My "Goodwill store find" TRC-449 Realistic AM/SSB

["Doc"Hammer]

Bone stock untouched UPD 858 Trc-449.....A dream radio....Totally virgin radio still had the factory seals on the case, all the hardware, power cord, mic etc.....no scratches, no blemishes on the face or anywhere...It was in a plastic bag at a local Goodwill store in Salina....brought it home, it powered up and talks!....20 bucks!
Got cases off doing check-ups and will give it a tune this evening. Here's some pics...will put some more up after I put the cases back on it...Good old school hinged speaker mount....gotta love it....

[Sandbagger]

Nov 21, 2015 17:51:54 GMT -5 "Doc"Hammer said:

Bone stock untouched UPD 858 Trc-449.....A dream radio....Totally virgin radio still had the factory seals on the case, all the hardware, power cord, mic etc.....no scratches, no blemishes on the face or anywhere...It was in a plastic bag at a local Goodwill store in Salina....brought it home, it powered up and talks!....20 bucks!
Got cases off doing check-ups and will give it a tune this evening. Here's some pics...will put some more up after I put the cases back on it...Good old school hinged speaker mount....gotta love it....
View Attachment
View Attachment

Back during the period between 1977 to about 1983 (when export radios really started hitting scene), radios like that Realistic were THE radios to have. So many channels could be added and the TX and RX could be widebanded to cover nearly all of them. Good talkers too. I still have one of those 858 chassis radios in the form of a Cobra 139XLR. Good find Doc! Shame we can't hear it on the roundup......

[MonkeyMan]

Shot,SCORE!! Nice find indeed. I'm always hoping to find something as equally nice every time I walk into a thrift store.

["Doc"Hammer]

Back together after a "clean and tune"..something I noticed about this radio..there are 2 settings in this rig for controlling modulation on AM...1 is your regular AMC...the other is a "mic amp". The mic amp setting also affects the ALC adjustment for SSB..it doesn't take a lot for this radio to become an audio monster with the regular RS handmike!
I set the ssb to about 10 watts peak...the AM side was a bit more fun: Dead key 2.5 watts with a forward punch that would knock out Mike Tyson.....LOL (only peaking about 7 or 8 RMS) Damn pretty rig!

[Sandbagger]

Nov 22, 2015 6:52:24 GMT -5 "Doc"Hammer said:

Back together after a "clean and tune"..something I noticed about this radio..there are 2 settings in this rig for controlling modulation on AM...1 is your regular AMC...the other is a "mic amp". The mic amp setting also affects the ALC adjustment for SSB..it doesn't take a lot for this radio to become an audio monster with the regular RS handmike!
I set the ssb to about 10 watts peak...the AM side was a bit more fun: Dead key 2.5 watts with a forward punch that would knock out Mike Tyson.....LOL (only peaking about 7 or 8 RMS) Damn pretty rig!
View AttachmentView Attachment

The Mic Gain (VR6) pot is what is wired to the front panel "Mike Gain" control on the Cobra models. There are actually 2 different modulation limiting circuits. The first is the mic AGC compression circuit around the mic preamp right before VR6. The second is a back to back diode clipper circuit controlled by VR7. I've found that by eliminating the diode clipper and the following audio low-pass filter, you can get a smoother, sounding audio, with greater fidelity. And I set the mic gain (VR6) for 100% modulation and let the mic AGC do the work.

Lowering the dead key will make that radio scream. I also added a controlled carrier circuit that allowed the carrier to run at 2 watts and swing up about 8 watts (on an average reading wattmeter). Pete can tell you what that setup used to do back in the day.

SSB power will reach 20 watts with ALC turned completely up. It'll run nicely at 15 watts.

["Doc"Hammer]

I'm getting very similar results to what you described on AM..2.5 watts dead key and about an 8 watt peak using an RMS meter....I'm leaving the sideband to peak around 10...there are a bunch of little fixes that can be done to this rig to improve things and little oversights from the "factory"...one of those improvements was to change the insulators on the driver and final transistors which I will do before spring. I'm keeping the output settings about where they are now because of the age of the rig..."If it ain't broke, don't fix it"...one thing I will do is replace the mounting bracket that holds the channel selector internally behind the faceplate....its made of woefully thin material and I have a similar piece from an old Midland parts donor that will strengthen the mounting for the selector...This rig will never go mobile, but will go in my travel trailer as my primary camp radio...combined with the little 1 pill 1446 amp I built, I'll be able to get around 40-50 AM watts and 60 to 75 on sideband for those skip sessions out at the lake on weekends...and it won't "kill" my electrical resources doing it..

