aeg telefunken e1800a receiver racal ra-3701 ra-3791 ra-1792 harris RF590 watkins johnson 8711 rohde schwarz ek070 radio




A very responsive and well engineered tuning aid

This piece of equipment makes tuning using a digital receiver much more pleasant and it's very useful for tuning AM, CW and data signals

Built completely using 7400 and 4000 series discrete logic, no microprocessors or controllers. Beautiful construction within

These are quite rare, but if can get your hands on one of these, and your receiver can drive it (or you can make a suitable converter), then you will not be disapointed

Input is 100KHz centre frequency

Frequency span is 1, 2 or 4KHz, selectable with the scale multiplier switch

These are directly suitable for the Racal RA17 and also RA177x, RA179x and RA370x with a suitable 100KHz converter module. The RA379x provides 100KHz IF output as standard. Other receivers with 100KHz IF output may also be suitable

These units nicely match the Racal RA17, though manufactured many years later than the first RA17 receivers and not by Racal

Above shows an RTTY signal tuned in correctly in the receivers' passband

Very little information exists in the public domain about these tuning aids


The three position rotary switch multiplies the LED bar graph scale by x1, x2, or x4. Corresponding to 1, 2, or 4 KHz span
RTTY signal (x1 scale)


RTTY signal (x2 scale)


AM signal


The rear panel is very simple. A mains input connector and fuse, and the 100KHz IF signal input BNC socket, SK1



More will be added to these pages as my time permits
If you have any questions or comments about this website, send me an email. I will read all but I can't guarantee that I'll reply to all. This is just a hobby site and my normal days work takes priority
I am not a trader or professional buyer or seller of these great bits of kit. It's just a hobby of mine to collect, play with, digest technical information and then either keep safe or pass on to another equally dedicated individual who will take care of these wonderfully engineered machines!
This website is not affiliated to any manufacture or model and the information contained is of my own work and as such, measurements and figures quoted are for reference only and are not intended to discriminate any individual product
2018 by Andrew Cygan