Television RF Pre-amplifiers Models: A, B, C & D

Arthur Radford, before founding Radford Electronics, manufactured Television RF Pre-amplifiers through his company Cabot Radio Co. Ltd. in Bristol. These pre-amplifiers were designed to improve television signal reception and were available for both London and Birmingham frequencies.

Pre-amplifier Models
Cabot Radio offered several models of television pre-amplifiers:

• Model A: A two-stage model using 6SH7 valves with variable gain control, priced at £5.15.0 including valves.
• Model B: This model used a Mazda 6F1 valve and had an effective gain of 10 times with an extremely high signal-to-noise ratio. It could operate with an input as low as 5 microvolts without deteriorating picture quality. The bandwidth was 5 MHz, and it was entirely self-contained, operating from 200-250v A.C. 50 c.p.s. Priced at £5.15.0 including the 6F1 valve.
• Model C: A single-stage model using a 6SH7 valve, known for its high signal-to-noise ratio. It was priced at £4.17.6 including the valve.
• Model D: Another single-stage model using a 6SH7 valve, but it employed a capacitor for series heating the valve instead of a transformer. This model was the most affordable at £3.17.6 including the valve.

All models were self-contained with built-in power packs and operated from 200-250v 50 c.p.s. mains.

Technical Specifications
The Model B, in particular, stood out for its technical capabilities:

• Effective gain: 10 times
• Minimum input: 5 microvolts
• Bandwidth: 5 MHz
• Size: Approximately 4 inches cubed
• Valve: Mazda 6F1 in an up-to-date circuit1

These pre-amplifiers were available from local dealers or directly from Cabot Radio Co. Ltd. at 28 Bedminster Parade, Bristol.

In questo link sono elencati 32 modelli, di cui 25 con immagini e 10 con schemi.
Elenco delle radio e altri apparecchi della Radford Electronics Ltd.; Bristol