Thread: 13B2 for 70CM?
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Old July 13th 03, 08:34 AM
Ian White, G3SEK
 
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G.Beat wrote:
"AO KD5FXT" wrote in message
...
What abt using my 13B2 for us on 440? I don't have an analyzer for that

band
nor a swr meter. What are the thoughts on this? I have a friend in

Houston
who does it and verifies it to be ok. Responses and thoughts appreciated.


Seem like a waste of a good Cushcraft 13B2 (13 element yagi) 2 meter antenna
($ 150 MSRP)
for 440 MHz antenna. http://www.chq-inc.com/cush/13B2.html

What are you trying do on 70 cm ? (440MHz) SSB/CW DX, FM repeaters, ATV,
satellite work

1. When you move from 2 meters to 70 cm -- the coax you use from you
operating position to the antenna
becomes much more important than at HF or low VHF frequencies.

For example, for 100 feet of coax the attenuation in dB [from Cable X-perts
charts]
http://www.cablexperts.com/cfdocs/ca...ub=0&bskt=0&US
A_ship=1&c=0

RG-213/U at 150 MHz - 2.8 dB; at 450 MHz - 5.2 dB
LMR-400 at 150 MHz - 1.5 dB; at 450 MHz - 2.7 dB

2. Some designs to consider !

K5OE 70 cm yagi designs (in this case for AO-40)
http://members.aol.com/k5oe/P3D_ant/P3D_yagi.htm

VK3KHB 8 element design for ATV usage
[Uses 1/8" (~3 - 5 mm) solid rod for elements and round or square aluminum
tube (~ 10 mm)
http://www.gak.net.au/vk3khb/atv/antdesign.htm

WiMo products [Germany] - great for ideas
http://www.wimo.com/verteiler-e.htm?s1_e.htm

KK5UFO designs
http://www.homestead.com/kk5ufo/VHFbluprint.html

XE1MEX design (for 2m and 70cm)
http://xe1mex.gq.nu/antenas/yagi.html

Martin DK7ZB very nice designs
http://www.qsl.net/dk7zb/start1.htm

Derek, G4CQM
http://www.g4cqm.btinternet.co.uk/an...gner/yagis.htm

That's a start !!

w9gb


Also the 'VHF/UHF Long Yagi Workshop' on my site.

--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
Editor, 'The VHF/UHF DX Book'
http://www.ifwtech.co.uk/g3sek