Its not a standard car of truck. Were talking a MOTORCYCLE !!!
How much separation could you get? 1 foot? 18 inches?
73
Jim W7RY
-----Original Message-----
From: Hal W5GHZ
Sent: Monday, October 08, 2012 11:57 AM
To: Charles Harpole
Cc: amps@contesting.com
Subject: Re: [Amps] 300 W single band mobile amp needed
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.
>
> _______________________________________________
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> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
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