Bob,
This is a common problem for which there are two solutions:
1- use the battery booster
2- put in much bigger battery cable -- like awg No 4 cable. Believe
it or not, when you are drawing 20 amps the loss (amp squared times
resistance) is huge with cable that is not extremely low loss. I
found no 12 gauge or no 10 gauge simply too lossy. (you can find
resistance tables on the internet, and measure length of the cable as
the round trip distance to /from the battery). Also, replace the
in-line fuses with contact switches, which are much less lossy
(although more expensive).
I have been operating mobile for 10 years now with a Delta II xcvr
from Ten Tec. I love the rig and it performs well with my option 2
solution. (I am thinking about getting the battery booster for future
mobile setups).
Good luck and 73,
Fred K6KX
----- Original Message -----
From: "Bob Stephens" <bstephens1@mindspring.com>
To: <tentec@contesting.com>
Sent: Tuesday, April 19, 2005 4:54 AM
Subject: [TenTec] boost mobile voltage?
> I thinking of getting a W4RRY battery booster for my mobile/portable
work.
>
> The problem:
> 1.The 50 watt (10 amp key down) Scout will not work
properly with
> the engine off or with the engine in idle. Among other things,
the
> frequency becomes quite unstable during transmit. However, the
rig work
> fine when the car is in motion and the RPMs are up. The
Scout also
> works fine when used in a base station with regulated voltage.
>
> 2. My Corsair has similar but less problems when operated
in the
> car. It will not operate properly with the engine off.
Sometimes it
> will work ok with the engine on idle, but other times it does
not. I
> think this may have something to do with whether or not the
> electric fan for the engine is on. It seems to me that the
amount of
> load is a factor (?)
>
> Meter readings:
>
> 1. With the engine off, the battery shows 12.51 volts at
the radio
> end of the cable. However, if I transmit in SSB for 10 seconds
and
> recheck the voltage , it drops down to 12 volts.
>
> 2.The meter reads 14.2 volts when the engine is running.
>
> conclusion?
>
> I'm guessing that my car electric system is not delivering full
power under
> load. Would the W4RRY booster be one way to solve the problem?
>
> tnx & 73
> Bob, KB1CIW
>
> p.s. tnx to those who helped me find the new site for W4RRY
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