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ANTENNAS ( AERIALS ) 1 THE ANTENNAS AT MØMTJ Before having to dismantle my shack and antennas to to a house move, I used five main types of antennas - this has now changed somewhat, see further down page: 1/ A trapped Inverted L for 80m and 40m fed by RG213 coaxial cable to the LDG Z-11 Pro antenna matching unit in the shack. This can be used on all bands from 80 through to 10 metres. The support post is installed at the bottom of the garden with the end of the antenna wire being supported by Dacron rope that is attached to a pulley on a pole at the apex of the roof. more 2/ A trapped dipole for 20m and 10m. This is fed by 75 ohm twin feeder to a 1:1 balun then on to the AMU via RG213 coaxial cable. It was initially installed horizontally, but more latterly installed with one leg supported vertically on a 7 metre fibreglass 'Sota' pole with the other leg supported horizontally about 2 metres above the ground. A rather unorthodox arrangement for a balanced dipole, but it seemed to work ok, it looked much neater than a horizontally slung dipole and also offered a more omnidirectional radiation pattern. more 4/ A compact Inverted L for the 160 metre band - Top Band - shortened with a loading coil. more 5/ As N9TAX Dual Band Slim Jim (J-Pole) antenna for 2m and 70cms. This is fixed near the top of a 10m telescopic fibreglass fishing pole that I push up whenever it is required. more 2011 : Current Set Up - As At December 2011: 1/ A trapped Inverted L for 80m and 40m fed by RG213 coaxial cable to the LDG Z-11 Pro antenna matching unit in the shack. This can be used on all bands from 80 through to 10 metres. The support post is installed at the bottom of the garden with the end of the antenna wire being supported by Dacron rope that is attached to a pulley on a pole at the apex of the roof. Top Band added with the addition of a switchable base loading coil. more 2/ Dual Band Fan Dipole, made from thick loudspeaker wire, mounted in the loft space for 10 meters an 6 metres. 3/ G Whip End Fed Zepps (EFZ's) for either 20m, 15m or 17m or; 4/ UnTenna style antenna for 20 through 10m using high efficiency G Whip 9:1 UnUn 5/ Watson W-50 vertical dual band colinear antenna for 2 metres and 70cm mounted on a lightweight aluminium push-up relescopic mast to a height of approximately 7 metres a.g.l. 6/ A DK7ZB design dual band yagi antenna, with 5 elements for 2 metres and 8 elements for 70cms, mounted horizontally for SSB. A lightweight antenna rotator is employed and uses the same push-up telescopic mast that the W-50 is mounted on. Hight above ground level is again around 7 metres. 7/ N9TAX Dual Band Slim Jim (J-Pole) antenna mounted in the loft as a back-up antenna. Inverted L Antenna for 80m and 40m (and some other HF Bands from 80m to 10m)  The basic layout of the Inverted L Antenna (Practical Wireless) The first antenna that I installed was for
HF. I decided on an Inverted
L that incorporates a 7MHz trap so that it can be used on both 7MHz (40
metres) and 3.5 MHz (80 metres).
The design of this Inverted L is well known and a good design has been published previously in Practical Wireless by Len Paget GM0ONX. It is based on one half of the famous W3DZZ trapped dipole antenna. It can be made entirely from scratch as a DIY project, or the 7MHz trap could be purchased commercially as a ready made item, or whole antenna can bought as a complete kit from Tony Nailer, G4CFY, at Spectrum Communications. I opted to buy the 7MHz trap from Spectrum Communications, as I already had most of the other materials required - rope, egg insulator, plastic box, and some good aerial wire. The Spectrum Communications trap is solid and well made and 'potted' to protect against the elements. This antenna is tuned for 40 metres and 80 metres, but the VSWR is acceptable on several other bands being in the region of 2:1 to 5:1. The designer anticipated that this antenna would be usable on five of the H.F. bands. I have found that with the use of the Antenna Tuning Unit it can be used on all of the H.F. bands. However the polar radiation pattern may very well be less predictable on bands other than the intended 40 and 80 metres, and it may well be less effective than might be desirable - but it does work! The antenna is in the back garden, while the shack (radio room) is in a bedroom at the front of the house. It is fed by a 30 metre length of RG213 coaxial cable (it is not possible to use twin feeder for this type of antenna as the Inverted L is an UN-Balanced aerial, whereas Twin Feeder is BALANCED). With this length of cable I estimate the loss in the feeder alone to be about 1dB at 7MHz. The feed point of the aerial is located at the base of a 16 foot high wooden pole near the bottom of the garden. The horizontal top wire returns to a fibreglass pole installed at the apex of the roof.  Photograph
showing
the wooden support post and termination point of the Inverted L antenna
The post is coloured green with green fence treatment to mast it somewhat. I have also placed it near the bush to provide further camouflage.  The low loss RG213 coaxial cable runs from the shack at the front of the house up into the loft and exits into the back garden down the rear wall, through some garden hose to offer some protection along the flower bed to the bottom of the garden where it is connected to the base of the Inverted L antenna.
