EEVblog

How much has UHF technology progressed in 20 years?
A teardown of a 2000 vintage Uniden 500mW UH040 UHF Walkie Talkie to a modern kids 500mW version at half the size and 1/10th the cost!
Bonus UH750 5W teardown.
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[@Mobin92]

"Copyright 2000" ... hold on I thought he said 20 years ago ... oh :(

[@EEVblog]

Yeah...

[@MrBrymstond]

It is 2020 now.

[@markpitt5248]

We be old

[@AltimaNEO]

@@MrBrymstond that's the joke

[@stranger7968]

omg :|

[@RedwoodRhiadra]

That 5-watt "professional" model might be more expensive materials, but Vietnam is where you go these days when Chinese labor is too expensive...

[@Klokopf52]

@Abstractism They also started to increase working conditions and paid there workers more than just a grain of rice and already companies are leaving... Disgusting how profit oriented parts of our world are :(

[@jskratnyarlathotep8411]

@@Klokopf52 you're saying that like you're never consider the price while buying something

[@whiskeyinthejar24]

My grandparents have been using those old school Uniden uhfs daily for 16 plus years on the farm. They have held up surprisingly well.

[@VintageTechFan]

13:00 That's most likely just an RF-MOSFET. Those RF-FETs typically have the source on the cooling pad for good low-impedance grounding. I see an RC feedback network from drain to source (very common!) and a matching/filtering network to the antenna. The diode marked "W4" looks like a PIN diode for the RX-TX switching (there is a second one under the edge of the shielding can). It's actually a quite nice design, as soon you switch on the drain voltage BOTH diodes are going to conduct and you connect the TX to the antenna, and short the RX input to ground to protect it. The SOT23 would then be a bias regulator, since they would be using the FET in Class C there is no idle current, you just have to bias it somethat under Vth to get the right conduction angle. So no adjustment needed here.

[@TechNed]

It's a 2SC3356. NPN BJT with a Gain-Bandwidth product of 7GHz!

[@conodigrom]

10:30 solder balls, coming to a short near you!

[@brendancarlson1678]

Imagine a pair of shorts with 2 solder balls

[@conodigrom]

@@brendancarlson1678 "GOT BALLS?"

[@edwardfletcher7790]

Eventual failure guaranteed 👍

[@maicod]

you saved the new transceiver from an untimely death by removing that solder ball

[@edwardfletcher7790]

It's pretty hard to kill 5V devices...

[@Stefan_Payne]

Nice to see a longer Teardown Video from you again! Godspeed!

[@Syntax.error.]

When I was a kid in the 90s I had a rich friend that got very fancy walkie talkies that we used to play around. I was amazed by them at the time.

[@thehandyman83]

Oh man I just had the exact thought about these last summer. I bought a few of these in 2001 for chatting when off-roading when we were out in our Jeeps. Fast-forward to 2019 and went shopping for some 'real walkie-talkies' for my 4 and 5 year olds to play with and to my amazement they dropped to like two for $30. They arrived and they are absolutely tiny. Blew my freaking mind. We have since bought them for all the neighbor kids and now they all play with them all the time.

[@L0j1k]

2:38 Shoutout to Dave chortling at "People's Republic" LOL! 10 for style and finesse!

[@urbbs09]

Geeked me out

[@zakofrx]

Just like how East Germany was the Democratic Republic.

[@EEVblog]

Finesse is my middle name :->

[@TechNed]

... and don't forget that bastion of democracy, the DPRK (Democratic People's Republic of Korea), north of the 38th parallel.

[@vk3ye]

The UH040s were a classic. Top seller and top performer. >50 km range from a high spot. The use of AA (not AAA) batteries was a masterstroke for long life. only thing extra I'd have liked is a detachable antenna. From memory they were $149 when they came out, dropping to $99 for a long time.

[@KiwiCatherineJemma]

I believe that the non detachable antenna aspect was a required part of the UHF PRS/CB radio licencing regime from the Aust/NZ governments.

[@Zardox-The-Heretic-Slayer]

that is so bloody weird - I literately just took some of these exact same walkies apart about 30 minutes ago

[@vincei4252]

Spooky attraction at a distance :-O

[@Najvalsa]

Maybe he heard you over them.