[Sandbagger]

Nov 23, 2015 10:39:00 GMT -5 "Doc"Hammer said:

I'm getting very similar results to what you described on AM..2.5 watts dead key and about an 8 watt peak using an RMS meter....I'm leaving the sideband to peak around 10...there are a bunch of little fixes that can be done to this rig to improve things and little oversights from the "factory"...one of those improvements was to change the insulators on the driver and final transistors which I will do before spring. I'm keeping the output settings about where they are now because of the age of the rig..."If it ain't broke, don't fix it"...one thing I will do is replace the mounting bracket that holds the channel selector internally behind the faceplate....its made of woefully thin material and I have a similar piece from an old Midland parts donor that will strengthen the mounting for the selector...This rig will never go mobile, but will go in my travel trailer as my primary camp radio...combined with the little 1 pill 1446 amp I built, I'll be able to get around 40-50 AM watts and 60 to 75 on sideband for those skip sessions out at the lake on weekends...and it won't "kill" my electrical resources doing it..

There was a factory design correction for the very early versions of those 858 radios, affecting the final bias circuit. The original design allowed for way too touchy a bias adjustment and it was very easy to overbias and blow the final transistor.

The service bulletin is not available for the Realistic, but here's the one covering the Cobra 139XLR. If your parts match these, then you're probably ok:


Cobra 139XLR Service Bulletin

["Doc"Hammer]

According to the inspection sticker on the inside sidepanel of the radio, the date of manufacture was 9-77..Serial # is intact as well ...would seem to indicate a late summer of 77 manufacture date...I'm going back inside it tommorrow to modify the channel selector mounting plate, so I'll check the board for the service bulletin updates. The bulletin itself is dated 4-77 so its possible that the update was already in use when my rig was manufactured.

[Sandbagger]

Nov 23, 2015 22:58:47 GMT -5 "Doc"Hammer said:

According to the inspection sticker on the inside sidepanel of the radio, the date of manufacture was 9-77..Serial # is intact as well ...would seem to indicate a late summer of 77 manufacture date...I'm going back inside it tommorrow to modify the channel selector mounting plate, so I'll check the board for the service bulletin updates. The bulletin itself is dated 4-77 so its possible that the update was already in use when my rig was manufactured.

Or at least some of the mods. It would seem that there was an addendum to the original bulletin, which also addresses changing the temp sensing diodes that mount to the transistors. But this should only apply to the very early production units. If the final bias pot has to be set nearly all the way to one end to get the proper bias, it probably needs the mods. After they're done, the bias pot setting is much closer to midrange for 15 ma. of bias current.

[2600]

Don't forget to change C174. I think that's the number. It's a tiny tantalum cap adjacent to the posts on the pc board where the two bias-test jumpers unplug. It's a 25-Volt rated cap. So long as your modulation never exceeds 100%, it's okay. But a 35-Volt or higher cap lasts longer once the AM modulation gets cranked up. When the stock cap dead shorts, bad things can happen.

73

[Sandbagger]

Nov 25, 2015 0:37:48 GMT -5 2600 said:

Don't forget to change C174. I think that's the number. It's a tiny tantalum cap adjacent to the posts on the pc board where the two bias-test jumpers unplug. It's a 25-Volt rated cap. So long as your modulation never exceeds 100%, it's okay. But a 35-Volt or higher cap lasts longer once the AM modulation gets cranked up. When the stock cap dead shorts, bad things can happen.

73

It's marked C179 (2.2 uF) on the roadmap, and yes it fails far more often than a part like that has any business doing. When it goes bad, it will either put a dead short on the main B+ line when you're transmitting in SSB mode (which should pop the fuse), or it'll put that strain on the AM regulator in the AM mode. First time it happened to me, I thought the final had shorted at first. Now I go right for that part, and that's usually the problem.

