• W8CDX Takes Field Day Back to its Roots

    From ARRL de WD1CKS@VERT/WLARB to QST on Wed Jun 28 18:21:15 2017
    06/28/2017

    Some younger radio amateurs may not realize that ARRL Field Day[1] has been a staple operating event for more than 80 years. Former ARRL Communications Manager F. E. Handy, W1BDI, is credited with conceiving "International Field Day" in 1933, although it wasn't until the following year that he described it as the "test of the emergency availability of portable stations and equipment" we know today. For Field Day 2017, the crew at W8CDX once again took Field Day equipment back to the 1930s - a time when the notion of "portable" applied only loosely to equipment of the era. Last year, W8CDX used a National HRO-5 receiver and a style of transmitter similar to something that could have been used at that first Field Day. This time, everything was home built.

    "We had a lot of fun putting up another 1930s-style station for Field Day 2017," said Eric Tichansky, NO3M, the trustee of W8CDX, the Karns City Amateur Radio Club station. The transmitter was based on an August 1934 QST article, "A Medium-Powered Phone-C.W. Transmitter with Pentode Power Tubes," the receiver on a May 1934 QST article, "A De Luxe Crystal Type S.S. Receiver." Tichansky has documented[2] the receiver project from start to finish.

    "This would have been a possible setup used in the third Field Day in 1935," Tichansky told ARRL. "The entire station was 100% homebrew, including the power supplies, T/R switching, and link-coupled antenna tuner - inspired by a 1935 ARRL Handbook project." Power supplies were based on standard designs from that era, using 866s in the amplifier supply and 83s in the buffer and oscillator supplies. The bias supply used an 80 rectifier and an 874 regulator of late 1920s vintage to supply the needed -90 V bias.

    Tichansky said the T/R switch, which could be operated by foot switch, not only switched the antenna between receiver and transmitter but opened the keying line in receive, grounded the receiver input on transmit, lifted the grounded end of the receiver's RF/IF gain pot, and put a 15 kW potentiometer in line to adjust the side tone level. The antenna was an 80-meter doublet fed with homebrew open-wire feed line[3].

    Using the replicated vintage gear, W8CDX logged 305 contacts, about evenly split between 40 and 80 meters - up from 153 on 40 meters alone in 2016. The biggest issue on the air was chirp, "depending on how the stages in the rig were tuned." Sometimes the receiver would decide on its own to change frequency. Tichansky gave the gear a trial run during the Breezeshooters Hamfest at the Butler Fairgrounds in Prospect, Pennsylvania, on June 4, making several contacts.

    "We plan to keep this going as an annual event," Tichansky told ARRL. "It's really a lot of fun putting this antique-style gear on the air."

     


    [1] http://www.arrl.org/field-day
    [2] http://no3m.net/2016/10/1934-superhet-receiver-10-final/
    [3] http://no3m.net/2010/08/open-wire-transmission-line/

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