Ham Radio

Amateur radio, also known as ham radio, is the use of the radio frequency spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergency communications.

I immediately fell in love with ham radios when I was 13 years old, after learning a tutorial on how to make a crystal radio receiver from my physics textbook. I started with designing antenna at MF bands, then followed by designing rectifiers and amplifiers.

My first crystal radio receiver circuit, designed at age 13.

Handmade inductor crafted with enamel-insulated wire, set to around 300µH for the MF band.

Upgrade the reed speaker by using a tiny enamel-insulated wire to increase the DC impedance

I received my license and callsign in 2022. I’m also a member and operator of BY1QH, which stands for the Tsinghua University Amateur Radio Club.

My Rigs

Currently, I have several transceivers for different bands.

My main device for VHF and UHF bands is the Yaesu FT-5DR.

Yaesu FT-5DR for VHF/UHF bands, with a Diamond SRH770 or SRH771 antenna.

For satellite contacts, I prefer to use a handheld Yagi antenna.

My friend and I are using the Yaesu FT-5DR and a U7V4 Yagi antenna, trying to make QSOs on the FM repeater from the satellite SO-50.

I enjoy QRP portable operations! Just like camping, it’s cool to drive to a park, assemble the antenna, connect the power bank, and make the whole system work in an unfamiliar environment.

During portable operations, I often use an ICOM IC-705 with a DIY V-pole or inverted-V antenna.

My IC-705, paired with a DIY V-pole antenna, operates on the FT8 mode of the 20m band.

Under Construction: My Ham Radio Base Station

Recently, I was lucky enough to acquire rooftop access thanks to my friend BI1OLC. This has given me the opportunity to build my own ham radio base station at ON70.

For satellite communication, I purchased Diamond Yagis for the base station.

The Diamond U15 Yagi antenna at my base station, temporarily mounted on a tripod.

Typically, Yagis should be mounted on a rotor. However, the Yaesu rotor is too expensive for operating just 2 Yagis. Therefore, I decided to buy a cheap industrial camera rotor instead, and modified it to serve as an antenna rotor. I plan to add encoders inside the rotor to obtain precise azimuth and elevation values. Then, I will write a script for the motion planning part.

For HF communication, I purchased the ICOM IC-7300 in Akihabara during ICRA ‘24. It will be the main device I operate in the HF band.

Got an ICOM IC-7300 at Akihabara, Tokyo, Japan.

My QSL Cards

I have several different designs of QSL cards.

V1

The first commemorative card is available in limited numbers from October 2023 to March 2024.

The first commemorative card shows me using an RTL-SDR and a U7V4 Yagi antenna to receive the SSTV signal from the International Space Station.

V2

The second QSL card, also printed in limited numbers, commemorates my first Summits On The Air (SOTA) operations.

The second commemorative card features my DIY HF antenna and a baby van. Just 2 days after this SOTA operation, my friend BI1OHI began a road trip around China in this baby van.

V3

Currently, the third QSL card is in use and aims to advocate for our robot, ArrayBot.

The third QSL card advocates for our robot.

I enjoy collecting paper QSL cards! If we have a QSO, please send me your card, and I will send back my card. SWL QSLs are also welcome. For more details, see here.

Friends in Ham Radio

Tsinghua Amateur Radio Club, BY1QH

Yurihou, BH9DWE

Hydroxide, BI1QGX

My Logbook

You can use the HRDLOG search service below to check our QSO.