Thank you so much, now I understand more about spectrum analyzers, to use tracking generator and cavity filter or duplexers. Amazing in one video you teach and share a lot of knowledge material, hope you are always healthy and blessed 🙏🏿
Thanks for another great video Peter! I had a duplexer like that on my old Regency repeater. No idea what I did with it. Brought back a lot of memories with that one lol. Have a good day and take care. 73 Buddy
I think it is fascinating to watch a spectrum analyzer while a filter is being adjusted, and see what each adjustment actually does to the attenuation spectrum!
On most duplexer connections, isn't the high connection used for receiving the signal and the Low connection used for transmitting the signal. Assuming the repeater receives on the high frequency and transmits on the low frequency?
Great video Peter! I have often combined these flat pack notch duplexers with additional cavity filters to help with out of band performance, essential for RF busy comms sites. One quick question, what equipment are you using for the spectrum analyser and tracking generator?
When adjusting a duplex filter, you must connect a 50 ohm termination to the port that is open, and after adjustment you must use a SWR bridge to get the correct point where the filter has its optimal and lowest SWR still with 50 ohm termination on the open port..
correct on terminating the other port properly, it wasn't done here ! simply adjusting for deepest nulls and lowest loss is insufficient without considering return loss also all these multiple rf connector adapters are highly inappropriate another serious consideration is lengths of the coax - ignored here as well poor job this repeater will work like crap
@@srdjanstanojevic4287 With a SWR bridge you get a much greater dynamics and resolution as well as a better control of the impedance in the selected frequency that you intend to tune the filter to, I recommend a very good page about tuning Duplexer and the difference between using SWR bridge, look at W2AEW's site he is tuning with both ways, 73 the SM4PDP
Peter, i agree with some of the other comments: The unused open port had not been terminated with a 50 Ohm load. Most, if not all duplexers need ALL the ports terminated during the tune up process as the unconnected port is still in circuit, despite not being "part" of the tune up circuit! Especially true with the small cavity multi-port duplexers that were originally designed for mobile use! Having said that, great video Peter and hope the new repeater is on air as we speak! Continue with the super work, 73, Brian EI8EJB
Hi Brian, yes you are right but as you said MOST duplexers needs to be terminated. This type is not vulnerable to it. I have tested it before with and without termination and no difference. In our final test we had both ports terminated tidily and our pre calculated and finally measured results are completely matching. But I see that I should have shown it with both termination loads simply not to confuse viewers and to teach what always is the right way and not what will only work partly. Thanks for comment 73
Wonderful reply Peter and I hope that you did not take my comment as a negative criticism; this was not my plan!! You have forgotten more electronics theory than most (including myself) will ever learn in a life time Peter! Alles gute! 73... :)
Great video as always Peter. Thank you for the efforts. Would like to ask what result have to expect if leave the notch and pass frequency little bit missaligned, but match the VSWR more close to 1:1. In other words, which is better: To keep notch not so deep (let say LF at -60dB and HF at -80 or -70dB) and VSWR close to 1:1. New ham here TA1OSN, Ferit. Respect and 73!
Hello, I'm wanting to setup a personal use repeater, Can I use the MX-72 Duplexer to do it? I see the one that you are using is setup high at 438.100 Mhz and low side is 430.500 on the J-unoda duplexer can you do the same with the MX-72 Duplexer? Sorry for the question, I'm new to ham radio. Or how can it be setup using the MX-72 Duplexer. I'm wanting to set it up as a GMRS repeater. I'm wanting to use just 1 antenna if possible. Thanks.
Interesting. 7.6 MHz offset? I figured it would be 5. Almost any amateur radio automatically adjusts for a 5 MHz offset. New info for me. Great video and got some great knowledge watching this. Keep them coming. 73, ad0am
@TRX Lab would you be kind to let me know what software and hardware you have you are using in this video to tune? I like how this one is setup and the hardware under monitor.
I have 2 VHF Motorola GM300s with a jumper cable on the back which makes the unit a repeater. I run 2 antennas for the Rx and Tx. I would like to run only 1 antenna. Can I purchase a duplexer, have it tuned and get rid of the jumper cable? Also, do I have to have a repeater controller just to make the GM300s and duplexer work? I would like to get by without using a controller.
