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Neil H. Gray
Based on suggestions, I tried to follow using the direwolf calibration tones(-x).
For my test setup I have a C-Media USB Audio attached to a yaesu ft-817, and a kenwood tr-2500 or kenwood tm-241 connected to a ASUS Xonar U7 MKII back to the same computer to monitor how the signal looks over the air.? Note that I also ran two instances of direwolf, and I was able to communicate between them, but I have still had no luck talking to other stations. I am looking at the received audio coming back from the kenwood radio in audacity(first program I tried), and when I look at the transmit tones, it appears that my higher frequency is way down compared to the lower frequency.? Changing the playback volume doesn't appear to solve this.? The output looks the same when normalized(which audacity seems to do automatically). Am I looking at this correctly? 
2022-04-21_successful_packet_radio_to_radio.jpg
audacity__direwolf__caudio_play_1__received__kenwood_tr-2500.png
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¿ªÔÆÌåÓýHello Neil, I am looking at the received audio coming back from the kenwood radio in audacity(first program I tried), and when I look at the transmit tones, it appears that my higher frequency is way down compared to the lower frequency.? Changing the playback volume doesn't appear to solve this.? The output looks the same when normalized(which audacity seems to do automatically). I think you you're seeing the effect of pre-emphasis or the lack of it.? When you connect your packet equipment to your radio, more basic radios can only be connected using their microphone port or possibly a "1200 bps" packet pin.? Those those signals will have pre-emphasis added to them and are transmitted over RF.? More advanced radios or modified radios have a "9600 bps" pin that does NOT add a pre-emphasis stage to the signal before it's transmitted over RF.? Pre-emphasis is already covered on but also has good descriptions here: ?? --David KI6ZHD |
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The Data Jack (6-pin mini-DIN) on radios does NOT have a 9600 baud TX pin. There are 6 pins in the jack: 1??? PKD (Data In) 2??? GND 3??? PTT 4??? RX9600 5??? RX1200 6??? SQL The TC path is the same for either baud rate. Robert Giuliano
On Thursday, April 28, 2022, 11:13:45 AM EDT, David Ranch <direwolf-groupsio@...> wrote:
Hello Neil, I am looking at the received audio coming back from the kenwood radio in audacity(first program I tried), and when I look at the transmit tones, it appears that my higher frequency is way down compared to the lower frequency.? Changing the playback volume doesn't appear to solve this.? The output looks the same when normalized(which audacity seems to do automatically). I think you you're seeing the effect of pre-emphasis or the lack of it.? When you connect your packet equipment to your radio, more basic radios can only be connected using their microphone port or possibly a "1200 bps" packet pin.? Those those signals will have pre-emphasis added to them and are transmitted over RF.? More advanced radios or modified radios have a "9600 bps" pin that does NOT add a pre-emphasis stage to the signal before it's transmitted over RF.? Pre-emphasis is already covered on but also has good descriptions here: ?? --David KI6ZHD |
¿ªÔÆÌåÓýRob is right here (sorry for the confusion).? I did have them reversed BUT it's the "DATA IN" signal that also needs the ability to enable or disable the application of pre-emphasis if your radio supports this.? For say Kenwood v71/d710 models, here is a thread about it: ?? /g/VARA-MODEM/topic/74742391 Ultimately, when in doubt, assume your radio is applying the emphasis / de-emphasis to your signal which is the CORRECT choice for 1200bps packet used with APRS, classic connected packet, etc. --David KI6ZHD On 04/28/2022 08:28 AM, Rob Giuliano
via groups.io wrote:
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