Micro magic duplexer

[K7lon]

I am looking at a micro magic duplexer to replace a fumei junk unit [90% loss of power] . Has anyone had success with this unit 1.5 db loss or better? I would like to thank John E for the db loss chart. It has been very helpful in understanding  equipment. I am operating a  5 watt repeater for my grandkids.

Thank you

Lon

[JohnE]

I've seen and measured their duplexers. losses pretty much on the money .

typical real world loss I have measured was 40 in 28-32 out so that would be around 1dB loss or a little more.
just an FYI

JE

[gman1971]

Lower loss will require a larger duplexer. Most same size duplexers have about the same loss, in theory, that is

The Fumei at 1.5dB sounds about right for a small mobile duplexer.

I think the Fumei will be okay for now. (yes I said that!) 1.5 dB loss is not really much loss at all.

If more range is desired, raising the antenna 10 feet would have more profound impact in range than swapping duplexer.

G.

[gortex2]

don't forget your jumper from TX to the duplexer has loss. If you use a cheap jumper I have seen some with almost another DB of loss. Did the duplexer get tuned for the channel you are using ? 

 

[K7lon]

Thank you for the information. 

The fumie was tuned to the frequency with a cheap spectrum analyzer/ signal generator. The cabling is good quality rg58 coax with no adapters six inches long. I used a bird power meter for testing, 5watts into the duplexer .5watts out to the antenna. I have a celwave and a Hong Kong unit preforming much better. 

[gman1971]

12 hours ago, K7lon said:

Thank you for the information. 

The fumie was tuned to the frequency with a cheap spectrum analyzer/ signal generator. The cabling is good quality rg58 coax with no adapters six inches long. I used a bird power meter for testing, 5watts into the duplexer .5watts out to the antenna. I have a celwave and a Hong Kong unit preforming much better. 

That seems like a 10 dB insertion loss. I would use a Return Loss Bridge (RLB) to tune duplexers, its far easier than tuning them with the Analyzer alone.

G.

[tcp2525]

There's no such thing as a good quality RG58 cable no matter how short it is. RG400 with N connectors at a minimum.

[JohnE]

On 2/20/2022 at 11:09 PM, K7lon said:

Thank you for the information. 

The fumie was tuned to the frequency with a cheap spectrum analyzer/ signal generator. The cabling is good quality rg58 coax with no adapters six inches long. I used a bird power meter for testing, 5watts into the duplexer .5watts out to the antenna. I have a celwave and a Hong Kong unit preforming much better. 

I would be curious to see what that looks like on my tracking gen, just for s's and g's

and a little eye candy