fredbox


Posted on Feb 6, 2014

This is the story of the Fredbox, a rig that first saw the light of day in 1974 in Cambridge. In the last few months it has been restored to full working order to enjoy the renewed interest in AM operation on 2m in the UK. For several years I`d worked local stations with a simple very low power 10mW AM transmitter. This was coupled with a super-re


fredbox
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gen receiver that first appeared in Practical Wireless in the late 1960s. Incidentally, this receiver design has just been republished in a recent copy. The simple combination was used on the bench with just a toggle switch change-over. For some time the antenna changeover consisted of unplugging the antenna from the receiver then plugging it into the TX and vice versa. The antenna at that time was a small dipole or indoor yagi rotated by hand. Combining these two circuits into one small handheld took only a couple of weeks. A small PCB was etched after a suitable box was found and the circuit worked first time. People working along side me were so impressed by its small size that very soon 3 other copies were made. The first Fredbox to Fredbox QSO was over about 0. 3kms. Local contacts were frequent around the Cambridge city area and the most regular QSOs were on 145MHz with a local disabled amateur, Fred, G8BWI. Because of this, the little box became know as the FREDBOX. I dedicate the circuit and the memories of those fun times to dear old Fred. How Fred could talk! Sometimes you`d start a QSO, then hand over to Fred, have your tea, and he`d still be talking away. Such good, fondly remembered, times indeed. The most exciting results took place away from Cambridge in Yorkshire and in South Devon. In Yorkshire the Fredbox was regularly used to make QSOs from my wife`s parent`s house in Barnsley up to Leeds about 20 miles...




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