 The Inverted L antenna - lower section now nicely camouflaged. The wooden support post is some 6 metres long.  The photograph above shows the Dacron ropes
supporting the ends of the Inverted L and Dipole antennas are held in
place at the top of the fibreglass support mast by a pulley - one
pulley for each
support rope. This facilitates rapid lowering of either antenna for
adjustment or replacement. This
photograph also shows a second
rope and pulley system that was originally used to support the 20m
dipole and is now used for the top band inverted L wire aerial.
I needed a good reliable knot for securing ropes when installing wire antennas and have found the Bowline to be one of the most useful, it is strong and easy to tie. A Bowline will not slip in any circumstances and, usefully, the more load that is put on it, the tighter it gets.  The Bowline Knot A Bowline can be used to tie two ropes together and should be used to tie a support rope to a pulley, dipole centre and other antenna items. It's
important
to use the correct knot for the job when fixing up wire
antennas. I find the Bowline is a very
useful for fixing end, egg and dog-bone insulators to the ends of the
wire and/or ropes. The Round Turn & Two Hitches, Anchor Bend
(Anchor Hitch) and
Buntline Hitch knots are very good for tying a rope to a pole or a
mast. A Double Sheet Bend can join two pieces of rope together - even
if they are of unequal size. 'Animated Knots' will show you how to do
them: http://www.animatedknots.com
 Photo showing pulley fixed to the top of the wooden support post and the aerial support rope that it holds in place.  The
Spectrum
Communications Trap
View
of trap showing
that the joints have been thoroughly sealed against the weather with self amalgamating tape and silicone sealant.  Just for good measure I sealed the internal side of the machine screw that forms the connection terminal against the weather with Watson sealant putty. Adding Top Band to the 80 / 40 metre Inverted L Antenna:
Due to an aborted house move in 2010 I had removed all the antennas. While re-establishing the aerials in 2011, and considering space limitations, I decided to expriment with adding a loading coil to the 40m / 80m Inverted L aerial. The loading coil has a link wire to short it out of circuit when using the aerial for 80 metres and 40 metres. The link wire is removed when Top Band is required. The coil consists of approximately 37 turns of PVC covered antenna wire wound on a short piece of PVC pipe. Once the required points of resonance were set for 40 metres and 80 metres, the link wire was removed and number of turns on the coil were adjusted until the required point of resonance was found on the 160 metre band. I set it to around 1900 kHz - the bandwidth is quite narrow. Once the work was done, the joints and connections were sealed with either Liquid Electrical Tape or self amalgamating tape, then the connecting box, V bolts and white PVC pipe were sprayed with green paint to help it all blend in with the sorroundings a little better:  Work In Progress! - September 2011 Reconfiguring Inverted L with additional Top Band Loading Coil for 160 metres. A fibreglass pole replaces the heavy wooden post.  Adding 160 metre loading coil to the 80m / 40m Inverted L Aerial. The loading coil has a link wire to short it out of circuit when using the aerial for 80 metres and 40 metres. The link wire is removed when Top Band is required. The coil consists of approximately 37 turns wound on a piece of PVC pipe.  Adding 160 metre loading coil to the 80m / 40m Inverted L Aerial. The loading coil has a link wire to short it out of circuit when using the aerial for 80 metres and 40 metres. The link wire is removed when Top Band is required. The coil consists of approximately 37 turns wound on a piece of PVC pipe.