Hallo Peter, schön gemacht! Richtig lustig wird es bei den 2m Duplexern mit 600kHz Breite..Da habe ich schon eine Kaskade von "Ölfässern" gesehen, die man mit der 1/2 Zoll Ratsche abstimmen musste;-) Gruß und 73 de Olaf, DK6KF Nice Work, Peter! Another funny thing is to do the alignment to 2m band duplex filters with 600 kHz bandwith. I have seen a "cluster of oilbarrels" that needed to be aligned with a 1/2" ratchet ;)
Peter, ich schaue schon von Video 42 an zu...;-) und arbeite mich noch rückwärts. Macht Spass! PS: Falls Du mal Teile aus dem kommerziellen Bereich brauchst, habe viele Ersatzteile zum Spenden..Ich arbeite gerne mit Bosch, Ascom und Motorola.
Another great video, I have never seen a duplexer being calibrated before, so it was fun for me. So, amateurs in Germany are allowed to use 12.5 KHz steps in Germany? We are still stuck with 25 KHz here in Turkey.... :(
What is inside the Duplexer cans? PI/PI-L networks? (I don't know anything about these) SWR: I would think that 1.5 swr would start to matter @ 440? Thanks, 73
Hi Bud there are many different concepts how this can be achieved. The best is to google it as it is far to much to answer it all here...Sorry mate. Thanks for watching 73
Surprisingly there is little information about what is exactly inside, I only found one example, it was a cavity filter which to me a basically a notch filter. So apparently there is nothing exotic going on inside them...
K5AZE Bud not much inside. There is some element (like the other end of that tuning rod) which effectively alters the physical dimensions of the cavity favoring only certain electromagnetic oscillatory modes. It is very much like the wineglass filled with different amounts of liquid resonating at only certain (audio) frequencies.
O.K......! Now I'm really confused ! Another video showed the opposite of how this video described the ports of the duplexer. Here he says that the High side is for the transmitter ? Another video I watched, claimed you should use the Low port for the transmitter ? Who is correct ? Or are the ports interchangeable, as long as you, the Tech/Operator understand how you designate each port ? 🤔....?
If any public safety LMR folk are watching and reading.... especially if you handle QC2 2-tone sequential paging / DTMF station alerting / etc... Check out the TPI-1005a RF communications device.... It has just about everything in a single package to permit local transmissions of alerting tones etc.. and RF (CW) signal & function generation all in a very affordable (aka cheap - $200-300 bucks?) package. A few UA-cam videos have been done on the device, so check them out if you have a spare sec.
If a signal is coming in on the "wrong" frequency it will be attenuated by the filter depth of the filter and if the filter depth is 50 dB yes it will be attenuated by 50dB
Just one doubt..it's possibile to use both of inputs at the same time using a single antenna with a duplexer !? Thank you for your commitment !! '73 :)
Exactly. One is used for recieve, and one for transmit, at the same time. This is the purpose of a duplexer. It allows a repeater to recieve on one frequency and re-transmit the signal simultaneously
A duplexer is needed in a repeater because the transmitter needs to be active at the same time as the receiver into the one antenna. You can use separate antennas for transmit and receive, but you would still need to have some kind of filtering to keep the transmitter energy out of the receiver antenna socket. Two antennas also means two coax cable runs and often more running costs if you are leasing space on a tower.
This is one antenna repeater system for both tx and rx. The receive signal is needed to pass thru the duplexer and go to the receiver, and at the same time the information is transmitting thru the same antenna. As Peter pointed out, the duplexer will notch out the tx frequency signal at the rx port. If a switch is used while transmit, then the receiver will not be connected to the antenna to receive any signal.
only problema here is you need used 50ohm in port duplexer for adjust you figure for tracking generetor no is good you need setting with 50ohm terminal 73 Raul
Nick, do you really think we could get our final result as we have seen it if my approach if it is a fatal error? All pre calculated and finally measured results are completely matching. At the finial test both ports were terminated... So my results are meaningless? Are you sure? Thanks for watching 73
hi thanks for replying, I really enjoy your videos & appreciate the time & energy that goes into making them, hope my comment didn't cause offence! Best wishes nick
I like your videos.Very professional and informative.Keep up the good work buddy ! Have a good day.
Thank you glad that you liked it 73
Excellent! Been years since I tuned a Duplexer!
Great explanation of duplexors. Excellent tutorial!
Glad that you liked it. Thank you 73
Fantastic video Peter, as always!!!
