UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Building the 'Minimod' AM modulator-questions!

crackle · 1st Oct 2018, 12:07 pm

I have made some more mods to my circuit.
I have replaced the Spectrum coil for L1 with a Toko yellow coil. I broke away the cap that was in the base. I removed the small trimmer cap and by experimentation found that a 56pf polystyrene cap across the coil gave me the 1188kHz frequency I needed + or - a little for adjustment.
I have set the frequency, the nearest I can get is 1188.13kHz, it has been spot on that for 30 min now.
I am now going to turn off and see what the frequency is when I turn it on again in an hour.
This really does now look like the coil supplied by Spectrum Coms was sub-standard.

Mike

1st Oct 2018, 12:07 pm	#57
crackle Rest in Peace Join Date: Mar 2011 Location: Basildon, Essex, UK. Posts: 4,100	Re: Building the 'Minimod' AM modulator-questions! I have made some more mods to my circuit. I have replaced the Spectrum coil for L1 with a Toko yellow coil. I broke away the cap that was in the base. I removed the small trimmer cap and by experimentation found that a 56pf polystyrene cap across the coil gave me the 1188kHz frequency I needed + or - a little for adjustment. I have set the frequency, the nearest I can get is 1188.13kHz, it has been spot on that for 30 min now. I am now going to turn off and see what the frequency is when I turn it on again in an hour. This really does now look like the coil supplied by Spectrum Coms was sub-standard. Mike