Off the wall ham "history" question...

[Martinjmpr]

This one is for the real "old timers" out there but it's something that's been buzzing around in my brain for a while.

By the time I got my first ham license in 1994, "no code" tech licenses were the hot thing and digitally tuned radios like the Radio Shack HTX series were the "go to" for a new amateur operator. I think they sold for $150 - $200 (which would be the equivalent of $400 or more in todays dollars) so with the plethora of <$30 cheapies from the likes of Bao Feng you can see how much less expensive the hobby has gotten (and you can even get a Yaesu for under $100.)

So my question is this: How did the VHF and UHF radios work before they had direct digital tuning where you could just punch in a frequency?

I know that in the mid 1970's when the CB craze first hit, the lower-end CB radios could only use 3, 5, or maybe 7 channels, and you would actually have to buy a "crystal" for whichever channels you wanted (each channel corresponded with a specific frequency.) At that time, circa 1974 or so, the only CB radios that could use all 23 channels (before the FCC expanded to 40 - I think that was around 1977) were the high-end models.

So did the VHF bands like 2M work the same way, with a frequency dedicated to a specific "channel" and the user having to buy a crystal or do something else to have it programmed in?

There's no real reason for me asking this, beyond idle curiosity. My undergrad major was history so I'm always interested in "how we got here" because I know we've come a long way.

I came across this on eBay.

Vintage Regency HR-2 2 Meter Transistor Transceiver Ham Radio | eBay

Find many great new & used options and get the best deals for Vintage Regency HR-2 2 Meter Transistor Transceiver Ham Radio at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Not a lot of info but would I be right in thinking this was probably made in the 50's or 60's? Note that it has blanks for the send and receive frequencies - that's what makes me think the user must have had to buy a crystal or chip for whichever specific frequency he wanted to use.

Any thought on what these numbers might represent? 94-94, 34-94 and 16-76?

 

[Heading Out]

Well, I had a radio shack scanner in the mid 70's that could receive 4 channels and you had to buy a crystal
for each frequency.

My first CB, around 1975 was 23 channels with a dial numbered 1-23 no crystals, but you did need to
send for a license LOL
Makes me think of doing fox hunts LOL

a neighbor across the street had a ham set up in the house and in his car. don't know what it was
but when he would transmit our TV would become distorted.
I remember the base unit having a round dial with a pointer he set to the freq. he wanted.
The guy was an electrical engineer at Delco, so chances are it was Heathkit or similar.
Like the tuner knob on an old AM radio

 

[metalcarver]

Quartz crystals. They have naturally resonant frequencies depending on the size. They were mounted in little cases with plugs after having been measured and ground to size. This controls the frequency of the main oscillator or the first stage of rf before it's amplified. On those labels, probably 146.94 mhz. The 34 -94 is a repeater split. Transmit on 146.34 and receive on 146.94. The repeater transmits on 146.94 and listens on 146.34. 16 -76 is also a repeater split.
94-94 is a simplex - transmit and receive on the same frequency. The frequency split is so that the repeater can transmit and listen at the same time. I believe Regency was mostly a CB manufacturer and this is a two meter transceiver 146 -148 mhz. As far as channels there is a band plan to separate the different modes. FM and digital are fixed frequencies. SSB and CW are more like hf operations.

 

[DaveInDenver]

There's other ways to tune than using a crystal-control. Prior to crystals radios used BFOs (beat frequency oscillators) and later higher end radios used VFOs (variable frequency oscillators). Now both have generally been replaced with digital synthesized frequency oscillators.

FWIW, the HTX wasn't a direct digital synthesis but kind of a digital-analog hybrid known as a VCO, voltage controlled oscillator that used the microprocessor to control a PLL, phase locked loop, voltage reference. Most radios from the 1980s until today were and are actually PLL-controlled VCOs. It wasn't until SDRs (software defined radios) where the need for constantly improving oscillators and mixers wasn't needed. At the basic level a FTM-400 isn't fundamentally different than an HTX in this case. It's more sophisticated and takes advantage of improved processors but the fundamentals haven't changed that much.

