I'm going to order this kit off you . I have a first gen 2970 , I take it the instructions ID the TX voltage point on the board to solder the one 'important' wire ? Thanks
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Wire in an external PTT line to a CB radio
- Thread starter Xjeepguy
- Start date
This Jurassic web page shows that detail for the original 2970 pc board, but in the base radio model.
http://www.nomadradio.com/OldNomadWebPages/KBTurbo/index.htm
Should be the same main pc board as your radio.
Just one difference. The current version of the "Keyboard" uses an orange wire for the transmit-side voltage, not a green wire like the pics.
73
http://www.nomadradio.com/OldNomadWebPages/KBTurbo/index.htm
Should be the same main pc board as your radio.
Just one difference. The current version of the "Keyboard" uses an orange wire for the transmit-side voltage, not a green wire like the pics.
73
Makes me wonder if we should come up with a miniaturized version of the Keyboard. The 5-Amp power relay we use looks like a tight fit in that radio.
73
73
Was looking for more of an external solution outside of the radio to be honest like something similar to this
To be honest wouldn't even know where to start. The way it's explained in the video seems pretty straight forward but to build one from scratch is a bit beyond me.
Well i tried the Zetagi pre-amp option and it didn't work out while using
SSB the clicking of the relay in the Pre-amp and the SDR TX/RX switch was driving me crazy. Be interested in building a ptt push button box if you could give me some instructions on how to get started.
This is the back of the SDR TX/RX switch its just a 3.5mm jack that actives the PTT Relay.
Would be nice if whoever designs it adds a brief delay to the radio PTT so the amp isn't being hot-switched. Maybe add pin headers too so if the box is used on a radio with different mic wiring, its a simple matter to open it up and switch it over. A one box fits all type thing.
Assuming the device being keyed already has its own relay, and to activate it, a signal must be pulled to ground, it might be possible to use a couple diodes to isolate their pull-up voltages and use the same mic switch to pull them both down. No relays needed. This, of course, requires that both the radio and the device being keyed can tolerate the added voltage drop of the isolation diodes. This offers no delay though.
I know, some mics are switched too using the other half of the switch. Simplified drawing.
Edit to add
Maybe an RC network can be added between the radio TX pin and the diode so that the radio's TX takes a split second longer to activate, but since some radios use a comparator for TX switching that activates before reaching 0v, it might be tricky that way. The only hang-up with making a more complicated external circuit is that it would need power, and the only source of it is the pull-up on the radio's TX pin that disappears once keyed.
I know, some mics are switched too using the other half of the switch. Simplified drawing.
Edit to add
Maybe an RC network can be added between the radio TX pin and the diode so that the radio's TX takes a split second longer to activate, but since some radios use a comparator for TX switching that activates before reaching 0v, it might be tricky that way. The only hang-up with making a more complicated external circuit is that it would need power, and the only source of it is the pull-up on the radio's TX pin that disappears once keyed.
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Putting the relay in the radio, activated by the radio's internal transmit-switching voltage is just simpler. A standalone external gadget is the popular choice, but a lot
more labor to produce than a tiny pc board that bolts inside the radio.
73
more labor to produce than a tiny pc board that bolts inside the radio.
73
There is a guy that sells a pre built add on kit that goes in the radio.
Here are the instructions for one of the Galaxy radio base stations..
73
Jeff
Here are the instructions for one of the Galaxy radio base stations..
73
Jeff