Basic built 4x2SC2879 transistor mobile amp. Started having an issue with the amplifier. My SWR is normally 1.0 on channel 20, as well as 1 through 40, with just the radio on. With the amp on it raises to 1.4. My antenna and power setups are fine. I noticed recently if I keep the mic keyed up with the amp on for about 20 seconds+-, the SWR almost jumps from 1.4 to 1.8 and then slowly creeps up to 2.0 before I unkey. Any idea what it could be? Thank you in advance.
-
You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
400HD Mobile Amplifier Issue. Requesting experienced amplifier person to reply.
- Thread starter bobeboilerman
- Start date
-
- Tags
- amlplifier help problem swr
Something getting hot, causing its circuit function to change.
Sounds like.
A capacitor, maybe. The ideal tool would be a FLIR thermal-image camera. Whatever gets hottest first will show up right away.
Just checking parts with a fingertip after it's keyed up long enough to start misbehaving might reveal where to look. Just don't brand yourself with the capacitor's printed rating. They can get hot if the builder cheaped out and used capacitors not built for the peak currents in a linear's output circuit.
73
Sounds like.
A capacitor, maybe. The ideal tool would be a FLIR thermal-image camera. Whatever gets hottest first will show up right away.
Just checking parts with a fingertip after it's keyed up long enough to start misbehaving might reveal where to look. Just don't brand yourself with the capacitor's printed rating. They can get hot if the builder cheaped out and used capacitors not built for the peak currents in a linear's output circuit.
73
Thank you. Just what it was. From what I found out, my issue was my mount had some hidden corrosion on it and SWR jumped to 3.8 for a few seconds before I caught it and then it started doing as explained. Thanks again!