Re: FT-100D lowest usable voltage

Roy,
Here is a re-post of some data that I collected last year regarding the
ft-100d and supply voltage. I hope it helps.

I measured the output of the TA7809S internal 9v regulator at different
supply voltages. I did this only on receive. My power supply only has one
decimal of precision but the meter I used to measure 9V has 3. The
following are input current (to the rig) and 9v regulator voltage readings
at different input supply voltages.

V-in          I-in          V-9v
15.1V       1.27A      9.017V
13.8V       1.23A      9.017V
12.4V       1.19A      9.017V
12.0V       1.18A      9.017V
11.7V       1.18A      9.017V
11.3V       1.17A      9.017V
11.2V       1.16A      9.011V
11.0V       1.15A      8.875V

You can see that the regulator stays in regulation until 11.2 Volts.

I tuned to the 2m band and connected a 2m j-pole antenna. I checked in to a
local repeater and got a couple of signal reports at different input
voltages. I got clean audio reports all the way down to 11.7v. I did not
try any lower, but I think it would hold together a little lower.

-----

 Transmitting at 445MHz into a dummy load, I started getting a CW chirp
right around 11.9V. At 11.7V the chirp was quite pronounced. This would
have likely been fine if using FM. I also tested on 40m (7.285MHz). Same
setup but slightly different results. The CW note was clean down to 11.5V.
By 11.3V there was a noticeable chirp.

------

Mike M.
KU4QO

On Sun, Sep 23, 2018 at 3:51 PM, Roy Ashkenaz roya-b4T0evRm615ZmPDBg+/6q1aTQe2KTcn/@public.gmane.org
[FT100] <[email protected]> wrote:

>
>
> I am running my FT-100D (with WSJT-X etc) off of some 12v batteries. It
> works fine for 1-2 hrs, until at some point, the radio and rig control
> starts to do weird stuff - seems to be due to low voltage being fed to
> the radio.
>
> Does anyone know from experience what the lowest voltage I should use to
> run my radio? Specs for the radio show 13.8v +- 10% (1.38v) = 12.42 but
> it seems like I've run below this voltage.
>
> I am in the process of building/buying a low voltage alarm for my
> batteries (built ones are just a few $$ on ebay) and want to set it to a
> reasonable value.
>
> Thanks, Roy K2RMA
>
> --
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