Motorola Car Radio 122. - UK Vintage Radio Repair and Restoration Discussion Forum

kevinbush · 30th Dec 2016, 9:12 pm

Hi. My radio is not working in my classic car. I have removed the radio ready to repair or send to a specialist, however I'm wondering what stations I can access once working . I like radio 5 but the m/w scale does not reach 693 , can anyone advise. Thanks in advance.

paulsherwin · 30th Dec 2016, 9:36 pm

The dial is probably marked in wavelengths not frequencies. 693KHz is 433 metres.

Tom_I · 30th Dec 2016, 10:07 pm

Paul is right. You will find that the medium wave scale on this radio is marked (left to right) from 550 to 200, but that is in metres. The frequency equivalent is 545 to 1500 KHz.

'LIVEWIRE?' · 30th Dec 2016, 10:20 pm

Most UK made radios, both In-Car types and domestic sets had dials marked in Metres. An odd thing in a way, when (a) Britain never used metres for any other purpose, and (b) all continental and American radio dials were always marked in Kilocycles (Kc), later changed to Kilohertz(Khz) ito honour Heinrich Hertz. For Long & Medium Wavelengths, it's useful to remember that 300Metres = 1000khz (or 1 Megahertz), so, by dividing 300000 by the wavelength in metres equals the frequency in Kilohertz.

julie_m · 30th Dec 2016, 10:43 pm

For some reason, radio stations stopped being measured in metres about the time everything else started being measured in metres! (Or litres, or kilos.)

As a general rule, if you divide 300 000 (which is the speed of light, in km/s.) by the frequency in kHz, you will get the wavelength in metres (or vice versa).

Note also that all assigned MW and LW frequencies are multiples of 9 kHz.

paulsherwin · 30th Dec 2016, 10:57 pm

Quote:

Originally Posted by 'LIVEWIRE?'

Most UK made radios, both In-Car types and domestic sets had dials marked in Metres. An odd thing in a way, when (a) Britain never used metres for any other purpose, and (b) all continental and American radio dials were always marked in Kilocycles (Kc), later changed to Kilohertz(Khz) ito honour Heinrich Hertz. For Long & Medium Wavelengths, it's useful to remember that 300Metres = 1000khz (or 1 Megahertz), so, by dividing 300000 by the wavelength in metres equals the frequency in Kilohertz.

This isn't wholly true. The French marked dials in metres, and I think a few other markets did too.

30th Dec 2016, 9:12 pm	#1
kevinbush Retired Dormant Member Join Date: Dec 2016 Location: Brighton, East Sussex, UK. Posts: 1	Motorola Car Radio 122. Hi. My radio is not working in my classic car. I have removed the radio ready to repair or send to a specialist, however I'm wondering what stations I can access once working . I like radio 5 but the m/w scale does not reach 693 , can anyone advise. Thanks in advance.

30th Dec 2016, 9:36 pm	#2
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,970	Re: motorola car radio 122 The dial is probably marked in wavelengths not frequencies. 693KHz is 433 metres.

30th Dec 2016, 10:07 pm	#3
Tom_I Heptode Join Date: Jul 2006 Location: North Herts. UK. Posts: 549	Re: motorola car radio 122 Paul is right. You will find that the medium wave scale on this radio is marked (left to right) from 550 to 200, but that is in metres. The frequency equivalent is 545 to 1500 KHz.

30th Dec 2016, 10:20 pm	#4
'LIVEWIRE?' Rest in Peace Join Date: Mar 2006 Location: N.W. Oxfordshire(Chipping Norton) Posts: 7,306	Re: motorola car radio 122 Most UK made radios, both In-Car types and domestic sets had dials marked in Metres. An odd thing in a way, when (a) Britain never used metres for any other purpose, and (b) all continental and American radio dials were always marked in Kilocycles (Kc), later changed to Kilohertz(Khz) ito honour Heinrich Hertz. For Long & Medium Wavelengths, it's useful to remember that 300Metres = 1000khz (or 1 Megahertz), so, by dividing 300000 by the wavelength in metres equals the frequency in Kilohertz.

30th Dec 2016, 10:43 pm	#5
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: motorola car radio 122 For some reason, radio stations stopped being measured in metres about the time everything else started being measured in metres! (Or litres, or kilos.) As a general rule, if you divide 300 000 (which is the speed of light, in km/s.) by the frequency in kHz, you will get the wavelength in metres (or vice versa). Note also that all assigned MW and LW frequencies are multiples of 9 kHz. __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.