Another interesting observation:

In a recent evaluation of our club's glider batteries (all 7AH
12v), we observed a very significant variation in weight. Is it
reasonable to deduce that a light battery cannot provide the same
hours of operation as a well designed heavier battery of the same
physical size? If so then we should also be watching out for
cheap-and-nasty batteries, where the manufacturer is skimping on
the lead content!

Cheers,

Jim Kelly.



"Malcolm Austin" wrote in message
...
Hi,
Just to dive in here, with a slightly off track comment.
The
benefits of extra
voltage on the radio transmit are not worth the effort. A quick
trawl
through
the figures shows that you need to make an x10 output improvement
in output
to
hear/notice it at the other end.

Changing the coax feeding the antenna to a good quality low loss
grade,
followed
by tuning the antenna for the frequency range your using, would
give more
useful benefits. The receive improvement gained here, is also
not to be
sniffed at.

I wonder how many have put a VSWR meter on their setup? Any SWR
above 1.5
is going to be a detrimental. On most gliders I would estimate
that the
power reaching
the antenna is only 50% of that, that left the radio!!

Malcolm - G3REM (but only a poor, K6 pilot)



"T o d d P a t t i s t" wrote in
message
...
"bumper" wrote:

By the time most modern radios would start to falter, the
battery is
already
pretty much discharged. Using an up-converter is this
circumstance would
only result in a very limited amount of additional radio
use - - along
with
a very discharged battery!

I don't think he was advocating an up-converter to increase
voltage when the battery was dying. I think he was
suggesting it for the additional transmitted power you would
get from 14 volts even when the 12V battery is fresh. Even
if it was practical (which I doubt) you'd be losing battery
capacity to gain the higher voltage - that's probably not a
good trade-off for reasons discussed in Tim Mara's post.


T o d d P a t t i s t - "WH" Ventus C
(Remove DONTSPAMME from address to email reply.)