AM operation began as WA2HMH in Iselin, NJ back in 1970, when I put a Heathkit HW-17A together. This little transceiver put out 10 watts of plate modulated AM on the 2 meter band. At the time, AM activity thrived in the New York metropolitan area on the 2 meter band. All one had to do is warm up the rig, turn the antenna toward New York City, and call CQ early in the evening. On the weekends, some big groups would form around 145.08 and 145.1 Mc, with activity lasting into the wee hours of the morning. When the FCC expanded the repeater subband below 145 Mc, the AM activity died out. Some VHF AM activity remains around 144.3 and 144.4 Mc.
160 Meters - A New Beginning
I took a hiatus from AM operation until 1997, when my boss at a regional broadcast station group asked me if I wanted a large AM transmitter. I agreed to take a look at the unit and drove to WNNJ in Newton, New Jersey. The transmitter was a beautiful Collins 20V, which went on the air in September, 1953. The station's chief engineer, Mick Rapeer (W2YNO), helped me tag wires, remove the heavy iron, and load the transmitter into my pickup truck. We had to temporarily remove the doorjamb to get the transmitter out of the building! After I got the transmitter home, a work party from the Old Barney Amateur Radio Club helped me offload the unit and get it into the house. The radio room is a former bedroom that contains several operating positions. My house is a small Cape Cod and there was no room in the radio room for this beast. Because the 20V weighs half a ton, it could not be moved into the basement. So the transmitter ended up between the living room and the kitchen.
The 20V was already in working order, as it had been the backup transmitter at WNNJ. Since WNNJ operates on 1360 kc, conversion to the 160 meter band was easy. To get on 1885 kc, one needs only to retune the buffer and driver, then change some taps on the coils in the PA tank circuit. The Pi-L PA tank circuit is tuned and loaded in the conventional manner.
For safety, a 230 volt disconnect panel was installed on the wall next to the transmitter and a shorting stick was added inside the unit. Although two shorting bars automatically short the B+ line to ground whenever the doors are opened, they do not short the low voltage supply. When working on the 20V, the shorting stick is used to short the IPA supply and to ensure that the primary voltage has been turned off. All control and audio wiring was passed through the basement. Since the plate contactor coil operates at a very dangerous 230 VAC, a 12 VDC slave relay was installed for keying and unkeying the transmitter. The plate voltage is turned on and off by switching the primary of the high voltage transformer. Because of this, the RF decays slowly when the transmitter is unkeyed. A delay in the T-R relay is necessary in order to avoid zorching the receiver.
The Bug Bites
When I made my first AM contact on 160 meters with the 20V, the AM bug bit - hard. I later acquired a Collins 20V-2 from WOON in Woonsocket, Rhode Island. It and the 20V form a room divider between my living room and kitchen. In May, 2001, I acquired a Gates BC-1T from WBUD in Trenton, NJ. That transmitter now sits in the living room across from the 20V. A switching rack allows me to remotely switch transmitters within 30 seconds. I built a remote "studio" and control point at my new primary residence between Shickshinny and Huntington Mills, Pennsylvania. It includes a Heathkit DX-100 and a Collins 21E broadcast transmitter. The 21E was acquired from WMTR in Morristown, NJ and has been reassembled in a shed in the backyard. It was first put on the air from its new home in late February, 2007. The New Jersey site is now a backup site, which I can still operate by remote control from Shickshinny. It also serves me well when I crave a weekend at the Shore, as one is ill-advised to swim in the "delicately scented" Susquehanna River here in northeastern Pennsylvania! You can often hear me on 1885 kc. in the evening, with operation during critical hours and around local sunset in the summer (for the purpose of avoiding static) and at just about anytime on winter nights. 1890 and 1945 kc. are alternate frequencies.