202-R Arrived

[audmod01]

As promised, here are some pictures of the mostly completed and functional WX Multiplex Adapter Chassis:





I had a short AC cord that only required removal of its molded on strain relief to make it useful here. The AC cord will plug into the back of the 202-R so that when it is turned on, the WX Multiplex Adapter Chassis will turn on at the same time. I installed one of the compressible black strain reliefs on the chassis after first drilling a 3/8" hole and enlarging it with some rat-tail files until it was large enough to permit installation. There is a fuse clip under the terminal strip that holds the bridge rectifier, electrolytic capacitors and B+ resistors. The yellow wire is the one for connection to a multiplex indicator. I have not yet decided exactly how to implement that. There is a 12.6VAC winding that came with the HV power transformer I used. I could use that to make a low voltage power supply for a transistorized circuit to operate a two-color LED to illuminate the FM tuning meter and use it to change the color of the light illuminating the meter when tuned to an FM stereo signal. I will likely use a chassis mounted Molex connector and custom cable to connect this adapter to the 202-R chassis and its FM Signal illumination circuitry. I will generate a schematic of the power supply I built for this adapter and post it here later.

Joe

 

[audmod01]

I plan to first try the 202-R tuner with the MPX Adapter using the existing OEM Ratio Detector transformer. If the unit works well enough I will leave the OEM Ratio Detector in the tuner. If it does not, I do have a wide-band Ratio Detector from a model 400 receiver that Matt sent me a while back.

Joe

 

[bfrohwein]

Joe! I found your thread.. looks good!

 

[dcgillespie]

Looks very very good Joe! If you want a little more B+ for filtering or to get the 160 volt source closer, consider tying the 12.6 vac secondary in series with the 125 vac secondary. that could give you another 20 volts or so of B+ to play with. You could still operate your LED indicator circuit off of the heater power transformer.

Neat job!

Dave

 

[audmod01]

Joe! I found your thread.. looks good!

Bret;

So glad to see you here! Good luck with your projects.

Joe

 

[audmod01]

Dave;

Yes, I thought about that. The phase would have to be right of course. The two transformers I chose might also be good to use in a separate preamp design for magnetic cartridges. That would mostly be useful for some Fisher console chassis that were originally designed to use ceramic cartridges. However, the HV power transformer, P-T442, is limited to 15mA current for B+.

I did construct an audio cable yesterday to pass the composite signal to the input of the multiplex adapter. I kept it short to avoid excessive capacitance as recommended (less than 1ft.). If I am lucky today I may get to try it out.

Joe

 

[gadget73]

Any thoughts on just fitting an EM84 eye tube like Fisher would have done originally as your indicator? I suppose you could also do it with a meter that is sufficiently buffered. The eye tube grid drive was just a 19kc detector circuit, so it could feed to an op-amp that drives a signal strength meter.

 

[audmod01]

An eye tube would work and even the MPX-65 was designed to detect the 19kHz signal and operate an indicator lamp. I want to avoid using more tubes and try to keep it as simple as possible. I also want to keep the original appearance of the 202-R. That is why I am thinking about using LEDs and simple transistor switches for those. Dave and I both like the idea of just changing the color of light hitting the back side of the FM signal strength meter in the 202-R. Changing from the normal white back-lighting to red or green comes to mind.

Joe

 

[gadget73]

I was thinking install the eye on the MPX chassis, not add it into the 202R. Unless the MPX unit is not going to be visible at all in which case that would be pointless. My bodged up WX chassis MPX unit is my general use multiplex converter so it sits somewhat visible. Not nearly as nice looking as yours though. I just knocked it together with some junk I had laying around.

 

[ivan100000]

Woke up in the middle of the night, couldn't get back to sleep, and stumbled across this thread. Nice to see interest in the 202-R: a high-end and fairly uncommon tuner from the short-lived period where the idea for stereo tuners was to broadcast one channel on FM and the other on AM.

I have a nearly pristine 202-R in my main rig, though it's a sore subject these days. It was great listening to the jazz stations in Los Angeles years ago--particularly KJazz 88.1 in the wee hours--but now that I've moved to a fairly remote barrier island where I can only pull in a small handful of stations that don't interest me anyhow, the mighty 202-R has been relegated to prop status for its illuminated dial glass. Even that doesn't get used; it's probably been 3 years since I've fired it up. Ah, the passing of time...

Off to work for me soon after yet another nearly-sleepless night.

 

[audmod01]

Ivan;

Yes the 202-R has many features that make it a real stand-out tuner. Only the FM-1000 has as many FM IF stages and it is also the only FM tuner that has a front end that is more sensitive and selective than the 202-R among Fisher's tube type tuners. It is sad that so many stations now have such poor quality of source material and poor broadcast practices. It seems that only the apparent loudest signal on the band is the goal, with high bass boost and maximum compression being the norm. I have a good friend in the San Francisco area who has some great tuners including a Marantz 10B, which he never listens to any more due to lack of decent program material. I am indeed lucky that I live in a spot where I can get one mostly classical music station plus some college stations that broadcast a variety of music types.

Perhaps when you retire you can move back to the mainland and pick a spot with better radio station choices. There are a few spots where people have gone on the air with low power stations to provide more variety of music. Lets hope that more will do so.

Have fun!

Joe

 

[mrphilco]

Here in southern Indiana it seems that the FM stations here are 85% country, 10% pop/rock, and the other 5% are Spanish, college, and religious.