[@Digalog]

Google programmed both your brains

[@agvulpine]

I think that's what he's driving at. Google has tapped into the algorithm of ordained-by-suggestion in order to manipulate the things we do and to, ultimately, synchronize society to its design.

[@Zardox-The-Heretic-Slayer]

@@Digalog I just found them in a charity shop and thought I'd take them apart cause they were £2

[@ksbs2036]

That was tremendous fun. Thanks Dave

[@StreuB1]

Videos like there, where Dave gets all hopped up and his passionate Aussie side comes out, are the best. Can always tell when he's REALLY into a topic like this one. Again, fantastic video Dave. As for Uniden, we all remember these from the Radio Shack/Tandy store days. Always have been a high end brand, even today they stand up there with Kenwood and the lot.

[@Digalog]

haha topshit

[@sanityd1]

I always love a teardown and one of the few fun parts of taking apart printers is seeing the evolution over the years from different companies.

[@redtails]

the remarkable thing is that the 15$ kid transceiver is 75% empty. The board is massive but there's almost nothing on it. It literally has that size so that the batteries and the LCD can fit on it without cables

[@Raptor50aus]

Happy New Year Dave. Used to have 2 of these Uniden's with the external mic speaker. Worked great on a friend's farm.

[@Grcbyte]

Yeahh!! Thank you and Happy new year!!

[@TKomoski]

Hey Dave Happy New Year stay safe with you and your fellow countryman

[@giver666]

Is not a CB radio 27MHz !!! Is a PMR radio 446MHz !!!

[@freda5344]

counted 9 comments already of this same. American right? FFS the whole world is not the USA. In Australia CB legally refers to either of the allocated 27mHz or UHF band.

[@electronic7979]

Good teardown video 👍

[@mjsnosk8er720]

Thanks! I'm just finishing a project where one transmits the Call signal in response to a sensor. Great vid!

[@R2AUK]

15:00 RDA1846 is extremely popular these days. You will find it in many inexpensive UHF/VHF radios. Baofeng radios are probably most famous. Also RDA1846 is used in some low-end Yaesu radios.

[@zachdemand4508]

It would be nice to see more teardowns of radios.

[@horiamorariu8612]

Hi Dave. A very interesting teardown, thank you. The RDA chips are also the core in Baofeng VHF/UHF transceivers. One minor thing to clarify: all of them are PMR (446MHz), not CB (27MHz). Cheers, take care!

[@chrisjones8741]

I thought the same thing about CB at first too. But apparently that’s what they call that band in Australia.

[@1ytcommenter]

in australia 446 IS! citizen band. aswell as 27 megacycles frequencies.

[@ammocraft]

As soon as I saw the spec sheet, I immediately thought Baofeng, as otherwise you wouldn’t need VHF with PMR, GMRS, FRS, and our CB all being UHF. BTW, to the other commenters....UHF CB here in Aus is 477MHz FM, with AM/SSB still legal on 27MHz too.

[@ctyragdoll]

Yep, here in the US it's called the FRS (Family Radio Service, 462/467Mhz UHF). It's also FM, while CB is AM/SSB on 27Mhz (again, in the US).

[@hopkinskong]

Or 409MHz here in Hong Kong/PRC.

[@stevenm.2380]

I remember as a teenager in the late 90s going to six flags and everyone had those mini walkie-talkies as cellphones hadn't't taken off yet. Literally hours of fun scanning the channels and saying rude things. I would just imagine someone in the park, stood in line and suddenly a loud fart noise emanating from his person. : )

[@shadow7037932]

My friends and I still use these for autocross/track days because it's a lot more continent than dialing a phone number.

[@wjodf8067]

yep same tricks but the log flume rides used to kill them we had double b\plastic baggies for the wet

[@dglcomputers1498]

We still use licenced radios at work, much easier and quicker than calling someone, plus they still work if we have a power cut and the mobile networks go down. As for scanning radio channels, there is a story from one of the audio forums where someone having gone into a supermarket in England and getting rubbish customer service (returning something or suchlike), noticed the greeter with a wireless microphone. He got back to his car, either left and came back already had his scanning equipment on him managed to find the frequency of the wireless microphone and broadcast "half price alcohol today" or something like this over the Tannoy a few times, ended up with the police being called due to the problems caused by said message!

