Until recently I have been very satisfied with M&P Hyperflex 13 cable and
have found their connectors to be among the best. However, recently
investigating a degradation of my system performance I have become unhappy
and disillusioned, particularly with the Hyperflex 13. I have four
32-meter lengths of Hyperflex 13 purchased about 3 years ago. These are
used on the VHF/UHF (144-222-432-1296) bands. To date I have removed and
measured loss on two of these lengths. Loss measurements were done first
by a Rig Expert AA-2000, then verified with a Rigol signal generator and a
HP-435 (and again with HP-436) power meter. I have also removed and
reinstalled the connectors and no change in performance was seen. Losses
found are completely unacceptable.
Measured Losses (per 32m length)
* 144MHz ~3db
* 222MHz ~3.5db
* 432MHz 5.5db
* 1296MHz >7db
These losses were very similar with both measured cables. The two cables
not measured exhibit degraded performance as well but were not removed for
testing. Very careful and close physical inspection has not revealed any
damage to the cable PVC jacket. However, both cables have sections of the
length that appear to be somewhat stiffer than the remaining lengths.
Cutting into the cable at these points did not reveal any confirmable water
intrusion, but the braded shielding was quite sticky. I believe water
intrusion to be unlikely as all cables terminate one end in my home, and
the other in weatherproof enclosures. The cable terminations in the
weatherproof enclosures are prior to loops around my rotor system, therefore
any strain and repeated flexing is not a cause of the high losses. My
cables also do not lay on the ground. They are supported overhead by a
cable attached with zip ties.
I am mystified as to the cause of the performance degradation. Finding no
physical damage, I can only suspect defective materials used in manufacture.
Has anyone else experienced issues with M&P cables?
Dave - K3SK
FM07
Farmville VA USA
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