There is a classical music station in Louisville which I can pick up in the truck but not at home without a really good antenna (and a very sensitive tuner) since where I live is out of their coverage area.

I have a low power FM transmitter through which I play the kind of beautiful/mood music that was played on FM in the 1960s, so I always have something relaxing to listen to.

Hey Joe -

I will generate a schematic of the power supply I built for this adapter and post it here later.

Please do so when you can. I'd like to build one when I am able to do so.

 

[audmod01]

Ron;

Kudos for your approach! One of the best things we can enjoy is music that pleases us. Having access to vintage LPs and CDs can provide hours of listening pleasure. I can use the Fisher 300 MPX generator to serve as a low power FM MPX station after I finish going through it.

I do need to go back and document the power supply I put together for the WX Multiplex decoder I put together. It is pretty simple, a suitable power Xfmr. (basically a low powered isolation Xfmr.) and a separate 12.6VAC center tapped filament transformer with enough current capability to easily run the three 12V filament tubes in the unit.

More later.

Joe

 

[Dave451]

Joe,
Just picked up a Fisher 300 unit for alignment work and had no idea you could use it as a low-power transmitter. Very creative! I have to get it going now.....
Dave

 

[ivan100000]

Joe/Ron--

I haven't investigated it at all, but is there a big difference in roof-mounted antennas that would let me pull in stations from appreciably farther away? I see there is a nice 202-R on eBay now (wrong knobs) though I'm out of the loop on the value of these.

I just got home and switched mine on for the first time in years. Not much in the way of reception due to remote location and the attached ferrite antenna, but at least it looks cool.

 

[mrphilco]

The only 202-R I see on the auction site has the older "Stereophonic" script on the right side of the front panel and yes, those knobs appear to be incorrect unless it came that way when it was sold as part of a console unit. I think I paid about half as much for mine as the auction site seller is asking for that 202-R, maybe a bit less.

Anyway...

I still have a simple omnidirectional double dipole (as in it appears to be a large "X" when looking at it from the top or bottom) FM antenna in my garage, which I am soon going to place back into service in the attic of my house when I feel well enough to do so. I bought it decades ago from Radio Shack and it saw duty for years mounted on the edge of the roof of the house where I lived at the time. It picked up stations for many miles around with no amplifier. I've kept it all these years because it worked so well back then. I'm hoping it will still do so now (and I see no reason why it wouldn't).

I'll be hooking mine up to a Coronet (100-T) tuner/preamp in our living room. Not as good a tuner as the 202-R, certainly, but it looks cool...

 

[audmod01]

Yes, the Fisher 300 has a RF output at about 98 mHz which can be tuned over a few mHz to find a quiet spot.

There is a big difference between rabbit ears or a twinlead dipole tacked to a wall or ceiling. I live over 60 miles from the station I like best and use a 9-element FM only yagi antenna and get good reliable reception. It is pointed straight south to Dallas, TX and gets all of those stations plus many in Ft. Worth and Denton. There is another station 4.5 miles north of my house. The rear and side signal rejection of the antenna goes a long way toward allowing so many of my tuners to receive what I want to listen to. I use 75 ohm low loss RG-59 an balun transformers at the antenna and at the back of the tuner.

Joe

 

[mrphilco]

I'm not talking about rabbit ears or a twinlead dipole. This is what I have (image "borrowed" from the net):

I bought mine in the early 1980s and it served me very well indeed for a decade or so. I will use RG-6 when I install it in the attic (the RG-6 is already there). It will replace a TV antenna we will no longer be using.

Oh, and it appears these are no longer being made. I've also learned these were called "turnstile" antennas.

A directional antenna such as Joe is describing is certainly a better antenna, but it is directional (which may be better for you, Ivan). The one above is not.

 

[fred soop]

I have a similar home built antenna in the attic. The construction is 300 Ω twin lead dipoles mounted at right angles and connected in parallel. A 300 Ω to 75 Ω balun (yes, it's a mismatch with 2 300 Ω antennas in parallel) gets it to the coax cable. The old 600-T will pick up 60 stations across the band, 40 miles from downtown where most of the transmitters are located. Unfortunately, here in suburban Chicago, we have one remaining classical station and no jazz stations. If I were starting over today building a new system, I'd probably just forget the tuner and stream from the phone. Most stations anywhere have a web site and streaming.

 

[audmod01]

Fred;

I understand your situation. I see a few Fisher FM-1000 tuners for sale for over $2K and I have the same thoughts as one of my friends in Pennsylvania - no tuner is worth that much to me. There is even one Fisher AM-80 for sale for $1.5K on eBay now. The only thing I hear much on AM these days is continuous news stations, talk radio and very few that play music of any kind and none of them play either classical, jazz or pop music that I like to listen to. In addition, the AM band is so fraught with digital interference buzz-saw noise that even some local stations get covered up. A Fisher R-200-B might be a fair investment at under $400-500 since it has a low wave and short wave band too, but even on SW bands these days there is not all that much to listen to in the way of international broadcasting like it was many years ago. I can remember listening to Europe and Russia plus various South America stations as a teenager and was fascinated. There was a surprising variety of music played on those SW stations back then. Nowadays, hardly any music is played.

I get some satisfaction just from restoring some of these vintage tuners and receivers, but am not optimistic about their viability as far as receivers in these times. I hope I will be proven wrong, but the future of radio broadcasting does not look too bright to me.

Joe