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From: al@qiclab.scn.rain.com (Al Peterman)
Newsgroups: sci.electronics
Subject: Re: Garage door openers (was 12 V car -> 3 V cd)
Message-ID: <1991Jan6.064323.26554@qiclab.scn.rain.com>
Date: 6 Jan 91 06:43:23 GMT
References: <5910003@hpihoah.cup.hp.com>
Organization: SCN Research/QIC Laboratories of Tigard Oregon
Lines: 26

In article <5910003@hpihoah.cup.hp.com> jwatts@hpihoah.cup.hp.com (Jon Watts) writes:
>From: al@qiclab.uucp (Al Peterman)
>>I can't vouch for 7803's but I am using 7809's to run my garage door
>>openers in both cars.  Never a problem.  
>
>Where did you mount the transmitter so that it can radiate effectively?  Most
>of them are kind of wimpy and if you mount them in a typical out of the way
>place the car body would block off the signal pretty effectively.  I thought of
>extending the antenna but it seems to be just a trace on the PC board and not
>easy to tap.  Or did you find this is not a problem?

I've done this on 3 cars so far.  In all cases, I installed the 7809
inside of the transmitter, and mounted the transmitter under the dash.
I know this should give lousy performance, BUT it actually works swell.
I get 2 block range with 2 of the cars, and 1 block with the Acura..which
is still more than enough.  I actually get more range out of the mounted
units than from the identical transmitter which I use for the bicycle and
motorcycle that runs on it's own battery.  I suspect the battery typically
is a bit below 9 volts under load (particularily since I don't replace the
battery until it gets weak) and the regulated supply is easily able to
output up to 1 amp.


-- 
Alan L. Peterman                                   (503)-684-1984 hm
                       al@qiclab.scn.rain.com