They may be used in some low-power part of a transmitter or receiver these days, but with semiconductors rather than tubes. The most notable advance in transmit- ter technology during the early days of amateur radio came with the invention of the quartz crystal.   the result is the am transmitter shown here in an altoids tin on top of a radionette kurér radio. Several hundred thousands were produced, and it was exported from norway to 60 countries. Weve assembled one of the largest selections of ham radio transmitters for sale in one place making it easy to find what youre looking for. The 2-meter amateur radio band is a section of the vhf radio spectrum, which includes frequencies ranging from 144 mhz to 148 mhz in international telecommunication union region (itu) regions 2 (north and south america plus hawaii) and 3 (asia and oceania) and from 144 mhz to 146 mhz in itu region 1 (europe, africa, and russia). K1iw amateur repeater and broadcast transmitters database websearch use this form to generate a list of amateur repeaters and broadcast transmitters to your specifications. States, the district of columbia, and the ten canadian provinces. Amateurs use a variety of voice, text, image, and data communications modes over radio. Generally new modes can be tested in the amateur radio service, although national regulations may require disclosure of a new mode to permit radio licensing authorities to monitor the transmissions. Encryption, for example, is not generally permitted in the amateur radio service except for the special purpose of satellite vehicle control uplinks. A milliwatting enthusiast enjoys the challenge of communicating on the amateur radio bands while using the lowest possible rf power level. However, along with this challenge, ive recently begun to wonder what are the minimal performance limits of the active devices that i use in my qrp transmitters.   glowbugs - homebrew tube amateur radio transmitters and receivers glowbugs - homebrew (diy) tube gadgets, receivers and transmitters, dedicated to the golden era of amateur radio. Generally, any small, home-built tube-type transmitter or receiver may be referred to as a glowbug. Discovered amateur radio, was given a copy of the 1957 allied radio catalog no. 160 (the cover with the satellite on it), and started to learn the code. Sometime later, a neighbor loaned me his 1957 arrl the radio amateurs handbook and i discovered a one-tube two-band transmitter for the novice.