Author Topic: How is inside a helicoidal ham-radio antenna in rubber ?  (Read 2938 times)

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Offline 1enry1

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How is inside a helicoidal ham-radio antenna in rubber ?
« on: February 01, 2016, 07:51:19 pm »
in the  ham-radio dualbander handy  like  Kenwood TH-79 or th-f7 ect....

used a dual band  144 - 430 Mhz helix inside the rubber antenna, where is project and function in the two bands ?

thanks, best 73
 

Offline Paul Rose

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Re: How is inside a helicoidal ham-radio antenna in rubber ?
« Reply #1 on: February 01, 2016, 09:17:04 pm »
Not sure if I fully understand the question.

What makes the helix a dual band antenna, or how well do these work on each band?

I found the following:  http://herwig.mobimail.de/2m-en.htm   which shows that they typically don't perform very well, especially not on both bands.

 

Offline 1enry1

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Re: How is inside a helicoidal ham-radio antenna in rubber ?
« Reply #2 on: February 02, 2016, 09:19:17 am »
thanks !

both...my question on this rubber antenna on handy , is :

1)  where is inside ? and how is the tecnical and  RF sulution to work it ?

2)  in how mode function in 144 and in 430 mhz ?

best 73
 

Offline WA5PSA

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Re: How is inside a helicoidal ham-radio antenna in rubber ?
« Reply #3 on: February 02, 2016, 01:19:08 pm »
Are you asking how it switches from one band to another? If so...there is no switching. If you transmit on 144, then the 2meter section will present the best impedence match to the transmitter, and the RF energy will simply follow that route.

Sent from my SM-N910V using Tapatalk

 

Online Chalcogenide

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Re: How is inside a helicoidal ham-radio antenna in rubber ?
« Reply #4 on: February 02, 2016, 01:27:22 pm »
Here is an explaination in Italian, as obviously 1enry1's is not a native English speaker:

L'antenna è semplicemente fatta in modo tale per cui l'impedenza è "decentemente" adattata in entrambe le bande. Non c'è nessuno switch, nessuna parte attiva, e nessuna diversa modalità di funzionamento. Per questo, le antenne bibanda tipicamente sono peggiori di un'antenna monobanda (che invece è quasi perfettamente adattata nella banda di funzionamento).
 

Offline 1enry1

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Re: How is inside a helicoidal ham-radio antenna in rubber ?
« Reply #5 on: February 02, 2016, 01:32:10 pm »
thanks to all...


have a schematic diagram to has built inside the rubber antenna ?

tnx and 73
 


Offline HAL-42b

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Re: How is inside a helicoidal ham-radio antenna in rubber ?
« Reply #7 on: February 03, 2016, 05:33:32 pm »
Here are some plans if you want to make one yourself:

http://www.cqham.ru/rubberduck.htm
 

Offline 1enry1

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Re: How is inside a helicoidal ham-radio antenna in rubber ?
« Reply #8 on: February 04, 2016, 08:20:35 am »
GREAT , thanks to all !


i try an very interesting article  in this rubber ANTENNA on this  web site of an  amateur radio collegue :

http://rodolfo-parisio.jimdo.com/nuovi-articoli-2015-bis/


best 73 :-)
 


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