[@catalinalb1722]

Lovely. Teardown & RF. Great match!!!

[@VintageTechFan]

6:30 May be for capacitive coupling to the holding hand to use the user as a RF counterpoise. Handhelds generally do that to some degree.

[@conodigrom]

"You're holding it wrong" cit

[@SolidStateWorkshop]

DL3CE Or maybe some sort of coupled ESD protection. Not sure if i see anything particular sensitive underneath though

[@hjups]

It might be to help fix the inductance of the spiral inductors (possibly for a filter?). If you notice at 7:07 there are four coils that appear to be custom for the application. I know that working with RF stuff, near-plane coupling will change the values of components like that (most of the time you have to do an EM simulation to make sure that the components are still tuned correctly after assembly). That could also be why the metal wraps around, so that it makes contact with the rest of the can.

[@atmel9077]

This is probably to prevent capacitive coupling between the circuit and the user's hand. On the old portable superhet FM radios, waving your hand close to the VCO tank circuit would tune it to the previous station.

[@hopkinskong]

Those RDA chips always uses direct conversion like SDR Radio, unlike expensive one usually uses double conversion superheterodyne.

[@ronniepirtlejr2606]

I have a beautiful TRC-236 Radio Shack Citizens Band transceiver. Got it at a yard sale for $4.00. The only thing I had to do to it was make 2 blank batteries (according to the manual) for the proper voltage, using alkaline batteries. If you're using rechargeable they are not necessary. It is a beautiful piece of vintage electronics, in fantastic shape! *Edited to add. It picks up the truckers on the interstate 7 miles away.

[@edwardfletcher7790]

Those things were the dream of every teenage kid in the 80's 👍 Annoys me watching the kids on Stranger Things playing with them when they cost a weeks wage when new !!

[@Bazzawombat]

Still have my original 20 year old Uniden handheld you showed first, been using them at the NSW bushfires, still very reliable. Uniden have always made quality. Cheers, Barry, VK2FP

[@donwald3436]

Neat, UHF CB. Makes much more sense than what was allocated in America. Imagine taking a long distance band and legally mandating local communication on it!

[@thebobbit2740]

Great video... Cheers !!

[@richardhead8264]

Hi Dave, other than explicit date codes, what physical characteristics prompt you to conclude at *4:57* that the board was manufactured in the early 2000's? Thanks!

[@electronicsNmore]

I had a nice Uniden marine transceiver similar to that unit in 2000.

[@Darryl603]

Hope you're safe from the fires and Happy New Year, Dave.

[@mrkitty777]

Weow 😼

[@alanhowitzer]

@@mrkitty777 Isn't it 'meow'?

[@mrkitty777]

In Australia cats Weow due to the accent that's different. And cats burrrr too in Australia. In most countries they do meow and purrr, 😄😃

[@Darryl603]

@@mrkitty777 What sounds do cats make in China?

[@mrkitty777]

Cheow, chaewow, chiweow, chuweow, and they probably churrrr 😮

[@longriderxx]

cheers ...Happy new year

[@edwardbyard6540]

I had a Uniden 4W 40 channel hand held CB in the 90s. It ate batteries like there was no tomorrow. Uniden base stations were the mutts nuts back in the day. Really good, sturdy and good audio quality.

[@chrisjones8741]

Nice, thanks for sharing! It looks like the top might come off of that first can instead of the whole can having to come off? Also on the commercial unit, you might be able to unscrew the antenna and pull the knobs off, and then the whole board slides out? Instead of unsoldering.

[@snafu6548]

Not sure how other countries designate bands, but CB (40 channel Citizens Band) in the USA is an AM radio using the lower HF band (26.965 to 27.405 MHz). FRS (22 channel Family Radio Service) radios are FM, in the UHF band (462.5625 to 462.7250 MHz)

[@THEDRAGONBOOSTER8]

Hi ,I am from Tassie and I have 2 of the older ones ,Both work fine but one the squelch hangs on when you let go of the button when you send . How can I fix it .paid a lot years back.cheers.

