[Elecraft] [W2] Waterproofing the sensor

[David Ferrington, M0XDF]

This will be a 2M sensor, about 10m from the PA and just before a preamp, connected to a 17 ele Tonna.
The preamp can handle 150W and the contests I'm interested in have a 'restricted' section for 100W max, so I want to ensure I'm not pushing more 100W into the pre-amp, which with losses I guess could be 110-120 PEP at the amp.

Not two worried about SWR at the amp and I have a simple MJF the I can use to measure that in the shack.

Plus I'm considering options to 'A-B' switch sensors if I have more than 2.

I'm also feeding an SGC to a long wire, which is remote by approx. 30m and considering putting a remote HF sensor down there. This is fed direct from the K3/100 in Bypass mode, so SWR readable on the rig.

73 de David, M0XDF (K3 #174, P3 #108)
-- 
Any hound a porcupine nudges, Can't be blamed for harboring grudges.
I know one hound that laughed all winter, At a porcupine that sat on a splinter.                                                 
- Ogden Nash (1902-1971)

On 28 Jan 2012, at 00:50, Mike WA8BXN wrote:

> 
> 
> Its not clear to me why one would need to put the sense element at the
> antenna. About the only benefit to it that I can see is you can make sure
> your coax to that point has not become extremely lossy. Just about anything
> else can be measured with the sensor in the shack. One would be more
> interested in knowing the SWR looking into the feedline at the transmitter
> than at the antenna end. 
> 
> If an automatic antenna tuner is near the antenna feed point, if its working
> then the SWR should be low in the coax from the tuner to the rig. Trying to
> read the SWR between a tuner and antenna is not all that useful and many swr
> sensors may not be accurate when not used in 50 ohm feedlines. I didn't
> quite say that right. Between a tuner and antenna we would expect a high swr
> and the feedline not matching the Z of the antenna. If the antenna is
> resonant, then a tuner would not be needed. 
> 
> So I am missing something, perhaps someone could fill me in! 
> 
> 73/72 - Mike WA8BXN
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