When did tuning dials change from Metres to kHz?

[Robsradio]

Hello
I have a couple of identical Bush clock radios with tuning fork movements from the 70s, one is marked up in Metres and the other in KHz, was there a legislation that made this change necessary, any idea what year it may have been?
I assume that KHz replaced Metres as I remember Radio 1 as 247m and then went to 275/285m don’t ever remember it referred to in KHz.
Any thoughts
Regards
Rob

[Radio Wrangler]

I don't think there ever has been legislation. Manufacturers are free to mark radio dials in whatever units they fancy.

Radio 1 had plugged '247' to the hilt as a sort of brand. Locked into their target audience's group memory, they weren't going to change it.

Of course, converting the advertised and marked wavelengths to Hertz will make everything more modern, thrusting, youthful.. essential for any station that's 'where it's at' or for being carried by those at the cutting edge. But 247 (and 208 just as much if not more) were locked in.

Quintessentially British Radio 4, but everyone knows it's still the Home Service, despite the name change, on 4921 feet, 3 inches.

Really deep stuff on radio three, (who at least got to keep their number 3 ) at 253 and a half fathoms.

I think you need to look at what the dials were marked in and when different models changed. It's complicated by how the stations pushed themselves. When the Beeb mentions measurements, they are still inclined to convert them into London buses or olympic swimming pools.

David

[paulsherwin]

There was a gradual shift from the mid 60s to the early 80s. The change seems to have been initiated by the import of Japanese and Hong Kong sets designed for a global market.

designed for a global market.

Isn't the metre global? Odd to think we (UK) used metres well before metrication when quite a lot of the world was metric.

[paulsherwin]

Of course, but most of the world adopted frequencies rather than wavelengths quite early under American influence. Globally, wavelengths hung on longest in the SW 'metre bands'.

[Dave Moll]

Once electromagnetic waves go beyond the radio spectrum, wavelength then comes back into its own, this time in microns, nanometres et al (presumably because frequencies become unwieldy beyond the GHz range) - that is until you get to the really high end stuff where photon energies (in multiples of the electron volt) take over.

[KeithsTV]

Originally Posted by Radio Wrangler

When the Beeb mentions measurements, they are still inclined to convert them into London buses or olympic swimming pools.

So Radio 4 Long Wave is on 135 London buses

Keith

[Radio Wrangler]

The occupied bandwidth of a modulated radio station is fixed if seen in frequency terms, irrespective of the frequency/wavelength of the carrier.

So a band filled with stations, each just clear of its neighbours would naturally place them on equal increments of frequency, but on a reciprocal scale of wavelengths. So, the frequency-centric view is the most logical choice.

Metres came along because it was easier to measure the lengths standing waves in a traceably accurate way than it was to directly measure frequency. So wavelengths made sense in the beginning, then frequency took over.

If I design a superhet in frequency terms, I'd know the wanted signal would maintain the same bandwidth and spectrum whatever IFs it passed through. I'd hate to have to do it in wavelengths, especially before the pocket calculator. I'd have to get my slide-rule out.

Interestingly, the set dial may be marked in metres, but the maker's service info told you the IF in kilocycles! They knew which side the bread was buttered.

David

[ekjdm14]

Another one for the experts, when did Hertz replace Cycles/second as the preferred terminology for units of frequency? Have to say, I prefer the frequency system over wavelength also but mainly because when I was growing up frequency-centric was the norm so never really considered wavelength until I got into vintage electronics! Although when it comes to those frequencies, I like to refer to them in Kc/s, Mc/s etc rather than KHz or MHz. I just like the way it looks in writing more...

[Dave Moll]

According to Wikipedia, the Hertz was established by the International Electrotechnical Commission (IEC) in 1930. It was adopted by the General Conference on Weights and Measures (CGPM) (Conférence générale des poids et mesures) in 1960, replacing the previous name for the unit, cycles per second (cps).

[Herald1360]

Originally Posted by Radio Wrangler

Quintessentially British Radio 4, but everyone knows it's still the Home Service, despite the name change, on 4921 feet, 3 inches.

And its brow height has increased by 69 feet 8 and a half inches, too.

[Boulevardier]

Originally Posted by Radio Wrangler

Quintessentially British Radio 4, but everyone knows it's still the Home Service, despite the name change, on 4921 feet, 3 inches.

For me, it will always be the Light Programme - R4 is relatively an upstart newcomer on 200 (OK, 198)kc/s.

I too prefer "cycles per second" to Hertz. As a word Hertz is meaningless, whereas c.p.s is totally self-explanatory (provided you are a reasonable person and speak the lingua franca).

Mike

[Radio Wrangler]

I think Hertz replaced cycles per second about the same time pounds replaced guineas in their prices. There wasn't a sharp change.

David

[bluepilot]

Originally Posted by Boulevardier

I too prefer "cycles per second" to Hertz. As a word Hertz is meaningless

Hmm well, come to that so are Volt(a), Amp(ere), Watt, Ohm, Farad(ay), Henry, and a few others.

[Paul_RK]

I've mentioned it here before, so apologies to longer serving forum members for the repetition, but small manufacturer Pegasus, of Leeds, for some reason in the mid-'30s marketed sets with tuning scales marked only in kilocycles (/sec.). I don't know whether the feature contributed to the company's demise, but unless there's something I've not thought of it must have proved a significant impediment to sales. The sets weren't thirty-odd years ahead of their time in any other respect.

Paul

[kalee20]

Originally Posted by Boulevardier

For me, it will always be the Light Programme - R4 is relatively an upstart newcomer on 200 (OK, 198)kc/s.

My Ever-Ready 5033, pre-war, has the LW scale marked 'Droitwich.'

They future-proofed it against the 1978 station shuffle.

[Graham G3ZVT]

I was an avid shortwave listener in the broadcast bands in the mid to late 60s. I think the first station I heard change to Hz in their station announcements was the Swiss SBC (later to become SRI). The station I remember hanging on doggedly to c/s was Radio Moscow, and Mike (post #12) will be pleased to hear they always said it in full, "Megacycles per second".

Small Japanese transistor radios were invariably marked 55 - 16, exactly what that was intended to convey alluded me for some time!

[Boulevardier]

Originally Posted by bluepilot

Hmm well, come to that so are Volt(a), Amp(ere), Watt, Ohm, Farad(ay), Henry, and a few others.

But there may be a good reason for that - do you fancy substituting “the potential difference between two points on a conductor carrying a current of 1 Ampere when the power dissipated between those two points is 1 Watt” every time you mention a Volt? Conversely, "cycles per second" is brief and contains it’s own definition.
Similarly, in normal circumstances, we don’t have a unit for “kilometres per hour”, nor do we need one.

Mike

[Richard_FM]

My Fidelity Rad 24 has a scale in metres but the BBC radio stations are marked on the 1978 frequencies.

The Radio 1 jingles were still quoting metres (275 & 285) until about 1984.

[Phil G4SPZ]

Originally Posted by Boulevardier

...we don’t have a unit for “kilometres per hour”, nor do we need one....

But we do have a unit for a "nautical mile per hour" - the knot.

I have a 1973 Philips RL230 radio with dials marked up in kHz, although also carrying the legend GO and PO (Grandes Ondes and Petites Ondes) as well as LW and MW respectively.

There is only one correct way of abbreviating "Hertz" and that's Hz, whereas I've seen "cycles per second" abbreviated variously as CPS, C.P.S., cps, c/s, C/S and probably others.

I can remember Practical Wireless announcing formally that its policy would be to adopt the Hertz, which must have been in the very late 60s or early 70s but I can't be sure.