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Unread 05-07-2007, 05:01 PM   #1
expat
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Default Tuning a Ham antenna

How do you correctly SWR a Ham dual band antenna?

I've even read that you shouldn't!!!

According to the flier that came with my antenna you should aim for approx 1.1 on 144MHz and the same on 445MHz but if I get 1.1 on 144 by extending my antenna a cm., then its off the chart (needle scale actually!) on 445. I don't seem to get anywhere near close for both frequencies.

Am I meant to SWR it like a CB?

I have searched a few Ham sites but can't find the step-by-step procedure.

Any links or advice welcome.

Thanks
Mark
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Unread 05-08-2007, 10:58 AM   #2
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Are you using a 2m/440 swr meter or a cb swr meter? Just curious cause I have not tuned mine at all yet.
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Unread 05-08-2007, 03:18 PM   #3
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It is vital to use a meter made for the bands you are tuning for... a CB SWR meter will not be accurate at higher frequencies.

That being said a lot of dual band antennas are "factory-tuned" which means they are "kinda already tuned" - and you don't need to do anything but maybe check it with a meter.

The thing you find out about meters is that most are innacurate to a degree anyway - unless you buy a bird directional wattmeter (or the like) which are very accurate but expensivish.

-Mike
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Unread 05-08-2007, 05:48 PM   #4
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ok, I was using my cb SWR meter.

Maybe I'll just go to the guy down the road..he charges $15 to tune antennas and then I can see how a pro does it.

On another issue, today while waiting for the kid to finsih soccer, I was tuning around the stations and was on 448.900 and was listening crystal clear to a guy in Australia talking to a guy in SoCal (LA) and another guy in San Diego.

How is it I heard the guy in Oz so clear on that band? I assume a repeater was involved but he was crystal clear??????
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Unread 05-08-2007, 06:41 PM   #5
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Quote:
How is it I heard the guy in Oz so clear on that band? I assume a repeater was involved but he was crystal clear??????
You stumbled on a "linked" repeater. Probably using Echolink or IRLP. Echolink and IRLP (Internet Radio Linking Project) allow you to get on a repeater and direct it to link to another repeater. Also, in the case of Echolink, you can get on your computer and talk on any Echolink repeater you wish... all from the comfort of your computer. IRLP doesn't allow any direct computer use... you need a radio on each end.

Check out Echolink.org or IRLP.net

It's a very cool way to communicate, but many hams are leery since this uses the Internet as the backbone of the link. The old fashioned way to link repeaters was via Satellite - some repeaters are still linked this way, and often the link is a permanent one and always on.

On the 220Mhz band lives the "Condor Connection" a series of linked repeaters that goes all the way up the coast and as east as Phoenix. It is one of the oldest and most respected networks of repeaters, but you need to keep conversations short and to the point - it is free to use though.
If you want to see the map of the system go here:
http://www.condor-connection.org/md/map40C1.jpg

Many 440 repeaters & some 2M are private linked systems which have many linked machines in a certain area. Usually you need to pay dues to use these systems.

Hope that helps

73,

-Mike

Last edited by K6UK; 05-08-2007 at 06:45 PM.
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Unread 05-08-2007, 07:17 PM   #6
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Cool! Thanks for that explanation. This is all so different from my experiences many years ago in Oz.

I didn't want to get in the way, but could I have transmitted on the Echolink or would I have to have codes/permission/payment? I gotta read up on this. What is the best Ham forum in your opinion Mike?

I have so many questions!!!!!!
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Unread 05-08-2007, 10:59 PM   #7
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There are no fees for Echolink or IRLP (well Echolink does charge a dollar to get an online account going... but that is just so they know who you are)

But individual repeaters may be "closed repeaters" - that is for members only.
In this case you would have to pay for the priviledge of using there system. If you pick up a repeater guide, you can see which repeaters are open or closed.

I have yet to find a HAM forum that I really like.
I might have to look around more.

Okay enough off topic for now.

-Mike

PS - And back on topic - if your antenna says that it is pre-tuned, but still has bad SWR, then make sure the antenna is grounded properly. That may be your problem. Trying to tune the antenna might be asking for trouble, if it is a factory tuned dual-band like the Larsen 2m/440

Last edited by K6UK; 05-08-2007 at 11:01 PM.
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Unread 05-09-2007, 05:07 PM   #8
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i have about six antennas all dual band and none of them needed to be tuned. i have had three checked and found out that it was either a bad coax or connecter.
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