[time-nuts] Any reason not to use one power amplifier and splitter for distribution amplifier?

paul swed paulswedb at gmail.com
Sat Jan 3 22:37:33 EST 2015

I am sure there will be many answers. But yes indeed it will work fine. All
of the outputs should have the same delay also and that may be useful.

There really are the two approaches. The big power amp thats a 1/2 Watt you
are talking and the many small amps as in the distributed mode.

Whats interesting is the telcos always do the big amp splitter and the test
equipment manufactures use precision distributed distribution amps. I guess
its a pick your poison. Or maybe the test equipment manufacturers needed
more isolation port to port. Or heavens maybe they could just sell them for
more money. Would they do that?
Humor aside each has a very good reason for doing the distribution and its
driven by the requirements.

I have several of those spitters and picked them up for $ 0 at hamfests.
Seems no one had a use for them when all of the 900 Mhz gear came out of
the sites. Mostly gone at this point. A 1/2 watt 10 Mhz amp is not that
hard to build look at the many Ham sites we have a band close to 10 Mhz/ 30

On Sat, Jan 3, 2015 at 6:09 PM, Dr. David Kirkby (Kirkby Microwave Ltd) <
drkirkby at kirkbymicrowave.co.uk> wrote:

> I was looking to make a 10 MHz distribution amp to feed test equipment with
> the output of a GPSDO.
> I see this
> http://m.ebay.com/itm/201244302355
> 16-way Minicircuits splitter on eBay which I got for $40. I guess the loss
> is around 12 dB.
> I actually bought another for $35 which was similar but  one of them, the
> isolation data made no sense,  so given their low cost I just bought both.
> I suspect internally these 16 way units might have a pair of 8 way dividers
> as there are two isolation figures,  depending on what ports one is
> measuring between
> Is there any reason not to just drive that with 22 dBm or so of power to
> get 10 dBm at each of 16 ports?
> Is 10 dBm an optimal value?
> I see several distribution amp designs witb one amplifier on each output,
> but is it just a lot less hassle to split a higher power amp.
> I have a range of Minicircuits amps in my junk box in little enclosures,
> which means a distribution amp can be built from just 3 main components
> * PSU
> * Power amplifier
> * 16 way splitter.
> That seems a *lot* simpler than many designs I see.
> I was looking to feed it with an HP 58503A or similar device.
> I do have an amplifier in my junk box which will produce 27 dBm. If I
> combined that with 16 x 5 dB attenuators I could improve the isolation by
> 10 dB, but I am unlikely to find the attenuators cheaply, and buying new
> would add at least $200-$300 to the price, for what I suspect is no
> significant benefit.
> Dave
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