R.L. Drake

Drake Mods - TR7

Authored by VE3EFJ

12.0 TR7

    By the mid 1970's it was obvious that a new generation transceiver was required. Vaccuum tube equipment was being replaced by solid state radios - especially for those that wanted to operate mobile. The solid state equipment was obviously the way of the future. Drake answered this challenge with the TR5 and TR7 transceivers. There also was an R7 receiver. This receeiver is not that common due to its intial expense and the fact that those that have them tend to keep them.

    Yes, there was a TR6. That was a 6 meter SSB transceiver circa 1970 in much the same vein as an SB-110.

    Yes, there was an 'A' model of the TR7. This is around a 1982 flavor. What the 'A' model of the TR7 and R7 really was all about is that the equipment contained standard such as noise blankers and crystal filters that were options on the earlier model.

    The TR7, as is common for most Drake equipment, is over built. This is characteristic of most well made American equipment. While a TR7 may not have all of the useless 'features' of foreign equipment, it is as reliable as a rock and solidly built. Drake made sure it was a quality piece of radio and not intended to be disposable. An example - the TR7 generates 150 watts (250 in or so) output, yet the PA is capable of at least 225 out. At its nominal power rating, the final transistors are under utilized. The transceiver is big and heavy at 17.5 lbs despite an aluminium chassis. Glass epoxy boards are employed throughout the radio. The receiver is dead quiet and almost immune to overload. A large part of the reason for this is the lack of an RF amplifier and a strong passive DBM in the front end (ala Atlas 210). The TX SSB audio is rich and clean. The AGC switches with the mode setting for near optimum tailoring. The only item to be missed is an IF notch filter. You'd look at a TR7 today perhaps with some distain if you didn't know any better.

    A TR7 is a classic example of old ham gear easily overlooked since it is 'old tech'. Yet quite a few of the same amateurs will get very excited over a Racal or other piece of 'commercial' equipment. At the end of this document is a readers comment regarding the flexibility of the TR7 design for commercial applications. You see, Drake just didn't make amateur gear.

    A well working TR7 is a treat to use. Transmitted audio is excellent and the receiver is a gem. The AGC is typical Drake - peerless. It can be used for hours and hours without operator fatigue as the audio is clean and near hiss free. The transmitter PA stages are constructed for heavy use. The major downside of the radio is its current requirements. Nominal drain on receive is about 3 A, on transmit, it could run to about 22 to 25 A. Both of these figures are considered slightly excessive today. The size of the radio rules out mobile operation in most of todays cars and the red LED frequency display washes out in sunlight.

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