Using CTCSS or DCS to filter traffic
#7
(29-08-2020, 07:52 AM)VK4ADC Wrote: I've tried transmitting CTCSS in conjunction with DCS Doug but no go, you were right. Setting one on the radio results in the other dropping out. Another possibility: I've just learned that the Mt.Alexander repeater VK3RCV needs no CTCSS after all. I had been working from obsolete documentation. I don't know when it was changed. In that case I can include a tone in my transmissions and set my transceiver to ENC/DEC, i.e. to require the same code to pass received signals to the audio. As long as I keep an eye on the radio's display to ensure I don't barge into a conversatiton my brother and I can use the frequency in silence.
Do you see any hitch in that arrangement? I haven't tried it yet. My brother is currently on the road, broken down north of Dookie and I can't reach the Shep repeater from where I am. Thanks for your time.
Rob

The 'I can also send DCS Encode/Decode in conjunction with CTCSS so I'll try that.' has me in doubt a bit. Can you actually set that up - have you tried it ??

As I mentioned previously, you will need continuous 91.5 Hz CTCSS to open the repeater and keep it open and then you would need to see how faithfully DCS would pass through the repeater and that DCS is set to open the remote receiver (not CTCSS). My recollection is that DCS signals are basically square wave in shape and may not go through without distortion. Trial and error.

Transmitting the 91.5 plus one other CTCSS tone is probably the best possibility, the 91.5 opens the repeater and the second tone is what the other transceiver CTCSS decode is set to. CTCSS encoders are small these days too.  Pick a high-ish CTCSS tone (near 250 Hz) as that is more likely to pass through the repeater receiver/transmitter combination.

The DTMF or 5-tone option would need an extra suitable decoder if the radio itself did not provide that function internally. It was just an idea floating round the brain at the time as I am sure that tones in that range would transit the repeater.

Older radios destined for Europe (plus others) had a 1750Hz tone generator in lieu of CTCSS but I think the idea has been dropped in more recent models. Of course you would need to decode that tone at the far end.

Probably time for you to 'think outside the box' as this is not a problem normally presented to the amateur fraternity : everyone listens to everything. 

No simple answers, but some experimentation may provide one.

73 Doug

I've tried transmitting CTCSS in conjunction with DCS Doug but no go, you were right. Setting one on the radio results in the other dropping out. Another possibility: I've just learned that the Mt.Alexander repeater VK3RCV needs no CTCSS after all. I had been working from obsolete documentation. I don't know when it was changed. In that case I can include a tone in my transmissions and set my transceiver to ENC/DEC, i.e. to require the same code to pass received signals to the audio. As long as I keep an eye on the radio's display to ensure I don't barge into a conversatiton my brother and I can use the frequency in silence.
Do you see any hitch in that arrangement? I haven't tried it yet. My brother is currently on the road, broken down north of Dookie and I can't reach the Shep repeater from where I am. Thanks for your time. Rob
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Messages In This Thread
Using CTCSS or DCS to filter traffic - by VK3TKO - 28-08-2020, 09:03 AM
RE: Using CTCSS or DCS to filter traffic - by VK3TKO - 03-09-2020, 08:51 PM

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