[aprssig] 9600 APRS

[Ray Wells]

I ran 6m/2m voice diplexed to a common antenna for 25 years in the car.

The antenna was a 2m 5/8. There are two ways to *tune* a 5/8 on 2m. One 
is to use a tuned circuit as seen in ARRL publications. The other (used 
commercially in Oz) is to add a series loading coil at the base so the 
antenna appears electrically to be 3/4 wavelength - a good match to 50 
ohm coax. There is little radiation from the coil - typically 6 turns of 
18# wound over 1.5".

That same antenna is close enough to resonance on 6m that any reactance 
can be removed with a tuneable diplexer. My homebrew diplexer used a 
band pass and a band reject circuit in each leg. Opposite band rejection 
was >60dB and insertion loss <1dB. It didn't look pretty, in its 
cut-down metal ice cream can, but it worked a treat. A later version was 
manufactured from double-sided PC board, soldered up as a box.

Ray vk2tv


On 01/03/11 08:08, Wes Johnston, AI4PX wrote:
> Just to throw another fish in the kettle, you can run 9k6 on 6m.  
> (>50mhz)  .  Back in the 70's in a magazine I read, there was a such 
> thing as a 6m/2m dual band antenna.
>
> Wes
> ---
> "Language shapes the way we think, and determines what we can think 
> about." -- B. L. Whorf
>
>
>
> On Mon, Feb 28, 2011 at 16:01, Tom <nineback at gmail.com 
> <mailto:nineback at gmail.com>> wrote:
>
>     This is what we need to figure out.  No more loss of audio on 2
>     meters.
>     Tom
>
>     ---------- Forwarded message ----------
>     From: *Bob Bruninga* <bruninga at usna.edu <mailto:bruninga at usna.edu>>
>     Date: Mon, Feb 28, 2011 at 1:00 PM
>     Subject: Re: [aprssig] 9600 APRS
>     To: TAPR APRS Mailing List <aprssig at tapr.org
>     <mailto:aprssig at tapr.org>>, earl.kd5xb at gmail.com
>     <mailto:earl.kd5xb at gmail.com>
>
>
>     My personal goal is to change my voice operations habits to UHF
>     repeaters
>     (I'm tired of the same'o-same-o on the local 2m one anyway).  Its
>     amazing to
>     see the 2m APRS keep working even while I am talking, and not lose
>     syllables
>     whenever my packet goes out.  Bob, WB4APR
>
>
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