{"id":1734,"date":"2015-11-01T13:36:41","date_gmt":"2015-11-01T13:36:41","guid":{"rendered":"http:\/\/www.tsgarc.uk\/?p=1734"},"modified":"2015-11-01T13:36:41","modified_gmt":"2015-11-01T13:36:41","slug":"drive-levels","status":"publish","type":"post","link":"https:\/\/www.tsgarc.uk\/?p=1734","title":{"rendered":"Drive levels…"},"content":{"rendered":"

Over the last few years I have not had to think too hard about ensuring I’m driving my FT-2000<\/a> at a good<\/em> level.\u00a0 i.e. its not being overdriven.\u00a0 It has an Automatic Limit Control <\/a>(ALC)\u00a0meter\u00a0and its been a matter of adjusting the\u00a0audio amplifier gain such that the ALC triggers occasionally and only on the\u00a0highest signal peaks.\u00a0\u00a0If a good quality transmitted representation of the input signal is to be produced its essential that the equipment stages are not overdriven.\u00a0 I guess we all rely on the ALC <\/a>and its correct adjustment is second nature, however, take away the ALC function and what do you do?\u00a0 How do you ensure you don’t overdrive the radio or downstream amplifiers?\u00a0 This is the problem I had \ud83d\ude42<\/p>\n

I’m using the FT-2000<\/a> as an exciter for my Kuhne Electronic VHF transverter<\/a>.\u00a0 In this mode the ALC circuitry of the FT-2000<\/a> no longer works and\u00a0the transverter does not output a drive\u00a0level signal\u00a0which I could connect to the FT-2000<\/a> or to a homebrew ALC meter.\u00a0 But the transverter does have a red ALC LED which illuminates when the drive level becomes excessive.<\/p>\n

The\u00a0signals\u00a0I’m\u00a0presenting to the radio are audio and are either voice from the microphone (voice chain)\u00a0or data from a SignaLink USB audio interface (data chain).\u00a0Each of these chains has several amplifiers which\u00a0can be adjusted by an operator:<\/p>\n