[hpsdr] Amps for HPSDR

[Jeremy McDermond]

On Feb 9, 2011, at 10:34 AM, <lstoskopf at cox.net> <lstoskopf at cox.net> wrote:

> ***** High Performance Software Defined Radio Discussion List *****
> 
> One of the difficult steps in getting high power with the HPSDR is that the present line up puts out about 10 watts while off the shelf linears require 30 t0 100 watts.  There has recently been a lot of discussion on the moon lists about the DUBUS article using the MRFE6VP1K25  device for more than 1 KW out on 144 MHz.  You can Google that and look especially at the DUBUS supplement video.  4 watts drives it to full power.  A 6M version is coming.  The 50 v supplies are readily available from used telecom -48 use and I have two new in the box purchased on line at $30 each.  Awaiting an application to see if SSB dynamic loads work with them.  Someone will surely be out with a broadband HF board.

Remember that a lot of what prevents amps like this is FCC rules.  For anything under 144MHz, an "external" amplifier (or kit) that is sold, imported, modified, or attached to any station regulated by the FCC must be certificated under the rules in 47 CFR §97.315.  That flat out prohibits any amp that reaches its full design power with less than 50 watts drive.  47 CFR §97.317(c)(6)(i).  There are also provisions regulating the maximum gain an amplifier can have, see 47 CFR §97.317(c)(6)(ii), and requiring them to have no gain on the CB bands.  See 47 CFR §97.317(b)(2).

You can, of course, build your own amp that violates these certification requirements because there is an exception for that, but it must not be from a kit.  47 CFR §97.315(b)(3)(i).

So, finding a kit or built device that drives legal limit power on HF from 4 watts is going to be not only unlikely, but illegal in the United States.

> N0UU

--
Jeremy McDermond (NH6Z)
Xenotropic Systems
mcdermj at xenotropic.com




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