Ham Radio Duplexer Tuning

This is probably the best explanation of how to tune a duplexer I have seen on YouTube. You explain in detail assuming the viewer has no experience. It certainly gives the viewer a good starting point. Thanks VK2ZB

This is an excellent video, I purchased the same unit with no experience in lab equipment use or in cavity tuning and was able to successfully tune my duplexers and while doing so also managed to find a bad jumper. Thank you for the video.

Thanks!! I bought a Rigol 815 to tune both of my repeater’s duplexers. It has just sat on the bench now for close to 5 years due to medical issues... But.. With the current state of affairs here in the PRNJ (“People’s Republic of New Jersey “) during the CCP Virus and #StopTheSteal Election fraud matter, I decided it’s time to get everything squared away. I have 2x Motorola BpBr rack Mount GTR style duplexers and am replacing cheap-ass “mobile” style (notch) duplexers that are currently in place. As I have a Quantar UHF P25 repeater installed, it’s been painful to have it tuned down to 25w due to the ratios the mobile duplexer. (Licensed for 100w at this particular site). Plus I have a Hytera RD982 (analog/ DMR) repeater also tuned down to 25w. It is capable of 50w and its connected to a 100w PA which has been disabled awaiting the new duplexers. I ended up keeping one of the mobile style duplexers away to a “prepper” type group for GMRS use (and tossed them over an older MototXPR8400 repeater (it’s DMR / “mototrbo” — with digital capabilities disabled since its being used on GMRS bands) and... I kept the other mobile duplexer around as a “spare” for the Quantar or Hytera in the event of a lightning strike or BLM-Antifa attack of the repeater site. LOL Thanks so much for motivating me to get this stuff done!! Great video. One item: always use high quality test cables!!

A good explanation. If your SA has averaging capability, that will help you see the deep notches more clearly.

Hello! Thank You!! Might I suggest a 10dB pad in the generator output. It would then see a 50 ohm load. You may want to try that next time. Great presentation. The camera person should stay on the Rigol as your speaking. 73 de K8KEM DAVID

1.25 meter is starting to get a foothold here in middle Tennessee. The Alaska Morning Net is broadcasted on our 220mhz repeater. 73 👍

Thanks for sharing

Very good video. Congratulations. It would be nice if you did the steps in the Rigol. My other question would be if the Rigol DSA 1054 Z would be useful to adjust duplexers? Alexander CE2SCP from Chile.

How did you hook up the Spectrum Analyzer ? You hookup up the output from the Tracking Generator to the antenna side of the Duplexer. What did you do at the other end of the duplexer where you have two connections [one for transmitter and one for receiver] ? What did you change when you did the other cans ? did you change the connections? Thanks

hi there, we are running a 2 meter repeater, 147.165, 147.765 . it is old but still works well, Almost ,LOL, it has been giving us some issues, the issue seems to be we are getting some RF signals into the receiver, causing the repeater to stay on, breaking squelch, and sending noise out. if we lower the power output of the amp, the problem disappears and all is well. but as soon as we use any amount of power it acts up again. Do you have any ideas of first determining the issue, and second resolving the a issue ? thank you so much Bill VE3WTK

Ryan, trying to email you via Facebook, or? I need a step by step of the operation of the Rigol. I have one, I am getting close on my own to tune a 6 can set bpbr duplexers. Sam

Minor correction, you do not have "duplexers", but rather "a" that is "one" duplexer which are made from mutiple cavities. A particular assembly of certain cavities when properly cabled together is 1 duplexer

Could you please repeat that ? 😁

I might also suggest that you normalize your tracking generator

I have a question; why didn't you add a directional coupler and check your return loss while you were tuning ? It may have given you a clue as to whey your insertion loss was so high.