TenTec
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Re: [TenTec] SOTA RADIO

To: tentec@contesting.com
Subject: Re: [TenTec] SOTA RADIO
From: Lee <lee@wa3fiy.com>
Reply-to: Lee <lee@wa3fiy.com>, Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Sat, 19 Mar 2016 20:42:59 +0000
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
I was following some bunny trails re that Chinese 50 watt amp and saw a fairly extensive set of graphs run by one owner and they looked ok. Sorry, I don't have the url for that. Maybe someone here knows where they are.



-Lee-



WA3FIY

------ Original Message ------
From: "Jim Brown" <k9yc@audiosystemsgroup.com>
To: tentec@contesting.com
Sent: 3/19/2016 2:04:27 PM
Subject: Re: [TenTec] SOTA RADIO

On Sat,3/19/2016 10:39 AM, geoffrey mendelson wrote:
Both MFJ and Ten-Tec bought rights to sell them assembled, and in order to pass FCC approval had to add output filtering. I forget which, but one company sold them as two band radios, and the other as single band.

I would have the same concerns about FCC approval and harmonic suppression with that 50W amplifier being mentioned earlier in this discussion. There's no way a ham should put either of those no-name imports on the air without first checking them for spurs and harmonics with a spectrum analyzer into a dummy load.

Don't have a spectrum analyzer? That's no excuse -- if there are harmonics or spurs, YOU are in violation. Indeed, that's part of the responsibility of having a ham license, and it's why we as hams CAN build stuff without having it FCC approved. We should KNOW, because we've studied, that virtually any ham amplifier creates harmonics that must be filtered. The second harmonic in a power amp is typically only 6 dB below the fundamental before the output network filters it! But it still must meet FCC requirements for RF cleanliness.

73, Jim K9YC
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