[Lowfer] Operating from 12VDC battery full time.

Sun, 24 Feb 2002 19:24:20 -0600

After reading about the difficulty for isolating the feedline on a
whip antenna, I suspect that it would be nearly impossible to
fully decouple the AC wiring from your battery charger.
Les, why don't you try this simple test?

1) First confirm that when you switch from your power supply to
the battery, your noise level goes down.

2) When you have observed that and while still on battery,
connect the ground pin of your AC outlet to the LF rig.
If this adds noise, you have work to do.

3) When you still have the battery powering your LF rig,
add one lead of your battery charger to the battery.
Does the noise go up? If so, you have work to do.
If not, add the other battery charger lead too.

You may be able to devise a filter to minimize the contribution
of noise from you AC wiring, but carefully controlled test are in
order. Keep us posted.

You may have to charge the battery, only when you do not use the
rig for critical LF reception or even switch to AC power supply
and charge the battery when not using the rig for critical LF reception.

Jim Shaffer, WB9UWA.

----- Original Message -----
From: John Davis <[email protected]>
To: <[email protected]>
Sent: Sunday, February 24, 2002 11:40 AM
Subject: Re: [Lowfer] Operating from 12VDC battery full time.

> >
> >Is there a way to filter the charger's input so that I don't pick up more
> >noise from it? Someone mentioned putting  a choke on the charger but
> >no details.
> >
>
>
> It may be possible to filter the AC going into the charger enough to help,
> but I suspect an isolation transformer would be the most effective
approach.
> The less coupling between the gear and the AC mains and the AC ground
lead,
> the better.  Some capacitance across the rectifier junctions could be
> helpful too.
>
> 73,
> John
>
>
>
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