hpr-knowledge-base/hpr_transcripts/hpr2321.txt

Episode: 2321
Title: HPR2321: Baofeng UV5R VHF/UHF Handset part 7
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr2321/hpr2321.mp3
Transcribed: 2025-10-19 01:18:48

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Hello and welcome, Hacker Public Radio audience. My name is Mr X. As usual I'd like to start
by thanking the people at HBR for making this service available. If we all contributed a show
with more shows than we know to do with, the show is provided by the community for the community.
It's actually very easy. They've gone to a great deal of effort to streamline the whole process
and it's really quite, quite easy. The hardest part I find is getting down to writing the show notes.
It's just about picking up a microphone and hitting the record button. We should must have
something interesting that we'd all love to hear. Okay, here I'll attempt to cover the menu options
of the bofing UV5R handheld transceiver. I'll cover some of the options in detail. The more
obvious ones I'll just briefly cover. I'll highlight any options I don't understand and can't
get information on. The options I know a little about will likely be either bofing specific options
or options that are not really relevant to the radio amateur. If I remember, I'll try to include
the radio announcements of the menu selection. Okay, menu 6, A, B, R, display illumination time.
The radio doesn't announce it at all. It just bleeps. There's option 1 to 5 or off.
Time out for the LCD backlight. Time in seconds the display remains illuminated.
Note, a much longer time interval may be set using the open source chip programming software.
Dual standby or menu 7 TDR. Dual watch allows you to monitor two frequencies simultaneously
on off. In certain situations, the ability to monitor two channels at once can be a valuable asset.
This can be achieved in one of two ways. You can either have one receiver in your radio
and flip-flop between two frequencies at a fixed interval,
known as dual watch, or you can equip a radio with two receivers known as dual receive or dual
VFO. The firmware method is cheaper to implement and far more common than the latter.
The bofing UV5R features dual watch functionality, having a single receiver that flip-flops between
two frequencies, with the ability to lock a transmit frequency to one of the two channels it is
monitoring. Refer to menu option 34 DTR-AB. Tasmix selection in dual watch mode.
Certain functions are not available while in dual watch mode. You cannot use the reverse function.
You cannot use the keyboard to switch between high and low transmit power in channel mode.
In channel mode, you cannot save duplex channels. Menu 8, beep prompt, I think that's what they're saying,
beep keypad on off. When enabled, your radio will emit an audible tone at every key press.
Menu. Transmit overtime.
Menu option 9, TOT. There's a numeric value enterable is from 15 to 600, TOT transmit time out
timer. If the radio PTT button is held down either by accident or by intention, the radio will stop
transmitting after a predefined amount of time has passed. This option will stop the radio from
overheating, possibly causing damage, not to mention and convincing to anyone listening to the
frequency. Setting the timer to desired time interval is not completely straightforward,
however, the manual provides a formula which explains how to calculate the value to enter.
For example, let's assume you would like to set the transmit time out interval to 300 seconds,
you'll use the following calculations. To get 300 seconds, take 300 seconds and subtract 15
to get the value 285, then divide the value 285 by 15 to get the value 19. This is a value you would
need to enter into the option to set the time out timer for 300 seconds. Hopefully that makes sense.
Menu DCS or menu option 10 are dash DCS receiver DCS. If you're new to radio, this may not make
a great deal of sense. It's just really a fancy form of squelch and more or less performs the same
function as CTCSS, which I'll explain in excruciating detail next. For now, I'll cover a basic
description I grabbed from Wikipedia. According to Wikipedia, DCS, digital coded squelch,
generally known as C-D-C-S-S, which stands for Continuous Digital Coded Squelch System,
was designed as a digital replacement for CTCSS. In the same way that a single CTCSS tone
would be used on an entire group of radios, the same DCS code is used in a group of radios.
DCS is also referred to as Digital Private Line or DPL, another trademark of Motorola.
And likewise, General Electric's implementation of DCS is referred to as Digital
Charnel Guard or DCG. DCS is also called DTCS Digital Tone Coded Squelch by Icom.
Other names by other manufacturers or radios with DCS options are generally compatible with,
provided the radios encoder decoder uses the same code as radios in the existing system.
Menu 11, R-CTCSS, in other words receiver, CTCSS. According to Wikipedia,
Intellectual Communications Continuous Tone Coded Squelch System, or CTCSS,
is a circuit that is used to reduce annoyance of listening to other users
on a shared-to-redio communication channel. It is sometimes referred to as a
Tone Squelch or sub-channel since it has the effect of creating multiple virtual channels
which are all using the same radio frequency. It does this by adding a low frequency audio tone
to the voice, where more than one group of users is on the same radio frequency called
co-channel users, CTCSS circuit mutes the users who are using a different CTCSS tone,
or no CTCSS tone. The CTCSS feature does not offer any security.
A receiver with just a carrier or noise squelch amutes from any sufficiently strong signal,
and CTCSS mode amutes only when the signal also carries the correct sub-audible tone.
The tones are not actually below the range of human hearing, but are purely reproduced by
most communications-grade speakers, and in any event are usually filtered out before being sent
to the speaker or headphone. CTCSS can be regarded as a form of inbound signaling. Here's an example.
As a simple example, suppose the two radio frequencies shared by a pizza delivery service,
and the landscape maintenance service. Conventional radios without CTCSS,
we did all transmissions from both groups. The landscapeers have to listen to the pizza shop,
and the pizza shop has to hear the landscape activity. With CTCSS and a different tone for each
group, radio is only here at the activity for their own group. This is supposed to reduce
messages and the distraction of unnecessary radio chatter from other users.
Note that in the example above, there are only two groups of co-channel users. In dense two
radio environments, many separate groups may coexist on a single radio channel.
