[VHFcontesting] VHFcontesting Digest, Vol 268, Issue 16

[Dana Shtun]

Possibly the plasticizer in the dielectric is breaking down? If its sticky around those spots 
It could be some kind of breakdown.. ?  Also moisture can get pulled in over time but 
Not 3 years.. 

Due to RF heating… are the stiff points any kind of wavelength from one end?? Mfg issue??

I*d query the manufacturer, that stuff looked good at Dayton, other than the aluminum/copper plate...

I’ve that gooey issue happen with some foams, and rubber materials, and dielectrics, it  happened  in very very old Belden 214 but after 15 years up on the tower exposure.
In fact I need to change my 2 m line above the rotor for that reason. Hi

73 Dana VE3DS



> On Apr 20, 2025, at 12:00 PM, vhfcontesting-request at contesting.com wrote:
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> Today's Topics:
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>   1. Extreme loss with M&P Hyperflex 13 (K3SK at buckwalter.co)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Sun, 20 Apr 2025 11:08:33 -0400
> From: <K3SK at buckwalter.co>
> To: <Moon-Net at groups.io>, <vhfcontesting at contesting.com>
> Subject: [VHFcontesting] Extreme loss with M&P Hyperflex 13
> Message-ID: <037701dbb206$161626e0$424274a0$@buckwalter.co>
> Content-Type: text/plain; charset="us-ascii"
> 
> 
> 
> 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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> End of VHFcontesting Digest, Vol 268, Issue 16
> **********************************************