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Old July 24th 15, 07:01 AM posted to rec.radio.amateur.antenna
Helmut Wabnig[_2_] Helmut Wabnig[_2_] is offline
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First recorded activity by RadioBanter: Sep 2007
Posts: 135
Default Advice on antenna length

On Wed, 22 Jul 2015 14:41:10 -0400, "Ralph Mowery"
wrote:


"hunt4mac" wrote in message
...
I have an Garmin Astro 220 GPS that uses the MURS frequencies, 151.82 -
154.60 Mhz. Using an online calculator I learn that the antenna should be
18.5 inches for 1/4 wavelength and 9.25 in. for 1/8 wavelength (based on
the 151.82 Mhz frequency)

.I was considering buying an antenna on eBay but it is only 8 inches.
(eBay item# one, eight, 1, 3, zero, two, 327, 578. Sorry for this
workaround, the admins think I'm posting a phone number).

How much difference would this mismatch cause? Or is it a mismatch?


I don't think you would have any mismatch as the shorter antenna is probably
a 'rubber duck' type. It is sort of like a spring inside the rubber
covering and loaded to match the frequency. Many Ham handi talkies use this
type of antenna on 146 MHz without any problem.
The range is slightly shorter with this antenna, but for tracking dogs I
would not think the reduction in range would really matter. Doubt they would
be over 1/4 of a mile from you.

Most, if not all, rubber duck antennas which come with the 2 meter
amateur radios are designed for the 150 to 160 MHz band,
the commercial radio between trucks and their boss.

I have measured dozens of them, all were out-of-band,
the ICOMs the KENWOODS the WEIERWEi and YAESu and and...

Never trust the content of a new box.

w.