PMP450 Medusa

[colinhowlin]

Hi

We're going to be getting a couple of Cambium PMP450 Medusa radios over the coming weeks.
Their spec sheet says they typically draw 70W, increasing to 80W at peak.

Is there any Netonix switch that can take that kind of load?
Any switch we have in production can take 72W at 48VH - 36W at 48V.

Anyone out there deployed 450m with anything to share?

Thanks
Colin

[Julian]

Apparently Medusa is a thirsty beast, isn't she.

I recommend reading ISO/IEC TR29125:2010.

As a short abstract of the previous, the 72W limitation is an industry standard, and meant for keeping a cat5E cable from melting itself.

I can say that our switches are physically capable of pushing amperage in excess of 1.5A (1.5A*50V=75W) per port, exactly how much depends primarily on ambient temperature, although there are some other minor factors not worth mentioning in this context.

If you use a slightly higher input voltage (say 53V? the math gets very involved, but higher voltage = less current if power usage is relatively constant), and Cat6 cable to increase cable ampacity, I don't know that you would have a problem running it with one of our models which doesn't condition 48V (WS-6-Mini, WS-12-DC, etc.).

Just the tech guy's $.02.. standards are generally there for a reason, and I do tend to trust them. That being said, however, there are occasionally cases where standards can be safely exceeded with minimal issue. I'm curious to see what Dave's feedback here is, though.

[sirhc]

Also note that our 48VH port is 1.5A (1.5A*50V=75W) [using all 4 pair] in a 55C environment. This is a "constant" current draw, it can pike above that without tripping the Polyfuse.


At cooler temps the poly fuse will push more but the Ethernet Transformers are only rated at 1A per pair so if the switch is in a cold environment and the Poly fuse does not open and you pull more than 2A you risk blowing the Transformer.

[tcknudson]

So you are saying we could try it (Cambium Medusa) with some safety?
No so concerned as to blowing polyfuse, but as to not damage the radio?

[tcknudson]

I am running one on Netonix WS-12-250 on 48VH,
straight cable,

Update, not sure if this power supply is too low at 52 volts, radios are not performing well, and cambium is blaming the low voltage,
have not seen ap pull over about 70 watts, but have not turned power all the way up on the radios,

My bigger issues was overran the full capacity of the switch, not necessarily one port maxxing out,

[colinhowlin]

We didn't even try run the Medusa through netonix after.
We ended up using Cambium's own AC+DC Power Injector: https://www.tessco.com/products/display ... sku=515433

This takes AC as well as DC input so we could run it off AC and hook it up to our existing DC battery system.
No issues whatsoever.