A disadvantage of using CTCSS and shared frequencies is that since users cannot hear transmissions
from one group of other groups, they may erroneously assume that the frequency is idle,
and then transmitting top of another user. This is accidentally interfering with other
groups transmissions. For example, in the above situation, a landscapeer may be communicating
with another landscapeer. Meanwhile, a pizza delivery driver, not hearing any transmissions,
assumes that the frequency is clear and calls his dispatch office.
Depending on several factors, locations and power, etc, the two simultaneous transmissions could
easily interfere with each other, resulting in one or both not clearly being understood.
The more separate groups share a single frequency, and the more frequently they transmit,
the more likely that this accidental interference will occur.
Radio is equipped with the busy channel lockout feature will prevent transmitting in this case.
Note the bo thing UV5 has this facility referred to menu option 23.
Theory of operation. Radio is in a professional two-way radio system using CTCSS,
always transmit their own tone code, whenever the transmit button is pressed.
The tone is transmitted at a low level, simultaneously with the voice. This is called CTCSS encoding.
CTCSS continuously superimposes any one of 32, 38, or as many as 50,
precise very low distortion low pitched audio tones on the transmitted signal ranging from 67 to 257
hertz. The tones are usually referred to as sub-audible tones.
In the FM2 radio system, CTCSS encoder levels are usually set for 15% of the system deviation.
For example, in a 5 kHz deviation system, the CTCSS tone level would normally be set to 750 hertz
deviation. Engineered systems may call for different level settings in the 500 hertz to one
kHz, 10 to 20 percent range. The ability of a receiver to mute the audio until it detects a carrier
with the correct CTCSS tone is called decoding. Receivers are equipped with features to allow the
CTCSS lock to be disabled. On USA licensed systems, Federal Communications Commission rules
require CTCSS users on shared channels to disable the receivers CTCSS to check if code channel
users are talking before transmitting. It's got a citation needed for this.
On a base station console, a microphone may have a split push to talk button,
pressing one half of one button often marked with a speaker icon or the letters
mon, short for monitor, disables the CTCSS decoder and reverts the receiver to hearing any signal
on the channel. This is called the monitor function. There is sometimes a mechanical interlock
the user must push down and hold the monitor button or the transmit button is locked and cannot
be pressed. This interlock option is referred to as a compulsory monitor before transmit.
The user is forced to monitor by the hardware design of the equipment itself.
On mobile radios, the microphone is usually stored in a hang-up clip or a hang-up box containing
a microphone clip. When the user pulls the microphone out of the hang-up clip to make a call,
a switch in the clip box forces the receiver to revert to conventional carrier squelch mode monitor.
Some designs relocate the switch into the body of the microphone itself.
In handheld radios, an LED indicator may glow green, yellow or orange to indicate that another
user is talking on the channel. Hand-held radios usually have a switch or a push button to monitor.
Some modern radios have a feature called busy channel lockout,
referred to bofing menu option 23, which will not allow the user to transmit as long as
radios receiving another signal. A CTCSS decoder is based on a very narrow band pass filter,
which passes a desired CTCSS tone. The filtered output is amplified and rectified,
creating a DC voltage whenever the desired tone is present. The DC voltage is used to turn
on, enable or unmute the receiver speaker audio stages. When the tone is present, the receiver
is unmuted when to not present the receiver silent. And the communications receiver designed
for CTCSS, a high pass audio filter is supposed to block the CTCSS tone below 300 hertz,
so they are not heard in the speaker. Since audio curves vary from one receiver to another,
some radios may pass an audio level of the CTCSS tone to the speaker. Lower tone frequencies
generally are less audible. Because the period is inverse of frequency, either lower the frequency,
lower the tone frequency can take longer to decode depending on the decoder design.
Receivers in a system using 67 hertz can take noticeably longer to decode than one using 203 hertz,
and they can take longer than on 250.3 hertz. And some repeater systems, the time lag can be
significant, the lower the tone. The lower tone may cause one or two syllables to be clipped before
the receiver audio is unmuted. This is because receivers are decoding in a chain. The repeater
receiver must first sense the carrier signal on the input, then decode the CTCSS tone. When that
occurs, the system transmitter turns on, encoding the CTCSS tone on its carrier signal, the output
frequency. All radios in the chain start decoding after they sense a carrier signal, then recognize
the tone on the carrier as valid. And the distortion on the encoded tone will also affect the decoding time.
Engineered systems often use tones in 127.3 hertz, 162.2 range, to balance fast decoding with
keeping the tones out of the audio part of the receiver audio. Most amateur radio repeaters
control their manufacturers offer an audio delay option. This delays the repeated speech audio
for a selected number of milliseconds, both forest is retransmitted. During this fixed delay period,
the amount of switch is adjustable during installation, then locked down. The CTCSS decoder has
enough time to recognise the right tone. This way the problem with lost syllables at the beginning
of the transmission can be overcome without having to use higher frequency tones. In early systems,
it was common to avoid the use of adjacent tones on channels where every available tone is not
in use. This is good engineering practice. For example, an ideal would be to avoid using 97.4
and 100 on the same channel. The tones are so close that some decoders may periodically
falsely trigger. The user occasionally hears a syllable or two of cold channel users on a
different CTCSS tone talking. As electronic components age or through production variations,
some reviewers and a system may be better than others at rejecting nearby tone frequencies.
Okay, I think that's enough for part two of the bofing menu system. Hopefully you didn't
all fall asleep. Okay, that's about it for this episode. Hopefully you haven't found it too boring.
If you want to contact me, I can be contacted at mrx at hpr at googlemail.com. That's mrx
at hpr the at symbol googlemail.com. So until next time, thank you and goodbye.
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