[Elecraft] W2 wattmeter maximum Cat5 cable length

[Jack Brindle]

The cable is indeed not cat-5, but rather 8 individual wires that carry power and ground one way (to the box) and analog sensor signals back. The twist action in CAT-5 does not help here at all.
The things to watch for are signal loss due to resistance (shouldn’t be too bad, depending on the wire and length), and RF pickup. The latter can lead to bad and erratic readings.
The best advice is to keep the cable as short as possible.

73,
Jack, W6FB


> On Jul 10, 2018, at 12:06 PM, Dick Green WC1M <wc1m73 at gmail.com> wrote:
> 
> Thanks. First real info I've gotten. I said Cat5 because the documentation mentions it and I believe it says you can use a standard Ethernet cable.
> 
> I haven't taken a close look at the coupler circuitry. If it's like most remote couplers I've seen, a too-long cable can cause a drop in the DC voltages that carry the forward and reflected power signals. If the coupler does a conversion to digital, then the cable length wouldn't be an issue. But that sounds pretty fancy!
> 
> 73, Dick WC1M
> 
> -----Original Message-----
> From: Jeff KC9WSJ <jeff at kc9wsj.us> 
> Sent: Tuesday, July 10, 2018 12:47 PM
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] W2 wattmeter maximum Cat5 cable length
> 
> the standard cable is not Cat5, it's just a ribbon cable with RJ45's (I
> think?) at each end.
> Cat5 should work, though, and I'd be surprised if anything less than ~50ft+ would be an issue.
> 
> --
> Jeff KC9WSJ <jeff at kc9wsj.us>
> 
> On Mon, 2018-07-09 at 23:51 -0400, Dick Green wrote:
>> The W2 wattmeter comes with a 5-foot Cat5 cable to connect the coupler 
>> to the display unit. I need to use a longer cable, maybe 10-15 feet. 
>> I’ve searched the reflector archives and web for any information about 
>> the max
>> Cat5 cable length but haven’t found any.
>> 
>> Does anyone know? Does the calibration routine in the W2 Utility 
>> compensate for different cable lengths?
>> 
>> 73, Dick WC1M
> 
> 
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