From: Harry Popov <lz1bb@mail.bg>
To: "H.Haines Brown" <brownh@hartford-hwp.com>
Cc: dplatt@radagast.org, linux-hams@vger.kernel.org
Subject: Re: struggling with gMFSK setup
Date: Fri, 03 Nov 2006 21:07:27 +0200 [thread overview]
Message-ID: <1162580847.4376.27.camel@ham> (raw)
In-Reply-To: <20061103140739.06C951173@teufel.hartford-hwp.com>
BTW...
> The FT-817 manual says nothing about limiting power for digital
> modes. So apparently it's safe to run a full 5-watts, but based on
> what you say about IMD, 2.5 would be a good idea.
One good hint for FT817 users. Radio is getting hot on 5W. But most of
heat is coming not from power transistors but 7V inside voltage
regulator. Solution is to power it from low voltage. I use around 10V.
With 10V you still have 5 Watts power but much less heat. If your supply
is with fixed 13.8V output just connect 4 silicon diodes in series.
Connect one end to the power suplay and second to radio. You have
roughly 0.7 V dropping in a single diode. So 4x0.7=2.8V.
13.8-2.8=11V. You will be surprised how cool is FT817. Diodes should be
capable to pass 2A. I use 5A/30V diodes.
73, Harry LZ1BB
next prev parent reply other threads:[~2006-11-03 19:07 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-10-29 20:50 struggling with gMFSK setup Haines Brown
2006-10-29 21:52 ` Tomi Manninen
2006-10-29 22:47 ` Haines Brown
2006-10-31 19:25 ` Haines Brown
2006-10-31 22:58 ` Dave Platt
2006-11-02 21:32 ` Haines Brown
2006-11-02 22:05 ` Dave Platt
2006-11-03 14:07 ` Haines Brown
2006-11-03 18:48 ` Harry Popov
2006-11-03 19:07 ` Harry Popov [this message]
2006-11-05 4:35 ` Dave Platt
2006-11-01 4:38 ` Harry Popov
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