[Yaesu] New VX-5R """Thanks""""

[Ronald Walters]

Thanks for your input Frank, I received several replies and I want to
express my thanks to everyone that contributed.  I was a little surprised at
the efficiencies that most of the group stated, guess I went brain dead
since I should have realized that the case was acting as a heat sink.  Again
thanks to everyone who took the time to send a reply, it indeed is the
season of giving.  What a great group

Best wishes for a very happy new year

Ron - W4LDE

----- Original Message -----
From: "A10382" <a10382@snet.net>
To: "Yaesu - qth reflector" <yaesu@mailman.qth.net>
Sent: Thursday, December 26, 2002 16:59
Subject: Re: [Yaesu] New VX-5R


Suggestion... reduce output power.  Most folks run at more power than
needed, particularly when operating on local repeaters.  If you find that
reducing power does not let you trip the repeaters, then just keep your
transmit time to a minimum.  An HT is not the best rig to ragchew on.
-----

My Yaesu HTs are about 30% 'rf efficient.  To get the ratio, you need to
know the battery voltage and power draw at both transmit and when idle.
Numbers for various output power setting can be found in the user manual.
Subtract the 'idle' current (needed to run basic radio electronics) from the
Tx current and then figure the power in watts for both (battery voltage x
amps).  Divide the Tx wattage by the radio battery TX wattage draw.  Mine is
something like 5W / 18W = 28%  (almost 13W is expended in the radio in
getting the 5W out the antenna (on my FT-530 - measured at 4.9W with a fully
charged 12V battery).

If it takes 1500ma at 12V of battery draw to output 5W from the radio, the
'rf efficiency' is approx.  30%.  30-35% is rather typical for 2-5W HTs.
Base station units can fare a little better - sometimes running 35% 'rf
efficient'.  Most power over and above that radiated (the 5W) is lost as
heat in the radio and even a bit in an inefficient and mismatch antenna
system.  Some of the 'lost power' is also used to light leds - which can
draw as much as the whole radio while in 'power saver' mode.

?? How long could you hold onto a small metal box that contained a 7W
'Christmas tree' bulb ??   Not very long, I'd bet.
-----

I'd like to see ARRL's lab add 'power efficiency' to their extensive lab
test regimen.  It should be an important item for those who operate from
emergency power.


Frank


 ._._.
----- Original Message -----
From: "Wilson A. Caselli" <K1MIJ@webkorner.com>
To: "Ronald Walters" <rwalters8@cfl.rr.com>; "Yaseu Users Group"
<yaesu@mailman.qth.net>
Sent: Thursday, December 26, 2002 11:49 AM
Subject: RE: [Yaesu] New VX-5R


> You will also observe the heating "Phenomenon" when using the unit on 2
> Meters.
>
> If the transmitter output stage is only 50% efficient, then for 4.5 Watts
of
> output power,
> the radio would actually be expending 9 Watts of energy.  4.5 Watts out
the
> antenna
> jack, and 4.5 Watts of inefficiency expended as heat.
>



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