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VE3RNR Duplexer Replaced

The Duplexer on the UHF repeater VE3RNR in Fonthill was replaced this morning by Dave, VA3UL. Tests done earlier indicated abnormal power losses and it was traced to the Duplexer. Dave gives us some insight about the duties of a duplexer in a radio repeater below.

The Duplexer device serves a critical role in a repeater. To make a long story short, the duplexer separates and isolates the incoming signal from the outgoing and vice versa. Even though the repeaters input and output frequencies are different, the duplexer is still needed. Why? Have you ever been in a place where there's lots of RF activity, and noticed the receive performance of your radio degrades to some degree? This is called desensitization, or desense, and it's a bad thing on a repeater. The receiver goes deaf or gets desensitized from the strong RF signals being radiated in its vicinity and confused about which signal it should receive. The result is poor receive quality, or in extreme cases, complete lack of receive capability. Keep in mind that in this example, the radios are picking up radiated power from one another and that's enough to cause trouble. Now imagine how much trouble there will be if you not only have the transmitter and receiver close together, but connect them to the same antenna! Transmitting only a few hundred kHz away in frequency would blow away the input to the receiver if the equipment was simply connected together with a Tee. That's where the duplexer comes in; it prevents the receiver and transmitter from 'hearing' one another by the isolation it provides.

A duplexer is a device that is referred to by several different names like cavities or cans. A duplexer has the shape of tall canisters and is designed to pass a very narrow range of frequencies and to reject others. There is some loss to the system because of the duplexer, however, the advantage of being able to use a single antenna usually outweighs the drawbacks.

Thank-you for your information Dave.

Peter, VA3WET
Wednesday, December 6th, 2006

Upcoming Meetings

Meeting Event and Guest Schedule 2017-2018
Sept 2017   Welcome of new Board
Oct 2017   Auction Night
Nov 2017   Michael Walker - Flexradio
Dec 2017   Tech Night: Christmas/Holiday Meeting
Jan 2018   Big Event Planning
Feb 2018   TBD
Mar 2018   TBD
Apr 2018   TBD
May 2018   Field Day Planning
June 2018   NPARC Elections
     
    Note: No general meetings scheduled for July and August.

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General Meeting

The next meeting will be Thursday, December, 14th 2017 at 7:00 P.M. at the Col. Talbot Trail, Royal Canadian Legion, Branch 613 in Fonthill, Ontario. The Legion is centrally located in the Niagara Peninsula at 141 Highway 20 East, Fonthill, Ontario. Click here for a map and directions.

Everyone is welcome to attend, including those interested in membership or learning more about the hobby.

Events for this evening's meeting are listed here.

After the meeting, members are free to discuss their future in the club and answer any questions about becoming an Amateur Radio Operator if you are not one already.

Refreshments will be available following the meeting and a mini flea-market for members to sell or trade their new and almost new equipment. Guests and Non-members may find this very interesting. Again all are welcome.

Come on and Register

Hey NPARC members!

You are HIGHLY encouraged to register here and setup an account.  There are many sections and selections that are only available to NPARC members.  Those menu items will have  beside the selection,

To everyone else, feel free to register as well although your access will NOT include NPARC specific sections.

If you wish to become a member of the Niagara Peninsula Amateur Radio Club (NPARC), please visit this article which explains the process.

Take care and 73

Kaitlynn
2017 Ham of the Year

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Testimonials and Comments

OK8RF Rich
2017-01-31, 10:29
Hope you guys have good weather and good attendance like we had for the BIG EVENT #1 which I helped to organize. Wish I could come but am 6705km away … read more
VE3ISX Barry
www.ontars.com
2016-12-24, 06:51
Excellent job on your website.
The BIG EVENT #39 is now displayed on our main ONTARS.COM page and TPN7055.COM websites.
Good luck with the … read more
GDaveuest
2016-09-11, 08:07
Nice work on web page finally connected too me.
73 Dave VE3FOI Vineland