Can anyone help me to understand this 12.5Khz spacing prob

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Can anyone help me to understand this 12.5Khz spacing prob

Postby i like old stuff » Sat Apr 14, 2018 7:32 am

Ive been hours and hours trying to work this out/find a solution and finally I have but there is no clear reason for the problem and Id really like to understand what is/was gong on.

The problem,
I wanted to set up a simple search to see if I was doing if properly. I decided to search something that I could easily check so decided to search PMR 446.
Of course, I began by setting the limits at 446.00625 and 446.09375 with a step of 12.5. This proved to be a problem and the scanners , BCT15 X and UBC125XLT would not find any of the 8 pmr channels.
Holding and scrolling through to see where it is searching it is apparent that they are not even looking at the correct channels

I next tried it on auto step, same results, they wont look on the right channels.......

Finally I changed the spacing to 6.25 just out of interest and bingo, that did it but they now are searching the right channels as well as the ones in between at the 6.25 spacing.

What the hell is gong on here? Try it yourself on your uniden to see the problem for yourself if this sounds impossible...

Thanks
ILOS
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Re: Can anyone help me to understand this 12.5Khz spacing pr

Postby m0lsx » Sat Apr 14, 2018 8:47 am

It is not about the steps, but where those steps fall within the radios band.
Imagine you are on a motorway with exits every two miles. You set your GPS to check at one mile onto the motorway & then every two miles from then on. So every two miles you will be checking for an exit, but it will not be there, as the initial check was wrong.
Or you can set your GPS to check at one mile & then every mile from then on. Some will be spot on, others will be wrong. But you will find them.
It is the same with radio frequencies. Your Scanner has 12.5 khz steps, BUT each band has it's own start point for those steps, so you need to take that into account, not just the spacing between the channels.
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Re: Can anyone help me to understand this 12.5Khz spacing pr

Postby Minus1 » Sat Apr 14, 2018 10:47 pm

Unidens are not capable of accepting offset frequencies.
(We might hope that the US are not obsessed with this irrational offset nonsense like Britain and the EU is.)
If you search at 12.5 kHz, they will only search channels that are multiples of that.
PMR channels are 12.5 kHz apart but are offset by 6.25 kHz. The only way you can search them is to use the 6.25 kHz step.

You can of course define the 8 (actually now 16) channels rather than tie up a search band for such a small range.
I reserve the right to ignore people who have made no attempt to the read the manual, and expect others to do it for them.
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Re: Can anyone help me to understand this 12.5Khz spacing pr

Postby i like old stuff » Sun Apr 15, 2018 4:20 pm

Many thanks to you both. I really appreciate your input there and have learned from you.

I actually already have input them all a while back in a bank I call UNLICENSED. This has stuff like muppet and PMR

I was just using the original PMR analogue 8 to see if I was doing it right as I happen to have a couple of these which means I can test my search.

Im set to buy a AOR DV 10 as soon as they are available and learning fast from good folks like you.

Cheers..

ILOS.

PS, Ill very soon have an absolute mint condition month old BCT15X and a UBC 125X for sale as i wont be needing then once ive got the AOR.
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Re: Can anyone help me to understand this 12.5Khz spacing pr

Postby Minus1 » Sun Apr 15, 2018 11:17 pm

i like old stuff wrote:PS, Ill very soon have an absolute mint condition month old BCT15X and a UBC 125X for sale as i wont be needing then once ive got the AOR.


Apart from the fact that the AOR DV10 has a pityful 2000 channels, whilst the BCT15X (which is 9 years old) has 9000…
Memory is SO expensive these days - not :rolleyes:

To put that into some perspective, the VHF airband now has 2,280 x 8.33 kHz channels.
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Re: Can anyone help me to understand this 12.5Khz spacing pr

Postby m0lsx » Mon Apr 16, 2018 8:16 am

The AOR DV-10 looks to be a reasonable handheld radio for the Amateur bands, but I am not sure it offers anything extra on the commercial bands than what is already available & for half the price.
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Re: Can anyone help me to understand this 12.5Khz spacing pr

Postby i like old stuff » Tue Apr 17, 2018 6:42 am

I was thinking I will need digital functionality very soon is all so intended getting that one as it handles a lot of the different digital standardss. Aside from the cost of it, is there a better mobile choice?
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Re: Can anyone help me to understand this 12.5Khz spacing pr

Postby Metradio » Tue Apr 17, 2018 10:46 am

The AOR AR-DV1 and DV10 will not allow you to filter DMR by Talkgroups or User ID, so you can only select Colour Code and Slot..
The Uniden and Whistlers allow DMR Colour Code, Slot, Talkgroup and ID filtering..

Mike
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Re: Can anyone help me to understand this 12.5Khz spacing pr

Postby i like old stuff » Thu Apr 19, 2018 8:37 pm

Metradio wrote:The AOR AR-DV1 and DV10 will not allow you to filter DMR by Talkgroups or User ID, so you can only select Colour Code and Slot..
The Uniden and Whistlers allow DMR Colour Code, Slot, Talkgroup and ID filtering..

Mike


Thanks Mike, Noted. Ill leave such a purchase then until I really understand what i'm doing.
Much obliged.
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Re: Can anyone help me to understand this 12.5Khz spacing pr

Postby m0lsx » Thu Apr 19, 2018 10:17 pm

i like old stuff wrote: Thanks Mike, Noted. Ill leave such a purchase then until I really understand what i'm doing.
Much obliged.
ILOS


It is possible to have a play with Digital for only a few pounds of outlay. However it is not plug & play.
Buy a cheap TV dongle, plug it into your PC, laptop, tablet or mobile phone & use some freeware to decode the digital signals. There are plenty of options & information available.
Buy a database from Kimmy JS19 via http://ukscanningdirectory.co.uk/
Or do Google search of this forum via http://www.google.com/cse/home?cx=partner-pub-6291336405621919:2662881632
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