, I have also tidied up the connection with the radials. I have also shortened the section of fishing pole which sits inside the ground spike, it was initially too long and one windy day with it moving about it split the fibreglass tube and fell over. Lowering it takes away that strain on the tubing.

During another day out on the farm in mid-February 2007, my first contact of the day was with PT7CB in Brazil! Wow I was over the moon; this was using the internal batteries on the 817. I also had a contact with CN8PA in Casablanca which was a first for me, so I was also very pleased with that.

Initially the Antenna was not intended to be used solely for QRP and it could certainly be used with more power or as a home base antenna, but I get such a buzz from making a contact using it on QRP that I am now totally hooked, and I would always keep sure that I have a Tank antenna for portable work.

Coming up to date in August 2018 twelve years on from when I first used the antenna.

I still have the antenna; the connections and radials are still working perfectly, and it has been used on many occasions at various power levels. The only further development that I have made with it is a tripod mount for use when I’m on a hard surface and cannot hammer the ground spike into the ground. It is a camera tripod that I was given with the tilt/mounting head on a central pillar that can be raised or lowered in the tripod. I simply took the tilt head off and the section of fishing pole with the antenna mount attached slides over the top of the pillar.

If you have a moment come and ask me about my Tank antenna, I’ll be only too pleased to tell you about it.

Enjoy your radio… 

 

 

 

 

 

 

Graham M0GAE

 

 

M6OZA on ADSB Flight Tracking

M6OZA on ADSB Flight Tracking

So if you’re like me, a bit of a geek or maybe handy with technology, you’ve probably got drawers and shelves at home full of bits and bobs that “may come in useful one day”. This article is about how I made some of my “bits and bobs” into something quite useful…

I’ve always had an interest in radio, technology, and programming so when I was given a Raspberry Pi and a RTLSDR dongle for Christmas a few years ago I wanted to combine them into a radio project.

Up to this point the Raspberry Pi had spent a few short weeks being a Kodi box, and then a WiFi repeater, before being destined to the bottom drawer. My first experience of Software Defined Radio (SDR) was with the RTLSDR dongle, an entry level model, but it had done the trick of luring me back into radio monitoring and listening to shortwave. After a while I upgraded to a better model but having explorered everything I thought I could, it also ended up in the bottom drawer.

I’d started to acquire a small collection of old 1980’s – 1990’s Realistic scanners, these analogue scanners had served me well. Military air scanning had become “my thing” and I found myself scanning the frequencies after work listening to transmissions from practice flights off the North East coast. These flights were mainly controlled out of RAF Boulmer, not far from my location at the time. However, after a while I guess listening wasn’t enough and I was on the hunt to improve my setup when I came cross ADSB and MLAT aircraft tracking. I read up on the subject and eventually found an article that described how it was possible to use a Rasberry Pi and a RTLSDR dongle to make a suitable receiving station. I’ve included a link to the original article here.

I suggest you simply follow the instructions on the website to upload the software onto an sdcard and install it in your Rasberry Pi. All you then need to do is plug in your usb RTLSDR dongle and you’re ready to go.

So what type of antenna do I use, as the ADSB aircraft signals are on 1090MHz? As with a lot of things today the antenna can be purchased online, but why not make your own. You’ll need an empty beer can, if you don’t like beer a lager one will work just as well 🙂

The picture below is one I made. The beer can acts as a ground plane and the short vertical wire (1/4 wavelength long on 1090MHz) is connected to a sma connector.

The paint was just for practical reasons, to stop rain water shorting out the antenna to the can (groundplane). I happened to have Citroen saxo blue in the cupboard, but any colour will do. A blob of silicone around the connector would serve just as well. The measurements should you require them are: Antenna length 69mm, Can length 69mm.

For maximum receive range mount the antenna on a non-conductive mast, mine is on the chimney stack as a temporary measure. At this height I’m seeing a range of 100-150 miles from 200-350 tracked flights a day. It will work at ground level but range will be much shorter and the number of heard aircraft will be less.

Now I don’t only hear them I can see them as well…brilliant !

A year or  so down the line, I have now upgraded my system to include a flight-aware dongle to replace the RTLSDR, a 1090mhz pre amplifier, and I have upgraded the antenna to a high gain 8 section co-linear. Although not needed to get started, these upgrades have improved my receive capability significantly.

 

So don’t throw away your “bits and bobs” as they may come in useful one day. Have fun building your own ADSB receiver. If you liked this article please give it a thumbs up.

73 Ray M6OZA