Vega Multicoupler - Amplifier Orientation

[prcguy]

I must apologize for my math in post # 19, I subtracted attenuator and divider loss twice. So the way its wired up in the picture it can output a maximum of 10dBm per carrier with 4 carriers present going by the advertised output power of 25dBm. That's an IP1 output level and you can't run multiple carriers at that level unless you wanted IMD at about 20dB below the carriers and nobody would design such a terrible system. Subtract a good 10dB from that to leave you with a cleaner combined output of 4 carriers and now your at 0dBm or 1 miliwatt per carrier. It doesn't make any sense as a transmit amplifier plus why is it a dual four channel unit, which is more typical of a diversity four channel receive multicoupler?

The amplifier can output a total of max 50mW of power to the single antenna from 4 transmitters of 10mW each being combined and seem to match the recommendation for RF Venues TX combiner. That bad noise figure doesn't matter as it is not for recording and it might be a digital modulation as well. It's probably for in-ear monitoring for 4-8 musicians and stage performers.

" Unless you are using your IEMs across a football field you almost never want to run them at full 50 mW power levels. 30 mW or better 10 mW will provide better performance and less interference."


/Ubbe

 

[Ubbe]

nobody would design such a terrible system.

That's probably the reason why they turn up now on Ebay. They had terrible IM problems that interfered with their diversity receivers frequencies.

/Ubbe

 

[Twlighting]

Well, finally came across a photo of this multicoupler in used for its intended purpose on another forum. Think this demonstrates it's age pretty well.


For what it's worth, ended up swapping the amp out in my unit with a PGA103+ and it's been serving well as a RX multicoupler for a few radios here.