| Net14 The World Wide APRS Net |
| HF APRS Frequencies |
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| Bands Communications |
| Band Mtrs | Frequency | Mode | Baud Rate | PSK/GMSK Tone | Remarks |
| 10 | 28.140 | USB | 300 | Net14-10 Frequency | |
| 10 | 28.140.5 | USB | 300 & 600 | Net14-10 Frequency. Dual Baud Rate. Tones 300bps 1200Hz, 600bps 2KHz | |
| 15 | 21.117 | LSB | 300 | In use in Africa | |
| 20 | 14.103 | LSB | 300 | 1300 Hz | Net14-20 Frequency |
| 30 | 10.147,600 | USB | 300 | 2100 Hz | Use when carrier is out of band. Net14-30 Frequency |
| 30 | 10.151 | LSB | 300 | Link to G3NRW Band Utilization Chart here |
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APRS being a mode that uses the same protocol as Packet it has naturally followed the same practices. On the VHF bands it employs FM modulation while on HF, with the exception of some activity on 10m where FM is used, SSB is used. Not SSB as we normally think of it with phone but with just two tones. These are generated by a TNC or a computer program and results in two corresponding sideband frequencies when SSB is selected on the transceiver. The tones are always 200Hz apart but their actual frequency is dependant on the standard used, of which there are two: - KAM 1600Hz & 1800Hz i.e. centred on 1700Hz and PK-232 2110Hz & 2310Hz i.e. centred on 2210Hz Where a carrier (dial) frequency is quoted, as above, it is normally for KAM tones and therefore when PK232 tones are used it is necessary to make an adjustment to the carrier frequency. If PK-232 is used with LSB the carrier should be increased by 510Hz. If USB is used with PK-232 then the carrier frequency must be reduced by 510Hz. If you use the AGW Packet Engine with the computer sound card instead of a TNC please note that it uses PK-232 tones. With regards to PSK/GMSK tones if PK-232 is used add 510 Hz to the tone frequency. We all like to think that the frequency shown on our pet transceiver dial is the frequency that is being transmitted but in a serious moment we have to admit to ourselves that it is not. With HF APRS, on SSB, frequencies need to be quite close for proper decoding. Time to put aside one's pride and ideally align your frequency to a regular station that appears to be on the agreed QRG or go along with the crowd. On 14.103MHz, in Europe, station IZ4EFV-14 is the station that is recommended for Net14 alignment. It is a club station and is QRV 27/7. |