Thank you Mauricio. 73
Thank you so much, now I understand more about spectrum analyzers, to use tracking generator and cavity filter or duplexers. Amazing in one video you teach and share a lot of knowledge material, hope you are always healthy and blessed 🙏🏿
Very detailed video which is very helpful thanks again Peter
Great video, explained in great detail
thank you for the informative video about the duplexer. well done.
glad that you liked it 73
Thanks for another great video Peter! I had a duplexer like that on my old Regency repeater. No idea what I did with it. Brought back a lot of memories with that one lol. Have a good day and take care. 73 Buddy
The Radio Shop
It's buried in a pile somewhere. You'll find it when you need it the least. Look for it and you'll never find it. :-)
Thank you Buddy, yeah I have seen you diy video very good stuff. Take care my friend 73
Yeah Mike never try to find what you need :^)
exellent as ever looking forward to many more..cheers peter.
Thanks for feed-back 73
Congratulations! Great video explanation! much
clear and pointfull!
Glad that you liked it 73
Great video as always ,thank you Peter
Always glad to see you Dennis. Thank you 73
Great information on the subject clear and understandble.
Thanks for feed-back Patrick.
I think it is fascinating to watch a spectrum analyzer while a filter is being adjusted, and see what each adjustment actually does to the attenuation spectrum!
Yes I agree a vector network analyser is something amazing. 73
On most duplexer connections, isn't the high connection used for receiving the signal and the Low connection used for transmitting the signal. Assuming the repeater receives on the high frequency and transmits on the low frequency?
thank you for sharing so more information!
Thanks John 73
i hope yopu do vhf pre amp projects for repeater use, love you videos
Another great video by Peter. Excellent. Peter, can you do a video on folded dipoles for VHF or UHF base station repeater antenna.
Thank you Allen! Sorry I don't have the stuff to do a antenna video....
I am interested which can-adjustment does what to the notch or the bandpass, even if it is wishy.
Great video Peter! I have often combined these flat pack notch duplexers with additional cavity filters to help with out of band performance, essential for RF busy comms sites.
One quick question, what equipment are you using for the spectrum analyser and tracking generator?
You are right you can improve the performance that way. Thanks for watching Michael 73
When adjusting a duplex filter, you must connect a 50 ohm termination to the port that is open, and after adjustment you must use a SWR bridge to get the correct point where the filter has its optimal and lowest SWR still with 50 ohm termination on the open port..
Can you please explain SWR bridge? How do you do that? Thanks for the answer.
correct on terminating the other port properly, it wasn't done here !
simply adjusting for deepest nulls and lowest loss is insufficient without considering return loss
also all these multiple rf connector adapters are highly inappropriate
another serious consideration is lengths of the coax - ignored here as well
poor job
this repeater will work like crap
@@srdjanstanojevic4287 With a SWR bridge you get a much greater dynamics and resolution as well as a better control of the impedance in the selected frequency that you intend to tune the filter to, I recommend a very good page about tuning Duplexer and the difference between using SWR bridge, look at W2AEW's site he is tuning with both ways, 73 the SM4PDP
Peter, congratulations for your work! What Spectrum Analyzer do you used in this video? Thank you! 73`s, Chris, YO8RZE
Peter, i agree with some of the other comments: The unused open port had not been terminated with a 50 Ohm load. Most, if not all duplexers need ALL the ports terminated during the tune up process as the unconnected port is still in circuit, despite not being "part" of the tune up circuit! Especially true with the small cavity multi-port duplexers that were originally designed for mobile use!
Having said that, great video Peter and hope the new repeater is on air as we speak! Continue with the super work,
73, Brian EI8EJB
Hi Brian, yes you are right but as you said MOST duplexers needs to be terminated. This type is not vulnerable to it. I have tested it before with and without termination and no difference. In our final test we had both ports terminated tidily and our pre calculated and finally measured results are completely matching. But I see that I should have shown it with both termination loads simply not to confuse viewers and to teach what always is the right way and not what will only work partly. Thanks for comment 73
Wonderful reply Peter and I hope that you did not take my comment as a negative criticism; this was not my plan!! You have forgotten more electronics theory than most (including myself) will ever learn in a life time Peter! Alles gute! 73... :)
Ah,,... no the repeater is not yet up. I have to work on the receiver as well. Hope I can do a video on crystal temperature stabilisation...
No No don't worry Brian I'm not superman an do fail as anybody else....
You are too modest Peter! Looking forward to the next video and thanks as always for the detailed and very interesting videos!