[ab5ni]

Nice find, Doc! I have a question, though: what's with the "swing" modification? Also, would this type of mod overdrive 3-4 input CB amps? Another question: anyone know if it would be legal to modify old CB amps and use them on 10 mtrs?
I was thinking about purchasing one and putting al 7-pole low-pass filter on the output and reworking a few things if necessary.

73,

Randy, AB5NI

[BBB]

You can run anything on any Amateur Radio Frequency provided you are currently licensed to do so, keep below the associated max power limits and the transceiver and output signal meets the FCC requirements for bandwidth limitations and spectral purity.

That's the great part about the hobby! If you can dream it and make it work within the parameters spec'd below, have fun doing it:

www.w8ji.com/fcc_97_307.htm

I have to laugh out loud when snooty Ham radio dudes say "you can't run X amp or X radio because it's not approved by the FCC" Doesn't have to be on the HAM bands as long as the stuff rates within the above parameters

There is another level on the Pro side of things you can take. The CBSE or Certified Broadcast Radio Engineer Exam.

Here's a taste of that: www.radioworld.com/article/the-equipment-measurements-question/3415

[Sandbagger]

Nov 28, 2015 10:57:32 GMT -5 BBB said:

You can run anything on any Amateur Radio Frequency provided you are currently licensed to do so, keep below the associated max power limits and the transceiver and output signal meets the FCC requirements for bandwidth limitations and spectral purity.

That's the great part about the hobby! If you can dream it and make it work within the parameters spec'd below, have fun doing it:

www.w8ji.com/fcc_97_307.htm

I have to laugh out loud when snooty Ham radio dudes say "you can't run X amp or X radio because it's not approved by the FCC" Doesn't have to be on the HAM bands as long as the stuff rates within the above parameters

There is another level on the Pro side of things you can take. The CBSE or Certified Broadcast Radio Engineer Exam.

Here's a taste of that: www.radioworld.com/article/the-equipment-measurements-question/3415

There are a LOT of misinformed hams (and others) out there. They think because you can't legally run ham equipment on other services, which require type accepted equipment, that the reverse is also true. It's not. There is no FCC certification for ham transmitters beyond part 15 regulations, although there are regulations for ham amplifiers (primarily to keep them OFF of bands like CB). The bottom line is that hams are given broad latitude to run whatever they buy, build, cobble together, whatever. The responsibility for compliance lies with the operator, and he alone will bear the brunt of whatever goes wrong. Much different than other services which require type accepted equipment. Since the operators of those services are not expected to be technically versed, the responsibility for compliance lies within the design restrictions of the equipment. That's why ham equipment is not authorized to run on other services. But there's nothing illegal about re-purposing a CB, a land mobile radio, or some other band-specific radio to run on ham bands. As long as the operator ensures technical compliance.

[ab5ni]

Nov 28, 2015 10:57:32 GMT -5 BBB said:

You can run anything on any Amateur Radio Frequency provided you are currently licensed to do so, keep below the associated max power limits and the transceiver and output signal meets the FCC requirements for bandwidth limitations and spectral purity.

That's the great part about the hobby! If you can dream it and make it work within the parameters spec'd below, have fun doing it:

www.w8ji.com/fcc_97_307.htm

I have to laugh out loud when snooty Ham radio dudes say "you can't run X amp or X radio because it's not approved by the FCC" Doesn't have to be on the HAM bands as long as the stuff rates within the above parameters

There is another level on the Pro side of things you can take. The CBSE or Certified Broadcast Radio Engineer Exam.

Here's a taste of that: www.radioworld.com/article/the-equipment-measurements-question/3415

That's what I thought was the answer. I mean, even if I just stripped the parts and put em all on another chassis, what the hell would the FCC care about that, as long as the output is clean and the spurs meet spectral requirements.
Actually, I would just purchase the thing and strip it for parts and build my own chassis . My main problem would be not knowing if the transistors still worked, which I would highly doubt. I've never, ever seen SWR protection in
a CB amp.

I've talked with W8JI quite a number of times on 160 mtrs. Great engineer, and knows his stuff when it comes to amps and antennas, for sure. If I remember correctly, he used to work for Dentron, back in the day. We used to have some great conversations on current in-rush protection and such.

Interesting links, BBB! I sometimes wonder what it would be like to take an exam like that, not study at all, and see if I could pass the damn thing. I seriously doubt it, with all the regulation stuff you have to memorize, but I would be curious to know how many I'd get right on the technical aspects of the test.

