Celwave VHF duplexer: info?

[IK1MVX]

Hi, I have a Cellwave VHF duplexer: there is no ref model labeled, only a "CAT no Z173F" and a serial number.
I just checked where is the tuning and it seems around 165 MHz (even though I saw a strange notch behaviour...)
Plus there are a sort of small screw close to the tuning piston: I guess it is a sort of lock for the piston...

Anyone has info about this? There is easy to tune for 600 KHz repeater spacing? I tried to search info/manual on web with no success... I would like to use it in a VHF ham repeater.

I'm attaching three pictures...
DSC_0012.JPGDSC_0007.JPGDSC_0010.JPG

Thanks in advance
73, Andrea IK1MVX / KC2ZDR

[WB2WIK]

I'm not familiar with that model, but the Celwave duplexers that support 600 kHz VHF spacing that I am familiar with are different from the model you show. Looks to me like that duplexer was one of their standard "5 MHz" spacing models, which normally would not have sufficient isolation at 600 kHz.

The "ham" 6-cavity duplexers which support 600 kHz split operation are from the Celwave 497-1 family; I've owned and used a lot of those, and they're very good.

[K8JD]

The trace on your tracking generator looks like what I see WHEN tuning duplexers. The funny thjing about commercial/public safety vhf is the spacing between input and output of repeaters is not a standard. Unlike hams , the frequencies are based on availability in an area within the channel use alolocations.
In other words they can be all over the place !
You have to tune your duplexer for peak and notch for the channels you have been assigned and licensed for. Not for a fixed spacing like hams and UHF services have.
Generally the big threaded rod sets the pass (fairly broad) and the little one sets the spacing, mostly where the notch is (very critical tuning).

[K7FED]

Hi, I have a Cellwave VHF duplexer: there is no ref model labeled, only a "CAT no Z173F" and a serial number.
I just checked where is the tuning and it seems around 165 MHz (even though I saw a strange notch behaviour...)
Plus there are a sort of small screw close to the tuning piston: I guess it is a sort of lock for the piston...

Anyone has info about this? There is easy to tune for 600 KHz repeater spacing? I tried to search info/manual on web with no success... I would like to use it in a VHF ham repeater.

I'm attaching three pictures...
DSC_0012.JPGDSC_0007.JPGDSC_0010.JPG

Thanks in advance
73, Andrea IK1MVX / KC2ZDR

My guess is these are pass only cans designed for probably no less than 2mhz seperation between TR/RX as I do not see any reject or notch adjustment in the pictures. For 2m operation you typically need duplexers specifically designed for our tight spacing of the pass/reject type. Another consideration is that to move the tuning that far (~20mhz) would probably require changing the loops out and a different length of the jumper cables between the cavities.

[IK1MVX]

Hi,
thanks for your infos...
I tried to align the TX part: it seems a 600 KHz shift is feasible (see pictures)
TuningCelwave.jpg
the problem is related to insertion loss which is quite hig (almost 9 dB)
I tried to work with compensator and tried to turn the coupling ring (around the connector) with no big success...
cellwave_part.jpg

any idea??

73, Andrea IK1MVX / KC2ZDR