Great video as always Peter. Thank you for the efforts. Would like to ask what result have to expect if leave the notch and pass frequency little bit missaligned, but match the VSWR more close to 1:1. In other words, which is better: To keep notch not so deep (let say LF at -60dB and HF at -80 or -70dB) and VSWR close to 1:1. New ham here TA1OSN, Ferit. Respect and 73!
-70 to-80 is a good result so go ahead if you have a good VSWR! 73
why there is not dummy load on open port?
I have a question can a 25 watt repeater handle a 30 watt duplexer or will I have to go at low power
Hello, I'm wanting to setup a personal use repeater, Can I use the MX-72 Duplexer to do it? I see the one that you are using is setup high at 438.100 Mhz and low side is 430.500 on the J-unoda duplexer can you do the same with the MX-72 Duplexer? Sorry for the question, I'm new to ham radio. Or how can it be setup using the MX-72 Duplexer. I'm wanting to set it up as a GMRS repeater. I'm wanting to use just 1 antenna if possible. Thanks.
Interesting. 7.6 MHz offset? I figured it would be 5. Almost any amateur radio automatically adjusts for a 5 MHz offset. New info for me. Great video and got some great knowledge watching this. Keep them coming. 73, ad0am
Forgot, you are in a different country. that explains the 7.6 offset. sorry
Yes that is the answer, Adam...Thanks for watching 73
@TRX Lab would you be kind to let me know what software and hardware you have you are using in this video to tune? I like how this one is setup and the hardware under monitor.
I have 2 VHF Motorola GM300s with a jumper cable on the back which makes the unit a repeater. I run 2 antennas for the Rx and Tx. I would like to run only 1 antenna. Can I purchase a duplexer, have it tuned and get rid of the jumper cable? Also, do I have to have a repeater controller just to make the GM300s and duplexer work? I would like to get by without using a controller.
Question: Can I run a 5w receive radio on one port and a 50 watt transmit on the second port? (Lets assume this duplexer is rated for 100watts)
Thank you so much. Can you do video tunning duplexer with nanovna?
I would like to see that.
Excellent video! 73 de SM4VFA
The high mhz side for transmitting and the low mhz for receiving please let me know im confused and learning
You are tuning a duplexer without a dummy load on the other end of the filter LOL. Good luck with the performance of it.
If I were you, I would technically and socially be careful in choosing my words to Peter.
@@pixeluser8243 you amateurs amaze me all the time
@@leosedf Bring your girl and she'll be too.
@@pixeluser8243 I wouldn't expect any other reply from an idiot amateur like you. Now go tune a duplexer without a load lol
Hallo Peter, schön gemacht! Richtig lustig wird es bei den 2m Duplexern mit 600kHz Breite..Da habe ich schon eine Kaskade von "Ölfässern" gesehen, die man mit der 1/2 Zoll Ratsche abstimmen musste;-) Gruß und 73 de Olaf, DK6KF
Nice Work, Peter! Another funny thing is to do the alignment to 2m band duplex filters with 600 kHz bandwith. I have seen a "cluster of oilbarrels" that needed to be aligned with a 1/2" ratchet ;)
Vielen Dank Olaf, ja da gibt es die wildesten Konstruktionen...., aber der hier ist echt handzahm :^) Danke fürs vorbeischauen. 73
Peter, ich schaue schon von Video 42 an zu...;-) und arbeite mich noch rückwärts. Macht Spass! PS: Falls Du mal Teile aus dem kommerziellen Bereich brauchst, habe viele Ersatzteile zum Spenden..Ich arbeite gerne mit Bosch, Ascom und Motorola.
Freut mich das es dir so gut gefällt, Olaf...Auch vielen Dank für das Angebot man weiß nie was man braucht. Ich komme gerne darauf zurück. 73
Another great video, I have never seen a duplexer being calibrated before, so it was fun for me. So, amateurs in Germany are allowed to use 12.5 KHz steps in Germany? We are still stuck with 25 KHz here in Turkey.... :(
Thank you Bora. Yes 12,5 is allowed...73
What is inside the Duplexer cans? PI/PI-L networks? (I don't know anything about these)
SWR:
I would think that 1.5 swr would start to matter @ 440?
Thanks, 73
Hi Bud there are many different concepts how this can be achieved. The best is to google it as it is far to much to answer it all here...Sorry mate. Thanks for watching 73
Surprisingly there is little information about what is exactly inside, I only found one example, it was a cavity filter which to me a basically a notch filter. So apparently there is nothing exotic going on inside them...
