WR4CV-10 block diagram

WR4CV-10 is a VHF/UHF gateway located at the Wintergreen resort and ski area on the Blue Ridge in Central Virginia. It supports AX.25 packet and the new FX.25 (AX.25 with error correction) on VHF. It also supports VARA FM on both VHF and UHF.

VHF configuration

For VHF, the RMS Packet, EA5HVK VARA FM, and UZ7HO Soundmodem settings are:

VHF RMS Packet

VHF Site Properties

VHF Packet Engine Configuration

VHF VARA FM TNC Settings

Note that you will need to specify unique port numbers for Soundmodem and the two copies of VARA FM. If you leave the port numbers set to the defaults you’ll get port conflicts.

VHF VARA FM Setup

VHF VARA FM SoundCard Settings

VHF VARA FM PTT Settings

VHF Soundmodem Settings

VHF Soundmodem Modem Settings

UHF configuration

For UHF, a second copy of RMS Packet and a second copy of VARA FM are started. After you’ve installed RMS Packet and VARA FM, make copies of the folders for each before you start configuration. That way you start with a clean configuration for both the VHF and UHF sides.

UHF RMS Packet

UHF Site Properties

UHF VARA FM TNC Settings

UHF VARA FM Setup

UHF VARA FM SoundCard Settings

UHF VARA FM PTT Settings

RMS Relay configuration

I use RMS Relay so the Gateway will still be usable for local VHF/UHF traffic if the Internet connection fails.

RMS Relay Site Properties

A little wrinkle here: if your gateway is connected to an AREDN mesh network (as is my other gateway, W4UVA-10) then your gateway computer will need an additional Ethernet port to connect to the mesh network, and you will want to select the gateway computer’s mesh IP address at “IP address to receive connections” on the “Site Properties” panel. You will also need to tell the RMS Packet instances to use that IP address to communicate with RMS Relay. Incoming connections from either VHF/UHF or mesh will be processed as they arrive. Winlink over the AREDN mesh works really well, both via the gateway and P2P. (See https://www.cvadn.net/winlink-mesh/ for client configuration details.)

RMS Relay Operating Mode and HF Forwarding Control

Windows startup configuration

I use Startup Delayer (https://www.r2.com.au/page/products/show/startup-delayer/) to make sure things start in the right order: Soundmodem, RMS Relay, RMS Packet (VHF), RMS Packet (UHF). The two instances of RMS Packet are configured to automatically start the two VARA FM instances.

Startup Delayer configuration

Tuning

Proper setting of transmit and receive audio levels is critical for fast and reliable VARA FM performance. I have discovered that VARA FM and AX.25 packet have somewhat different optimal transmit audio level settings; I set levels for VARA FM and let packet levels be “good enough,” as we have pretty much switched to VARA FM. It is so much faster, more forgiving of noise, and more reliable.

The best results are to be had by using the “Auto Tune” feature in VARA FM. You want to see something like this:

Gateway VARA FM Auto Tune successful

You should do “Auto Tune” on the Winlink Express end, as well…

Winlink Express VARA FM Auto Tune succussful