Compact
Antenna
for
Top
Band
A Shortened Inverted L for 160 Metres
Despite the dreadful noise on top band caused by modern electronic gadgets and the difficulty in accommodating a necessarily large aerial in a small garden, I was keen to try to get on to top band. I experimented with some different ideas during 2009, some of which are shown on this page. Eventually I settled on the design shown below. It is an Inverted L type aerial, shortened by the use of a loading coil. It uses a fibreglass telescopic fishing pole to allow it to be easily lowered out of sight when not in use. Read more here>  uses a fibreglass telescopic fishing pole to allow it to be easily lowered out of sight when not in use Read More Here > End
Fed
Zepp Antennas for 20m / 17m and 15m
 The end fed Zepp is extremely versatile - it can simply be hung from the facia board or guttering just outside one's window: The 1/2 wave wire radiator made of high strength Kevlar is easily sloped down the garden and is camoflage green in colour so as to be almost invisible. The G-Whip Zepp is supplied with a facia board insulator, a throwing line with plus cable strain relief and fittings, the IP65 waterproof resin potted box fitted with UHF connectors (SO239) for coax feeder. The Zepp can be mounted vertically (e.g. using a telescopic fibreglass pole), horizontally or sloping and can be ready in a matter of minutes. I then decided to try an excellent new design developed by Geoff G4ICD - an End Fed Zepp antenna with a difference. The G-Whip End Fed Zepps are high efficiency, resonant mono band antennas utilising a half wave radiator, however this new G-Whip design by G4ICD dispences with the long trailing 1/4 wave twin feeder matching section and counterpoise and, instead, uses a helical tuned unit. Using versions for 20m, 17m and 15m will enable me to get on the air with the minimum of fuss since the G-Whip end fed Zepp can simply be hung from the facia board or guttering just outside one's window. The high-strength Kevlar, camouflage green 1/2 wave wire radiator is easily sloped down the garden to be almost invisible. VHF - UHF (2008) Initially I used a Watson W-2000 tri-band
antenna 10m aluminium telescopic pole.
(2011) In mid 2011 I experimented with an excellent N9TAX designed dual band Slim-Jim (J-Pole) antenna for 2m and 70cms. This is made from lightweight 450 Ohm ladder line which can be fixed to the top of a 10m tall fibreglass, telescopic, fishing pole. N.B. I tried to home-brew the DJB-1 dual band J-Pole antenna using plans published by the ARRL in QST magazine. I wanted a neat antenna that could be enclosed in a protective tube to minimise weathering effects. However trying to tune this antenna at UHF frequencies proved to be frustratingly difficult to do and after two full days work I could not get the thing resonate accurately at the correct frequency. Sadly, for this reason, I cannot recommend the Dual Band J-Pole as a home-brew project. The N9TAX antenna on the other hand works very well. However it cannot be enclosed in a tube due to the velocity factor effect de-tuning the antenna's resonant frequencies. (Late 2011) Due to difficulties with the stability of a lightweight fishing pole as a support I moved back to using the lightweight aluminium telescopic mast, with stays, to support a Watson W-50 vertical dual band colinear for 2 metres and 70 cms FM. KNOTS FOR SECURING WIRE ANTENNAS I have found the Bowline, Round Turn & Two Hitches, Anchor Bend and Buntline Hitch to be some of the most useful. The Bowline I find most useful for fixing end, egg and dog-bone insulators to the ends of the wire and/or ropes. The Round Turn & Two Hitches, Anchor Bend and Buntline Hitch knots are very good for tying a rope to a pole or a mast. A Double Sheet Bend can join two pieces of rope together - even if they are of unequal size. More at Animated Knots.com: http://www.animatedknots.com I know that if I use the correct knot that the these parts of the antenna will be as strong as possible. OTHER ANTENNAS Our good friend in Australia Felix Scerri, VK4FUQ, uses Inverted V antennas but also highly recommends the Quad Loop style antenna for HF work. These are well worth investigating, and you can read more here: Antennas 3 with more antenna ideas on Antennas 2 and Antennas 4 and the Links Page here and here Q.T.H. Move in 2010 !%*?"