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Advice for portable 23cm beam
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g8hxe <g8hxe@...>
Looking for a reasonably small and lightweight beam antenna for 23cm
SOTA activity. The best choice to me looks like the TONNA 23 element or possibly the 35 element (a bit big and heavy), does anyone have experience of using these in a portable (ie carrying the thing on a backpack) environment ? Or maybe somebody could suggest something else - looking mainly for SSB usage. Keith.
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D&R Friend <friends@...>
Hello Keith.
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I made my own fit-in-a-suitcase sized one according to the standard DL6WU design software. No, it's not 'SOTA', but it sure was fun to use from high locations around the UK back in March-April! There was a picture including it in Scatterpoint around that time. What you're planning seems to also suggest a need for mechanical durability, another significant issue! Somehow, I don't think small size and 'SOTA' can occur together.... Best 73, Doug Friend, VK4OE, Brisbane, Australia. g8hxe wrote:
Looking for a reasonably small and lightweight beam antenna for 23cm
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Liviu Babi <electronicguest@...>
Dear Keith, I use for portable 23 cm operation a small 15 elements yagi, home - made, after DL6WU design software. The construction it's very simple. It was made from copper heat system pipe, 1,5 m long boom and 15 mm diameter; copper 2.5 mm diameter (electrical cables) for elements. Soldered togheter. The adaptation was made from copper-teflon semirig coax. DL6WU design software will explain you all operations. I do not like big (long) antenna for por portable operation. My ideea it's not to have small angle in contests. You can easy stack 2 or 4 antenna for better results. For small antenna also very easy to find a place in the car. The best results I had with 80 cm, dish antenna (prime focus type) and home made circular feed horn. Have 23 cm DB6NT transverter 20W out.
73's YO4FNG Liviu
----- Original Message ---- From: D&R Friend To: ukmicrowaves@... Sent: Monday, December 31, 2007 3:30:15 AM Subject: [ukmicrowaves] Re: Advice for portable 23cm beam Hello Keith. Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now.
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SAM JEWELL
Happy New Year,
Another option may be WA5VJB's 23cm 'Easy Yagi' design. This is lightweight, disposible and costs next to nothing to build, whilst having a good 'power to weight' ratio! It is one in the series yagis designed by Kent and extremely popular in the USA. I need to check where the design has been recently published . I'm not sure that it's on Kent's web page yet. I think it has appeared in CQ VHF. I would dearly love to receive some reports on the 23cm (and up) activities of the SOTA enthusiasts for the RSGB RADCOM GHz Bands column, please? 73 de Sam, G4DDK
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Mike Willis <m.j.willis@...>
Yet another option is to use a flat plate type of antenna that is easy to pack. A double quad - or several in a vertical stack. This has the advantage of a broad horizontal beamwidth and a narrow vertical beamwidth. Gain is lower than a 23 ele Tonna but so is size and weight. You can make the backplane out of mesh and if ambitious, put a 2.3 GHz array on the other side. The basic double Quad has 9 dBi of gain, an array of two stacked vertically should give you 12 dBi.
FRARS have a design on their pages http://www.frars.org.uk/ and there is a double version in the old UHF DX Book. You might also look at G4CYAs' pages http://www.vhfman.freeuk.com/radio/23cmantennas.html Mike
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G3RIR <g3rir@...>
Mike,
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Could you be a little more specific with your reference to the old UHF DX Book, please. Do you mean VHF/UHF DX Book? My version doesn't go above 432. I have a number of other UHF books but can't easily find the flat plate antenna to which you refer. 73 Neil, G3RIR
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From: ukmicrowaves@... [mailto:ukmicrowaves@...] On Behalf Of Mike Willis Sent: 31 December 2007 10:15 To: ukmicrowaves@... Subject: Re: [ukmicrowaves] Advice for portable 23cm beam Yet another option is to use a flat plate type of antenna that is easy to pack. A double quad - or several in a vertical stack. This has the advantage of a broad horizontal beamwidth and a narrow vertical beamwidth. Gain is lower than a 23 ele Tonna but so is size and weight. You can make the backplane out of mesh and if ambitious, put a 2.3 GHz array on the other side. The basic double Quad has 9 dBi of gain, an array of two stacked vertically should give you 12 dBi. FRARS have a design on their pages http://www.frars.org.uk/ and there is a double version in the old UHF DX Book. You might also look at G4CYAs' pages http://www.vhfman.freeuk.com/radio/23cmantennas.html Mike Yahoo! Groups Links
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Mike Willis <m.j.willis@...>
The UHF Compendium, a German publication translated into English in the 1980s. Unavailable now but I have a copy.
