[SOLD] Poor man 10MHz distribution amplifier with PPS now $150 + ship

[Zucca]

This is a poor man one. Let me explain....
It is a hacked Extron ADA 4 300MX HV so that it can be used as 10MHz distribution amplifier with a TTL section for a PPS signal.
I moved the coax connectors around and swapped all inputs and outputs resistors with precision 50 Ohm ones.



Inputs are in the middle, outputs left and right.
The first two rows from the top, red section, have 1 input and 12 outputs. The next third row, green section, have 1 input and 6 outputs. Those two sections should have 300MHz bandwidth, did not tested it. I tested the 10MHz, and I was happy with it.
These are two independent sections,  so you could leave the third row available for future funny experiments when you need to buffer a high speed < 300MHz signal in max 6 multiple points (all terminated in 50Ohm).
The fourth row, blue section, is the TTL one for PPS, 1 input and 4 outputs.

Ebay price is absolutely insane.

More pics here
https://extron.zucca.me

Asking $200 plus shipping.

[44kgk1lkf6u]

If you cared to replace the resistors with 50 Ω, why do the connectors look like 75 Ω?

[dxl]

I'm also using a VGA splitter to distribute 10MHz to all my Test equipment, but left all the 75 Ohm resistors in there. Didn't notice any problems so far (more than 2 years now), and don't think the mismatch causes trouble.

[Zucca]

When the transmission line is not terminated properly, a stationary wave is observed with nodes and anti-nodes.
If you are interested ONLY in the frequency, the stationary wave has the same frequency of the incoming (and reflected) wave.
Unless you are in the unlikely situation of:
- the receiver is sitting on an (anti/)node
- it has some problem of detecting the frequency due to the (low/)high signal
you will not observe any problem by leaving the 75Ohm resistors in and using 50Ohm in the rest.

For the pps signal the situation is slightly different, the edge will have some ringing if not terminated properly.
Again normally not a problem, it just depends on the situation.

I just replaced all the 75Ohm because it was cheap and the right thing to do. I do not want in the future to run into problems, maybe in the middle of a critical measurement/development.
 

[coromonadalix]

https://www.eevblog.com/forum/testgear/diy-10-mhz-distribution-amplifier-requirements-gathering/50/
https://www.jackenhack.com/reference-10-mhz-distribution-amplifier/

[KungFuJosh]

The jackenhack link is malicious. You should delete that.

[Zucca]

It is also disturbing in 2018 these were floating on Ebay for $20...

[Zucca]

On feebay for 20% more:
https://www.ebay.com/itm/298277847051

[Zucca]

down to $150