*!?! We decided that we'd like to move housein 2009, we found a new property in early 2010. My amateur radio aerials were duly taken down and the ham shack packed away. However after months of delays we still had not moved by August 2010, but we were still hoping to move. However after months of messing about and stringing us along our buyer pulled out the very day before we were to exchange contracts later in August 2010. This cost us a lot of time and a great deal of wasted money. Thank you Mrs xxxxxx :-( After a wasted year we decided to stay where we were and take the house of the market. Instead we spent the next eight months remodelling and redecorating. No time for playing radio of course and besides everything was still all packed away in boxes! In mid 2011 I was getting frustrated that I had no radio. So I suppose it's time to think about re-establishing the station and to start planning the installation of some antennas. Of course Jules, my XYL, understandably questions my antennas and experiments! Due to time constraints I will probably start again with a somewhat temporary antenna. I was thinking along the lines of an "Untenna" - so I installed a 7.2 ish long wire supported on a vertical fibreglass pole with a horizontal 'counterpoise' connected via a 9:1 balun to the coax back to the shack. Of course it is a fairly low efficiency multi-band (wideband) antenna, but easy to get going quickly. The GWhip Widebander antenna by Geoff Brown G4ICD is possibly the highest quality antenna of this type available, using a very high efficiency, top quality 9:1 UnUn with a 17 meter wire radiator and 10 metre long counterpoise - a very useful, versatile 'all situations' antenna. As time progressed I re-established my full size trapped Inverted L antenna for 80metres and 40 metres and added a switchable loading coil at its base for use on 160 meters, as described above. Then I gradually re-established the 2 metres and 70 cms antennas with the vertical W-50 and horizontal dual band DK7ZB yagi.   More project ideas here> I hope to add updates here when things begin to progress...... M0MTJ 2011 Prevous Antenna insallation: W-2000 -
Vertical
Collinear mounted on a temporary 10m telescopic pole:
I no no longer have the Watson W-2000 because the 10m telescopic pole that it had to be mounted to was too cumbersome. This is how it used to be installed: The Watson W-2000 covered VHF (2 metres / 144 MHz) and UHF (70 cms / 430 MHz) and also, rather usefully, 6 metres (50 MHz) too. The W-2000 is 2.5 metres long and enclosed in white fibreglass with three radial elements at the base. Unfortunately I had nowhere practical to install a separate mast for the VHF / UHF antenna, so this was mounted on top of a 30 foot (10 metre) high telescopic aluminium mast in the back garden. The base of the mast was placed in a handy metal sleeved hole that was already present in a small wall in the garden. Very fortunate indeed! The antenna is connected to the radio via the very low loss Westflex 103 coaxial cable. The cable was left in place permanently, running from the shack in the front bedroom, up into the loft and out of a small hole in the back of the house, down a drain pipe into the back garden. From there the aerial can be connected as an when required: When VHF or UHF operation is required I have to connect the coaxial cable to the Watson W-2000, fix it to the top of the telescopic mast, which is very quick using two V bolts and 4 wing nuts, put the mast in the hole and raise it to a good height. I tend to extend it so that the bottom of the antenna is at about 24 feet in the air, the height of the apex of the house, so it is in fairly clear space. A VHF and UHF aerial needs to be as high as possible since at these frequencies communication is essentially local and 'line of sight' - unless heightened propagation conditions, such as Sporadic E or a Temperature Inversion is prevailing at the time. Even at 24 feet the mast is rather wobbly, so it was tied down using three nylon guy ropes.  The
Watson W-2000 on to of the extended telescopic pole - about 8 or 9
metres high.
  Photograph
of
a Watson
W-2000
on Telescopic Mast at the lowest position
Links to further reading: Introducing The All Band Doublet: http://www.cebik.com/content/edu/edu6.html N.B. Create a free account at http://www.cebik.com The All Band Doublet - http://www.cebik.com/wire/abd.html The ALL Band HF Doublet on Ham Universe - http://www.hamuniverse.com/hfdoublet.html Multi Band Dipoles Compared - by ARRL on QST and DX Zone: http://www.arrl.org/tis/info/pdf/9611073.pdf http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=7499 PDF Document - The W3DZZ Antenna - http://www.users.icscotland.net/~len.paget/GM0ONX%20trap%20dipole.pdf (**!!! But don't use coaxial cable with a 'choke balun' at the centre of the dipole! Use twin feeder with the Choke Balun at the other end. Less power loss.!!!***) See Practical Dipole Antennas Compared: http://www.qsl.net/ta1dx/amator/practical_dipole_antenna.htm Practical Antenna For 160 Metres - http://www.iw5edi.com/ham-radio/?a-practical-antenna-for-160-metres,32 http://www.ik1mnj.net/id202.htm More: The website of GM0ONX http://www.gm0onx.co.uk/ The Inverted L - PDF document: http://www.users.icscotland.net/~len.paget/5%20band%20Inverted%20L.pdf Adding Top Band To The Inverted L - PDF Document: http://www.users.icscotland.net/~len.paget/Inverted%20L%20adding%20top%20band.pdf The All Band Inverted L - http://www.antennex.com/preview/archive3/ltv.htm  Antennas 2 | Antennas 3 | Antennas 4 G-Whip Antenna Products Geoff G4ICD offers a multitude of high quality solutions for portable, mobile and permenant base installations |
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M0MTJ
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