Batboard

I have a XTS3000 V2 that I use for Ham Radio..

The Issue is it appears to be a little off frequency when used with a MMDVM Ham Radio Module

My Chosen Frequency if 432.200000 but It Appears to be Transmitting on 432.199200

I did buy some software to Program the Radio which came with the Alignment Software I think but Obviously I don't own a Frequency Counter or Oscilloscope.

Can anyone advise a on the fly way to maybe make the smallest adjustment to bring this closer to the Target Frequency ?

Thanks

Rob..

memorex wrote:I have a XTS3000 V2 that I use for Ham Radio..

The Issue is it appears to be a little off frequency when used with a MMDVM Ham Radio Module

My Chosen Frequency if 432.200000 but It Appears to be Transmitting on 432.199200

I did buy some software to Program the Radio which came with the Alignment Software I think but Obviously I don't own a Frequency Counter or Oscilloscope.

Can anyone advise a on the fly way to maybe make the smallest adjustment to bring this closer to the Target Frequency ?

Thanks, Rob..

With out some sort of calibrated device to measure your actual frequency, you out of luck. Bottom line here is a frequency counter you know is calibrated or use a service monitor.

memorex wrote:I have a XTS3000 V2 that I use for Ham Radio..

The Issue is it appears to be a little off frequency when used with a MMDVM Ham Radio Module

My Chosen Frequency if 432.200000 but It Appears to be Transmitting on 432.199200

I did buy some software to Program the Radio which came with the Alignment Software I think but Obviously I don't own a Frequency Counter or Oscilloscope.

Can anyone advise a on the fly way to maybe make the smallest adjustment to bring this closer to the Target Frequency ?

Thanks

Rob..

If you do not own a freq counter or service monitor how do you know it is transmitting on "432.1992" ?
Incidently that is only about 80Hz away from right on frequency and it usually does not get much better.
You would have to use the tuner application along with a counter or service monitor to tweek it back to
right on frequency.

Specs on UHF radios is 1ppm so at 432 MHz the spec would be +-432Hz

fineshot1 wrote: Incidently that is only about 80Hz away from right on frequency and it usually does not get much better..

Your decimal point is off, it's 800Hz.

I am pretty sure that someone in your local ham club will own or have access to a service monitor. Ask around. Find an Elmer.

jackhackett wrote:

fineshot1 wrote: Incidently that is only about 80Hz away from right on frequency and it usually does not get much better..

Your decimal point is off, it's 800Hz.

And even at 800hz, Memo's radio should still be working. He needs to explain the problem he's having that he thinks is related to being slightly off freq.

jackhackett wrote:

fineshot1 wrote: Incidently that is only about 80Hz away from right on frequency and it usually does not get much better..

Your decimal point is off, it's 800Hz.

oops - yes ya got me but even at 800Hz that's
not too bad!

If the receiver is off-freq by over 600 Hz, the Rx sensitivity / error correctibility for ASTRO25 codewords begins to fall off quickly.

Karl NVW wrote:If the receiver is off-freq by over 600 Hz, the Rx sensitivity / error correctibility for ASTRO25 codewords begins to fall off quickly.

Yes, 800Hz might not be that noticeable on analog, but on digital things start to get flaky. For example I remember when the old Motorola VRMs would start to get bad connectivity, checking the frequency would always show them off around 1kHz and a quick freq adjustment would get them working again.

The spec on the UHF XTS3000 is 2ppm, so 800Hz is right on the edge. With a good freq meter you should be able to get them within a couple of hertz.

Bill_G wrote:

jackhackett wrote:

fineshot1 wrote: Incidently that is only about 80Hz away from right on frequency and it usually does not get much better..

Your decimal point is off, it's 800Hz.

And even at 800hz, Memo's radio should still be working. He needs to explain the problem he's having that he thinks is related to being slightly off freq.

disagree, on narrow modulations frequency accuracy is substantially more important than wideband, especially when data is involved

escomm wrote: disagree, on narrow modulations frequency accuracy is substantially more important than wideband, especially when data is involved

But only at the margins of performance.

I would suspect the issue is with your MMDVM. They have known issues with frequency tolerance and, as far as I'm aware, cannot be adjusted. I'm familiar with it being more of an issue with DMR than P25, but neither one would surprise me.

When tuning the reference oscillator in an XTS3000 the recommended spec is +/-250 Hz. In practice you can usually get it it +/-100 Hz but not much better due to temperature fluctuations.

Got the Radios Aligned..

I got 2 and they were both around 1200hz off..

motorola_otaku wrote:When tuning the reference oscillator in an XTS3000 the recommended spec is +/-250 Hz. In practice you can usually get it it +/-100 Hz but not much better due to temperature fluctuations.

Yes - I usually get it down to +/-60 Hz by waiting until the radio is at its optimum operating temperature,
just have to wait until after the radio has been on for about an hour to be sure.