Duplexer Specs... Are these considered acceptable/Good?

[smokey222]

Good Morning on this Memorial Day.  Came across a duplexer brand called "Intermod" model Model: D440N-4, made in Canada, for what seems to be a great price (about 268.00 USD).  I am seeking input from someone knowledgeable about what is considered decent parameters as I just don't know.  Below is what is listed...

 

Electrical Specifications       Frequency Range MHz 406 to 470 Return Loss(min) dB 18 Insertion Loss(nominal) dB 0.6 Isolation(nominal) dB 80 Impedance Ω 50 Tx-Rx Separation (*) MHz 5 Average Power Input (max) W 100

 

 

Thanks in advance, 

Scott

[Radioguy7268]

The specs look pretty decent. I have not seen that brand before, but it appears that he's got pretty good reviews on Ebay from his buyers - with a 100% feedback rating. The only negative comments seem to regard the shipping from Canada taking too long.

 

80dB of isolation is more than acceptable from a 4 can duplexer. Rule of thumb is 30dB per can (per side), but I can see that there are what appears to be some trimmer capacitors - which will sharpen the notches & help isolation. Generally, those are a good thing, but the quality with which the trimmers are built will ultimately decide the useful lifespan of the duplexer. See: http://www.duplexerrepair.com/2016/12/26/trimmer-capacitor-failures-in-decibel-products-duplexers/

 

It appears from the pictures & pricing that they're trying to strike a reasonable balance between quality and price, and they're shooting for the ham and hobby market - and at that price, they should have pretty good response if the quality holds up.

 

Assuming you're going to use it as a lower power repeater duplexer, it looks like it should perform well.

[smokey222]

The specs look pretty decent. I have not seen that brand before, but it appears that he's got pretty good reviews on Ebay from his buyers - with a 100% feedback rating. The only negative comments seem to regard the shipping from Canada taking too long.

 

80dB of isolation is more than acceptable from a 4 can duplexer. Rule of thumb is 30dB per can (per side), but I can see that there are what appears to be some trimmer capacitors - which will sharpen the notches & help isolation. Generally, those are a good thing, but the quality with which the trimmers are built will ultimately decide the useful lifespan of the duplexer. See: http://www.duplexerrepair.com/2016/12/26/trimmer-capacitor-failures-in-decibel-products-duplexers/

 

It appears from the pictures & pricing that they're trying to strike a reasonable balance between quality and price, and they're shooting for the ham and hobby market - and at that price, they should have pretty good response if the quality holds up.

 

Assuming you're going to use it as a lower power repeater duplexer, it looks like it should perform well.

 

 

Thanks for taking a look!  This would be for a GMRS system with 50 watts max.  Thanks again!

[wqzw301]

I just purchased the same one.

Pretty good so far.

50watts in 43watts out.

80db of isolation is just as good as my 4 big cans decibel vhf band pass/band reject duplexer. Very impressive.

I like the use of silver plating. Nickle makes a mess out of tx'n uhf.

Great construction and size.

[smokey222]

I just purchased the same one.

Pretty good so far.

50watts in 43watts out.

80db of isolation is just as good as my 4 big cans decibel vhf band pass/band reject duplexer. Very impressive.

I like the use of silver plating. Nickle makes a mess out of tx'n uhf.

Great construction and size.

I am glad you posted... I haven't pulled the pin yet and am happy to hear from someone that actually put their hands on it!  Thanks! 

[wqzw301]

Hello again,

How has your intermod duplexer held up?

Mine became very discolored due to the dissimilar metals used in it's construction.

I contacted intermod and the guy got pretty mad at me.... 

Thanks 

d

 

[nokones]

Shipping from Canada isn't too bad if it is shipped through the US Post Office.  It seems that the eBay sellers from Canada, near Toronto, have some ability to get their wares to the US Post Office system for shipping.  I have ordered stuff and it usually took about a week.

[Radioguy7268]

Yeah, silver will tarnish (turn black) when exposed to air if they're using silver for their connections. Inside, the connections should still be nice & shiny.

I can't understand why the guy would have gotten mad, unless  you were somehow blaming him for the fact that he used actual silver for your connections. Good customer service shouldn't make people think you're getting mad at them. 

Were you able to make any performance measurements to see how it's  holding up against the bench-marked spec's?  That's what matters, much more than any appearance issues or tarnishing.

[Lscott]

17 hours ago, nokones said:

Shipping from Canada isn't too bad if it is shipped through the US Post Office.  It seems that the eBay sellers from Canada, near Toronto, have some ability to get their wares to the US Post Office system for shipping.  I have ordered stuff and it usually took about a week.

I remember flying out of the Toronto airport years ago back to the US. Weird part was I went through  US customs at the airport before boarding the flight! Arrived at DTW as a domestic flight. I guess that was the point.