Opportunity knocks
The curators of the local Fauquier 145.730 MHz packet node decommissioned their system on the very same hill we hope to rollout our version of the Virginia Packet Network. The antenna and cavity filter are still in place. This makes our 2m packet frequency open for use with relative ease. With some lobbying efforts from us, the local radio club is offering us some space in their radio rack. To sweeten the deal Virginia Packet Network will pick up the tab for a double conversion rack mount UPS system to mitigate the power issues at this location.
What this means for the VAPN
Setting up single band, 2m packet network is the fortunate happenstance from the above circumstances. Once we successfully specify a suitably fault tolerant, rack mount, linux capable, computer system, the next steps involve creating the 2m radio assembly
- Purchase a 2U fully enclosed rack mount box to house transceiver, TNC and power supply;
- Purchase a switching, AC to DC, open-frame power supply;
- Specify and select an appropriate 2m transceiver with the standard 6 pin MiniDIN data jack;
- Figure out a relatively quick TNC – probably an SCS Tracker in 1200 bps mode;
- Purchase rear panel AC connectors, etc. and modify back panel to accept these components;
- Modify rack box to vastly improve RF shielding.
TNC
The main diagram shows a Raspberry Pi with DireWolf as the TNC. That is still the plan, but for this quick initial rollout a traditional TNC makes sense. Since the SCS Tracker is in the plan for the HF ports, we may as well use one for the 2m TNC to get things rolling sooner. Later, it will move to a future HF radio rack mount assembly.
UPS
One of the larger costs is the procurement of a UPS. Lower cost makes and models that can tolerate generator power are not very common. Fortunately if you are willing to pay a bit more, double conversion UPS units solve this problem. A suitable model is in the plan.
Timeline
Depending how fundraising goes, the hope is to have the Virginia Packet Network initiation on a 2m frequency sometime this fall.