[TenTec] For FD, running Pegasus from lead-acid cell, need booster ?

[Thomas Jednacz]

I found it necessary for my FT-100 and for my friends ICOM 706. In case you
cannot measure the point where distortion or other problems occur then just
use the DC - DC converter to guarantee 13.8 V.

Tom, W7QF

-----Original Message-----
From: tentec-bounces at contesting.com
[mailto:tentec-bounces at contesting.com]On Behalf Of Mark W4CHL
Sent: Thursday, March 06, 2003 1:23 AM
To: tentec at contesting.com
Cc: TenTec_Pegasus at yahoogroups.com
Subject: [TenTec] For FD, running Pegasus from lead-acid cell, need
booster ?


Dear TenTec Pegasus lists,

? is a N4UAU type DC-DC regulator (booster) advisable or necessary for a
Pegasus running QRP off lead-acid batteries ?

In planning for Field Dqy, for the GOTA station thinking about
using the Pegasus with a laptop instead of:

- the club (original) IC-706 at GOTA HF station with control
software + logging laptop

- FT-817 also with control software + logging laptop

(I know, a K-2 beats 'em all, and one club member uses his, not
all of us have 'em !)

Of all, measured idle PS current on rec'v with squelched audio
out was:

 IC-706: 1.75A, Pegasus: 660ma, FT-817: 350ma

5W xmit into dummy load w/ 13.8VDC in:

 IC-706: 2.3A, Pegasus: 2.1A, FT-817: 2.0A

Laptop drain, IBM ThinkPad 755: 300ma idle, 1.1A peak @14.8V
(measured).

Other advantage is that operator is already at the PC keyboard
so logging to laptop is easier than with separate rig & logging
controls. Can almost get the FT-817 to operate same, but
receiver doesn't seem as sensitive (nor as flexible) as Pegasus,
programmed band scan isn't as nicely done (FT-BASIC).

What I didn't measure was drop-out voltage or stability under
12VDC.

We operate QRP, understand that the N4UAU design is 4A peak,
plenty for the Pegasus QRP, at least no PS volt droop measured
on 4A Astron PS at 5W out.  May get a separate kit for the
laptop, since that was an issue last year and ran an inverter
to laptop charger which drained cells faster than anything else!

Tx for advice and comment !

Cheers & 73s de Mark W4CHL

Mark R. Smith  W4CHL at arrl.net
Chapel Hill, NC http://www.qsl.net/w4chl
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