First, the rubber duckie has less than unity gain. That means that for every
watt you put into it, there is much less than a watt radiated.
Second, we are talking about 20 meters, not 2 meters.
I think that on SSB, you get about one-third the peak output as average
output. So, at 300 watts PEP, it is like sitting next to a 100 watt FM
transmitter on 20 meters. While running 100 watts, you are sitting next to a
33 watt FM transmitter as far as exposure goes. That is only when you are
transmitting. So yes, you really aren't getting that much RF exposure because
you aren't talking all of the time. At least I hope you aren't. (yuk, yuk).
A big filter cap on the power leads gives you great dynamic stability on the
power output. So does a bank of gel-cell batteries in the trailer. That way
the electrical system wouldn't be overworked.
If I were going HF mobile on a motor-cycle, I really would get a trailer, bolt
a sheet of aluminum to the top, mount the antenna to the aluminum (maybe the
102 inch CB whip), put about 80 - 100 amp-hours worth of 12 volt gell-cell
batteries and an antenna tuner in the trailer. If I had to have an amplifier,
I really would go with a good commercially made 500 watt amp, drill some holes
in the side of the trailer and put an exhaust fan in the trailer. One would
have a really great motorcycle mobile and you could operate 40-6 meters (most
auto-tuners can tune a 102 inch whip to that range) and 2 meters and 70 cm with
the right rig (IC-7000, which I have). A small dual band VHF/UHF antenna on
the back rest mounted above your head on a small mast would round out the
antenna situation. You never know when you might need to call for help on a
local repeater or get directions to the best place to eat. Why limit your
options when it is so easy to have
it all?
Hal W5GHZ
________________________________
From: Charles Harpole <k4vud@hotmail.com>
To: k8ri@rogerhalstead.com; "amps@contesting.com" <amps@contesting.com>
Sent: Monday, October 8, 2012 1:36 AM
Subject: Re: [Amps] 300 W single band mobile amp needed
Could a motorcycle electrical system have enuf power to run such an amp? Even
if so, would you want that much RF on an antenna mounted on your bike? What is
the RF power output of the in car radios of police and EMS ? What about the
output on the rubber duckie on top of the hand mic, clipped to the officer's
epaulettes?
Charles Harpole
k4vud@hotmail.com
> Date: Sun, 7 Oct 2012 20:21:31 -0400
> From: k8ri@rogerhalstead.com
> To: amps@contesting.com
> Subject: Re: [Amps] 300 W single band mobile amp needed
>
> On 10/7/2012 11:24 AM, rick darwicki wrote:
> > I have a friend that runs a motorcycle mobile on 20 Meters at about 100
> > watts. He is looking for a schematic/info/link
> for a simple no tune amp of about 300W that would just cover the SSB
> section of 20. Any help?
>
> It takes almost as many components for a solid state, single band ham
> amp as it does for the all band amp and to make it narrow band would
> take at least some of those components. Looking for compact size and
> inexpensive is different, but...
>
> The basic amp is the same layout and it requires the same protective
> circuitry and the same cooling area as an all band amp. The only real
> addition would be the filtering for one band instead of all bands and
> you'd still need it to keep the harmonics off 10 meters.
>
> Now that much power would also likely put the user into an area of RF
> intensity higher than allowed by the FCC which "probably" would not be a
> health problem but it's still more RF than allowed.
>
>
> 73
>
> Roger (K8RI)
>
>
>
> >
> > Thanks
> >
> >
> > Rick, N6PE
> > ================================== Talk is cheap... except when Congress
> > does it.
> >
> > _______________________________________________
> > Amps mailing list
> > Amps@contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
> >
>
>
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