[ab5ni]

Nov 28, 2015 13:22:13 GMT -5 Sandbagger said:

Nov 28, 2015 10:57:32 GMT -5 BBB said:

You can run anything on any Amateur Radio Frequency provided you are currently licensed to do so, keep below the associated max power limits and the transceiver and output signal meets the FCC requirements for bandwidth limitations and spectral purity.

That's the great part about the hobby! If you can dream it and make it work within the parameters spec'd below, have fun doing it:

www.w8ji.com/fcc_97_307.htm

I have to laugh out loud when snooty Ham radio dudes say "you can't run X amp or X radio because it's not approved by the FCC" Doesn't have to be on the HAM bands as long as the stuff rates within the above parameters

There is another level on the Pro side of things you can take. The CBSE or Certified Broadcast Radio Engineer Exam.

Here's a taste of that: www.radioworld.com/article/the-equipment-measurements-question/3415

There are a LOT of misinformed hams (and others) out there. They think because you can't legally run ham equipment on other services, which require type accepted equipment, that the reverse is also true. It's not. There is no FCC certification for ham transmitters beyond part 15 regulations, although there are regulations for ham amplifiers (primarily to keep them OFF of bands like CB). The bottom line is that hams are given broad latitude to run whatever they buy, build, cobble together, whatever. The responsibility for compliance lies with the operator, and he alone will bear the brunt of whatever goes wrong. Much different than other services which require type accepted equipment. Since the operators of those services are not expected to be technically versed, the responsibility for compliance lies within the design restrictions of the equipment. That's why ham equipment is not authorized to run on other services. But there's nothing illegal about re-purposing a CB, a land mobile radio, or some other band-specific radio to run on ham bands. As long as the operator ensures technical compliance.

That's all good to know, SB. I was worried about some aspects of this, especially when the FCC requires that you are a licensed tech to work on electronics that are sold to the general public. For instance, I'm pretty sure I couldn't start up a small repair shop and fix things and sell them to the public without some form of license. From what u are saying, the reverse is not true if it's ham gear. Also, from your remark I gather that if I was to sell a piece of ham gear to another ham, it would now be his responsibility to make sure that the equipment is operated properly. Fun times.

[Sandbagger]

Nov 28, 2015 17:36:38 GMT -5 ab5ni said:

Nov 28, 2015 13:22:13 GMT -5 Sandbagger said:

There are a LOT of misinformed hams (and others) out there. They think because you can't legally run ham equipment on other services, which require type accepted equipment, that the reverse is also true. It's not. There is no FCC certification for ham transmitters beyond part 15 regulations, although there are regulations for ham amplifiers (primarily to keep them OFF of bands like CB). The bottom line is that hams are given broad latitude to run whatever they buy, build, cobble together, whatever. The responsibility for compliance lies with the operator, and he alone will bear the brunt of whatever goes wrong. Much different than other services which require type accepted equipment. Since the operators of those services are not expected to be technically versed, the responsibility for compliance lies within the design restrictions of the equipment. That's why ham equipment is not authorized to run on other services. But there's nothing illegal about re-purposing a CB, a land mobile radio, or some other band-specific radio to run on ham bands. As long as the operator ensures technical compliance.

That's all good to know, SB. I was worried about some aspects of this, especially when the FCC requires that you are a licensed tech to work on electronics that are sold to the general public. For instance, I'm pretty sure I couldn't start up a small repair shop and fix things and sell them to the public without some form of license. From what u are saying, the reverse is not true if it's ham gear. Also, from your remark I gather that if I was to sell a piece of ham gear to another ham, it would now be his responsibility to make sure that the equipment is operated properly. Fun times.

Actually that's no longer true either. The only services that require an FCC license (GROL) to perform repairs and adjustments, are the maritime, aeronautical, and international fixed. Land mobile, CB, and even broadcast services no longer require FCC licensing. I was interested in getting my GROL, 30 years ago, but was actively discouraged from doing so. The FCC no longer gives exams for it, they've subcontracted that out in much the same way as the ham licensing has gone to VEC's. Testing sites are limited, and there are none nearby to me, and since I no longer needed the license to work on land-based radios, I stopped trying.



wireless.fcc.gov/commoperators/index.htm?job=pg

[ab5ni]

Ah. Also great to know. OTOH, with the advent of SMT and "throw away" electronics, I really don't know why I would ever want to get into any kind of repair business anyway. I guess one could always repair old radios and such as a service over the net, but I'd imagine that the competition in that area is pretty intense.

