Hello all,
I have read with great interest the AA2TX article about an easy way to build the lindenblad antenna for 2m satellite band. I have some questions for the ones who actually use these antennas. I'm thinking about a portable setup for a three weeks operation in IS0 at the end of december. How does the antenna perform on LEOs? I've always used small yagis handeld with great results, but this setup is quite unsatisfactory for winter operations. How problematic is the fixed circular polarization of the lindenblad? And finally... does anyone have tested dimensions for a 70 cm easy-lindenblad design? I'm particularly interested in cw operations on AO-7 by the way.
Thanks in advance and best 73 Francesco IZ8DWF
Hi
I built the AA2TX 70 cms Easi Lindenblad exactly to the dimensions in Tony's article. I modified the hub to make use of materials easily available here in England. A 4 way plastic moulded electrical conduit junction box makes the hub very easy. I suggest you see if they are available in your country. I keept ALL the RF parts, dipole and reflectors as specified. I cut the reflectors slightly overlength the used a file to get them spot on and all identical.
On receive the Easi Lindenblad worked superbly. Mounted on a short pole out in the opoen, about 2m above ground, the 80mw cubesats could be copied almost on the horizion with a short run of co-ax straight into an FT817. LO-19, my primary test satellite was 59 at high elevations.
I can recomend this design, its far easier to construct than the "traditional" Lindenblad with folded dipole elements and phasing harness.
Thanks Tony
73 John G7HIA
Is the article available on line? I don't keep paper publications.
john heath wrote:
Hi
I built the AA2TX 70 cms Easi Lindenblad exactly to the dimensions in Tony's article.
Google "e-z lindenblad". it's the first hit on the list. Jim KQ6EA
--- On Tue, 12/2/08, Nigel Gunn G8IFF/W8IFF [email protected] wrote:
From: Nigel Gunn G8IFF/W8IFF [email protected] Subject: [amsat-bb] Re: EZ-lindenblad info To: "amsat" [email protected] Date: Tuesday, December 2, 2008, 5:55 PM Is the article available on line? I don't keep paper publications.
john heath wrote:
Hi
I built the AA2TX 70 cms Easi Lindenblad exactly to
the dimensions in
Tony's article.
-- <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><> Nigel A. Gunn. G8IFF W8IFF (have also held KC8NHF, M0NHF, 9H3GN) 1865 El Camino Drive, Xenia, OH 45385-1115, USA 937 825 5032 e-mail [email protected] www http://www.ngunn.net Member of ARRL, GQRP #11396, QRPARCI #11644, SOC #548, Flying Pig #385, Dayton ARA #2128, AMSAT-NA LM-1691, AMSAT-UK, MKARS, ALC <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><> _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Goddit. Thanks guys.
Jim Jerzycke wrote:
Google "e-z lindenblad". it's the first hit on the list. Jim KQ6EA
Has anyone made a metric version of this antenna ?
thanks
Tim
What's the difference between a metric version and any other version. Just multiply the inches by 25.4 and it will be metric.
Tim Tuck wrote:
Jim Jerzycke wrote:
Google "e-z lindenblad". it's the first hit on the list. Jim KQ6EA
Has anyone made a metric version of this antenna ?
thanks
Tim
Nigel Gunn G8IFF/W8IFF wrote:
What's the difference between a metric version and any other version. Just multiply the inches by 25.4 and it will be metric.
While it would be nice if it was that easy the problem arises when trying to buy aluminium in those odd sizes. i.e. 1/4inch is 6.45mm. Local aluminium suppliers don't have imperial sizes so I'm stuck with 5mm, 10mm, 15mm etc. thus the math needs redoing for the different sizes and I was wondering if anyone had done that before I attempt it. :)
regards
Tim
Diameters are not critical, lengths are. Use whatever fits. If you increase diameters significantly you might need to shorten elements very slightly.
Tim Tuck wrote:
Nigel Gunn G8IFF/W8IFF wrote:
What's the difference between a metric version and any other version. Just multiply the inches by 25.4 and it will be metric.
While it would be nice if it was that easy the problem arises when trying to buy aluminium in those odd sizes. i.e. 1/4inch is 6.45mm. Local aluminium suppliers don't have imperial sizes so I'm stuck with 5mm, 10mm, 15mm etc. thus the math needs redoing for the different sizes and I was wondering if anyone had done that before I attempt it. :)
regards
Tim
At 03:20 PM 12/3/2008, Tim Tuck wrote:
Nigel Gunn G8IFF/W8IFF wrote:
What's the difference between a metric version and any other version. Just multiply the inches by 25.4 and it will be metric.
While it would be nice if it was that easy the problem arises when trying to buy aluminium in those odd sizes. i.e. 1/4inch is 6.45mm. Local aluminium suppliers don't have imperial sizes so I'm stuck with 5mm, 10mm, 15mm etc. thus the math needs redoing for the different sizes and I was wondering if anyone had done that before I attempt it. :)
regards
Tim
Hi Tim,
Use 20mm aluminum tubing and no correction is needed. Of course you will have to do something clever with the PVC parts.
73, Tony AA2TX
Tim - What you need to do is calculate the reactance of the elements with the diameter of the specified elements. Then calculate the length of the element with the new diameter so that the reactance of the new element is the same as the old one. I think that the corrections may not be significant if the diameters are not too far apart.
L. B. Cebik wrote how to do this in his web page on scaling Yagis form one frequency to another. I wrote a spreadsheet to calculate these lengths for Yagis, mostly to go from 432 MHz to 144 MHz. You could use that with the appropriate diameters I think. If I can find it I can send it to you.
The calculations are straight forward, but the equations are not short. It can be done though and will be reasonably accurate as long as your diameters are similar. - Duffey On Dec 3, 2008, at 1:20 PM, Tim Tuck wrote:
Nigel Gunn G8IFF/W8IFF wrote:
What's the difference between a metric version and any other version. Just multiply the inches by 25.4 and it will be metric.
While it would be nice if it was that easy the problem arises when trying to buy aluminium in those odd sizes. i.e. 1/4inch is 6.45mm. Local aluminium suppliers don't have imperial sizes so I'm stuck with 5mm, 10mm, 15mm etc. thus the math needs redoing for the different sizes and I was wondering if anyone had done that before I attempt it. :)
regards
Tim
--
VK2XTT :: QF56if :: BMARC :: WIA :: AMSAT-VK :: AMSAT
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
-- KK6MC James Duffey Cedar Crest NM
At 08:28 PM 12/3/2008, James Duffey wrote:
Tim - What you need to do is calculate the reactance of the elements with the diameter of the specified elements. Then calculate the length of the element with the new diameter so that the reactance of the new element is the same as the old one. I think that the corrections may not be significant if the diameters are not too far apart.
Dear Friends,
Fortunately, it is not that complicated. 3/4" tubing is close enough to 20 mm so that it won't make any difference.
73, Tony AA2TX
participants (7)
-
Anthony Monteiro -
francesco messineo -
James Duffey -
Jim Jerzycke -
john heath -
Nigel Gunn G8IFF/W8IFF -
Tim Tuck