Customized PRO-77 & PRO-10

[gmclam]

I have two each PRO-10 & PRO-77 scanners. They are originally 8 channel crystal controlled scanners with incadescent bulbs to indicate which channel is active. The scanners are "identical", except that the PRO-10 covers VHF hi (147-174 MHz) and UHF (450-470 MHz) while the PRO-77 covers VHF hi and low (30-50 MHz).

I purchased the first PRO-10 in 1974 and the first PRO-77 in 1975. I originally modified each scanner to scan 16 channels and have single LEDs to indicate the selected channel. Over the next 10 years I acquired 2nd scanners of each model and redesigned their scanning logic.

I wanted individual switches for each channel on the front panel so I could "instantly" switch to a channel (the original design called for you to switch to manual mode and then advance one channel at a time to get where you wanted). Back then the best CPU I could get to do the job was an 8048. I was able to design it to scan 20 channels with the I/O available and drive a 2 digit 7 segment display. The units are still crystal controlled, but UHF is triple conversion! The scanners can operate on 110vac or 12VDC, but one issue I had with them was that the AC power cord could not be removed. I fixed that too and provided a LINE OUT where the cord was.

To this day it seems that Radio Shack (or GRE) has trouble calculating TWO SECONDS when it comes to a delay. My PRO-95 certainly does not delay for 2 seconds as it should (and neither does my PRO-92 when set to 2 seconds). So one more thing I added was an adjustable delay (with a pot - remember those?). There tons of other features written into the software I will not get in to here.

Pictures:
1. PRO-77 front (single unit)
2. PRO-10 and PRO-77 bolted together
3. Back of PRO-77 with power connector & line out
4. The guts (3 custom circuit boards) - also some dip switches to program other features still not available on any scanner I've ever seen over 20 years later.

George

 

[Mike-KC8OWL]

Wow, nice work for back in the 70's. I got my first scanner when I was in 5th grade - it was a Bearcat model III 8 channel crystal unit that covered VHF low and VHF high band. Though I have many other much newer scanners, I still have the Bearcat III on my desk too, and it still works just fine after about 20 years.

Your project scanners were way ahead of their time.

Mike

 

[gmclam]

Thank you for your kind comments.

My first "police radio" was a converter. You placed the converter near an AM radio, tuned it to about 530 KHz, and you were able to pick up 1 of 2 selectable VHF high band channels (police or fire). My how law public safety services have gobbled up the channels since then. First more channels, and now trunking many virtual channels on the same frequency.

 

[W9WSS]

Thank you for your kind comments.

My first "police radio" was a converter. You placed the converter near an AM radio, tuned it to about 530 KHz, and you were able to pick up 1 of 2 selectable VHF high band channels (police or fire). My how law public safety services have gobbled up the channels since then. First more channels, and now trunking many virtual channels on the same frequency.

If you ever decide to dispose of either unit, I'll be the first to make an offer! Love that homebrew stuff, especially when it works better than some of the trash ordinary schmoes like me had to buy. I remember when I had a run of bad BC-250's. I has SEVEN, yes, count them, SEVEN because they had this inherrent swishing/hum sound, that made listening to the impossible. I finally bought a used 20/20 that held out for about ten years, then started to smoke one day. Man, there were some pretty bad unit's out there, and Quality Control wasn't the greatest, either!

 

[gmclam]

What I want to do is work with one of the existing scanner manufacturers to get some of these features I've designed into new units. But then I was reading some threads here of all the features people already have on their dream lists, so I wonder if these companies will EVER get it together. It seems some "brands" have some features and other "brands" have different features. I am not sure if this is because they are proprietary, not cross licensed or what. I am strongly considering writing code for something like a PRO-95 from scratch (I've done this before on far more complex stuff). It will become necessary after rebanding if I want to use one to monitor affected systems. It seems like the only way to acquire a combination of features one wants on a single unit.

 

[trunker0205]

Pretty Cool stuff, I love the walk down memory lane...My first scanner was a tuneable Patrolman back in 1974 I was 15 then..Great to see the modifictions you did.Do you have the Bill Cheeks 3 books on Scanner Mods, I have them and read them all the time but im a little chicken to try some of mods on my mint Pro-2006 I would die if I killed it..

 

[gmclam]

Great to see the modifictions you did.Do you have the Bill Cheeks 3 books on Scanner Mods..

No, I do not. I have been an electronic hobbyist since I was in single digit years. I became a CBer (before it was a bad thing) when I was 10 in the same time frame I started listening to public service radio. I am self taught from vacuum tubes through transistors & ICs to modern day micro electronics. I've worked professionally as a product design engineer for about 30 years. When Intel came out with the 8080, I learned to program them. It did not stop there, I've learned (assembly) for all of their CPUs and lots of others too.

I possess a professional FCC Radiotelephone Operator's license. I work (non transmission) in TV broadcasting as well; which has become more of a hobby than work these days. So I am quite familiar with radio receivers, transmitters and the logic needed to make scanners operate. I got quite frustrated trying to find features that I wanted all in one package, so I decided to take action and do it myself.

Thank you for your nice comments.
Take care,
George

 

[ScanDaBands]

Man that's WAY COOL , you ever thought about getting a Pro-2006 and doing some of those Bill Cheek mods? LED s-meters , etc. NICE STUFF

 

[bluesman905]

Very VERY cool man

 

[ScanDaBands]

Very VERY cool man

Got change for an ice cube ????

 

[gmclam]

Thank you everyone

 

[kf4lne]

sweetness!

 

[jon_k]

Nice work on that old Radioshack Unit. You claim you added all these unmentionable features. If they are still relevant today, I can't imagine what they were. What in the world could you have done to a 30 year old scanner that isn't done on a scanner today? I guess we'll never know.

I would like to see a radio with plenty of firmware memory and open source firmware so anyone could make modifications to it. After all it's a small low power computer, why not make it open for development like the PC?

There are many many many features that could be added to these radios, ranging from simplistic to super-secret ones like gmclam speaks of. There are so many suggestions and the manufacturers never take notice. I know if one of them open sourced their firmware I would immediately flock to that scanner brand as that would be one of the few things to set them above the rest.

It's sad that to get anything done you have to do painful reverse engineering these days. I guess it's the norm with IP and patents that companies want to squat on, but in that compromised position all that seems to come out is crap that falls right on the IPO they protect.
--

 

[cpuerror]

Great job on the mods, but man, when the scanner starts developing rust holes it might be time to upgrade. I'm sure you'll be a lot happier with a modern scanner.