FPV vs Home Phone Wireless 5.8ghz Why hasn't anyone hacked a phone RF circuit? - Page 1
Forum section: electronics / beginners

author: jakeisprobably
author_rank: Regular Contributor
timestamp: July 12, 2016, 10:36:50 pm
content: I picked up a box full of old wireless phone stuff and took it all apart. I didn't find datasheets for any of the numbers I could find, but the actual radio modules are designed into their own PCB and solder connected to the main PCB, both on the receiver and the base unit.The phones are on the same frequency as most FPV systems, they both support similar data, at least from an (assumptive) analog data stand point, they even have about the same transmitter range from what little I've seen.I'm no 'RC enthusiast' just in the process of becoming a hobbyist. I find it odd that a circuit when, in a phone, is relatively cheap and commonplace, but becomes black magic expensive and marketed at two to four times as much money to the 'RC hobbyist.' Am I missing something about these circuits or is this consumer market BS?

author: jakeisprobably
author_rank: Regular Contributor
timestamp: July 12, 2016, 10:49:48 pm
content: Just a couple examples of the phone RF modules.

author: jakeisprobably
author_rank: Regular Contributor
timestamp: July 12, 2016, 11:10:26 pm
content: A quick peek under the iron curtain...And the main IC

author: hendorog
author_rank: Super Contributor
timestamp: July 12, 2016, 11:50:21 pm
content: Thats interesting - The bandwidth will be an issue of course, that one is optimised for audio but need to send video.FPV parts are really cheap too if you just get the modules themselves:http://www.aliexpress.com/item/Boscam-FPV-5-8Ghz-200mW-Wireless-Audio-Video-Transmitter-Module-TX5823/2040265101.html?spm=2114.01010208.3.73.c4oM8D&ws_ab_test=searchweb201556_8,searchweb201602_2_10037_10049_10017_405_404_407_10033_406_10032_10040,searchweb201603_8&btsid=02c284e5-c64e-4c6c-b3a3-243e085c0ae8The chips used in these modules are:http://www.richwave.com.tw/product_description.php?PNo=39The datasheets are a bit hard to come by but they are around.Some manufacturers use these other chips I think, I don't have anything that uses them:http://www.airwave.com.tw/en/2-2851/manufacturer/5-8GHz-RF-IC-id109511.html

author: jakeisprobably
author_rank: Regular Contributor
timestamp: July 13, 2016, 11:07:40 pm
content: Quote from: hendorog on July 12, 2016, 11:50:21 pmWhat part of the IC/circuit causes the bandwidth to be limited or that are the problem(s)? I am curious about the EE details side not the practical 'RC Hobby' application. If I had 2 datasheets in front of me one for a commonly used radio IC used in some FPV systems and another datasheet for a radio IC commonly used in some phone systems, what peripheral details differentiate the two IC's?

author: hendorog
author_rank: Super Contributor
timestamp: July 13, 2016, 11:37:51 pm
content: Quote from: jakeisprobably on July 13, 2016, 11:07:40 pmThe issue I was talking about was the bandwidth being limited by filters external to the chip, and the bandwidth limits of the devices built into the chip - like mixers.However I think I found the datasheet for your chip:http://pdf1.alldatasheet.com/datasheet-pdf/view/255927/MICRO-LINEAR/ML5800DM-T.htmlIts a digital chip whereas the one I have and mentioned earlier is analog.http://web.stanford.edu/class/ee102b/contents/DigitalModulation.pdfIt also says it has 1.5Mbps of digital bandwidth and can stream video. So it should work as long as you can fit your video into that data rate

author: jakeisprobably
author_rank: Regular Contributor
timestamp: July 14, 2016, 04:22:38 am
content: Quote from: hendorog on July 13, 2016, 11:37:51 pmAwesome, sorry I missed the datasheet. Thanks for the info. I took the phones apart a couple months ago and didn't really give them a second thought. I was more fascinated by a small heater with two PIC micros that I got in the same roadside trash raid. I happened to be on here, saw the box they were in and thought it might be worth finding out more.Now I suppose I should give a bit more detail, in case someone else sees this post and wants to pursue these details further than myself or match referenced make/model where I came across this ICUSA Based Consumer Market Device (just in case it makes any difference)Brand - UnidenModel - DECT 6.0 (bottom of phone)Model - " DECT1588-5 581E0808 BG60009205 Made in China FCC ID: AWMUC518R " (all details inside battery compartment)

author: Kilrah
author_rank: Unknown
timestamp: July 14, 2016, 07:32:43 am
content: DECT is digital, so basically completely different. What you have in there is actually closer to what the R/C radios use for remote control.