Questions tagged [duplexer]

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2 votes
1 answer
91 views

A passive splitter/combiner in full-duplex mode

We have an RF chain where a full-duplex radio transceiver with Tx and Rx port operating on different frequencies. These are connected to a single antenna (that can Tx and Rx) via a diplexer, so that ...
ITried's user avatar
  • 123
1 vote
2 answers
145 views

Is power output or something else to blame for my duplexer failing?

A Ham buddy of mine and I were trying to setup a UHF repeater in our area due to a lack of them. We had two Motorola CDMs, one a 1250 and one a 1550, and we purchased a $200 or so reject only duplexer ...
Caleb Krajnak's user avatar
1 vote
0 answers
88 views

Repeater transmit voice message/warning on input frequency?

I'm in the process of planning a UHF CB radio repeater. And I've heard there are ones around that transmit a voice message/warning on their input frequency (as well as standard output channel ident) ...
Hayden Thring's user avatar
3 votes
2 answers
457 views

Why do repeater duplexers have notch cavities between transmitter and antenna?

Why are notch filters used on the transmit side of a repeater duplexer? The primary purpose of a duplexer is to keep the transmitter output out of the receiver input, since they both operate at the ...
AC0CW's user avatar
  • 51
10 votes
3 answers
1k views

Why is my diplexer such a spectacular failure?

I'm trying to create a diplexer for the 2m and 70cm bands so that two antennas can share a feedline to my "shack". My radio is a Yaesu FT60 handheld, 5W max. I have home made a j-pole for 2m, and a ...
user avatar
6 votes
2 answers
2k views

Looking for a schematic of a DIY circulator

I would like to build a simple HF, VHF or UHF circulator to get a better understanding of how these devices work. Sadly at the moment I'm unaware of any articles or books that provide corresponding ...
Aleksander Alekseev - R2AUK's user avatar
1 vote
1 answer
450 views

Retuning 2m Duplexers (Q2330E) with Spectrum Analyzer and Tracking Generator

Yesterday I was trying to tune up the duplexers one can at a time as listed in this Sinclair Youtube Video. After tuning them my receive is awful and my transmit is somewhat not what it used to be. ...
Loren Tedford KC9ZHV's user avatar
3 votes
1 answer
613 views

Using a Duplexer and Diplexer in Series

I have 3 Motorola CDM750s that I’m using to build a multi-purpose, portable, temporary repeater. There are 1 VHF and 2 UHF radios. I want to be able to use it as either an in-band UHF repeater or as ...
Lance's user avatar
  • 941
1 vote
1 answer
125 views

Frequency Agile Duplexer

Duplexers are very annoying, you have to go up to the site with your service monitor and tune it up just to switch the frequency that it operates at. They are a pain to tune, and are designed to stay ...
Skyler 440's user avatar
  • 7,590