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Re: Elk Antennas for HTs?



The fact that the two antennas in the Arrow have two connectors is not 
because they are 90 degrees out of phase and not the reason for the 
duplexer.  You could easily use a standard BNC "T" connector and match the 
antennas impedance, which would accomplish the same as the Elk.  The 
primary use of the duplexer is isolation.

The original statement was about the IC-W32A which I own (I do not own the 
other radios you mention) so I can't speak for their built in 
duplexers.  However I don't believe the FT-530 is full duplex.  I seem to 
recall it turns off the second receiver whenever you transmit which is not 
the same as FULL duplex.  However since I don't own the radio don't quote 
me on that.

My experience with the Elk and the W32A in FULL duplex mode is that it 
desenses the receiver when you are transmitting so you cannot hear yourself 
coming back down on the downlink frequency.  I have tried the BNC T 
connector method mentioned above rather than the duplexer with the Arrow 
and it desenses, though not as bad as the Elk did since the 90 degree 
difference in transmit and receive antennas offers a little 
isolation.  With a duplexer you get additional isolation and it doesn't 
desense.

73,

Emily



At 11:24 AM 10/20/2004 -0500, you wrote:
>On Tue, Oct 19, 2004 at 10:37:06AM -0700, Emily Clarke wrote:
>
>| Also, you can't use the Elk for full duplex since it doesn't have a
>| duplexer.
>
>I'm a bit confused by this statement.
>
>The Elk Antenna is here --
>
>    http://www.elkantennas.com/2m4405element.htm
>
>in case somebody wants to see a picture of it.
>
>The main competitor seems to be this one
>
>    http://www.arrowantennas.com/146-437.html
>
>By default, the Elk antenna has one plug, and the Arrow II has two
>(since it's two antennas at right angles to each other.)  If you
>almost double the price, they'll throw in a nice little duplexer in
>the handle and then you have one connector to worry about.
>
>I've got two radios sutiable for doing 2m/70cm satellite work -- a
>FT-530 and a TM-D700A.  Both have a built in duplexer, both have only
>one antenna connection, and both can transmit on 2m and receive on
>70cm (and vice versa.)
>
>Are not these radios pretty `standard' for satellite work?
>(i.e. 70cm/2m, one antenna connector, built in duplexer, can transmit
>on one band while receiving on another.)  If this isn't standard, than
>what is?  Two different radios, one for transmitting and one for
>receiving?  Or radios with two antenna connectors?
>
>Why wouldn't I be able to do full duplex with one of these radios
>using the Elk antenna and no extra duplexer?  Certainly, I can do it
>with the little 1/4 wave whip I use with it.
>
>Forgive me if this is silly question ... I'm pretty new to this :)
>
>--
>Doug McLaren, dougmc@frenzy.com, AD5RH
>And in other news ... the pot called the kettle black again.



---------------------------------
W0EEC - CM87tm
AMSAT Area Coordinator - San Francisco Bay Area
http://www.projectoscar.net    http://www.PlanetEmily.com 
http://www.emilyshouse.com/experthams/ao7/

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