I would define a "wacky' project as one you could never justify what it costs, but did it anyway. Don't ask how much to buy one like this. If you have to ask you probably can't afford (or justify) the cost.
The converted Roger K board that we modify to make the "Bump-Bump" unkey noise normally gets installed inside the radio. A lot easier and cheaper, but it can be hard to say "NO" to a 30-year customer who brings us as much work as this guy does.
Just couldn't say no.
Or wouldn't.
Same thing, really.
He wants his "Bump" in an external box he can use with any radio that has a 4-pin mike socket. At least he came up with a case that has a power supply.
Originally he asked for a box with a RF-keying circuit, so it would key ham-type amplifiers that normally use a keying cord plugged into the rear of a ham radio. I didn't like the idea of having the radio's RF power and a mike-audio toy in the same box. Just too much risk the RF could sneak into the mike circuit, get rectified and create a feedback headache.
He supplied a Pride DB20 preamp. These have a bad (good?) habit of breaking down, and using it for this idea at least seemed useful to him. Saved me the trouble of coming up with an enclosure and power supply. Seemed logical to him that a RF keying circuit would work, with the radio's RF just passing through the preamp's two SO-239 sockets.
Then my idiot light came on. I would need to use one of our "4-pin conversion jack" modules with the Bump-Bump. It's a roger-beep board that has no relay. Gotta have a way to shut off the speaker for a 4-pin radio that needs the mike plugged in to receive. Without a relay, the roger beep comes through the speaker loud enough to blow it out. Never mind how annoying it is, even if you beef up the speaker's power rating.
This is what we use to install the Roger K, 5-tone beep and Bump-Bump in a Uniden-made 40-channel SSB radio like the Cobra 2000, 142, Uniden Madison, Washington etc. Found the simplest way to add that relay to those radios was to substitute our socket and relay module for the original 5-pin mike socket. Has one bonus. Makes the radio compatible with the old 4-wire mikes that don't have a separate ground wire for T/R keying.
So,,,, if I'm already putting a relay in the box controlled by the mike's PTT switch, why not just key the external ham linear that way? No need for coax connectors and a RF-sensing circuit at all. Should simplify filtering the snot out of it to prevent the amplifier from bleeding the mike audio.
The amplifier-keying relay is another board we normally install inside a radio, activated by the radio's internal transmit-only switching voltage. No big trick to trigger it from the relay on the 4-pin adapter board.
So, he ends up with a box that has a mike socket, cord with a 4-pin plug that goes to the radio's mike socket, and two RCA sockets on the rear, to key a ham-type driver and a big box, both.
The enormous "ON THE AIR" sign on the front is just a bonus.
The 4-pin mike socket module already has more RF filtering on it than the original 5-pin socket found on the Cobra 2000, Washington, etc.
For the radio mike cable, I settled for a string of ferrite beads on each of the five wires. Yeah, five wires to key a 4-pin radio. If he decides he wants a 5-pin plug on it later, all the wires are there. Just like wiring an Astatic mike to a 4-pin radio, tie the blue wire to the shield on pin 1.
The old AC/DC power socket is now a filtered IEC socket. Should prevent RF ingress from the power cord.
All the circuitry and the two RCA sockets are isolated from the chassis ground, with ceramic-disc bypass capacitors keeping the power supply grounded for RF. Don't want a ground loop between the AC power cord's ground prong and the mike socket of the radio.
Sure don't want a ground loop between the chassis of a big amplifier and the mike circuit.
So far, so good. Works okay on the test radio.
Next comes the LED strip to go behind the OTA light.
73
The converted Roger K board that we modify to make the "Bump-Bump" unkey noise normally gets installed inside the radio. A lot easier and cheaper, but it can be hard to say "NO" to a 30-year customer who brings us as much work as this guy does.
Just couldn't say no.
Or wouldn't.
Same thing, really.
He wants his "Bump" in an external box he can use with any radio that has a 4-pin mike socket. At least he came up with a case that has a power supply.
Originally he asked for a box with a RF-keying circuit, so it would key ham-type amplifiers that normally use a keying cord plugged into the rear of a ham radio. I didn't like the idea of having the radio's RF power and a mike-audio toy in the same box. Just too much risk the RF could sneak into the mike circuit, get rectified and create a feedback headache.
He supplied a Pride DB20 preamp. These have a bad (good?) habit of breaking down, and using it for this idea at least seemed useful to him. Saved me the trouble of coming up with an enclosure and power supply. Seemed logical to him that a RF keying circuit would work, with the radio's RF just passing through the preamp's two SO-239 sockets.
Then my idiot light came on. I would need to use one of our "4-pin conversion jack" modules with the Bump-Bump. It's a roger-beep board that has no relay. Gotta have a way to shut off the speaker for a 4-pin radio that needs the mike plugged in to receive. Without a relay, the roger beep comes through the speaker loud enough to blow it out. Never mind how annoying it is, even if you beef up the speaker's power rating.
This is what we use to install the Roger K, 5-tone beep and Bump-Bump in a Uniden-made 40-channel SSB radio like the Cobra 2000, 142, Uniden Madison, Washington etc. Found the simplest way to add that relay to those radios was to substitute our socket and relay module for the original 5-pin mike socket. Has one bonus. Makes the radio compatible with the old 4-wire mikes that don't have a separate ground wire for T/R keying.
So,,,, if I'm already putting a relay in the box controlled by the mike's PTT switch, why not just key the external ham linear that way? No need for coax connectors and a RF-sensing circuit at all. Should simplify filtering the snot out of it to prevent the amplifier from bleeding the mike audio.
The amplifier-keying relay is another board we normally install inside a radio, activated by the radio's internal transmit-only switching voltage. No big trick to trigger it from the relay on the 4-pin adapter board.
So, he ends up with a box that has a mike socket, cord with a 4-pin plug that goes to the radio's mike socket, and two RCA sockets on the rear, to key a ham-type driver and a big box, both.
The enormous "ON THE AIR" sign on the front is just a bonus.
The 4-pin mike socket module already has more RF filtering on it than the original 5-pin socket found on the Cobra 2000, Washington, etc.
For the radio mike cable, I settled for a string of ferrite beads on each of the five wires. Yeah, five wires to key a 4-pin radio. If he decides he wants a 5-pin plug on it later, all the wires are there. Just like wiring an Astatic mike to a 4-pin radio, tie the blue wire to the shield on pin 1.
The old AC/DC power socket is now a filtered IEC socket. Should prevent RF ingress from the power cord.
All the circuitry and the two RCA sockets are isolated from the chassis ground, with ceramic-disc bypass capacitors keeping the power supply grounded for RF. Don't want a ground loop between the AC power cord's ground prong and the mike socket of the radio.
Sure don't want a ground loop between the chassis of a big amplifier and the mike circuit.
So far, so good. Works okay on the test radio.
Next comes the LED strip to go behind the OTA light.
73