[@russellhltn1396]

I'd imagine the reason the 5W went back to discrete components is for better performance, particularly intermod (intermodulation) - where a strong off-channel signal can clobber what you're trying to listen to.

[@rkan2]

All too apparrent when using the RTL2832 for anything... Any strong radio signals make it very difficult to use for anything, especially without the proper antenna.

[@PE1MR]

Yeah, band-pass filters are required if you want to get more selectivity from SDR-based transceivers. The regional 70cm repeater at 200 meters from my home makes any UV-5R cry ;-)

[@ryantoomey611]

That is because you need better filtering, otherwise there will be too much spurious emissions and harmonics.

[@vincei4252]

The diode in the output circuit is probably a pin diode to switch TX/RX.

[@ingmarm8858]

The RDA 1846 single chip transceiver is the same chip used in most junk radios including the dual band BAOFANG VHF/UHF radios. Does the job but many manufacturers drop the ball with the band pass filter section meaning you have barely passable attenuation of harmonics.

[@patrickrobinson4973]

Those fires are looking pretty nasty. Not sure how close they are to you, but sure hope you and your family stay safe. Great vids. Love em. You actually make electrical engineering vids interesting to watch, funny and easy to understand. Awesome work bro. Keep it up. 2 thumbs up from me. 👍👍

[@antikommunistischaktion]

11:23 I wonder if you can get anything off of those serial pads below the asic.

[@lights-fo8et]

The two pins next to the serial interface could be SWD pins (normally labeled SWDIO and SWDCLK or TMS and TCK), which means that it's an ARM chip and you may be able to flash custom firmware.

[@dash8brj]

@@lights-fo8et Yes, the sets would probably be programmed for the market they are going to. The antenna and transmitter will have a frequency range it can work at (e.g. 430-480) so they can be programmed to work on the UK frequencies as well as the aussie frequencies. Us hams take it to a whole new level and get radios from ex government and commercial outfits that have moved up to newer gear and repurpose it for the ham bands in a similar fashion, by reprogramming the radio. I have an ex LAPD radio programmed up to listen to UHF CB, and TX/RX on the VK uhf amateur bands.

[@billsmith1823]

The PCB for the PTT button pushes up against the plastic spigot on the cover where the screw goes through.

[@mrepic789]

It's weird to thing that those were the radios that got me into the career i'm in today. Good on ya Dave for bringing back some good memories :). You think your fancy uniden is beautiful on the inside, check out the Motorola APX8000XE and the MOTOTRBO XPR7550e, the radios I get to play with on the daily :P -73 DE KG5PKX

[@agentsmith3577]

Do you still need a licence for CB in Oz? I googled last year to see how to get one but couldn't find any clear info

[@TheTallGirl]

It is insane how they can integrate all that RF black magic today Huge boxes full of colorful coils that was hand poked and coated with wax Today just replaced with simple LC filter and chip

[@EEVblog]

Yep, insane.

[@rkan2]

Today. more like last decade... Even GSM phones from the 90s were really the precursor to these. Even the famed RTL2832u was probably designed in the early 2000s. The first mention of the RTL2830 can be found in Realtek 2005 annual report. I wonder what is possible with ICs spun nowadays...

[@TheTallGirl]

@Steve Terry today with things like Si443x wireless chip cost less than connector and meter of wire

[@adamsiwek7995]

There are some thick traces (25:00) going to that board to board connector. Why are getting thinner at the end?

[@dingus153]

I'm amazed that for a similar price as the old one, I just bought a (basically) top of the range GME 5W hand-held, and it came with a rechargeable lithium battery and heaps of accessories 😂

[@JerryDodge]

Hey Dave, hope you're staying safe in all the fires in the down under mate

[@darthvader8433]

Really interesting tear down. I did my navy comms electronics apprentice training in the early 80s, things really have moved on! Dave - extra shot in the coffee before shooting this? ;^)==

[@FurEngel]

If you want to do your own project, I would recommend the ATmega128RFA1. It combines both a 8-bit AVR MCU with a 2.4GHz RF radio and supports fancy stuff like encryption, compression, error correction, etc.

