Friday, May 1, 2009

1.25 m/ 220 MHz HSMM XR-1


This is an interesting product with lots of possibilities. It's a powerful 802.11 non line of sight radio module. Designed for Metering Applications as an built to order- 180-280 MHz Frequency Band. (There is a minimum quantity of 1000 piece per order due to the custom frequency, but it does work out to about $150 per unit.)

The XR1 would fit into the 1.25m amateur (220MHz) band frequency wise. However there is a gap in the band. As most hams are aware, we have 219-220 MHz secondary, and 222-225 MHz primary. It would be nice if the full 219 to 225 MHz was available.

Like all Atheros based radios, the XR1 specs references that channel size can be set. Even with the minimum channel size 5 MHz it wouldn't fit into 222MHz band, but there may be ways to reduce the overall spectrum requirements. Could the transmission envelope be modified to be narrower channel? That would be a good question for the guys at Ubiquiti Networks, or the Atheros MadWifi project.

Lets not forget the channel may be 5-MHz but...keep in mind Carson's Rule, the channel may be 5-MHz but...the signal bandwidth could be much higher.

If a 2.5 MHz channel option was coded the throughput would still be very usable.

This card does not have these capabilities and is not legal for sale in the US. But I don't think that would be a major obstacle for hams if it could be modified to fit into the 220 MHz ham band.

The reason I point it out is because it is the first VHF 802.11 radio I have ran across.

3 comments:

Christopher said...

It's too bad, really... You know, the full 219-225 MHz _was_ available once. Then UPS petitioned the FCC to let them have 220-222 MHz for some crazy data network. UPS never deployed it, but we never got those frequencies back, either. 73! Chris N9YH

Raf said...

I would rather use 420-430MHz range where 5MHz could work.

I already use 900MHz @3.5MHz channel delivering @2.25MBPS

kb9mwr said...

How are you getting a channel that small?

Also here is a 400 MHz radio:
http://www.xagyl.com/store/product.php?productid=16450&cat=0&page=1