Yep. I thought I could do no wrong and nothing was impossible. I later noticed that other engineers were bailing me out of trouble a bit too often, and that at least one of my assigned projects really was impossible. It took me about 10 more years to make all the necessary mistakes, and to learn tact, humility, company politics, basic management skills, and when to ask for help. The last was the most difficult.
DC offset of +0.1 to +0.2mv would certainly have fixed my offset problem. However, the MPD-1 lists for $23.70. I don't think that would have been acceptable. The SBL-1 is about half the price but has no guaranteed DC offset spec. As I recall, the SBL-1 varied from -2mv to +4.0mv offset. Yep... this is for the similar SBL-1-1LH: Yech. -0.5 to +2.3mv.
The same radio with the 11C44 problem also used the MC145152 for both the 2nd LO synthesizer and the BFO synthesizer. Other than stupidly putting the VCO on the top of a plug in PCB, I don't recall any problems with the chip. We also used it in some VHF radios. At a different company, I later used it for 952MHz electric utility radio. Nice chip.
Ummm... that's complexicated.
I don't know him. My employer was Intech Inc (Santa Clara CA) which was short for International Technologies. Almost everyone in the company was from outside the USA. We had engineers and managers from Switzerland, Spain, Lebanon, Denmark, Tennessee, Romania, Canary Islands, South Africa and probably others that I've forgotten.
With PLL, everything seems to be a tradeoff.
That's exactly what we did, initially. The problem was that the radios were being used for SITOR (error correcting teletype), which required extremely fast transmit-receive switching. I vaguely recall
10 msec was the maximum allowed. That meant that everything I had done to allow FM modulation inside the loop went into the trash bin. Fortunately, there was no requirement for both FM and SITOR in the same radio, so two versions of the synthesizer were deemed acceptable.I don't think there's much to be gained by redesigning a 40 year old radio using modern technology. Still it's interesting to look back and speculate on how it might have been done if I had known what I was doing. Hindsight is always crystal clear.
I once cleaned up a radio design that was full of MLCC capacitors. It wasn't really microphonic, but nobody could figure out why the PLL would go out of lock when the vibrator (eccentric cam motor) would run. It was fun to hang the radio on an improvised shake table (made from a loudspeaker and some box cardboard) and watch the PLL go insane from the vibration.
Enough nostalgia. Back to work...