Ethernet controller chip test model

[Sapling]

Hi,I'm designing an Ethernet controller chip which has a 10M/100M PHY.I found a problem when I test it by using category 5 cabling.It work abnormal When the category 5 cabling is longer than 70m(It should work normal at 100m).It is very convenient if I have a Twisted-pair model which can work like 100m or anyother length category 5 cabling  to do test.
    There is a test model I found in IEEE 802.3 standard.But Idon't know it was equivalent to how long twisted-pair in real,50m or 100m or anyother length?
Someone said that this model it just used to intended to model certain properties of an ethernet twisted pair in a hardware test?but it can't  match to a real piece of hardware.

[azer]

RS has a test fixture for Ethernet compliance, maybe some information can be gleaned from it.
https://www.rohde-schwarz.com/fr/file/NEWS_211_RTO_Ethernet_english.pdf
https://cdn.rohde-schwarz.com/pws/dl_downloads/dl_common_library/dl_manuals/gb_1/r/rt_zf/RT-ZF2_UserManual_en_07.pdf

[Sapling]

Thanks.
Though I don't find the thing what I need.