Authored by VE3EFJ
14.0 R7 RECEIVERS
The receiver is very similar functionally to an Icom R71A or Kenwood R5000. The R71A is an excellent communications receiver. The R71A shares this functional equivelency in the areas of PBT, IF Notch, excellent noise blanker and 100 cycle display. The recovered audio of the Icom is not equal to the R7(A).
The R7(A) is still considered to this day to be an exceptional receiver. Its only negative is drift, for it uses the same synthesizer basically as the TR7. Its a VHF/PTO tracking synthesizer and consequently is no more stable than the PTO that drives it as a reference. The RV75 PTO is the method of choice to tame this drift. It is generally considered that the R7 is about as the best as it gets without reverting to more exotic, much higher priced units.
A more modern version, sort of, on a functional basis is the current day Drake R8A. In ultimate terms, the R7 is the better receiver, but the two are very specification close. It is the R7 that has the charisma, however. The R8A does not drift and has a real syncronous detector, but the notch circuitry is audio, not IF.
R7 receivers are not too rare, but they are not often seen because they are hoarded and cherished. When one comes up on the market, it usually goes for the asking price unless the seller is greedy. As per the TR7, it is best if you buy the receiver as loaded up as possible. Be warned that this receiver was expensive in its day, holds its value, is 'rare' and is in high demand. If you want one, you'll find one, most likely, but be prepared to open your wallet.
This is a triple conversion receiver, somewhat like an R4C. The last IF frequency is at 50 kHz in order to encorporate a notch filter. The signal flow is crudely similar to the receive section of a TR7 with the following exceptions:
In order to use the ECSS AM detector properly, the optional 4 kHz filter needs to be present.
The R7/R7A is a superlative receiver that has genuine charisma. It has one area of inconvenient operation in the area of the UP/DOWN buttons (500 kHz shift from the band switch setting) and it 'drifts' in that it has a free running PTO. The latter is rectified when using the RV75 remote VFO, since the RV75 is digital.
|Table of Contents||Previous Page||Next Page||Drake List Web Site|