Almost random swr spikes

Nico Smith All Messages By This Member #137786 These scans were all with the same antenna charging nothing. If I press t for tune it will be fine then spike to 3 or 4.
ajparent1/kb1gmx All Messages By This Member #137787 While it may be tuned is it mechanically secure, are the connectors functional or intermittent? ? Could the wind be causing the antenna to make contact with wires, tree limbs? ? ? -- Allison ------------------ Post online only,? direct email will go to a bit bucket.
Nico Smith All Messages By This Member #137789 I have a bit of coax that might have bad connectors but it's the same connected straight to the antenna toggle quoted message Show quoted text On Sun, Jan 26, 2025, 2:22?PM ajparent1/kb1gmx via <kb1gmx=[email protected]> wrote: While it may be tuned is it mechanically secure, are the connectors functional or intermittent? ? Could the wind be causing the antenna to make contact with wires, tree limbs? ? ? -- Allison ------------------ Post online only,? direct email will go to a bit bucket.
Nico Smith All Messages By This Member #137790 Also changing LPF readings. toggle quoted message Show quoted text On Sun, Jan 26, 2025, 2:29?PM Nico Smith via <nicosmith873=[email protected]> wrote: I have a bit of coax that might have bad connectors but it's the same connected straight to the antenna On Sun, Jan 26, 2025, 2:22?PM ajparent1/kb1gmx via <kb1gmx=[email protected]> wrote: While it may be tuned is it mechanically secure, are the connectors functional or intermittent? ? Could the wind be causing the antenna to make contact with wires, tree limbs? ? ? -- Allison ------------------ Post online only,? direct email will go to a bit bucket.
Nico Smith All Messages By This Member #137794 I just have a dipole in my room but I'm confused how it can all be 2 swr toggle quoted message Show quoted text On Sun, Jan 26, 2025, 2:33?PM Nico Smith via <nicosmith873=[email protected]> wrote: Also changing LPF readings. On Sun, Jan 26, 2025, 2:29?PM Nico Smith via <nicosmith873=[email protected]> wrote: I have a bit of coax that might have bad connectors but it's the same connected straight to the antenna On Sun, Jan 26, 2025, 2:22?PM ajparent1/kb1gmx via <kb1gmx=[email protected]> wrote: While it may be tuned is it mechanically secure, are the connectors functional or intermittent? ? Could the wind be causing the antenna to make contact with wires, tree limbs? ? ? -- Allison ------------------ Post online only,? direct email will go to a bit bucket.
@Ludwig_DH8WN All Messages By This Member #137809 Nico, you should use a dummy load for testing. Which values when using a dummy load? Which output on different bands? With a very low output you may have unstable SWR values. Which output is shown by the QMX and which by an external meter? ? 73 Ludwig
Nico Smith All Messages By This Member #137816 I don't have a dummy load or an inline swr/watt meter. I will try to get those to test. It somehow went back to normal without me changing anything. So I will use it for now but if it happens again I will try to keep looking for stuff. - Nico toggle quoted message Show quoted text On Sun, Jan 26, 2025 at 4:51?PM DH8WN via <DH8WN=[email protected]> wrote: Nico, you should use a dummy load for testing. Which values when using a dummy load? Which output on different bands? With a very low output you may have unstable SWR values. Which output is shown by the QMX and which by an external meter? ? 73 Ludwig
VA3CJO - Chris "CJ" All Messages By This Member #137828 Building on this: I've noticed a possibly similar behavior with my QMX mid-band lately, though not through terminal but simply the built-in SWR "TUNE" function. ? I have a dummy load connected which in past would result in a 1:1 VSWR, sometimes hopping to, say, 1.1:1. Recently, with noting else changed, the TUNE SWR is jittery, erratic and hops to over 2. It's... odd.? ? I'll do some more testing when I have a moment. (for example: plugging the dummy load into an antenna analyzer)
@Ludwig_DH8WN All Messages By This Member #137839 On Mon, Jan 27, 2025 at 02:37 AM, Nico Smith wrote: I don't have a dummy load or an inline swr/watt meter. Nico, when building a TX it's a good idea to use a dummy load for testing. You may use something like the QRP Labs dummy. It's not only a dummy. Connecting a DMM to a special connection you are able to measure the rf power. ? 73 Ludwig
David #137858 Its always nice to have a bunch of 1 to 5w resistors around. Especially the old carbon ones. couple of 100ohm resistors in parrallel for 50ohm load. A bunch of 20 1000 ohmers in parrallel. Or even incandescent ( getting hard to find) headlamps and turn signal bulbs in par/ser configurations. Even a bath of salt water or carbon rods from batteries. The possibilities abound. Or just a dummy load off amazon ? ?
Greg McCain All Messages By This Member #137860 Both Pacific Antenna and Elecraft have nice QRP dummy loads. Both also have test points for measuring voltages with a DMM that can be plugged into a simple formula to show Watts Output.? Greg? toggle quoted message Show quoted text On Mon, Jan 27, 2025 at 10:00 AM, DH8WN@... <DH8WN@...> wrote: On Mon, Jan 27, 2025 at 02:37 AM, Nico Smith wrote: I don't have a dummy load or an inline swr/watt meter. Nico, when building a TX it's a good idea to use a dummy load for testing. You may use something like the QRP Labs dummy. It's not only a dummy. Connecting a DMM to a special connection you are able to measure the rf power. ? 73 Ludwig
Donald S Brant Jr All Messages By This Member #137902 On Mon, Jan 27, 2025 at 12:25 PM, David wrote: Even a bath of salt water or carbon rods from batteries. My firm had business with Fort Monmouth when it was the Army's Electronics Command HQ.? They showed us a dummy load for a 1MEGAwatt DC power supply.? It was essentially a swimming pool filled with a concentrated copper sulphate (salt, essentially) solution and its resistance was varied by hoisting huge graphite electrodes in or out of the solution to vary the resistance. 73, Don N2VGU

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Almost random swr spikes