In any case crystals are still integral to almost everything although only as reference rather than being used directly.

The basic reason for any of them, from a simple crystal mixed circuit up to the most advanced direct digital synthesized design is the same, to generate a mixer heterodyning frequency. And in this case until SDRs how we built radios was really not really at root different than what Reginald Fessenden, Edwin Armstrong or Lee de Forest invented 100 years ago. Even here the basic math isn't different, the RF hardware is just simpler and all the magic is now done in software.

 

[BigSwede]

Yeah, what he said ^^^

 

[Herbie]

Another +1 for Dave's answer.

Building reliably controllable tunable oscillators was sort of the ground work for any Year 1/2 EE student. In the old-old days, one could build a tunable oscillator but it only worked over a narrow band, so one might actually need to switch between different oscillator circuits to get to different parts of the spectrum. The wider bandwidth afforded by transistor circuitry meant that even while still "analog", you could at least have a single VFO that covered the whole band. (But you probably still had different circuits in a radio that covered multiple bands - nothing like compact 2m/70cm combo radios we have today.)

 

[craig333]

Well, I had a radio shack scanner in the mid 70's that could receive 4 channels and you had to buy a crystal
for each frequency.

My first CB, around 1975 was 23 channels with a dial numbered 1-23 no crystals, but you did need to
send for a license LOL
Makes me think of doing fox hunts LOL

a neighbor across the street had a ham set up in the house and in his car. don't know what it was
but when he would transmit our TV would become distorted.
I remember the base unit having a round dial with a pointer he set to the freq. he wanted.
The guy was an electrical engineer at Delco, so chances are it was Heathkit or similar.
Like the tuner knob on an old AM radio

I had one of those scanners. CB license also. Wish I could find my call sign but I think those records no longer exist.

 

[metalcarver]

I guess if the OP had asked for the time we'd be telling him how to build a watch.

Analog. Gears are cool.

 

[Heading Out]

This one is for the real "old timers" out there but it's something that's been buzzing around in my brain for a while.



So my question is this: How did the VHF and UHF radios work before they had direct digital tuning where you could just punch in a frequency?

So did the VHF bands like 2M work the same way, with a frequency dedicated to a specific "channel" and the user having to buy a crystal or do something else to have it programmed in?

There's no real reason for me asking this, beyond idle curiosity. My undergrad major was history so I'm always interested in "how we got here" because I know we've come a long way.



Any thought on what these numbers might represent? 94-94, 34-94 and 16-76?

OP asked how the radios worked, Kind of like how does a watch work......

 

[DaveInDenver]

So my question is this: How did the VHF and UHF radios work before they had direct digital tuning where you could just punch in a frequency?

I guess if the OP had asked for the time we'd be telling him how to build a watch.

OP asked how the radios worked, Kind of like how does a watch work......

Exactly.

 

[DaveInDenver]

Any thought on what these numbers might represent? 94-94, 34-94 and 16-76?

The Regency HR-2 was made in the early 1970s.

https://rigreference.com/rigs/5972-regency-hr-2
http://www.n4mw.com/Regency/hr2.pdf

The 94-94, 16-76 and 34-94 I'd at first blush represent the TX-RX frequencies (or perhaps RX-TX) even though there's an RX and TX slot maybe the P.O. just shortened it. Hard to say.

I'd assume two of them are:
146.340/146.940 (e.g. as we now say 146.940 -600 KHz)
146.160/146.760 (146.760 -600 KHz)

Not sure about 94-94, which could mean 146.940/146.940 but that would imply it's the same input as output so simplex. Perhaps that's to allow talk around, e.g. hearing and talking on the output frequency of a repeater so that when you're near you don't have to use the repeater.

 

[Hilldweller]

We had a VFO HF rig in the 70s. It was big, like a dorm refrigerator big. None of us had a license so we just listened. You'd hear things from all over the world.

I also built a CB from a Lafayette Electronics kit. 23 channels, tubes. When warmed up it was putting out 15 illegal watts ---- I didn't have any idea at 11 years old how to detune it to 4 watts but never got in any FCC trouble. KEJ1917 was my CB license...