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Mike G3RIR wrote:
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Richard Newstead <g3cwi@...>
--- In ukmicrowaves@..., SAM JEWELL <jewell@...> wrote:
I would dearly love to receive some reports on the 23cm (and up) Sam There's not a huge amount to report although there are some signs of growing interest in 23cm. This may well be a chicken and egg situation? Perhaps a few more notes on practical lightweight portable equipment for 23cm might be useful? I will be trying to get people on to 70cm in 2008. The following are activators who have been active on 23cm in 2007: Activations 1 GW4BVE 9 =1 G6DDQ 12 3 GW8OGI 10 4 G0MJG 4 5 G4BLH 4 6 G0OXV 3 7 G4OIG 3 8 G4TQF 1 9 G7KXV 1 =9 2E0HJD 1 73 Richard G3CWI
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SAM JEWELL
Thanks Richard,
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even news that appears not to be so interesting to others, at first sight, can be of enormous interest when set amongst other items on portable etc. Details of Kent's antenna is due to appear in a forthcoming new Microwave book.... 73 de Sam Richard Newstead wrote:
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zl1ujg <zl1ujg@...>
Hi,
Happy New Year (Its the morning of the 1st here) I have taken out my elderly 23 element 23cm Tonna, both backpacking and static mobile. The plastic mounts for the elements break remarkably easily. The backpacking trip (4 hours up and 3.5 hours down) left me with only 18 el. The recent VHF field day here in NZ left me with a 22 element, and fitting of my last remaining plastic antenna mount (I think W&S had replacement parts, but that was many years ago.) I think there was a ATV antenna locally (NZ) which used plastic "P" clips to hold elements, which may have been a BATC design. Loop yagi antennas seem fairly forgiving, one just bends the elements back and one could cut the boom, so it could be put on a backpack Kevin ZL1UJG
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Peter Day <microwaves@...>
HI Keith...
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I use 23cm Tonnas (23 ele or 35 ele) for my portable work, VW van based. Even then they are easy to damage as the element stand off insulators are extremely easy to break if you catch an element on something. I would think you would break on or two if you backpacked it! Much better (and probably more useful in wet conditions in which I've found Tonnas to detune, would be a yagi of all aluminium construction (ie the so called "plumbers delight" )where only the driven element is insulated from the boom..... or one with elements passing through the boom yet insulated with plastic grommets. Such an antenna could be made in two halves, to be connected together on site and still be easily carried in some sort of bag (fishing rod bag??). There are a number of homebrew designs around... the DL6WU designs seem to work very well. There's some old DOS software around that does all the calculations for you. I think some data is on G3SEK's website... some Googling should get you there. I would think 35 ele is too large for backbacking. The 23 ele is ok if broken down into a couple of sections. 73 and good luck.. Peter, G3PHO
On 31 Dec 2007, at 00:16, g8hxe wrote:
Looking for a reasonably small and lightweight beam antenna for 23cm
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Richard Newstead <g3cwi@...>
--- In ukmicrowaves@..., SAM JEWELL <jewell@...> wrote:
even news that appears not to be so interesting to others, at first23cm Total SOTA Activations 2002 0 2003 3 2004 2 2005 15 2006 44 2007 48 Our database gives all the gen: http://database.sota.org.uk/ 73 Richard G3CWI
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SAM JEWELL
Thanks Richard,
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I didn't know of that page. Sota was always State of the Art to me! I wonder what ever happened to them? 73 de Sam Richard Newstead wrote:
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