puxing 777 sub channel help

[Hawke519]

Hey guys I bought a puxing 777 I have programmed the main channels. I tried putting a ctscc on one of the channels. For example I programmed 22 with a ctscc of 5 . If I turn on my crappy motorola and turn it to 22 I can pick up the radio that is on 22 sub channel 5. Any one have any ideas why its still transmitting on 22 when it shouldnt be?

[Styrak]

Won't 22-0 hear all of 22's subchannels? If you're listening to 22-0, you'll hear all of them, but if you have your radio set to a subchannel on 22, it mutes the other subchannels on 22.

[Hawke519]

Well that would explain it then lol. Thanks man much appreciated. I wasn't aware of that

[Styrak]

Well I THINK that's how it works. Someone else feel free to correct me.

[Kimbo]

Yep that's right. The base channels ie:22-0 will pick up all of the sub channels on 22.

[lanepratt]

The radio will pick up all of chan 22 and all of its sub, in order to communicate to a sub chan you need to set up the ctcss. Look here should give you all the info you need

http://www.airsoftcanada.com/showthread.php?t=18513

[Drake]

"sub channel" is a misnomer for CTCSS; what it does, when set, is "squelch" (mute) any broadcast which doesn't carry the appropriate overlaid frequency tone. Anyone not using CTCSS will still hear all the transmissions made on the frequency/channel.

[Cortex]

If you're on a sub-channel do you hear everyone on the main channel as well?

Ex: On channel 22-1 do I actually hear 22-0 and 22-1, but only transmit to 22-1?

Edit: Ninja'd by Drake. Thanks Drake that clears it up! So CTCSS is really only useful for "down-filtering" audio. Everyone without CTCSS setup will still hear us, we just won't hear them?

[Kimbo]

no, if you are on a sub channel like 22-1 you'll only hear and be heard on 22-1.

[Hawke519]

Thanks guys I appreciate it. Good to know I didn't program anything wrong lol

[Drake]

Originally Posted by Cortex

If you're on a sub-channel do you hear everyone on the main channel as well?

Ex: On channel 22-1 do I actually hear 22-0 and 22-1, but only transmit to 22-1?

Edit: Ninja'd by Drake. Thanks Drake that clears it up! So CTCSS is really only useful for "down-filtering" audio. Everyone without CTCSS setup will still hear us, we just won't hear them?

That's right.

CTCSS is an inaudible (to the human ear) tone which gets broadcast along with your transmission; if you could hear it there'd be a single tone, like a note of music or a dialtone, playing in the background of what you're saying. Each CTCSS "channel" has it's own tone, which is transmitted when you broadcast; on the receiving end, with CTCSS set, any transmission without the corresponding tone is muted.

Therefor if you have CTCSS set, channel 0/No CTCSS transmissions are squelched. Conversely, if you aren't filtering for CTCSS you'll hear every transmission on the frequency. You just can't hear the CTCSS tones (or actually I'm not even sure the speakers produce audio in that frequency range anyway).

Originally Posted by Kimbo

no, if you are on a sub channel like 22-1 you'll only hear and be heard on 22-1.

22-1 and 22-0.

And in practice, other channels (xx-0) may receive it as well: this is because most people are using high power UHF transmitters (4 and 5W) on FRS channels intended of 500mW transmissions. Increasing power to the transmitter only extends your range marginally (you need to roughly quadruple your output power to double your range) but it makes your transmission 'wider', i.e., it will bleed onto neighboring channels. "Channels" are set to given frequency spacings, based on the power that's supposed to be broadcast on them. In the case of FRS, the spacing is pretty close. So by dumping 4W onto those channels you bleed over onto adjacent channels.

Most programmable radios let you store 100 or more frequencies, and most of those Chinese radios have a Low and High power mode, so it's a good idea to program one set of channels on Low power and another set on High (total 44 channels for the 22 FRS/GMRS). My radio (PX777) has 128 channels, so I programmed 1-22 as low power and the 101-122 as the high power counterparts. This makes switching between them easy. I usually stay in low power unless I find I do need more power in which case I'll switch.

Bleeding onto other channels will only be heard by others and a possible, unintended consequence would be transmitting on non-FRS/GMRS channels you shouldn't be on.

[FlyGuy]

Not overly familiar with that particular radio but if the 777 is like any other "ham radio" out there, you should have the option to independently program CTCSS tones on the transmit as well as the receive frequency. In other words, you could select CTCSS on transmit to unmute your team radios but have carrier-squelch only on receive so you hear everything regardless. Or you could do the reverse but that would be extremely counter-productive as you'd hear your team because you have CTCSS receive enabled, but they wouldn't hear you because you're not transmitting CTCSS yourself. Usually, you either program CTCSS on both tx/rx, or you have CTCSS tx-only and use carrier squelch on the receive.

However with FRS/GMRS, there's usually enough discrete channels available that rather than using CTCSS or another form of conditional access squelch system (DTMF burst, DCS, etc.), most teams/events just pick a channel that the other isn't using and run with it. Less complicated that way than having to fumble with the correct squelch codes.


Fly

[m102404]

Leaving the power on low not only prolongs batt life quite a bit but also guards against the sender bleeding over or just plain squelching out (just sounds like static) others near him.

I'm no radio guru like Fly...that's just what we found in games/ops

[Cortex]

I'm likely gonna order a Puxing 777 as well, and setting up low/high power channels sounds like a great idea. Easy to stay on low, also easy to switch to high if needed.

Thanks for that suggestion!