Need help with Base/Offset/Step for WIN96

[jimvv]

Hi,
I am trying to determine the Base, Offset and Step size for the following trunked system...

--------
MAP=22222222
OPTIONS=nVdF
PLAN=0
DESCR=Type II 76.76 Hz
THRESHOLD=50
DISPOSITION=abcbdbebfulznbpbsn
v0x007 ,7,ffff,5d
v0x01c ,1c,ffff,3
v0x025 ,25,ffff,23
v0x029 ,29,ffff,3
v0x02a ,2a,ffff,2
v0x02e ,2e,ffff,3
v0x037 ,37,ffff,9
dv138.0900,183,ffff,7
d 138.2600,191,ffff,0
v138.3850,19b,ffff,1a
dv138.4600,1a1,ffff,832
v0x1a5 ,1a5,ffff,5eb
d 138.5500,1a8,ffff,0
v138.6750,1b2,ffff,30
v0x1b3 ,1b3,ffff,42a
v138.7750,1ba,ffff,457
---------------
I have caculated the Base frequency to be 138.000 and the offset to be 12.5 , but Win96 keeps changing my step offset 12. Any ideas?

 

[NINN27]

well heres your problem... your putting the step size in the offset block. try putting it in the step size block.

 

[DonS]

I have caculated the Base frequency to be 138.000 and the offset to be 12.5 , but Win96 keeps changing my step offset 12. Any ideas?

As the previous response mentioned, try putting the step size of 12.5 kHz in Win96's "Step Size kHz" field.

Win96 calls the three fields:

• Base Frequency: the "base" frequency to which channel-dependent offset products are added
• Offset: The value subtracted from the actual channel number to get one of the multiplicands for calculating the voice frequency
• Step Size: The frequency "step" between adjacent channel numbers (the other multiplicand in the above-referenced calculation)

The formula, using Win96's terminology, is:
VoiceFrequency = BaseFrequency + (Channel - Offset) x StepSize

The RR database lists the above as Base, Spacing, and Offset, respectively. I guess I can see why my "Step Size" might be called an "Offset", as it could be considered an inter-channel frequency offset. However, I don't understand why my "Offset" would be called "Spacing". Perhaps this usage is based on some legacy hardware, software, or manufacturer's convention?

 

[jimvv]

Thanx for the answers guys.... Now, how do I figure out the offset with the mentioned system?

 

[DonS]

Thanx for the answers guys.... Now, how do I figure out the offset with the mentioned system?

Well, just looking at the last entry:
> v138.7750,1ba,ffff,457

I'd guess the offset is 380:
138.7750 MHz = 138.0000 MHz + (0x1BA - OFF) x 12.5 kHz
OFF = 380

-Don

 

[jimvv]

Hey ya Don, if you are on Yahoo Messanger, mind giving me an IM... I am totally baffled on figuring this out.

 

[loumaag]

Jim in case you haven't gotten the rest of the voice frequencies you have listed, here is the list translated:

Hex value for Voice #1 183 Calculated freq 138.0875
Hex value for Voice #2 191 Calculated freq 138.2625
Hex value for Voice #3 19b Calculated freq 138.3875
Hex value for Voice #4 1a1 Calculated freq 138.4625
Hex value for Voice #5 1a5 Calculated freq 138.5125
Hex value for Voice #6 1a8 Calculated freq 138.5500
Hex value for Voice #7 1b2 Calculated freq 138.6750
Hex value for Voice #8 1b3 Calculated freq 138.6875
Hex value for Voice #9 1ba Calculated freq 138.7750

You willnote that some of the frequencies in the list are 250 hertz off of what you have, this is due to the rounding your scanner does. This does not affect the way you hear the traffic on the channel. The above was gotten using Brian Cathcart's fine Excel spread sheet for calculating Base, offset and step.

Don, the terminology used here is due to the crazy way Uniden started calling things way back and since there are so many Uniden out there using the wrong terminology it was left up to RS users to properly interpret the correct terminology. :lol:

Correct Terminology:
Base is the base frequency for either the output or input (they are different)
Offset is the channel number which the base frequency starts at. (Typically 380 or 0x17c for the output channels.)
Step is obviously the step size between adjacent channels in KHz.