How To Tune A Duplexer 

We have an RF engineer in our club that was able to do this for us,but its' neat to see how it's done.. We've had the same Sinclair 2 meter duplexer since the 1990's , it needed a bit of touchup a couple of years ago ,considering it's been in a block building for 30 + years , it's certainly understandable .. We also used to have a Sinclair 8 bay folded dipole array,which was amazing .... Thanks for showing this ..

I love getting to tune the Sinclair duplexers. I am not in anyway a part of Sinclair so please keep that in mind. Just wanted to say that Sinclair makes a great duplexer!! I have never had a problem in getting it setup perfect!!!!!!!

Nice video other than the music at the beginning and end being 10x louder than the rest.

Thank you. This helped me greatly in understanding the Anritsu SiteMaster and what it was giving me for readings. I had peaked the frequencies not notched.

Sinclair products are excellent. Duplexers are simple to tune. I do not have ant fancy test gear. I use a generator and a receiver to tune at first , then touch up with low power to the inputs hi/low with a watt meter and set to minimum reflected. Have had duplexers checked with an instrument and spot on.. Wish I could own an instrument ...but $$$ which vI do not have. Have also built multicouple sets the same way.. Using a Motorola XPR radio with the RSSI reading as my guide. Can set insertion loss and a wattmeter for reflected .. The loop position is very important !! .... they work..

Good job

Thanks, this video was very informative!

No mention was made as to the position of the loop to control IL and or reject depth. Also the importance of the proper frequency dependent length of the cabling harness. Good video nevertheless.

where do you get those soldered T pieces...!!

Is this for Ham radio?

GOOD TO KNOW. I never seen that kind of T connector.... i used to tune those DECIBEL and Motorola MSF 5000/Qantar duplexer during late 80s to mid 90s I used HP spectrum analyzer and Cushman/Farnell/HP RF signal gen. RF SIGNALGEN IS SET to 0.00 dbm so that I have a direct readind. Initially all rods was set to all up and adjusted one or 2 of the rods until isolation is 90db and other rod to within 3 db insertion loss. I keep on playing also with tuning cap until I got the desired result

I wish this video showed a more ordinary test equipment. I don't know what that thing is, but all we use are 2670s with tracking generators...

It not clear how these things wire up looks like all are parallel. and I den't understand what capacitor tuning does. Can you explain total wiring

I have struggled with cable lengths when tuning duplexers with a tracking generator, (not using a VNA). After tuning a duplexer, if I change the two cables with different lengths, the IFR shows the tuning at different frequencies than first tuned. What is the correct cable lengths used to tune a cavity/duplexer. 300/f x VF x 1/2 wave length?

Can the cable assembly be purchased separately? The cables on my Q3220E are damaged and need to be replaced.

I do not have a VNA so I'm trying to use the SA-TG for this. I understand the lower display of the R&S VNA to be the S21 return loss. I don't quite get how to duplicate the SWR reading of the upper two screens though. I can get a directional coupler but would that require an additional 50ohm load at the T connector when trying to measure the SWR? This would be the directional coupler to the T and instead of a wire back to the VNA as in the video, I terminate it with a 50ohm load. Is that about right?

Great video.

I have I bit of a strange case, personally I don't own the richt tools.. however I do own two identical filters, one came tuned by a professional, the otter I want to tune my self. equipment I do have: nanoVNA (cheap Chinese tool) RTL-SDR stick (also cheap Chinese "tool") SWR-power meter (again, cheap Chinese tool) now for the fun-part, I have tuned the filter using the nano-vna, but the dynamic range is poor on those things,.. to get more range u use the nano VNA in CW mode (so It does not sweep, just produce the right frequency) than I use a 10 db attenuator (also cheap Chinese tool) and hook it up to the RTL-SDR and note the exact pont of the signal (frequency and amplitude) note: set the SDR to the smalles sample size since it increases the dynamic range. add one side of the duplex filter and remove the attenuator. now the amplitude of has decreased to the noice floor.... but luckily there is a gain in te RTL-SDR set this to a level you can work with, (not it down) and tweek (very carefully and not by much) the duplexer to minimum deflection! (add gain if needed to allow for signal-noice ratio) use a cheap radio tuned to the right frequency (pass frequentie) and measure SWR (my measurements came to 1.00 :) ) if both sides are done, you'r done. im to CHICKEN to use this duplexer right now, how big is the chance I tuned it completely wrong? I don't want to blow up my repeaters/radio's if anybody has an other cheap way to tune filters I would love to hear it :) 73, PD0HOF / PI1HRN (DMR repeater)

EXELENTE

Do you hawe 600KHz 145.600MHz -600 shift ? and what is the price ?

How do I tune a Q2330e with a HP 8924c? I don't own a network analyzer.

Do you guys reply to your viewer questions?

Nice

Who is the manufacturer of that "T" connector, also where can one purchase those "T" connectors from?

This video makes me want to buy Wacom.