[@todayonthebench]

Rather decent build quality in all three of these units. Other then the solder ball tumbling about... Also, it is indeed fascinating how a new chip can come along and cut down production costs by a great amount.

[@manojroy657]

which dumpster in mumbai can I find such testing equipment. In laminton road there are computer dumpster buy where do i lookout for testing and measuring equipment

[@karljay7473]

I have an old pair of GMRS and would like to know if they have any use. I see motorcycle riders use them. Maybe for drone controllers, but seems those chips are pretty cheap. Don't know if there's any good usable parts in them. I really hate seeing them just rot away.

[@AstrosElectronicsLab]

Is that "CQ" box thing in the older CB a relay or something?

[@derosram9333]

Interesting video. I think the diodes in the RF part are a Pin-Diode-Switch, this would also be a cool topic.

[@DrDremelchausen]

Hello ! :) Thanks for video!

[@transtubular]

Kinda fun! Although here in the US the UHF public range is called the Family Radio Service, CB is only the 27MHz range. I do recall giving the nephews a set of FRS radios that I found that were about half the size of your smaller unit, roughly the same size and shape of a medium sized egg. I don't recall the exact price but I wouldn't have spent more than $40 US on them. This was roughly 20 years ago...so maybe they were more cutting edge than I thought at the time.

[@0MoTheG]

I bought 866MHz radios and the worst about them was the solderless LCD connection. Soon the bars in the display went dead. The range they get depends on the battery voltage.

[@chriswalker499]

do you still have the battery covers for the old one?

[@jaye1967]

I wonder how much of a component reduction there is between the units.

[@clearz3600]

2009 makes sense since that was around the time I remember seeing them radios starting to drop massively in price

[@edwardfletcher7790]

The battery life improvement has also been incredible 👍

[@linkinpark9812]

I love trying to predict when he'll say "Bob's your uncle".

[@rjordans]

Interesting to see the similarities between the old one and the 5W version here!

[@researchandbuild1751]

Do you think it may be this same chip uses in Baefong ham radio handhelds?

[@Rob2]

Yes. RDA 1846S

[@yar0nix224]

liberary tv website is not linked below like you said at the end

[@robertalabla]

Is the charging IC shown at 11:28 an LTC4054-4.2 lithium charger being used on what I assume would be three nimh/nicad AAA batteries in series ? I can't find any reference to a nimh/nicad charge IC with a LTH7B number. I am the hunt for a cheap 3s/4s nimh/nicad charge IC if any one has any suggestions.

[@EEVblog]

I didn't look at the part number

[@ozstriker1984]

Why would you go away from a single chip solution? How would the newer one perform better?

[@nigeljohnson9820]

What is interesting is how the circuit topology has changed. Older transceivers would be filled with inductors. The transmitter would have contained a collection of frequency multiple stages to get to the carrier frequency. The receiver might contain two local oscillators and two IF stages, maybe at 10.7 MHz and 455kHz with a crystal IF filter defining the radio channel bandwidth.

[@zakofrx]

What's the difference in Sound Quality in both directions?

[@ussovak5954]

Dave, one can not compare different classes of Two-way radios. There's Public Safety, Commercial, Amateur(HAM) and Consumer(FSR) models. Of course, quality varies greatly between them. PSR and Commercial radios are still much larger than Consumer models. Consumer models are basically toys.

[@Walking_Death]

I've still got the 2 Watt/0.5 Watt version. Still going strong. Also got an earlier version of the little one. AAA batteries don't last very long compared to AAs.

[@aaaaaaaaaassssssssdf]

i wonder if solder balls is the reason sometimes hitting something makes it start working again...

[@lstein3372]

Check out the DRA818u walkie talkie module on eBay or aliexpress. It contains the rda1846 chip. It is the only place I've found the chip for sale. Larry

[@lstein3372]

@Steve Terry Thanks Steve. I didn't know there was one in the 888. I have never been in one. Larry

[@wyokaiju992]

7:28 Silkscreen says CQ Nice

[@dazednconfused31337]

I took apart a BT DECT cordless phone and it said HIPSTER on the board. It stopped working then but the audio was too quiet and rubbish anyway. Inside my old Amiga A500+ it has ROCK LOBSTER on the PCB.

