Sunday, July 5, 2020

DMR hotspots and 70cm band Satellite segment interference

I have mentioned in the past, about people operating their DMR hotspots on strange frequencies,  ie. some in the 70cm weak signal segments, some on the band edge where they are in breach of their license conditions, but I also seen in the social media circles of people running their hotspots right in the Satellite segments of 2metre and 70cm bands.

I mean, just because your low powered hotspots ( typically mW) cant be heard when you drive down the road a couple kilometres, doesn't mean it cant be heard from a overhead satellite. Yes, low terrain kills your hotspot's  weak signal pretty quickly, but to an overhead satellite, your little digital hotspot at home can be easily heard and therefore causes interference to other modes used via the satellites.

I can't comprehend it, are amateur radio operators showing arrogance, or ignorance, or just plain stupidity ?    Well, just look at the Brandmeister dashboard you will see lots of them,  operating their hotspots smack in the middle of the satellite segments.  It would make you laugh, if it wasn't so serious.  We (licensed amateur radio operators) are supposed to be technical minded, who sat for a technical exam, yet some of us,  have no idea where we are running out DMR/MM hotspots, with respect to the bandplans designated against our licenses.   To use a phrase that celebrity chef,  Gordon Ramsay would probably say is :  "This is F###ing Incredible !!"

So, here they are :
the 2metre and 70cm Amateur Radio satellite segments
145.800 to 146.000 MHz
435.000 to 438.000 MHz
that means you don't run digital hotspots or any other RF devices in these segments, unless you intentionally plan to operate via one of the Amateur Radio Satellites and the designated modes.




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