Stacked array for 70cms

You might have noticed in the last picture in the blog, not only was there an MA5B on the mast, but I also have a quad 70cm omni array.

 This is the Jaybeam quad array just after being purchased at Dunstable Downs

The aerial was spotted in the back of a pickup truck with a whole load of ex-PMR stuff, and was purchased at the princely sum of £35. Bargain!

This was part of the plan to develop the 70cm side of transmission for GB2RS, the news broadcasting service of the RSGB, which i read for most Sundays. I have been using a duplexer to simulcast from two transceivers on my colinear, but the opportunity for a catastrophic failure was huge, with a fault developing on the duplexer possibly dooming either of the transceivers to meltdown! It would also allow me an opportunity to run maximum UK power on the array, which could handle it easily without melting! This is something the colinear could just NOT do.

I am now looking for a serious UHF linear, which is not going to bankrupt me. If you hear of anyone that has one for sale, please let me know.

 

Aerial rethink Part 2. Cushcraft MA5B

After using the radiator of the Jaybeam as a dipole for a while, I was really missing the Cobweb, as it provided more wavebands than the Jaybeams 20m, 15m, and 10m. I was also considering just keeping the cobweb as a backup and getting a mini beam with some gain.

It would have three advantages. Multiple bands, Gain and a reasonable front to back ratio. Ever since I have got my licence, I knew that I fancied a Cushcraft MA5B. This is a three element trapped beam with capacity hats. Whilst not offering the same performance on all bands, it is probably the biggest all around beam I can get away with at my QTH, but try as I might, I could never find one at a price that I could afford.

Well in July 2017, that all changed, when I heard that Roger Mansell Williams, M0RMW was selling his bungalow and downsizing his setup in a move to Selsey Bill! He was offering his MA5B for just £50, which is a considerable saving over a new one, which cost upwards of £530! All I have to do was to go down to Farnham in Hampshire to take it down.

It came down really easily, it had been well looked after and was in really good condition. It fit OK into the jag with the back seats folded down. Roger was a gent and provided a manual for me to piece my new jigsaw puzzle back together again. It was not too difficult as I put insulating taped codes on the elements as it took it apart to aid with reconstruction!

Waiting for a couple of days for a lull in the thunderstorms, I managed to whack up the beam in a few hours, consigning the Jaybeam radiator elements back to the pile of aluminium down the side of the house, which is the Tribander. Initially the I used the mini beam using the internal matcher in the Icom and it worked will out performing the wire antenna by at least 3S units and being far less susceptible  to noise. In increase of the signal to noise ratio meant I could hear station I just could not hear before. In order to increase efficiency, I will go through a tuning session with the antenna analyser. This will increase transmit efficiency and reduce losses to make this acquisition a real bargain and my find of the year.

Broken Cobweb causes a rethink

A few weeks back the XYL was complaining that that my tower, which is attached to the side of the house, was making a god awful racket when the wind got up. I ended up getting out of bed in the middle of the night to lower the mast and luff it over in order to stop the rattling which was being transmitted through the walls! The only problem was, it was dark and I did not see the spreaders bow as they hit the ground due to me luffing the tower over too much. I now have a cobweb with two broken spreaders and the support for the balun box also snapped.

Previous aerial setup before the damage!

Previous aerial setup before the damage!

Following the the damage, I decided to push a bit of kit into action that I have had down the side of the house for some time. I actually have a three element Tri-Band Yagi, which is too big to put up in it’s entirety, so I decided to mount the radiating element only in the form of a tri-band dipole.

The new HF setup!

The new HF setup!

After putting up the dipole, it was checked with an analyser and it all checked out great with little adjustment required. It was a little more noisy than the cobwebb, which is well known for its very flat signal pattern. It was giving me 2-3 S units over the wire antenna which was weird as I was not expecting such a big difference. It has given me a good reason to bring the wire antenna down and give it a good checking over, but that as they say is another day! I have had contacts into Russia, Saudi Arabia and even Iraq in it, so it must be working OK!

In the meantime the tower was put back up with a bicycle inner tube glued around the part that slots into the bracket on the wall. This has killed the rattling and hopefully I will not have to get up in the middle of the night again!

1st event of the years at the Royal Gunpowder Mills

My local radio club LEFARS (Loughton & Epping Forrest Radio Society) enjoys a great relationship with the Royal Gunpowder Mills at Bishops Waltham in Essex.

Formerly a factory for Gunpowder, established in 1850’s the site went on to manufacture nitro-based explosives and further more to become the Propellants, Explosives and Rocket Motor Establishment until 1991 when it closed ending 300 years of explosives production and research.

LEFARS has a permanent NOV to operate GB2RGM from the site and has a dedicated radio shack and aerial installation which is used during activations, which take place throughout the year.

