Why won't my PGP68 transmit?

[Risc_Terilia]

I can't get my Motorola GP68 to talk to my Motorola Talkabout T5930. You can transmit from the T5930 to the GP68 fine but not the other way around.

[ThunderCactus]

make sure CTCSS is off on both radios, and make sure your on the proper channel to transmit.
Also, if you plan on using CTCSS, the GP68 has a few extra channels than the talkabout so you'll need the conversion chart.
for example channel 2-12 on your talkabout would be 462.5875-13-13 (there are 2 subchannels on the GP68, listen and transmit)

[FOX_111]

It might have something to the frequency range sencitivity.

ex: GP68 transmit to 450.2500 Mhz on channel 1
T5930 on channel 1 is 450.2515

the 0.0015Mhz difference is enough to receive if the receiver is not very sensitive (happen in close range sometime), but your other radio is sensitive enought to filter out the 0.0015Mhz difference.

If you have an ajustable skwege (sp?), you could open it up a little.

EDIT: Thundercactus has it right too.

[Risc_Terilia]

Thanks for your help guys, the T5930 has very little in the way of controls, just channel (1-16) Volume, PTT and Monitor. The t5930 is received by the GP68 without any CTCSS on the GP 68 Rx.

[FOX_111]

If you can pull out their frequencys charts to see wich channel use what frequency, that could help you see what is the problem.

[Risc_Terilia]

Originally Posted by FOX_111

If you can pull out their frequencys charts to see wich channel use what frequency, that could help you see what is the problem.

Right now the GP68 Receives fine fron channel 2 of the T5930 when set to 460.595 so I guess that's the corresponding frequency for channel 2.

I can't find any documentation for the T5930, I have the manual but it doesn't tell you much.

[FlyGuy]

Originally Posted by Risc_Terilia

Right now the GP68 Receives fine fron channel 2 of the T5930 when set to 460.595 so I guess that's the corresponding frequency for channel 2.

I can't find any documentation for the T5930, I have the manual but it doesn't tell you much.

That frequency does NOT correspond to any FRS/GMRS assignment. For the definitive list of FRS/GMRS frequency assignments, see the table on page 10 (PDF page 12 / 86) of this document. And for a pretty good discussion regarding conditional access squelch methods (CTCSS / DCS), see this link and reference the CTCSS table about 1/2-way down the page.


Begin rant...

For the record, I've been in the "radio business" for almost 20 years and it aggravates me silly (pet peeve) whenever I hear people talk about these so-called sub-channels! There is no such thing as a sub-channel dammit! That terminology is patently wrong...period! If two radios are tuned to the same frequency, say 462.6125 MHz (GMRS 6 / FRS 3) and they transmit simultaneously, it doesn't matter if one of them is using a 100 Hz CTCSS and the other is using 88.5 Hz, they are BOTH ON THE SAME RF CARRIER FREQUENCY and to a receiver listening on 462.6125 MHz, it will hear these two transmissions interfering with each other. The ONLY reason CTCSS and its digital descendant DCS were invented in the first place; or for that matter any other form of coded squelch control (DTMF, etc.), was to allow multiple radios to share the same carrier frequency within a common operating area without always hearing everyone else's traffic. It in no way affects the tuned RF carrier frequency and therefore does not add "extra or sub-channels" to your radio...it merely controls when/how your radio's speaker will un-mute during reception of transmissions on the tuned RF carrier frequency. Nothing more...period...end of story!

...End rant

Now, back to the task at hand...If you're doing these tests with both radios in close proximity to one another, you are probably overloading the front end of each radio every time you transmit causing it to respond even though it's off frequency...you need select low power and physically separate them to do these tests properly. Try at least 6ft or so to begin with. Also and as previously stated, you should disable all transmit and receive CTCSS/DCS on your GP68 and similarly on your T5930 before continuing. Then, referencing the frequency chart supplied in the link above, tune the T5930 to one of the 16 available FRS frequencies and then select that same frequency in the VFO of your GP68 -- Note: The GP68 has variable tuning steps so you should be set to either 12.5 kHz or 25 kHz spacing otherwise you may not be able to tune correctly. If everything's ok, you will hear yourself out of the other radio when you transmit a test.


Good luck,

'Fly

PS: Here's a link to the GP68 documentation/manuals/etc.

[Risc_Terilia]

Originally Posted by FlyGuy

That frequency does NOT correspond to any FRS/GMRS assignment. For the definitive list of FRS/GMRS frequency assignments, see the table on page 10 (PDF page 12 / 86) of this document. And for a pretty good discussion regarding conditional access squelch methods (CTCSS / DCS), see this link and reference the CTCSS table about 1/2-way down the page.


