EEVblog #1275 - Uniden UHF Walkie Talkie Teardowns - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: January 02, 2020, 09:29:47 pm
content: 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.

author: kcozens
author_rank: Contributor
timestamp: January 02, 2020, 10:58:35 pm
content: The AT1846S is an SDR based device based on the block diagram. You can see the 90 degree phase shift in the receive path followed by blocks that mention I and Q. The extra tranny in the receive path may be used along with the RSSI output from the AT1846S for squelch. I was waiting for Dave to have a poke at the serial interface to see what messages it outputs when it is turned on.

author: johnlsenchak
author_rank: Frequent Contributor
timestamp: January 02, 2020, 11:13:55 pm
content: Hey Outback DaveWouldn't those custom ASIC chips also contain "quartz lock loop" circuitry for channel selections, since it also drives the display . You real didn't say if thoseunits where multi-channelIn the early eighties I use to lust over the Radio Shack walkie talkies that where 40 channels and put out 1 watt

author: tarasv
author_rank: Newbie
timestamp: January 03, 2020, 05:34:18 am
content: Just to compare with 10 years of progress. I opened my 10 years old Motorola walkie talkie. Same toy size as kids Uniden. But lot of discrete components, trimmers, three crystal oscillators etc and only 55 CAD for three of them and charger.Interesting, did Motorola any profit on them.

author: tchicago
author_rank: Regular Contributor
timestamp: January 03, 2020, 07:46:48 pm
content: Quote from: CJay on January 03, 2020, 07:52:20 amThe sequence of analog filters between power amplifier and antenna is tuned to the specific band. I.e. even if you hack the chip to output a frequency outside that band, it will be suppressed by that filter. Same applies to the receive path. Antenna is also made for the specific band and will significantly less effective outside that band.

author: aRGee
author_rank: Contributor
timestamp: January 04, 2020, 11:05:58 am
content: As mentioned by another poster : the Baofeng uv-5r .Dual band radio, VHF and UHF, 8 watt, recharchable battery for around 21 euro including delivery from China. Even more value for the money then the Uniden. I read a few things about them, most people were very happy with this porto, but it's of course not perfect. I remember buying my first porto for around 350 euro's around 25 years ago, a single band radio...It's incredible.

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: January 07, 2020, 12:48:14 pm
content: Dave Please add the datasheets links

author: Lord of nothing
author_rank: Super Contributor
timestamp: January 07, 2020, 03:35:38 pm
content: Well we in Europe have some Similar called PMR446 with 8 / 16 Analogue and Digital Channel depend on the Country.Here it relay depend on the Radio Quality from with side the Company come. There are this crap cheap Radio poor design and the Radio who are "just" reduced power to 0,5W and a little bit of Software Trickery.I would NEVER recommend to anyone who use them for Business use an Analogue one. Here Supermarked use them. Its funny when I have Time I annoy there Employees with Questions.

author: DH2ID
author_rank: Newbie
timestamp: January 07, 2020, 10:57:15 pm
content: Hi Dave,about the wire badly soldered in your "professional" WT:It is important to reconnect it to the shielding and it shouldbe resoldered (taking the surplus amount off).I'm more into hamradio and emergency radios, repairingthem as far as I can :-)As I volunteer for our Civil Protection Service and theRed Cross, my thoughts and prayers are with you Aussiesfacing the terrible fires.Alex DH2ID