[time-nuts] was there ever a "conclusion" on distribution amps ?

John Ackermann N8UR jra at febo.com
Wed Feb 23 18:58:05 UTC 2011


All --

I hesitate to make pre-announcements, but TAPR plans to produce a very 
high performance replacement for the TADD-1, as well as a single-channel 
version for buffer/isolation amp use.

I'm just on the verge of ordering alpha boards for the single channel 
version.  I really can't hazard a guess as to availability dates yet, 
but we'll make a more specific announcement when we have a better 
picture of the road ahead.

John
----

On 2/23/2011 12:52 PM, Pete Lancashire wrote:
> was thinking along the lines of this (now discontinued)
>
> http://www.tapr.org/kits_tadd-1.html
>
>
>
> On Wed, Feb 23, 2011 at 8:51 AM, Bob Camp<lists at rtty.us>  wrote:
>> Hi
>>
>> How good a 10 MHz do you need noise wise?
>>
>> If the stuff is common lab gear, there are a bunch of ways to go. If you are
>> driving dual mixer setups then your choices narrow down a bit. Having stuff
>> on one bench (and ground) is easier than running cables hundreds of feet.
>>
>> Assuming it's normal lab gear on one bench:
>>
>> Sixteen port power splitters from a junk pile should have about 12 db of
>> loss. Run about 100 mw / 20 dbm into it and you will have plenty of signal
>> to run normal lab gear. An ACMOS hex (or octal) buffer based amp can give
>> you that sort of power. Having the logic levels also helps get to 1 and 5
>> MHz. Not a lot of isolation, not real low noise, plenty good enough for 1 to
>> 2x10^-11 at one second.
>>
>> A few alternatives are also pretty easy. Use a single logic to sine amp per
>> output and drop the power splitter. Run video amp chips and forget about the
>> logic conversion. For better performance, run discrete 2N3904(6) based amps
>> for each channel. A lot depends on what you already have lying around.
>>
>> If it's not the garden variety stuff, then indeed you likely will need
>> something a bit more complex. I'd still consider a simple system to drive
>> the easy stuff and only go fancy for the one or two things that really need
>> something that's low noise / high isolation / what ever.
>>
>> If you also are trying to do RF work (like HF radio) consider the spray from
>> what ever you do. I have seen 10 MHz standard setups that put out massive
>> signals at 30 or 50 MHz. A bit of thought, a solid ground sheet, and some
>> cheap coils / caps can go a long way.
>>
>> Bob
>>
>> -----Original Message-----
>> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
>> Behalf Of Pete Lancashire
>> Sent: Wednesday, February 23, 2011 11:18 AM
>> To: Discussion of precise time and frequency measurement
>> Subject: [time-nuts] was there ever a "conclusion" on distribution amps ?
>>
>> I will soon have my 11 th piece of equipment that I want to feed 10
>> MHz (and some oldies 5 and 1).
>>
>> What is the current though on making one's own distribution box ?
>>
>> -pete
>>
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