N7WDZ

The ham shack

This is my base station: HF, VHF and UHF radios, packet and APRS, scanners and a few vintage pieces. Click any photo for a larger view.

The antennas

Most of my antennas stand on masts along the side of the house, with the HF wire antenna in the backyard. Several of them feed the live pages on this site. "Dual band" means 2 m and 70 cm.

1. Homebrew 1.25 m antenna (220 MHz), a twin-lead J-pole: how I built it
2. Comet GP-6, dual band
3. Comet GP-15, tri-band: 2 m, 70 cm and 6 m
4. MLA-30+ receive loop for 0.5–30 MHz, feeding the SDR receiver's shortwave side
5. Comet GP-3, dual band, used by the APRS station N7WDZ-1
6. ANLI dual band
7. Discone receive antenna, shared by the ADS-B receiver and the SDR receiver

HF

For HF I use a Chameleon EMCOMM III Base wire antenna, cut down to 73 feet and hung as an inverted V from a mast in the backyard. It's fed through the antenna's 5:1 unun in a weatherproof box on the wall.

The weather station

The live weather and records on this site come from a Davis Vantage Vue mounted on a mast about 25 feet above the ground. It reports wirelessly to a Vantage Vue console inside the house and to a WeatherLink Live receiver, which sends the readings to WeatherLink every minute. The station has been running here since June 2021.

The ADS-B receiver

Aircraft broadcast their position, altitude and speed on 1090 MHz (ADS-B). This station picks those signals up and shares them with ADS-B Exchange and with the live aircraft map on this site. The signal path:

1. Tram 1410 discone antenna, wall-mounted on a mast above the roofline
2. 100 feet of RG6 coax down to the shack
3. 2-way splitter (5–2400 MHz) that shares the antenna with the SDR receiver
4. Nooelec LaNA low-noise amplifier (20–4000 MHz), on the ADS-B side only
5. 1090 MHz SAW filter to keep out strong signals on other frequencies
6. AirNav Radar FlightStick receiver, plugged into a Raspberry Pi 3B+ running the ADS-B Exchange feeder software

You can also see everything this receiver hears, with flight history and replay, on my ADS-B Exchange feeder map.

The APRS station

N7WDZ-1 is an APRS iGate and digipeater on 144.390 MHz. It repeats nearby stations' packets on the air to extend their range, and passes everything it hears to the APRS internet network (APRS-IS), where it shows up on sites like aprs.fi. The APRS page shows what it is hearing right now.

1. Comet GP3 dual-band antenna, about 25 feet above the ground
2. Motorola CDM1250 VHF transceiver on 144.390 MHz
3. Digirig Lite audio and PTT interface
4. Raspberry Pi 5 in a metal case, running Graywolf APRS software as the modem, digipeater and iGate

The LoRa APRS station

N7WDZ-25 is a second, much smaller APRS iGate and digipeater for LoRa APRS on the 433 MHz (70 cm) band. LoRa is a long-range, low-power radio mode, and inexpensive LoRa trackers use it to send APRS positions. N7WDZ-25 passes what it hears to APRS-IS and repeats local stations on the air. It sits in a weatherproof box on a patio post, runs on 5 volts from the same 12-volt solar battery as the Meshtastic node, and connects over Wi-Fi. Its stations and their signal strengths are on the APRS page.

1. HYS 433 MHz ground-plane antenna (3 dBi), on a bracket at the top of the patio cover, about 15 feet above the ground
2. LILYGO LoRa32 (TTGO T3 v1.6.1 / v2.1) 433 MHz ESP32 board running the CA2RXU LoRa APRS iGate firmware
3. DROK buck converter stepping the 12-volt solar supply down to 5 volts for the board

The photos show the original build, which had a two-way booster between the board and the antenna. I removed it because the battery capacity I gained was worth more than the extra packets it brought in. The numbers are on the project page.

The Meshtastic node

Meshtastic is an off-grid text messaging network built from small LoRa radios on 915 MHz, where every node relays what it hears. My node is a Station G2 at the top of a pole in the backyard, about 12–15 feet up, running entirely on solar power. It's on my home Wi-Fi, and a small server in the house reads what it hears and feeds the Mesh page, which shows the nodes heard and the G2's battery. The full build is on its project page.

1. 8 dBi 915 MHz fiberglass antenna at the top of the pole
2. Station G2 (B&Q Consulting) in a 3D-printed holder I designed, inside an IP65 weatherproof box, set to the Client Base role
3. INA219 voltage and current sensor on the G2's QWIIC connector, since the G2 has no battery gauge of its own; attached at the G2's power connector, it reports the supply voltage (which follows the battery) and the G2's power draw
4. 12.8 V 6 Ah LiFePO4 battery, charged by a PolyEnergy 10-amp MPPT charge controller and a 100-watt solar panel; the same battery also powers the LoRa APRS iGate
5. Indoors: a small home server that reads the G2 over Wi-Fi and sends the data to this site every 5 minutes

The SDR receiver

Two software-defined radio (SDR) receivers let anyone listen live from a web browser, from the AM broadcast band and shortwave up to aircraft, NOAA weather and the 70 cm ham band. They share the Raspberry Pi 5 that runs the APRS station, and the Pi keeps the APRS station first in line, so visitors can't slow it down. The SDR page explains how to use it and links to the live receiver.

1. MLA-30+ active loop antenna, a receive-only loop for 0.5–30 MHz (medium wave and shortwave), feeding an SDRplay RSP1a
2. Tram 1410 Super Discone antenna, the same one the ADS-B receiver uses: after the shared coax and splitter, this side goes to a drop amplifier (54–1002 MHz, four outputs) that feeds a second SDRplay RSP1a as well as my Uniden SDS200 and BCT15X scanners. There's no low-noise amplifier on this side: strong local FM and TV signals overloaded it, and VHF and UHF sound much cleaner without it
3. A powered USB hub connecting both receivers to the Raspberry Pi 5
4. OpenWebRX+ software, which turns the receivers into a web page for up to 4 listeners at a time