Have a 98 vhp showing no output. Driver, finals, regulator all check ok. Transmit light turns red has talkback but zero modulation and carrier. Getting the 8 volts transmit and bias on finals are all correct. Took the amp out the loop and no change. Receive is good also. Any ideas appreciated thanks.
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Galaxy 98 VHP
- Thread starter Kung Fu Panda
- Start date
First question is to ask is a transmit signal being generated in the first place?
If so, you should hear something on a radio used as a monitor receiver. Since you have the red light, we'll assume the PLL is locked onto the correct channel. Pretty sure it stays dark if the PLL has lost its lock.
You might need to plug a coax jumper into your monitor radio, back the shell down on the other end and use the center pin as a "sniffing" antenna around the transmit mixer chip.
If you hear nothing, the problem is upstream from the transmitter mixer. If you do hear something, especially on sideband your problem is downstream from the mixer chip.
Didn't remember to ask. Is sideband receive working normally? If not, you can skip the monitor radio. The problem is upstream from the transmitter's mixer circuit, probably the 10.695 Mhz carrier-oscillator circuit.
73
If so, you should hear something on a radio used as a monitor receiver. Since you have the red light, we'll assume the PLL is locked onto the correct channel. Pretty sure it stays dark if the PLL has lost its lock.
You might need to plug a coax jumper into your monitor radio, back the shell down on the other end and use the center pin as a "sniffing" antenna around the transmit mixer chip.
If you hear nothing, the problem is upstream from the transmitter mixer. If you do hear something, especially on sideband your problem is downstream from the mixer chip.
Didn't remember to ask. Is sideband receive working normally? If not, you can skip the monitor radio. The problem is upstream from the transmitter's mixer circuit, probably the 10.695 Mhz carrier-oscillator circuit.
73
Would be incredibly nice if you had a receiver on hand that could tune in 10.695 MHz. Eavesdropping on the carrier oscillator would be my starting point, tune it in at 10.696 MHz LSB. Should get you a 1 kHz tone in the speaker if it's on frequency. And if tuning around reveals that it's way off from 10.695, that could be the whole problem.
More than once I've been caught off guard by how much RF energy at 10.695 leaks out the antenna socket of RCI-made radios while transmitting. The radio we use to monitor and set the carrier frequencies will pipe up when the radio being aligned goes onto the antenna to shout at the locals. Go figure.
73
More than once I've been caught off guard by how much RF energy at 10.695 leaks out the antenna socket of RCI-made radios while transmitting. The radio we use to monitor and set the carrier frequencies will pipe up when the radio being aligned goes onto the antenna to shout at the locals. Go figure.
73