HFNets

The following index has been created to track various efforts to utilize the HF bands for node hopping and mail forwarding. There are some existing networks that are primarily focused on casual operating, keyboard to keyboard messaging for personal mail delivery. Due to the nature of AFSK and SSB, it is possible to have many combinations of VFO dial frequency with audio tone selection. Please see WA8LMF's excellent article on their relationship. It is also possible to run multiple, concurrent modems as long as their audio pass range fits within the radio's SSB filter. These ranges can vary, but generally runs around 300-3000 Hz. The two most popular protocols are AX.25/FX.25 (compatible) and IL2P. The AX.25/FX.25 protocols use NRZI encoding, which means USB and LSB can communicate as long as the center frequencies match. The IL2P protocol uses NRZ encoding, which means sideband selection must match. The seeming standard for HF IL2P seems to be USB. For compatibility reasons, it is suggested to run USB for both AX.25/FX.25 and IL2P. This also aligns with VARA, ARDOP and Mercury modems using USB. Traditionally, AX.25 HF packet was LSB by convention, but can support both. For those running hardware based TNCs that do not support IL2P and have fixed tones at 1600:1800 Hz (1700 Hz center), LSB frequencies are provided. With the overarching goal of linking systems statewide, we must also employ antenna systems that favor NVIS type propagation. In general, this means horizontal wire antennas 1/8-1/4w wavelength above the ground or magnetic loops which are oriented vertically.

Current HF Packet Networks

Name	Band	Center Frequency	Speed	Protocol	Usage/notes	Dial Frequency+Tone pairs
NET105	20M	14.103.3	300 Baud	AX.25/FX.25	Keyboard to Keyboard	14.102.0 MHz USB, 1300 Hz (recommended) | 14.105.0 MHz LSB, 1700 Hz
NET105	20M	14.104.3	300 Baud	IL2P	Keyboard to Keyboard	14.102.0 MHz USB, 2300 Hz
NET40	40M	7.102.3 MHz	300 Baud	AX.25/FX.25	Keyboard to Keyboard	7.101.0 MHz USB, 1300 Hz (recommended) | 7.104.0 MHz LSB, 1700 Hz
NET40	40M	7.103.3 MHz	300 Baud	IL2P	Keyboard to Keyboard	7.101.0 MHz USB, 2300 Hz
NET80	80M	3.597.0 MHz	300 Baud	AX.25/FX.25	Keyboard to Keyboard	3.596.0 MHz USB, 1000 Hz (recommended) | 3.598.7 MHz LSB, 1700 Hz
NET80	80M	3.598.0 MHz	300 Baud	IL2P	Keyboard to Keyboard	3.597.0 MHz USB, 2000 Hz

Proposed/Experimental HF Packet Networks

Name (Compatible NET)	Band	Center Frequency	Speed	Protocol	Usage/notes	Dial Frequency+Tone pairs
OH71018AX3 (NET40)	40M	7.101.8 MHz	300 Baud	AX.25/FX.25	Intrastate Forwarding	7.101.0 MHz USB, 800 Hz (Recommended) | 7.103.5 MHz LSB, 1700 Hz
OH71028AX3 (NET40)	40M	7.102.8 MHz	300 Baud	AX.25/FX.25	Intrastate Forwarding	7.101.0 MHz USB, 1800 Hz (Recommended) | 7.104.5 MHz LSB, 1700 Hz
OH71038IL2P3 (NET40)	40M	7.103.8 MHz	300 Baud	IL2P	Intrastate Forwarding	7.101.0 MHz USB, 2800 Hz
OH35965AX3 (NET80)	80M	3.597.5 MHz	300 Baud	AX.25/FX.25	Intrastate Forwarding	3.596.0 MHz USB, 500 Hz (Recommended) | 3.598.2 MHz LSB, 1700 Hz
OH35965AX3 (NET80)	80M	3.598.5 MHz	300 Baud	IL2P	Intrastate Forwarding	3.596.0 MHz USB, 1500 Hz

The following networks are intentionally too far away in frequency to be compatible with NET105/NET40/NET80. The frequencies/tones selected exist just inside the Automatic Digital Control Station (ADCS) band edges in an effort to minimize co-channel interference. The dial frequencies are outside the ADCS range, but the audio tones are inside the range. Remote/unattended stations may wish to permanently reside here while local/attended may choose to QSY here for forwarding only. If you choose to run VARA and/or Mercury HF modems on the proposed dial frequencies, it is imperative that the bandwidth is limited to 500 Hz. This preserves the 250 Hz buffer between AX.25/FX.25 space tone (1100 Hz) and IL2P mark tone (1900 Hz). More importantly, it keeps the VARA and/or Mercury HF modems within the ADCS subband to allow legal automatic operation.

Proposed/Experimental HF Mixedmode Networks

Name	Band	Center Frequency	Speed	Protocol	Usage/notes	Dial Frequency+Tone pairs
OH104005AX3	30M	10.140.15 MHz	300 Baud	AX.25/FX.25	Intrastate Forwarding	10.139.15 MHz USB, 1000 Hz (Recommended) | 10.141.85 MHz LSB, 1700 Hz
OH1014065M	30M	10.140.65 MHz	Various	Mercury (500 Hz)	Intrastate Forwarding	10.139.15 MHz USB, 1500 Hz (Fixed)
OH1014065M	30M	10.140.65 MHz	Various	VARA (500 Hz)	Intrastate Forwarding	10.139.15 MHz USB, 1500 Hz (Fixed)
OH1014115IL3	30M	10.141.15 MHz	300 Baud	IL2P	Intrastate Forwarding	7.099.15 MHz USB, 2000 Hz
OH710015AX3	40M	7.100.15 MHz	300 Baud	AX.25/FX.25	Intrastate Forwarding	7.099.15 MHz USB, 1000 Hz (Recommended) | 7.101.85 MHz LSB, 1700 Hz
OH710065M	40M	7.100.65 MHz	Various	Mercury (500 Hz)	Intrastate Forwarding	7.099.15 MHz USB, 1500 Hz (Fixed)
OH710065V	40M	7.100.65 MHz	Various	VARA HF (500 Hz)	Intrastate Forwarding	7.099.15 MHz USB, 1500 Hz (Fixed)
OH710015IL3	40M	7.101.05 MHz	300 Baud	IL2P	Intrastate Forwarding	7.099.15 MHz USB, 2000 Hz
OH710015AX3	40M	7.101.05 MHz	300 Baud	IL2P	Intrastate Forwarding	7.099.15 MHz USB, 2000 Hz
OH359515AX3	80M	3.595.05 MHz	300 Baud	AX.25/FX.25	Intrastate Forwarding	3.595.15 MHz USB, 1000 Hz (Recommended) | 3.596.85 MHz LSB, 1700 Hz
OH359565M	80M	3.595.65 MHz	Various	Mercury (500Hz)	Intrastate Forwarding	3.595.15 MHz USB, 1500 Hz (Fixed)
OH359565V	80M	3.595.65 MHz	Various	VARA HF (500Hz)	Intrastate Forwarding	3.595.15 MHz USB, 1500 Hz (Fixed)
OH359615IL3	80M	3.595.05 MHz	300 Baud	IL2P	Intrastate Forwarding	3.595.15 MHz USB, 2000 Hz