Begin rant...

For the record, I've been in the "radio business" for almost 20 years and it aggravates me silly (pet peeve) whenever I hear people talk about these so-called sub-channels! There is no such thing as a sub-channel dammit! That terminology is patently wrong...period! If two radios are tuned to the same frequency, say 462.6125 MHz (GMRS 6 / FRS 3) and they transmit simultaneously, it doesn't matter if one of them is using a 100 Hz CTCSS and the other is using 88.5 Hz, they are BOTH ON THE SAME RF CARRIER FREQUENCY and to a receiver listening on 462.6125 MHz, it will hear these two transmissions interfering with each other. The ONLY reason CTCSS and its digital descendant DCS were invented in the first place; or for that matter any other form of coded squelch control (DTMF, etc.), was to allow multiple radios to share the same carrier frequency within a common operating area without always hearing everyone else's traffic. It in no way affects the tuned RF carrier frequency and therefore does not add "extra or sub-channels" to your radio...it merely controls when/how your radio's speaker will un-mute during reception of transmissions on the tuned RF carrier frequency. Nothing more...period...end of story!

...End rant

Now, back to the task at hand...If you're doing these tests with both radios in close proximity to one another, you are probably overloading the front end of each radio every time you transmit causing it to respond even though it's off frequency...you need select low power and physically separate them to do these tests properly. Try at least 6ft or so to begin with. Also and as previously stated, you should disable all transmit and receive CTCSS/DCS on your GP68 and similarly on your T5930 before continuing. Then, referencing the frequency chart supplied in the link above, tune the T5930 to one of the 16 available FRS frequencies and then select that same frequency in the VFO of your GP68 -- Note: The GP68 has variable tuning steps so you should be set to either 12.5 kHz or 25 kHz spacing otherwise you may not be able to tune correctly. If everything's ok, you will hear yourself out of the other radio when you transmit a test.


Good luck,

'Fly

PS: Here's a link to the GP68 documentation/manuals/etc.

Re: Rant Are you addressing me? I don't know why you think I don't know that.

As stated the only controls on the T5930 are Channel, Volume, Monitor and PTT so there is no way to turn CTCSS on or off.

I've tried the GMRS and FRS frequencies at a range of 10 ft, no joy in either direction, the only way i can get transmissions from the T5930 to the GP68 is by getting my housemate to hold ptt on the T5930 and scanning on the GP68, which turns up these odd frequencies. No way at all for the GP68 to talk to the T5930

[walks]

lets see if this works...
rPL.xxx PL Freq (Hz) Equiv. rPL.xxx PL Freq Equiv.

tPLxxx PL Code tPL.xxx (Hz) PL Code
0 CSQ - 22 136.5 4Z
1 67 XZ 23 141.3 4A
2 69.3 WZ 24 146.2 4B
3 71.9 XA 25 151.4 5Z
4 74.4 WA 26 157.6 5A
5 77 XB 27 162.2 5B
6 79.7 WB 28 167.9 6Z
7 82.5 YZ 29 173.8 6A
8 85.4 YA 30 179.9 6B
9 88.5 YB 31 186.2 7Z
10 91.5 ZZ 32 192.8 7A
11 94.8 ZA 33 203.5 M1
12 97.4 ZB 34 206.5 8Z
13 100 1Z 35 210.7 M2
14 103.5 1A 36 218.1 M3
15 107.2 1B 37 225.7 M4
16 110.9 2Z 38 229.1 9Z
17 114.8 2A 39 233.6 M5
18 118.8 2B 40 241.8 M6
19 123 3Z 41 250.3 M7
20 127.3 3A 42 254.1 -
21 131.8 3B

GMRS/FRS FREQ GMRS/FRS CTCSS
1 462.5625 1 67 23 146.2
2 462.5875 2 71.9 24 151.4
3 462.6125 3 74.4 25 156.7
4 462.6375 4 77 26 162.2
5 462.6625 5 79.7 27 167.9
6 462.6875 6 82.5 28 173.8
7 462.7125 7 85.4 29 179.9
8 467.5625 8 88.5 30 186.2
9 467.5875 9 91.5 31 192.8
10 467.6125 10 94.8 32 203.5
11 467.6375 11 97.4 33 210.7
12 467.6625 12 100 34 218.1
13 467.6875 13 103.5 35 225.7
14 467.7125 14 107.2 36 233.6
15 462.55** 15 110.9 37 241.8
16 462.575* 16 114.8 38 250.3
17 462.6*** 17 118.8
18 462.625* 18 1230
19 462.65** 19 127.3
20 462.675* 20 131.8
21 462.7*** 21 136.5
22 462.725* 22 141.3




