When I worked in the Motorola factory back in the early 1970s, we had a
calibrated Bird wattmeter on each systems test bench, and a reasonably
accurate DC voltmeter as well. We could take the same radio, and move
it from bench to bench being careful to set the supply voltage as
closely as we could to 13.8 volts. There would normally be at least 10
watts difference between the lowest reading bench and the highest
reading one. And just because a bench read the lowest on 450 MHz
radios, did not mean that it would also be the lowest on the low band
and the 150 MHz bands. I had to know this so that I could more readily
talk our way out of a quality audit rejection on a radio, because their
test bench read differently than any of ours. So, I am not surprised
when a Ten Tec radio reads differently in a variety of locations,
especially after being subjected to the tender mercies of UPS.
Steve WA9JML
On 4/1/2011 2:00 PM, wa3fiy@radioadv.com wrote:
Mike,
Are you sure your Omni VI should not have left the factory delivering only 80
watts? For that
matter, what was it's power output when it left the factory?
I ask that because there is a target spec and a tolerance involved. The target
spec for the
Omni VI according to my manual is 100 watts max. What is the tolerance?
Dunno. the
manual does not say. For the Orion, the spec is 100 watts max. plus or minus
1db. That
means that the radio may deliver anywhere from 79.4 watts max to 125.9 watts
max and be
within spec. I doubt TT ships radios at the extreme limits but even if they
did, who on the
other end of the signal would know? Since the power output depends upon the
setting of
two pots among other things, there are a number of reasons the max output power
may shift
over time, etc. If it is important that the power meter show exactly 100
watts, it can be done.
But I ask again....why bother?
BTW, I've owned a lot of radios over the years and worked on a lot more from
most major
manufacturers. I've not kept a record but my rapidly fading memory tells me
that the output
power rarely matches the rated power. Some higher, some lower according to my
so so
equipped lab. The numbers I see here and elsewhere whenever this subject
comes up
represent a VERY small sample of the total number of units out there and are
interesting
perhaps but of little meaning otherwise. One would need to take a fairly large
sample to get
an accurate mean and std deviation. I used to know how to do that but
remember that
fading memory..... :-)
73,
-Lee-
On 1 Apr 2011 at 13:21, mike bryce wrote:
Lee,
you're absolutely right!
but...
I still paid for a 100 watt radio. I shouldn't have to tweak and peak
the trimmers inside to set the power correctly.
The omni VI I own shows about 80 watts give or take a few. And I KNOW
that no one alive will know the difference.
But...
It should not have left the factory like that.
I talked to Paul at the dayton hamvention about this issue and he told
me that in the case of the Omni VI, each radio has to 'learn' what the
power output is. While all the staff was overwhelmed with people from
the hamvention, he was unable to give me more details other than "send
it down"
And...
It's like buying a new automobile and finding out that the speedometer
is off, it's just a quick adjustment, but you still paid $28,000 for
the car-it shouldn't have left the factory like that.
mike
Mike, WB8VGE
SunLight Energy Systems
The Heathkit Shop
http://www.theheathkitshop.com/
J e e p
o|||||||o
"If you can't explain it simply then you don't understand it well
enough" Albert Einstein
On Apr 1, 2011, at 11:04 AM, wa3fiy@radioadv.com wrote:
'Couple things,
The difference between 88 watts and 100 watts is about 0.55 db which
is slightly less than 0.1 S unit (using 6db per S unit). Can
anyone hear that difference under anything other than lab
conditions? Can anyone hear 0.55 db difference under any
conditions? Probably not.
BUT you say...."I bought a 100 watt transceiver and I want a 100
watt transceiver!" OK, no biggie. First of all, get a lab
standard power meter and dummy load and set everything up. Then
adjust the two pots (it's two pots in most of the later TT rigs. Not
sure about the Eagle though) in the radio to calibrate the radio
power and alc such that you get exactly 100 watts. Not hard. I've
never seen a 100 watt TT radio that would not deliver at least 120
watts or so if you coaxed it. The radio can do it but why do it?
In fact, I generally calibrate my radios so 100 watts indicated is
well under 100 watts, 80 to 90 typically. I rarely ever operate
over 50 watts. Why? Because that's all I normally need and every
thing runs cooler and cleaner. If I need more, I fire up the
amplifier and get about 500+ watts with 50 watts drive.
We're not buying a lab instrument...we're buying a radio. In the
case of the Eagle (and most other radios I imagine), they do quite
well at that task.
To each his own. But you can have it spot on if you so choose.
-Lee-
WA3FIY
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