Ok Skipp, and Jesse,
So, I supposed that the specification of such, should be presented by the
manufacturers of the said, and with the said, right! Or there is a general
concept for duplexers, as in both examples, .1 to 3dB Jesse, and Skipp input
loss 15 to 35%
And which will be more accurate to work from dB or %.
I always try to get a good balance when I'm tuning duplexers, most times I
ended up taking a loss on the power for a better result on the receiver side,
is this the best way to go? Or it depends on your situation, whether or not
the extra power would effect your weakest signal! (most times a final touch
up is done at the repeater site, it always make me feel like a "perfectionist")
Sometimes I still depend on my ears, then take a look at the test gears, 99% of
the time I go with my ears because the difference don't be much when the
duplexers are setup to the test gear figures.
So, is the figurers always the right thing to work with, or they are just
guides for a Tech with a bad hearing?
v44kai.....Joel.
----- Original Message -----
Fom: Jesse Lloyd
To: Repeater-Builder@yahoogroups.com
Sent: Wednesday, August 29, 2007 12:54 PM
Subject: Re: [Repeater-Builder] Re: Duplexer input and output power
Ya, duplexers will have insertion loss. Typically you get more insertion
loss with more rejection, so its a balancing act.
Insertion loss can range from .1 dB (very good) to 3 dB.
Typically if I can get a duplexer to less than a dB I'm happy.
Insertion loss (dB) = 10 log ( PIN / POUT )
So Pout = Pin x 10^(Insertion Loss/10)
So for 50 Watts:
.1 dB = 48.9 Watts
.3 = 46.7
.5 = 44.6
.8 = 41.6
1 = 39.7
1.2 = 37.9
1.5 = 35.4
2 = 31.5
2.5 = 28.1
3 = 25
Jesse
On 8/29/07, skipp025 <[EMAIL PROTECTED]> wrote:
Hi Joel,
In the real world it depends on the duplexer type, size, quality,
operation and setup values, which may be fixed or adjustable.
Just throwing out a generic rule of thumb... you will find many
duplexers lose about 15% to 35% of the input power. One would hope
for near zero loss but that will never happen.
A common quality duplexer has adjustable probes or coax ports (the
name used is based on the duplexer type), which often trade what we
generic call insertion loss for increased performance.
Loss through a duplexer is not always a linear graph of power in
vs power out.
Just to put something out... be happy if a properly setup and
working duplexer delivers 75% to maybe 95% of the input power.
Be grateful if you receive better than 85% of the rated power.
A really "tight" duplexer might eat as much as 35% to 40% of
your input power and there are much worse possible examples.
cheers,
s.
> "Joel" <[EMAIL PROTECTED]> wrote:
> Is there a table or formula or ratio for power input to a duplexer,
> to the resulting output power of the said? For instance, if I put
> 10, 20, 50, 100 watts to the input, what should be the output, with
> a 50 Ohms at the load?
>
> example 10,20, 50, 100 watts in = x output @ 50 Ohms. "BASED
> ON A PROPERLY TUNED DUPLEXER"
>
> I think someone had a short for-instance on this, can't find it,
> and will like some insight on this.
> v44kai.....Joel.
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