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Programming Problems

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After some advice here as this is all a bit new to me.

Basically ive purchased some Vertex Standard radios and im trying to get them to work with some existing Motorola GP300 Radius radios.

Ive used a frequency counter to determin the frequencies of the GP300 which showed 449.3994MHz with a Ctcss 0.0Hz.
Im assuming this should of been 449.4000MHz as this is the closest Business Lite Frequency, and the counter may be off slightly.

Ive programmed this into the Vertex radios but i can only receive! My transmissions are not being received on the GP300's.

Im thinking i could be the transmitter deviation of the channel, which I programmed as Narrow: Max. Deviation = ±2.5 kHz

Problem is i cannot take the GP300's away from site and there some distance away.

Please take a look at my screenshot below, any let me know your thoughts.

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GP300's could be using DCS, if you're certain there is no CTCSS on the carrier…

I miss communications.support, I'll try to be "nice".
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As KF5ZLI identifies the GP300's are almost certainly using a CTCSS tone or DCS code (Private Line (PL) or Digital PL (DPL) as Motorola call them!).

CTCSS has over 60 'standard' different sub-audible tones, DCS  consists of a 23-bit telegram sent repeatedly, this uses over 100 'standard' codes.
Both of the above can also be 'inverted' and some people create unique (non-standard) tones & codes…

The frequency of 449.900 is a valid 'Business Lite' frequency, also proven by it works one way (assuming the GP300's are correctly configured).

Without  "Reading" one of the GP300's to see its complete configuration, you will be blindly guessing, that is possible, but could take weeks.
If reading a GP300 is not going to be possible - Get a big list of all the CTCSS & DCS codes (available on the internet) start at the first one and methodically keep reprogramming and crossing them off your list until, hopefully, you find the correct one…

Good luck…
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449.900 is a ham frequency, do not use it unless you have a ham radio license.

73
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Sorry, Yes, that was my typo…
I meant 449.400 as 'Littledave' first posted.  :thumbs:
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449.400 is still a ham frequency at least in the USA.  I don't know about other countries.

73
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Quite possibly, but it is not ham frequency in the UK.
449.3125, 449.4000 & 449.4750 are Business licenced channels shared by multiple business users.

Regards.
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OK, that's interesting.  I guess it depends on what country OP is in.

73
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try programming 444.4000Mhz on the RX of your VERTEX  and tell me if you can hear now.

On your Vertex try programming this:

CH1  RX  444.4000   TX 449.4000 NO DPL or TONE

Tell me now if you can Tx and Rx now this should work. If not then best is to get the Motorola's re-programmed.
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