Personally, I'm thinking about going to garage sales, flea markets, and local auctions to see what kind of gear I can find, repair, and put up on e-bay. I think I could get a pretty decent radio collection doing that as well. I only wish I had the income to do such things. Too damn broke to even invest a couple of grand into something like that, although I might eventually dig into my retirement fund if push comes to shove.

Hopefully, the oil biz will pick back up soon, but I seriously doubt that's going to happen. The great thing about being a tech guy is that it's pretty easy to make a lateral move into another area. I could do this pretty easily, but in another field I'd just be another "joe blow," and they'd treat me as such. Had an insurance guy offer me $35K the other day. I laughed and told him I hadn't made that little money since I was 18, and I just turned 56.

73,


Randy, AB5NI

 

[grapeape]

I found a TRC-451 at a yard sale around 1990 for $15. Had it on a bench a few times. Everyone says it sounds nice and clean. It lives in what ever my daily driver is. A few months ago I aquired 2 more for parts radios. One was freq'd n roger beeped. Since my original radio has a cracked/repaired corner on the board I've opted to use the upgraded radio.

I learned the chassis has changed a couple times through the numbered series. The 450 was a Uniden mb-8719 PLL board and the 451 was a upd-2824 PLL. It's a Cobra 146 clone, but Im not sure if it's a Dynascan chassis or a Knock off. I heard by the late 70' that the Chinese had copies of knock off's from their own copies lol.

I'm glad to find y'all like RS radios. Most people badmouth them. I have found cap kits and other geek items to return your radios to better than new. This thread gives me inspiration to take on such an endever. Besides, I have a vintage RS power mic waiting for a full power radio to put it on.

Grape Ape

[Sandbagger]

Feb 4, 2016 6:36:59 GMT -5 grapeape said:

I found a TRC-451 at a yard sale around 1990 for $15. Had it on a bench a few times. Everyone says it sounds nice and clean. It lives in what ever my daily driver is. A few months ago I aquired 2 more for parts radios. One was freq'd n roger beeped. Since my original radio has a cracked/repaired corner on the board I've opted to use the upgraded radio.

I learned the chassis has changed a couple times through the numbered series. The 450 was a Uniden mb-8719 PLL board and the 451 was a upd-2824 PLL. It's a Cobra 146 clone, but Im not sure if it's a Dynascan chassis or a Knock off. I heard by the late 70' that the Chinese had copies of knock off's from their own copies lol.

I'm glad to find y'all like RS radios. Most people badmouth them. I have found cap kits and other geek items to return your radios to better than new. This thread gives me inspiration to take on such an endever. Besides, I have a vintage RS power mic waiting for a full power radio to put it on.

Grape Ape

Yea, Radio Shack, like Cobra and others, kept updating their radio models when their chassis suppliers (in this case Uniden), discontinued or changed their designs. Cobra had not used a "Dynascan" product since the very late 60's. Since then,up until the late 80's, Cobra had been using primarily Uniden-based chassis, with a few models being supplied by Toshiba. Radio Shack started their "Japanification" with models made by GRE, but in the mid 70's they started supplementing those with other models made by Uniden.

I have to laugh at guys who brag about certain brands (like Cobra) while at the same time knocking other brands (like Radio Shack), not knowing that they may very likely be the exact same guts inside.

The TRC-451 is one of my favorite mobile radios. No, it's not channel expansion friendly, but from a pure performance standpoint, it's hard to beat. Low noise receiver, great sensitivity, nice clean sounding TX and RX audio, and a great noise blanker. The smaller TRC-453 and 465 (Same as the Uniden PC122) are also great performers, although I prefer an analog meter to a 5 segment bar graph meter.

Shamefully, by the mid 80's, most of those great performing Japanese designs had been copied by China/Pacific rim countries with mixed results. I'm not a big fan of China-clones, they don't seem to work as well, primarily in the receive section. Much more white noise.