Don't forget it is from house to PCP and then PCP to Fibre cab. Add in maybe another 20m to allow for going up poles, down underground, sag in lines and spares cable loops. That will put your estimate up to around 310m ...
At 310 you could get a full 80 with a max attainable of hi 80's but at the low end if the wire gauge is small with plenty of cross talk you may well be down in the low to mid 60's.
You can now just wait and see. the attenuation will, at a guess be around 12dB
M H C
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