Showing posts with label Frequencies. Show all posts
Showing posts with label Frequencies. Show all posts

Monday, October 27, 2014

Watching the Watchers

Target Blu Eye:
"The £999 system (plus £100-£200 for installation) monitors the frequencies of emergency services’ Tetra and Airwave radios and, according to the manufacturer, listens for the distinctive regular pulses sent by the radios every four seconds. These could be emitted by marked or unmarked vehicles; by radios worn by beat officers or mobile speed camera operators; or by radios in police helicopters. When a transmission is detected, the driver is alerted."
And I agree they really wouldn't like this if someone created a network of dectors and publicized their locations.

Via Slashdot

Thursday, April 17, 2014

Baofeng UV-B5: The Best Kept Secret's Secret

Amazing... I had noticed a bunch of traffic on the Yahoo Group, but I had not made time to read through it. John sums up that the dual-band (2M/440) UV-B5 can do about 2 Watts out on 220. You can access the additional band frequencies by using Chirp to program the radio.

Monday, February 17, 2014

Thursday, April 4, 2013

TYT TH-UV3R: More Tri-band Success

This makes three people that have three bands working on their TYT TH-UV3R:
"I have a pair the 2m/1.25m versions. I even got the 70cm band unlocked and working. I am just wondering, is the 70cm band putting out the same watts as the 2m/1.25m bands or not? If not, how many watts? Or does anyone know?"
And, if I read all these correctly, the first guys had 2M/440 radios and added 220. The last guy above had a 2M/220 and added 440.

Also, Jay updates to say he gets:
"1.8 watts on 2 m, 1.9 watts 440, and 1.7 watts 220"

Saturday, March 30, 2013

TYT TH-UV3R: Tri-Band

I was reading the TYT USA Yahoo Group and was going to post that the TH-UV3R was getting some love from the group members.

That first post mentioned that the TH-UV3R would do 144/440 and 220. The 220 comment brought on a question and then a couple of replies about making the radio tri-band.

"The mod was done in the factory software. Under setup, then model information, Ijust changed the frequency range. 
Freq range 1 400 - 4702 136 - 1743 200 - 246
Works great.."
"Bryan, it is in tht tyt programing.  Open up the program, read from your radio then go to setup then in the dropdown menu click on model info. You will get a popup box with 4 frequency ranges. The 3rd box has 245 to 246mhz init already but is unchecked. Check the box beside it and change the frequency to your band plan. Be aware this will clear any entries you have already programmed. So be prepared to re-enter your frequencies. 
Good luck,
Barry KF5GC"

A little searching and I see that Sinotel UK is selling it as the "TYT TH-UV3R Tri-Band Handheld Transceiver With Dual Frequency Display."

I had written some about the TH-UV3R and remembered that it was Moleculo's favorite (his review). The eHam reviews are generally favorable, but don't mention tri-banding.

A happy little surprise for Easter.

Friday, May 11, 2012

Baofeng UV-5R: Extreme Receive Modification

[ Don't have a UV-5R yet? Get one here. ]

Alvin and b1gslacker have been editing the .dat file to expand the receive frequencies of the UV-5R. As usual the results are a big of a mixed bag given the limitation of the hardware and software involved. Steve, WB8GRS, details the limiting factors:
"There are two components (the DSP and MCU chips) in the UV-5R that determine the band limits.
 1. The RDA1846 DSP chip is the chip that generates all the transmit and receive functions and it specifies the band limit as follows.
134 MHz to 174 MHz200 MHz to 260 MHz400 MHz to 500 MHz
This information is provided in the RDA1846 documentation in the file area. Many have reported the UV-5R will operate outside of these band limit on the 134 to 174 and 400 to 500 MHz bands (no one has reported any success using the UV-5R on the 222 MHz band), so my guess is the above band limits are not "hard coded" in the DSP chip, but are just guaranteed band limits and in fact some chips may operate outside these band limits to some degree.
2. The MCU which I believe is a custom version of the EM78P568-44 microprocessor tells the DRA1846 DSP chip what frequency to tune. If the MCU does not send the correct commands to the DSP chip the right frequency will not be received or transmitted. If for example you load in a 222 MHz frequency, the DSP chip is capable of receiving and transmitting on 222 MHz, but only if the MCU provides the correct commands to the DSP chip. If the MCU does not provide the correct commands, the display may should the correct frequency, but the DSP chip is doing nothing. Even if the MCU send the correct commands to the DSP chip, the RF pre-amplifiers and RF amplifiers external to the DSP chip are not designed to operate on the 222 MHz band so even if the DSP chip was commands correctly by the MCU, the power output and receiver sensitivity would likely be very bad."
b1gslacker gives the details of how to make the change here. The usual warnings apply - do this at your own risk.
"For those of you who would like to attempt to destroy your brand new shiny UV-5R, here are the instructions for "slightly modifying" CHIRP to accept frequencies WAY outside of the manufacturers recommended operating boundaries. These instructions are for windows XP only (but will probably work for others also)
1) Download the UV5R.pyc file in the files section.
2) Using your favourite zip utility (I recommend winrar) open the file located in your C:\Program Files\CHRIP\ directory (location may slightly differ based on your flavour of windows, but you get the idea).3) Delete the UV5R.pyo file from the zip4) Add the UV5R.pyc file5) Save the modified
I know that your thinking, but if you don't understand the instructions, you should definitely not be trying this, so don't even ask.
Now that you have installed the "ever so slightly enhanced" version of the UV5R CHIRP module you should be able to program frequencies between 10MHz-999MHz in the CHIRP application.
NOTE: Even if the radio accepts the frequency and displays it on the LCD display, this does not mean that the radio will actually work on that frequency (in fact we do know that there are definitely limits)"