[Amps] 300 W single band mobile amp needed

[Jim W7RY]

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 at 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 at hotmail.com>
To: k8ri at rogerhalstead.com; "amps at contesting.com" <amps at 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 at hotmail.com
> Date: Sun, 7 Oct 2012 20:21:31 -0400
> From: k8ri at rogerhalstead.com
> To: amps at 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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>
>
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