Handhelds and alkaline batteries

Jim Weir wrote in
:

Alkalines have a problem when you get to the power levels we are
talking about for transmit. They last a mercifully short time in most
HTs. We've found that popping for the NiMH cells is far better from a
time and life point of view.

The trouble with NiMH in a handheld used for emergencies (i.e. toss it
into the flight bag and forget it) is the HORRIBLE self-discharge rate.
Basically you need to recharge then every couple of months - especially
if they are kept in a warm environment. [Worst case self-discharge rate
is listed at 3% per day!!! NiCad is almost as bad, at 1% per day.
Note that both of these are WORST CASE.]

Alkalines are great at shelf life, but as Jim (furture govenor) says,
they may not support the current draw during transmit.

Two possible tests:

1. Put a scope directly on the battery pack during transmit - if you can
see the modulation (or any significant change), that's the problem.

2. If the result of step 1 is that you actually see the modulation (as
opposed to the overall voltage simply dropping too low) then it might be
possible to rig a super-cap across the battery.

What's the transmit power of that little handheld supposed to be anyway?

-----------------------------------------------
James M. Knox
TriSoft ph 512-385-0316
1109-A Shady Lane fax 512-366-4331
Austin, Tx 78721
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What's the transmit power of that little handheld supposed to be anyway?

My ICOM supposedly puts out 5 watts peak.

So what's the battery solution here? Is there a battery that can (a) handle
the output and (b) not discharge while sitting in the seat pocket?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

"James M. Knox" wrote:
What's the transmit power of that little handheld supposed to be anyway?

The answer to that is, it depends on the battery pack the transmitter is
drawing from.
The more cells (volts and milli-amp-hours), the more power (up to a
limit).
For the old ICOM A2 and A20, I have a choice of five or six different
battery packs, each providing a different power output and
transmit/receive time.