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50ohm Oscilloscope Straight Through Termination BNC to BNC

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dazz1:
Hi

50ohm through terminations are most commonly used to terminate a 50ohm cable at the input of an oscilloscope.    They stop signals being reflected back down the cable.   They can be expensive.

I found a source on Aliexpress that is fine for general electronic workshop use.

https://www.aliexpress.com/item/33027400993.html?spm=a2g0s.9042311.0.0.27424c4ddHDFlc

If the link doesn't work in the future, search Aliexpress for "DANIU 1Pcs Y1078 50 BNC Male To Female Plug High Frequency Test Socket for CCTV System Connection High Quality"
You can see that the title doesn't really say what it is.  I was only certain when I dismantled it.

The termination consists of 2x 100ohm leaded resistors that are accessible by unscrewing the adapter.  I am considering replacing those with 4x  200ohm SMD resistors to raise the frequency response to a few GHz to plug into my 60MHz analog scope.  Why would I do that?? Because I can !!  8)

Dazz

thm_w:
So we are sure its easy to unscrew?

https://www.eevblog.com/forum/rf-microwave/inexpensive-50-ohm-attenuator-tests/
https://www.eevblog.com/forum/testgear/50-ohm-feed-through-terminator/
https://www.eevblog.com/forum/testgear/banggood-50-ohm-bnc-feed-through-terminator-a-quick-review/

ChristofferB:
What is the advantage of this, at 60 MHz over a BNC Tee with one arm terminated into 50 ohm? Aside from the obvious style points

David Hess:
The stub length of the high impedance input after the termination ultimately limits performance so even a 1 GHz termination is sufficient.  Better performance requires moving the switchable termination to a point inside of the oscilloscope or using a coaxial relay to switch between high and low impedance inputs.

Another option to reduce return loss is to insert an attenuating pad before the feed-through terminator.

magic:

--- Quote from: ChristofferB on August 06, 2020, 11:12:01 pm ---What is the advantage of this, at 60 MHz over a BNC Tee with one arm terminated into 50 ohm? Aside from the obvious style points

--- End quote ---
Another thread:
https://www.eevblog.com/forum/projects/home-made-feed-through-terminator-for-bnc/
I built this and couldn't or could barely tell any difference in rising edge on a 200MHz scope.
Both looked pretty much spot on, though the generator also was an uncalibrated DIY job, I just tried my best.

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