UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Cobra 150-GTL ( cybernet PTBM121D4X )

SiriusHardware · 9th Oct 2019, 10:43 pm

That happened a lot with 'high end' radios produced for the UK legal market. On a radio which really only needed a volume and squelch control it took a lot of imagination to fill up all those spaces on the front panel with something 'meaningful'.

You ended up with two or three position slide switches devoted to receiver tone control or rotary controls which dimmed the channel display (but not the meter illumination) or a three position switch which 'bent' the receive frequency up or down a bit - utterly pointless when used to communicate with other radios in the same class but sometimes unexpectedly useful if someone tried to talk to you from a nearby hi-band or superhi-band channel using a non UK radio.

Some of the extra controls were ridiculous, like Mic Gain - on an FM radio system where all channels were 10Khz spaced, what was the point of using less than the allowed maximum deviation?

Even RF gain was not as useful on an FM-only radio as it was on an A.M. radio, where a nearby signal could drive the receiver into distortion.

9th Oct 2019, 10:43 pm	#16
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,556	Re: Cobra 150-GTL ( cybernet PTBM121D4X ) That happened a lot with 'high end' radios produced for the UK legal market. On a radio which really only needed a volume and squelch control it took a lot of imagination to fill up all those spaces on the front panel with something 'meaningful'. You ended up with two or three position slide switches devoted to receiver tone control or rotary controls which dimmed the channel display (but not the meter illumination) or a three position switch which 'bent' the receive frequency up or down a bit - utterly pointless when used to communicate with other radios in the same class but sometimes unexpectedly useful if someone tried to talk to you from a nearby hi-band or superhi-band channel using a non UK radio. Some of the extra controls were ridiculous, like Mic Gain - on an FM radio system where all channels were 10Khz spaced, what was the point of using less than the allowed maximum deviation? Even RF gain was not as useful on an FM-only radio as it was on an A.M. radio, where a nearby signal could drive the receiver into distortion.