[Amps] OK, here's a home brewing question. I JUST DON'T GET IT!

[Larry]

Ron,

I assume from the clips below that you are objecting to the use of a big 
amp on the new bands. Clearly you have not realized the big picture.

Given that a 1/4 wave vertical for the 630 meter band is 500 feet tall 
and a "good" radial system would need a 2000 foot circle of dirt, 
practical amateur antenna systems are by necessity very lossy. Typical 
backyard antenna solutions run between -15 to -20 dBi gain. Please note 
the minus sign. That does not include the tuning unit losses. So it is 
not unreasonable to require 500 watts of transmitter power output to 
achieve the proposed legal limit of 5 watts EIRP.

The situation on the 2200 meter allocation is even worse with antenna 
gains running -30 dBi (or worse). So a 1 KW amp for 1 watt EIRP is typical.

Also note that those of us who reside in countries where the bureaucrats 
in charge of allocations are lazy and politically driven are using 
experimental grants for TX privileges. Basically with a grant you can 
have any power you ask for. In my case I am licensed for 20W ERP even 
though I cannot ever achieve that level.. Many other US grants are good 
for 100-200W ERP.

Amp builders can have a lot of fun with the 137 and 475 kHz bands. Most 
builders prefer class D/E but I favor linear designs. I built a 400 watt 
linear amp mostly using parts salvaged from obsolete servers. See my web 
page for pix, etc.

73,

Larry - W7IUV / WH2XGP


>   The 600 meter (or 630 meter) amateur radio band is a frequency band
> allocated by the International Telecommunication Union (ITU) to amateur
> radio operators, and it ranges from 472 to 479 kHz, or equivalently
> 625.9 to 635.1 meters wavelength.
>
>  The band is available on a secondary basis in all ITU regions with the
> limitation that amateur stations have maximum radiated power of 1 Watt
> effective isotropic radiated power (EIRP); however, stations more than
> 800 km from certain countries may be permitted to use 5 Watts EIRP.
>
>   from:  https://en.wikipedia.org/wiki/600-meter_amateur_radio_band
>   ==  ==  ==  ==  ==  ==  ==  ==  ==  ==
> The U.S. Federal Communications Commission (FCC) granted the American
> Radio Relay League an experimental license to explore such uses in
> September 2006. In 2015 the FCC proposed rules to permit amateur use of
> 630 and 2200 meters in line with decisions made at the World
> Radiocommunication Conference 2012.
>
>   from:  https://en.wikipedia.org/wiki/600-meter_amateur_radio_band