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Old 26-May-2020, 5:31 PM   #7
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Join Date: Mar 2016
Location: Beach Park IL
Posts: 292

Originally Posted by tripelo View Post

See one image. It is open combiner case.


There could be other difficulties, but a noticable one is:

A difficulty with combining UHF with Q-wave matching is the union of the three cables.
All parameters are more critical at UHF, than VHF.

Inside the open case, the impedance is no longer 50 Ohms or 75 Ohms.
Therefore the correct impedance match of 37.5 Ohms (parallel combo)
to 75 Ohms via the Q-line is not occurring.

Since at VHF the dimensions (wavelength related) are about three times larger,
then the mismatch caused by impedance bump at the joint has less effect (although it is still there).

Best to join all cable as closely as possible (including shields).
Maybe could do that by drilling the case and running shields all in.
That means very short distances of cable that are not fully shielded.
Even this approach is considerably less than perfect.

There could be other factors not considered.

Hi Tripelo.
Well, I can try that, since this isn't working.

I figured the "T" connector would do all that is required:

Attached Images
File Type: jpg 20200526_122429_copy_800x800[1].jpg (159.1 KB, 316 views)

Last edited by bobsgarage; 27-May-2020 at 4:12 PM.
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