UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

g4wim_tim · 22nd Feb 2019, 5:25 pm

Hi Guys,

well rightly or wrongly here is it powder coated with lacquered ventilation panels.

In some ways I preferred the 'naked look' but over a period of time I'm sure the scratches and marking out would have gotten to me whereas power coating hides all those sorts of marks.

I've also included a couple of shots of the chassis interior showing RF deck and modulator plus one from on top.

As for performance easy 70 watts carrier with 99% modulation and only 2% distortion at full mod as measured on my HP8901B.

AF response 340Hz to 3kHz -3dB and 220Hz to 4.8kHz -6dB

100Hz carrier ripple is -48dBc at full power on all bands and 50Hz hum is -68dBc - all in all acceptable AF performance and getting good audio reports on air.

RF harmonics are circa -60dBc when turned correctly.

For my next project I may well try some of the alternative finishes suggested, but first of all have to figure what to build next time !

73 Tim

22nd Feb 2019, 5:25 pm	#29
g4wim_tim Pentode Join Date: Nov 2018 Location: Freckleton, Lancashire, UK. Posts: 232	Re: To paint or not to paint ? Hi Guys, well rightly or wrongly here is it powder coated with lacquered ventilation panels. In some ways I preferred the 'naked look' but over a period of time I'm sure the scratches and marking out would have gotten to me whereas power coating hides all those sorts of marks. I've also included a couple of shots of the chassis interior showing RF deck and modulator plus one from on top. As for performance easy 70 watts carrier with 99% modulation and only 2% distortion at full mod as measured on my HP8901B. AF response 340Hz to 3kHz -3dB and 220Hz to 4.8kHz -6dB 100Hz carrier ripple is -48dBc at full power on all bands and 50Hz hum is -68dBc - all in all acceptable AF performance and getting good audio reports on air. RF harmonics are circa -60dBc when turned correctly. For my next project I may well try some of the alternative finishes suggested, but first of all have to figure what to build next time ! 73 Tim Attached Thumbnails __________________ Building and tinkering for over 50 years, from 807's to digital amateur TV.