145152 PLL Synthesizer

Well, nobody uses thumbwheels anymore, either :-).

AD has some parallel-program DDS synthesizers. I think they exist for really fast hopping (faster than can be programmed by a serial bus) but they're popular with the stuck-in-the-mud types who don't like serial programming. They will be more expensive than a Lansdale 145152 too, I bet!

Really, get yourself a little 8-pin microcontroller to do the serial program and use a serial PLL and a button/display interface. If you really like knob-programmed radios go buy yourself a RT-662/GRC-106 :-).

Tim.

I've used the 145152 meself, but just for prototyping, and a long time ago. If you really like multi-digit thumbwheels, you could use a serial-load PLL and some cascaded shift registers, or for a real 1970s feel, one 4-bit shift register, a 1->N demux for digit select, and 4N diodes for an N-digit switch. Alternatively, you could use a keypad to enter the frequency, which would work neatly with the shift register idea.

Cheers,

Phil "the glue is the logic" Hobbs

Digikey is showing 1000 in stock in soic. Lifetime buy?

Ok Lansdale just shipped me a phone book sized databook of former motorola RF, does this mean they are NOT going to produce the motorola synth stuff unless someone wants 100,000 pieces?

Steve Roberts

Hello Tim,

Thumbwheels are one of the fastest ways to change frequencies. The only other option would be a rotary encoder with a SW routine behind it that supports "inertia", that puts an English on things when the user turns it fast. But that requires an LCD display, meaning extra $$$.

It's the same with car radios. Nothing beats the old tuning knob. I hate having to press a button and wait, wait, wait some more...

Regards, Joerg

Joerg - You and I love dials and knobs. But tuning a radio around with a bunch of rotary switches (be they thumbwheels or those little things that you press the "up" and "down" buttons on or knobs) is a very non-ideal way of scanning the band for something interesting. For channelized operation, it's not so bad. (And indeed channelized comm is what the GRC-106 was intended for. Google for it if you don't hang around the military surplus radio shops much!)

And the traditional "pull lever to program push to set" car radio mechanism is such a perfect user interface. You get both knob-tuned scanning AND programmable channels with a user interface that has an obvious feel and tactile feedback. I bet 99% of web designers who put "radio buttons" on web forms never had this kind of radio in their car though, they're too young... (and they're ALL kids).

In any event it's rarely as simple in a synthesized transceiver as just hooking the switches straight to the synthesizer. Usually you need a way of adding/subtracting the IF frequency as you switch between transmit and receive.

Tim.

??? Just put a flywheel on the shaft, and lube the bearings. :-)

Somehow, I've never trusted that the frequency I've dialed up on thumbwheels is what's actually coming out, not that a display is necessarily any more "trustworthy". :-)

Heh! I have a knob on my 1986 Fiero radio, but it's got pushbuttons for volume up/down. And everything else, for that matter. :-)

But there's something to be said for digital tuning too, since it goes right to the freq, rather than maybe sitting in a sideband somewhere. :-)

Cheers! Rich

Yes I like dials, but the first time I saw a thumbwheel-tuned radio in the cockpit panel of a plane I was riding as a guest in 1963, I realized the tremendous speed advantage they have: no fussy tuning.

The GRC-106 was built about 100 feet down the isle from where I did QA work on the PRC-77 at Cincinnati Electronics, a long time ago. Can you believe that one of the guards was stupid enough to try to have me fired by claiming that I carried a GRC-106, complete system, out of the plant in my shirt pocket. ;-)