Tone Motorola PL Cobra Cherokee Midland Motorola Motorola RadioShack
Number 250/300 465 75-510 Sport TalkAbout 106
67 XZ 1 1 1 1 1
69.3 WZ 2
69.4 2
71.9 XA 2 3 2 2 3
74.4 WA 3 4 3 3 4
77 XB 4 5 4 A 4 5
79.7 WB 5 6 5 5 6
82.5 YZ 6 7 6 6 7
85.4 YA 7 8 7 7 8
88.5 YB 8 9 8 B 8 9
91.5 ZZ 9 10 9 9 10
94.8 ZA 10 11 10 10 11
97.4 ZB 11 12 11 C 11 12
100 1Z 12 13 12 12 13
103.5 1A 13 14 13 13 14
107.2 1B 14 15 14 D 14 15
110.9 2Z 15 16 15 15 16
114.8 2A 16 17 16 16 17
118.8 2B 17 18 17 E 17 18
123 3Z 18 19 18 18 19
127.3 3A 19 20 19 F 19 20
131.8 3B 20 21 20 20 21
136.5 4Z 21 22 21 G 21 22
141.3 4A 22 23 22 22 23
146.2 4B 23 24 23 23 24
151.4 5Z 24 25 24 24 25
156.7 5A 25 26 25 25 26
159.8 27 27
162.2 5B 26 28 26 26 28
165.5 29
167.9 6Z 27 29 27 27 30
171.3 31
173.8 6A 28 30 28 28 32
177.3 33
179.9 6B 29 31 29 29 34
183.5 32 35
186.2 7Z 30 33 30 30 36
189.9 34 37
192.8 7A 31 35 31 31 38
196.6 36
199.5 37
203.5 M1 32 38 32 32
206.5 8Z 39
210.7 M2 33 40 33 33
218.1 M3 34 41 34 34
225.7 M4 35 42 35 35
229.1 9Z 43
233.6 36 44 36 36
241.8 M6 37 45 37 37
250.3 M7 38 46 38 38
254.1 47

It took me a bit to get all the info when I got my GP-68
I have it in PDF format so if you want a better version PM your E-mail and I'll send'r off to you

[FlyGuy]

Originally Posted by Risc_Terilia

Re: Rant Are you addressing me? I don't know why you think I don't know that.

No, the rant was just a general comment/vent about the widespread and innacurate use of the term "sub-channel" by people who don't seem to understand 2-way radio all that much. It was not aimed at anyone in particular so no offense intended... However, upon researching the T5930, I can't seem to find any supporting evidence that it is certified (against RSS210) for use in Canada. If this is an offshore radio designed for a different marketplace, it may be part of the reason you're having compatibility issues.

BTW, nice list you've compiled there Field_Gunner...going to shamelessly steal it for my own use if you don't mind!


'Fly

[ThunderCactus]

Oh and don't forget to set your frequency increment to 12.5 so you can be exactly on the proper frequency. And set your squelch about one so you don't have to deal with static all the time lol
Shoot me a PM, I have the full GP68 manual in english

[Danke]

Originally Posted by FlyGuy

No, the rant was just a general comment/vent about the widespread and innacurate use of the term "sub-channel" by people who don't seem to understand 2-way radio all that much. It was not aimed at anyone in particular so no offense intended... However, upon researching the T5930, I can't seem to find any supporting evidence that it is certified (against RSS210) for use in Canada. If this is an offshore radio designed for a different marketplace, it may be part of the reason you're having compatibility issues.

BTW, nice list you've compiled there Field_Gunner...going to shamelessly steal it for my own use if you don't mind!


'Fly

That whole sub channel thing really had me pulling out my hair when I was punching the freqs into a Linton. The Cake is a Lie!

[Risc_Terilia]

Originally Posted by FlyGuy

No, the rant was just a general comment/vent about the widespread and innacurate use of the term "sub-channel" by people who don't seem to understand 2-way radio all that much. It was not aimed at anyone in particular so no offense intended... However, upon researching the T5930, I can't seem to find any supporting evidence that it is certified (against RSS210) for use in Canada. If this is an offshore radio designed for a different marketplace, it may be part of the reason you're having compatibility issues.

BTW, nice list you've compiled there Field_Gunner...going to shamelessly steal it for my own use if you don't mind!


'Fly

Ok, I was in a bit of a mood this morning hence my shortness, apologies. The T5930 is from Malaysia so I think you might be right. I'll see if I can get anywhere with Field Gunner's list

Thanks everyone for your help.