Yaesu: VX-7R and 12.5 KHz channel spacing
- Thread starter human8472
- Start date
- Status
nd5y
Member
That's not a 12.5 kHz channel if it has 4 decimal places and ends in 2.
From the manual, the radio can only be set to the following step sizes:
A frequency on the 12.5 kHz step would be in the form of 145.5000, 145.5125, 145.5250, 145.5375, 145.5500, etc.
A frequency on the 12.5 kHz step would be in the form of 145.5000, 145.5125, 145.5250, 145.5375, 145.5500, etc.
MTS2000des
5B2_BEE00 Czar
Not gonna happen. Very few ham toy radios can synthesize these steps, let alone operate at the correct RX/TX bandwidth.
I was under the impression that the VX-7R was a quality HAM radio and not a toy. My APX-6000 seems to be able to tune this frequency.
Nope. Closest you can get would be 138.450 or 138.455.
nd5y
Member
You don't understand.
For your example 138.4525
1 = 100 MHz digit
3 = 10 MHz digit
8 = 1 MHz digit
4 = 100 KHz digit
5 = 10 kHz digit
2 = 1 kHz digit
5 = 0.5 kHz (500 Hz) digit
The frequency has to be multiples of one the tuning steps the radio is capable of otherwise it will round off to the nearest value or give an error.
If you are only receiving an analog FM signal you can usually be up to about 5 kHz off frequency and not have a problem.
If you are transmitting then it could be a problem depending on the allowed frequency tolerance and other rules of the radio service you are licensed for.
N4KVE
Member
Of course the APX6000 can do that freq. It’s a professional radio that costs thousands of dollars. The Yaesu is a toy compared to it. OTOH, a Baofeng is a toy compared to the Yaesu.
Is this ability called channel spacing? If I wanted to look at the specs of a radio to see if it could tune to this detail of frequency what would the feature be called? For example, my APX-6000 can tune 138.4525, while the Yaesu cannot. What feature is different between the two radios? Thanks for your patience with me.
Last edited:
You would need a radio that can tune in 2.5 or 7.5 kHz steps.
This is what is confusing me. The specs for the APX-6000 list the channel spacing as 12.5 kHz being the lowest, yet I can tune 138.4525.
nd5y
Member
I screwed that up. The 4th decimal place should be
5 = 0.1 kHz (100 Hz) digit
Sometimes the term "channel spacing" is used instead of "bandwidth".
N4KVE
Member
I always referred to it as “frequency steps”. Don’t know if that’s the correct term, but people knew what I was talking about.
MTS2000des
5B2_BEE00 Czar
The narrowband channels are known as splinters. Ham radios aren't design to tune the steps, you're also confusing bandwidth with synthesizer steps. The ham toys aren't capable of tuning these 2.5 or 7.5KHz steps and ham radio isn't required to operate at these bandwidths.
So is that what the feature called … “synthesizer steps”?
Usually tuning steps.
- Status