[@alexderpyracc4053]

Dx

[@steviebboy69]

I have one of those old Uniden units although no leaky Duraleaks left in it. It is still in mint condition and has little use. I thought Tail Noise was something else hehhe.

[@thomasanreise3107]

It's all chippies and jobbies inside there. Great video, subbed!

[@grhinson]

Is this published on lbry yet?

[@antonyprasad5536]

I bought a kid's walkie talkie just to tear apart and see what's inside, it was just simple 2 transistors FM transmitter and receiver.

[@blahorgaslisk7763]

As a kid I had a japanese made walkie talkie that had a single channel and on the shell it proudly stated how many transistors it used... Can't remember what channel it was set to, but changing it took switching out a crystal. Same with a larger 5W Sanyo that we used in the boat. It had five channels (I think) and you choose what they were by what crystals was installed. This particular radio was over built like a tank, and a lot of people just feed it 24V instead of the 12 it was rated for and apparently they got a bit more power out of them that way. My parents used that radio for well over 20 years...

[@georgegonzalez2442]

My first VHF radio was a 1950's taxi radio. The size of a suitcase. About 30 vacuum tubes. Weighed about 40 pounds and drew 6 amps as 12 volts. You could buy them all day long at swap-meets for $10. Original price must have been near a kilobuck in today's dollars.

[@ZylonFPV]

Did you re-solder that loose wire on the can on the 5w one? Seemed like great build quality apart from that 🙂

[@einfelder8262]

has to track down the owner of the hair first.......

[@ZylonFPV]

that’s gonna be difficult 😛

[@Rob2]

You can buy ready-made modules (PCBs) with such chips to get a radio which you can connect to your own microcontroller.

[@rocketman221projects]

Those modules are not complete. They lack any output filtering and will spew harmonics all over the place unless you add a suitable low pass filter.

[@Trinitrophenylmethylnitramines]

Hi Dave, Vietnamese viewer here!!!!!

[@redtails]

12:17 genuine China rust on the can xD

[@olafelsberry9271]

I've got a similar UHF CB it's also got a detachable antenna

[@klightspeed]

15:14 16:04 look at the wording - it looks like the AT1846S "datasheet" copies the blurb word-for-word from the RDA1846 datasheet, only replacing "RDA1846" with "AT1846S"

[@thumbwarriordx]

>Hair in the thing I bought a monitor once with an eyelash laminated somewhere into the layers. That is an extra reason to pay for the color-calibration. Can't calibrate a display without turning it on and seeing that glaring flaw.

[@UpcycleElectronics]

What's this library TV thing?

[@yfs9035]

I have some of these, the auto squelch on one of them doesn't actually work anymore though and there's just constant noise.

[@robbieaussievic]

...... Sure it's not a setting that's been inadvertently activated ?

[@yfs9035]

@@robbieaussievic Nope, It had found the manual and it had no such option.

[@TorgeirFredriksen]

The cheap one one is ABS plastic, I assume the expensive one is PA-something, probably glass-fiber reinforced.... Anyway, thanks for the video!

[@laernulienlaernulienlaernu8953]

I can never get my head around how Chinese manufacturers can produce and ship some of these products for less than you can buy some of the individual components separately.

[@KiwiCatherineJemma]

Well the workers get 2 bowls of rice a day and a bullet in the head if they don't work fast enough. Or complain. Or wear the wrong coloured shirt. In civilised countries, workers need to be paid a fair wage, along with healthcare and pension benefits. It all adds to the cost.

[@mdasilvac]

Wonder if you could reflash the microcontroller and use custom channels... Or more! Maybe a digital modem?

[@Rob2]

The microcontroller usually is one-time-programmable. But you can buy bare RF modules containing only the radio part of this, and no microcontroller, and then add your own.

[@Jedda73]

Ive got the intermediate design from around 2010 sitting in the junk box. They were great little radios until one of my sons mates blew the arse out of them holding them against each other while transmitting.

[@jimyohe100]

You probably had Dura-Leaks in it when the batteries leaked.