Mark, this happened to me several times, under the following situation:
- My feed-line was about 12 feet long, connected to a home-made dual-band J-pole antenna
- The antenna was standing upright, about three feet away from the radio
I would receive traffic, and I would then press the PTT to respond. But after releasing the PTT, there was absolute silence. Only after pressing the squelch or [EXIT] key would the radio receive traffic again.
I decided that the radio's receive circuitry was being overloaded by my transmitting so closely to the radio. I'm thinking the stock whip antenna is better designed to eliminate this?
Anyway, the cure was making sure my external antenna was at least 10-20 feet away from the radio before transmitting.
I'm still a raw newbie, so I'm not at all sure that I'm understanding the problem well, but perhaps my experience will will with your troubleshooting?
Milt / KJ7PPX