K5AZE Bud not much inside. There is some element (like the other end of that tuning rod) which effectively alters the physical dimensions of the cavity favoring only certain electromagnetic oscillatory modes. It is very much like the wineglass filled with different amounts of liquid resonating at only certain (audio) frequencies.
O.K......!
Now I'm really confused !
Another video showed the opposite of how this video described the ports of the duplexer.
Here he says that the High side is for the transmitter ?
Another video I watched, claimed you should use the Low port for the transmitter ?
Who is correct ?
Or are the ports interchangeable, as long as you, the Tech/Operator understand how you designate each port ?
🤔....?
I like your accent. Love the video.
Please give some more informations about your measure equipment. What kind of analyser you use? Brand ? Model?
in video #77 you'll find the answer...
Why do you have the other unused port unterminated? I see people terminate the unused port
If any public safety LMR folk are watching and reading....
especially if you handle QC2 2-tone sequential paging / DTMF station alerting / etc...
Check out the TPI-1005a RF communications device....
It has just about everything in a single package to permit local transmissions of alerting
tones etc.. and RF (CW) signal & function generation all in a very affordable (aka cheap - $200-300 bucks?)
package. A few UA-cam videos have been done on the device, so check them out if you have a spare sec.
Will the transmitter desensitized the receiver at -50dbm?
If a signal is coming in on the "wrong" frequency it will be attenuated by the filter depth of the filter and if the filter depth is 50 dB yes it will be attenuated by 50dB
not really clear on video if your tuning the high side do you loosen all six ? the high side has 3 adjustments and the low side has 3 adjustments?
This is an iterative setting so you move all the controls over and over again
Can HIGH port transmit as LOW port?
Just one doubt..it's possibile to use both of inputs at the same time using a single antenna with a duplexer !?
Thank you for your commitment !! '73 :)
Exactly. One is used for recieve, and one for transmit, at the same time. This is the purpose of a duplexer. It allows a repeater to recieve on one frequency and re-transmit the signal simultaneously
is it also possible to use both of input on TX at the same time !?
Haha!! I've tuned many of those in my time!!
Yes that is pure fun 73
Probably should have a 50ohm dummy load on the open port.
What VNA are you using?
Hi, watch video #77 and/or #106. There you get all needed informations. Thanks for watching. 73
Peter was benutzt du als Spectrum Analyser?
Hallo Andre, schau mal mein Video #77 dort werden alle Fragen beantwortet
Peter hast du schon mal einen ICOM 718 in der Hand gehabt und du die RX Werte eingestellt?
Uhf can be vhf?
You'd have to terminate the terminals not used for measurement with 50 ohms.
why cant we just use a switch to disconnect between transmit and receive?
A duplexer is needed in a repeater because the transmitter needs to be active at the same time as the receiver into the one antenna. You can use separate antennas for transmit and receive, but you would still need to have some kind of filtering to keep the transmitter energy out of the receiver antenna socket. Two antennas also means two coax cable runs and often more running costs if you are leasing space on a tower.
because it you do that it is no longer Duplex......you need to be able to TX and RX at the same time with a repeater.
This is one antenna repeater system for both tx and rx. The receive signal is needed to pass thru the duplexer and go to the receiver, and at the same time the information is transmitting thru the same antenna. As Peter pointed out, the duplexer will notch out the tx frequency signal at the rx port. If a switch is used while transmit, then the receiver will not be connected to the antenna to receive any signal.
only problema here is you need used 50ohm in port duplexer for adjust
you figure for tracking generetor no is good you need setting with 50ohm terminal 73 Raul
This topic has already discussed here in the threat down below.. Thanks for watching 73
Flat packs should only be used in portable repeaters.
Too much talk..next time just tell wharts that thing use for
easy don't watch it :-)
great video but you made fatal error, you didn't terminate the unused port so results are meaningless!
Nick, do you really think we could get our final result as we have seen it if my approach if it is a fatal error? All pre calculated and finally measured results are completely matching. At the finial test both ports were terminated... So my results are meaningless? Are you sure? Thanks for watching 73
hi thanks for replying, I really enjoy your videos & appreciate the time & energy that goes into making them, hope my comment didn't cause offence! Best wishes nick
No No don' worry I'm always open for discussions. Have a nice day 73
This was so long and boring I had to skip through it. Was there a part where he showed how he trimmed the duplexer? I mean the physical box.
He must get paid per word or something. I can't take it any more! 3 minute of actual usable teaching and 47 minutes of "yeah", "um" and word salad.
taking too much time to explain :(