Activations tend to be timed to occur during special events either on the RGM calendar or in the ‘radio calendar’. The site having both waterwheels and gunpowder mills, and a light railway,  GB2RGM is fired up as part of Mills on the Air and also Railways on the Air and sometime Museums on the Air.

This year the first chance to activate the callsign was for the VE day celebrations over the Mayday Bank Holiday weekend. This event did not take place last year due to uncertainty over the future of the RGM, but this year, the venue enjoying a reprieve and hosted the event once again.

LEFARS exhibition Marquee

LEFARS exhibition Marquee

Lefars were invited to set up a display again and put together a collection of classic radios in keeping with the events Military and WW2 theme. Both sections of the LEFARS marquee were set up and a selection of Vintage military and domestic radio equipment was set up on display. Many of the exhibits actually work, and some were used to demonstrate that the technology of the time still works well today.

Information about current day Amateur Radio, including some history

Information about current day Amateur Radio, including some history & notable QSL cards 

A mixture of military and domestic radios.

A mixture of military and domestic radios.

Morse keys and eare SOE radios.

Morse keys and rare SOE radios.

A Valve collection, or 'Bulbs' as someone called them!

A Valve collection, or ‘Bulbs’ as someone called them!

More Vintage military Radios

More Vintage military Radios

More radios for spies!

More radios for spies!

M0VID's WW2 Canadian built radio gear.

M0IDF’s WW2 Canadian built radio gear.

There were many re-enactors on site, many of whom had a selection of non-working radio sets. Many of us tried to convince them it would be a great idea to at least get their M6 licence and use the things, but hey, we tried!

M0VID is not the only chap with a Jeep and a Radio

M0IDF is not the only chap with a Jeep and a Radio

M0IDF went walkabout with his 38 set which was only putting out 200mw and was designed for fairly local communication. GB2RGM worked him all around the site with fine audio, we were well impressed with the performance of this little radio on what is a really inefficient aerial!

M0IDF with his 38 set get in the swing of things in uniform!

M0IDF with his 38 set get in the swing of things in uniform!

For those people looking to get into the vintage military scene, there were even a few radios up for sale from some of the re-enactors.. check out the final pic..

For sale!

BC221 & 342 For sale!

I will be back at the RGM this weekend for Mills on the Air.

Active Summer 2016

Summer 2016 was an active time of year when I managed to get out and about to some great activations.. from Lighthouses on the air when LEFARS activated a light house and lightship at Trinity Buoy Wharf on the 20th August:bow-creek-lighthouse-aerials

 

 

 

 

 

lv95-long-shot

Helping LEFAR activate GB2ECS (The final Essex Country Show)

ecs-at-sunset

 

To me helping at Jota @ Gilwell Park

gilwell-current-antenna-farm

 

I am just amazed at how much you can do in this hobby. Sadly it has resulted in me ignoring my home station, so to make up for it, the next post will be all about that.

LEFARS Field Day approaches

It’s one of the times of year I always look forward to. It is when the club members pack all the gear into the cars and descend on a little pub called the Rainbow & Dove at Hastingwood, just off the M11 junction for Harlow.

The Rainbow & Dove. The location of good food and beer! and a big field for playing radios.

The Rainbow & Dove. The location of good food and beer! and a big field for playing radios.

What with the increase in electronic noise and interference (QRM), decamping to the countryside and setting up portable stations is sometimes the only way radio amateurs can work some of the more elusive distant stations around the world (DX). It also gives club members the opportunity to try out new antennas or equipment they might not be able to use at home do to having a diddy garden or being unable to run power without causing interference.

Me I have a neighbor with an extremely noisy plasma TV, who refuses to even allow me to get him a new LCD TV for FREE to replace it! So it is off to the field for me this weekend.

Field Day @ Rainbow & Dove 2015. (My Tri-bander was behind the camera)

Field Day @ Rainbow & Dove 2015. (My Tri-bander was behind the camera)

This week will be unlike others, as the battle wagon is currently off the road awaiting an MOT, so I will be turning up in the Jag, with a lightweight setup this year. I will be trying out my lightweight fiberglass military mast with an inverted V for 20 meters and running data (PSK 31, RTTY and anything else I can try). I might actually try the radiator of my 3 element beam on its own as a tri-band dipole & see how that works.

Tactical antenna mast ready for the weekend

Tactical antenna mast ready for the weekend

Whatever I get up to it will also include the club dinner on the Saturday evening, which usually sees about 18 of us crowd around a table for some fine food & beer. Some of the members will stay overnight and mind the fort, whilst I will have to go back home for the GB2RS news broadcast that I make at 09:30 every Sunday morning!

LEFARS will start to set up for the weekend starting Friday afternoon 26th and ending on afternoon of the 30th May 2016. Visitors are always welcome, although if you would like to join us for dinner on Saturday, you will have to book with Club secretary Marc Litchman.

GB2RGM activations this year.

