an.qth.net' <elecraft@mailman.qth.net>
Subject: RE: [Elecraft] K3 Power Reading/SWR/ALC Problem
>"From experience, I'd say nearby lightning strikes would be the
culprit."
Highly unlikely. Clear skies for days. No lightning activity here in a long
time here. Two years
> "This cable worked for me for several years but recently failed. Bring
some extra jumper coax with you..."
Karin,
Many thanks. I have several extra RG-400 jumpers that can be used as well
as confirming if the issue appears on ANT-2. Schottky diodes arrive
tomorrow, so I'll be ready later
Paul:
I had a problem with my K2 with the same identical symptoms you are
describing.
The fault was diagnosed to an intermittent ground/shield connection in the
RF output
Cable going to my amplifier. It was an old cable that was out in the
weather and when
I took it apart you could see the
--
Message: 6
Date: Sun, 21 Jan 2018 16:14:55 -0600
From: Bob McGraw K4TAX <rmcg...@blomand.net>
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] K3 Power Reading/SWR/ALC Problem
Message-ID: <9ff00d5b-d3ba-c49c-0293-c5d93e346...@bl
I bought a couple of these (TT3G50) from DX Engineering. Unscrewed the gas
discharge plug, took a look and some photos of the inside construction, and sent
them back. Simply awful, (Alpha-Delta, not DX Engineering) BTW, the only
"protection" is a 1000V breakdown gas discharge tube with
>"From experience, I'd say nearby lightning strikes would be the
culprit."
Highly unlikely. Clear skies for days. No lightning activity here in a long
time here. Two years ago, I had a similar problem with static-damaged Schottky
diodes in an Alpha 9500. Those diodes are used to sample RF
Knut and all,
Yes, BUT...
Lightning is a static charge which *will* produce transients in the
antenna system. As will wind static, rain static and snow static.
Large voltages can build up on the antenna and feedline, and will remain
until dissipated. Sort of like a charged capacitor that
I strongly agree with Bob's advice, EXCEPT that I've gotten really tired
of replacing Polyphasers on my high wire dipoles. I've recently switched
to the arrestors that Array Solutions sells, both because I like the
circuit better and because the gas discharge tubes are user replaceable.
The
From experience, I'd say nearby lightning strikes would be the
culprit. I strongly urge everyone to use protection devices on all
coax and balanced lines at the point where the feed lines and rotor
lines enter the house. I prefer Polyphaser devices. Don't buy cheap
or ham fest bargain
Hi Don and all,
I really don't understand why static build up on the antenna should be a
problem with the K3. Due to the (good) design of the SWR bridge (a two
transformer design with a voltage transformer right across the output) the
antenna port presents a dead short circuit at DC both in
Paul,
The diodes are the most likely suspect, so replace them first and re-check.
You are correct that the problem is that the wattmeter is not feeding
the power back to the MCU and the power becomes uncontrolled.
Wattmeter damage is normally a result of static coming in on the antenna
Sent: Sunday, January 21, 2018 1:18 PM
To: 'Paul Christensen' <w...@arrl.net>
Subject: RE: [Elecraft] K3 Power Reading/SWR/ALC Problem
I don't know where purchasing actually buys the parts, but...
D36 and D37 are BAS70INCT Diode, 70V, SOT23, like Digi-Key BAS70INTR-ND
U16 is LM358, DUAL OP
Paul,
I have not looked to be certain, but there is a 90% probability that
they are SMD.
Contact pa...@elecraft.com to obtain the part numbers. Those are not
normally Field Replacable parts.
73,
Don W3FPR
On 1/21/2018 11:02 AM, Paul Christensen wrote:
I have a K3 at a remote site about
I have a K3 at a remote site about an hour north of my home so
unfortunately, I cannot quickly investigate an issue that's recently
developed. After reviewing the K3 schematics, the root cause is likely
isolated to the following parts on the PA board: D36, D37 (BAS70 - Schottky
directional
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