Hi, Jerry,
very weird is a good description.
As you suspected, the rig did not want to transmit with the 10 nf capacitor across the antenna.
I moved the capacitor to C1 - added it parallel to C1 - and it fixed the receive audio, but again did not want to transmit with any power.
(I thought C1 would be out of circuit during transmit, but I¡¯m not great at reading the schematics!)
Back to square 1, I removed the capacitor and I can transmit ok, but back to noisy receive.
I checked C1 and it reads as 1200 pf instead of the 470 pf on the schematic. That might be my inaccurate capacitance meter.
The Bitx has had a big burst of RF from a nearby transmitter, maybe that upset something.
I¡¯ll keep experimenting. I do have a good antenna (ZS6BKW) so plenty of signal going into the Bitx.
John, VK2VOL
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On 8 Jul 2017, at 12:32 am, Jerry Gaffke via Groups.Io <
jgaffke@...> wrote:
My thought is that this is very weird.
I'd be checking all those connections around the antenna with an ohmmeter.
Make sure everything you think is connected is really connected.
If you want to try transmitting with the rig in such a questionable state,?
maybe start out with a 10v power supply into the IRF510 and increase it to 12v?
only if a watt or so is getting through to the dummy load. ?If you do have a bad
connection at the antenna BNC, the high SWR could blow the IRF510.
Especially if you are feeding the IRF510 more than 12v.
Jerry
On Fri, Jul 7, 2017 at 07:21 am, John Sharpe wrote:
The breakthrough stopped (surprisingly) when I grounded the centre contact of the antenna input. 7mhz ?SSB signals came through fine!
?