With the Royal Gunpowder Mills under the threat of closure, due to the planned takeover of a leisure group and their plans to turn it into a youth activities camp, LEFARS has been quite keen to make use of the permanent NOV GB2RGM while we can. As a consequence I have been down to lend some support while I can.

Me operating ably assisted by John Glover M0JGR (Photo John Ray G8DZH)

Me operating assisted by John Glover M0JGR (Photo John Ray G8DZH)

The first weekends operations (Mills on the Air) were pretty quiet as band conditions were pretty woeful, but the second weekend on the 14th & 15th we activated the site, coincided with the RGM’s Steam weekend, which saw a number of miniature and indeed the odd full-sizes steam engines turn up for a Steam Rally.

Lady of the Lake miniature showman's tractor. Show winner. (Pic Brian Porter 2E0FHU)

Lady of the Lake miniature showman’s tractor. Show winner. (Pic Brian Porter 2E0FHU)

We plan on running the station later in the year as well, especially for the Railways on the Air special event, as The gunpowder mills has a narrow gauge railway. So I am looking forward to getting back down there on the weekend of the 24th and 25th September.

The 'Hot Seat' at GB2RGM. showing the Yaesu FT1000 MP MK5 Field Radio that is in use with a doublet. (Photo by Marc Litchman G0TOC)

The ‘Hot Seat’ at GB2RGM. showing the Yaesu FT1000 MP MK5 Field Radio that is in use with a doublet. (Photo by Marc Litchman G0TOC)

Hopefully we will see the return of the remote ATU which inexplicably stopped working on the last day of operation, sending the SWR rocketing and requiring the internal ATU on the radio to be re-activated.

Visitors are always welcome. The shack is located next to the building that hosts the small arms museum, but it is always worth checking that the club is operating the station before visiting!

Shack re-organised for Christmas

Most people are spending time getting ready for friends and family descending on their house for the Christmas festivities, but yours truly, under orders from the station manager has been busy trying to sort out the home office, which doubles as the Shack / Workshop / Broadcast Studio.

The main issue was that I had a mammoth sized broadcast mixer taking up a huge amount of space and all the Radio gear was piled high on my work desk, which was not conducive to the day job. I therefore took the plunge to sell the broadcast desk (I have another in garage if I ever need to do some broadcast work anyway) and utilise the space more wisely and this is what I have come up with:

Shack

It certainly has cleared up a huge amount of space on the desk & I can now get to work sorting the rest of the office! The big pipe snaking up to the window is the Air Con which is essential during the summer when all the gear plus no less than 5 computers can be on at the same time.

Still to add, the clutch of handies and

Table Top sale at LEFARS: Friday 6th Nov 2015

lefars_yellow_&_green_logo no backgroundLefars (Loughton and Epping Forest Amateur Radio Society) are holding a table top sale this Friday, where members are invited to come and sell those things they just don’t need any more. You know what they say, “One man’s trash is someone else’s treasure”.

The club meets at All Saints House, Romford Road, Chigwell Row, Essex IG7 4QD starting at about 7pm.

So if you have  some surplus gear you want to convert into pennies and are not taking it to the Kempton Rally this weekend, when why not sell it to a local club member?

DMR, the voyage begins

OK, last week I took delivery of a TYT MD380. It is pretty much the same radio as the TYTTytera / Retevis, but with just a different badge. Apparently this is one of the last batches of TYT’s available from the supplier in Germany, and the next batch of radios he is getting will be Retevis. He said that the firmware is basically the same to, but might just be a newer revision.

I plugged mine in, downloaded the latest codeplug from LEFARS and updated it with my ID and copied into the radio. I switched it on expecting a rush of DMR traffic, but was disappointed not even being able to open the Barking repeater. A bit of home-brewing and I knocked up an SMA to PL259 connector, plugged in, connected to my collinear and it all burst into life. I was amazed at how easy I could get into NS (North Surrey) in Caterham, and of course Barking was now available and even better, the biggest surprise was Rochester (IK) which was giving me the highest signal levels in the area, even more than Thurrock (SE) and even though the coverage map does not even feature anywhere near my QTH in Hainault .

A weekend away for my daughters wedding in Devizes saw me test out the radio in the van, hitched up to an SG7900 antenna on the van, I easily got into Bristol (BS) while the Reading repeater remained elusive! In fact I managed to get into BS all the way out near Upavon, which was some feat!

It just goes to show that the coverage maps are a nice guide, but no-where near accurate! From the van I managed to have decent copies with someone in Ashford whilst near Heathrow, which I would never have been able to work simplex on 2m. So for communications on the move, it is undoubtedly a great mode if you want to talk to someone and not have the same challenges of working analogue modes. I will always keep the VHF / UHF and HF gear in the van though as that is my primary interest, but for a decent quality chat on the move, then DMR really does have its place.

I am also going to purchasing a dedicated antenna for 70cm now as well! Stacked dipoles so I can use it with a linear for GB2RS?