hpr-knowledge-base/hpr_transcripts/hpr2296.txt

Episode: 2296
Title: HPR2296: Baofeng UV5R VHF/UHF Handset part 2
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr2296/hpr2296.mp3
Transcribed: 2025-10-19 00:58:39

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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. I've gone to a great deal of effort to streamline the whole process and it's actually 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.
This is part two of my podcast covering the bullthing UV5R feature, a few HF handheld transceiver.
Today I'm going to cover the general specification of the radio.
Remember, if you find this boring, this is all the blame of Cain Fallon. You know who to blame.
Sit back and enjoy.
Let's cover the general specification of the radio.
First of all, it's got a standard broadcast radio receiver and it's looking listen to standard FM radio stations.
That's within 65 MHz and 108 MHz general frequency band.
That's international isn't it? It's with normal radio broadcasts happen.
If you're out and about and you get a bit bored, you can just listen to the radio. That's quite handy.
It's also covers the VHF band.
It won't allow you to transmit on the 65 to 108 MHz section of the band for obvious reasons.
What's the main primary uses for VHF and VHF use?
The range that it covers, this particular radio covers a subset of the frequencies of the VHF band.
VHF extends from 30 MHz to 3 GHz.
This radio does on a VHF band it does 136 MHz to 170 more than 174 MHz, both receive and transmit.
It also covers a portion of the VHF section of the band and in this case it covers 400 MHz to 480 MHz and that's both receives and transmit as well.
The Amateur bands that we use in the UK is around around about 145 MHz section for 2 MHz and it's 430 MHz for the VHF part of the band for Amateur use at 70 cm.
The radio is equipped with 128 channels which you can program using software.
It claims a frequency stability of 2.5 PPM that's parts per million.
How much drifts, how much radio will drift off its frequency?
The radio tends to be channelised so you can jump and set certain steps.
You can select 2.5 KHz steps, 5 KHz steps, 6.25 KHz steps, 10 KHz steps, 12.5 and 25 KHz steps.
For Amateur use that would be typically 12.5 KHz steps, I'm sure it's 12.5 KHz steps, used to be 25 here but for 2 m but I think it's now 12.5 KHz.
The antenna impedance is 50 ohms, that's the type of impedance of the antenna.
Operating temperature can operate between minus 20 and plus 60 degrees centigrade.
Supply voltage, rechargeable lithium ion battery, 7.4 volts and 1,800 mAh.
Consumption in standby, less than or equal to 75 milliamps.
Consumption in reception, 380 milliamps.
Consumption in transmission, less than 1.4 amps.
You can see that the huge difference between receiving transmits and receiving is 1,380 milliamps is 0.38 of an amp.
So between 0.4 and 1.4, so 3 times as much.
So you've got the radio last 3 times as long in reception as transmission.
Generally when they give, they'll mention so much talk time or so much reception time or a ratio of the two and that gives you how long the radio is going to last or thing.
Modive operation, simplex or semi-duplex.
I'm going to explain that later on.
Oh yeah, here's what talks about duty cycle.
So 03, 03, 54.
So it's assumed to be a reception for three minutes on transmission for three minutes and on standby for 54 minutes.
That's how they get their operating time.
So I don't see here, but other thing is of course is if you transmit too long, the radio might get too warm.
And there's the circuit in there to stop that if you were to take the transmit button down, it wouldn't overheat.
It would protect itself, I would assume.
Weight is 130 grams, approximately.
So transmitter, it says RF power 4 watts or 1 watts, that's selectable.
Time for modulation FM, that's frequency modulation.
Modulation, another rabbit hole.
It's a way of encoding the audio signal onto the radio signal and so it can be...
You can't just set...
I mean if you were to just...
An audio signal, you couldn't just shout 15 miles, it would be hell of a loud.
You've got to be sent via radio waves.
So they've got to encode that audio onto the radio wave so it can be pulled out and decoded on the other side.
And there's a number of ways that you can do that.
So you're modifying something in sympathy with something else, that's what modulation is.
So common ways you can do via FM, frequency modulation or AM, amplitude modulation.
And frequency modulation, as you talk, the frequency of radio, ever so slightly,
waivers up and down between a certain type of signal frequency.
An AM, the amplitude of the radio wave varies very slightly in sympathy with your voice.
That's the difference between AM and FM.
Emission class.
These are just classifications for the emission.
I don't fully know all this.
I'll have waffle mean 16k.
F3E, that's a class, that's a classification for FM, I'm not sure.
But you can ignore that, or I don't understand it.
Maximum deviation.
Less than or equal to plus or minus 5 kilohertz.
I don't know if that's for the VHF and UTF part of the spectrum.
I'm guessing that's what it is.
But anyway, sparse emissions less than minus 60 dB.
So that's just saying that how many, when the transmitter's never completely pure
and there's always, I cannot explain it.
You'll get very, very slight emissions on harmonics of the frequency of transmitting on.
A multiple of that frequency, because nothing's perfect and you get some emissions.
But there will be 60 dB down below the main frequency that you're transmitting on.
So that's what that's stating.
Receiver sensitivity is 0.2 microvolt at, this is getting very complicated.
At 12 decibels.
So now I don't understand half of this.
Intermodulation 60 dBs.
Audio output 100 milliwatts.
That's how loud it is.
Adjacent channel selectivity.
65 dB, 65 and 60 dBs.
So that's how much attenuation frequencies outside the band you're listening to.
It's attenuated by, it gets reduced by, so that if you get a very, very strong signal
and it might end up kind of appearing on the channel you're listening to.
But it's not really there.
It's somewhere else.
The video just can't reject the unwanted signal.
But I mean, that's pretty reasonable.
65 dBs down.
That would be VHF and 60 for UTF.
So that's the general specification badly covered.
I hope that it all makes sense.
Okay, that's about it for part two of the both in UE5R, VHF, HF and HL transceiver.
If you want to contact me, I can be contacted at MrX at hpr at googlemail.com.
So until next time, thank you and goodbye.
Thank you.
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