Electronics > RF, Microwave, Ham Radio

Experimenting with waveguides using the LiteVNA

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Still looking for a better coupler to replace the old Narda part I have been using to measure S11.  The Narda 3095 looks like it would be a good fit.  Cheap, covers the X-band and good directivity.   These use the APC7.  There are some <$15 USD from China.  Searching this site, someone had asked about them a few years ago but I don't see any data.  They advertise them good for 6GHz.  Wonder how they perform at double that frequency. 


Cheap APC-7 SMA adapters from China.

Datasheet for couplers

3096, directivity 25dB

3095, directivity 33dB 

Wow you can sinter with a extruder printer?

I am guessing its a high copper content 3d print wire that is then baked in a kiln for burn out and sintering?

I am just waiting for my ground cable to come in for the tig lol, got the wrong gas lens in my kit so I only have the quartz one.

I think usually they say that out side of the frequency band of operation for the next octave you might be able to find a stable narrow region of operation that is potenitally usable in spite of the 'modeing' that occurs. But I have no idea for the band under. I think its potentially usable at a higher frequency for some small random bandwidth, but not with the lower end.. that is a hard cut off I think? Wavelenght too small for wave guide = odd transmission modes, wavelenght too big for wave guide =? (I think its very high reflection but not sure)

from what I understand : the most out of bounds components you have (operating past their max frequency) the less likely you can find a useful transmission band, since each component might have a random area that transmits some frequency but they are not correlated so with more then 1 component you might not have a path through.

I would say we tried to sinter with an extruder printer.   Yes, as you described.

All of the parts for that extender are fine for the X band now, except that coupler.  Even at 11GHz, it works better than I would expect but this is really the problem.   The mixer's IF is limited to 4GHz but right now, I can't even sweep up that high.   


Thinking I may add in that terminated SPDT relay as well so we don't have to move cables.   Eventually, it needs to get mounted into a box but for now I'll leave it as a 3D mess. 

Try finding couplers with over 25 dB directivity.   They are not common.  I want to keep the coupling at 10dB and plan to give up the half dB loss by leaving it in-circuit.   HP offered the 33311B relay with a 5V option.  It seems like it would be a good fit.   


here is a 50db coupler

hidden behind a quote wall.

it appears they are quite long for higher directivity

A 779D or similar is like 30dB.


might be worth checking the Flann brand out on ebay, they seem to be all that shows up for higher db directivity


your finger sir


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