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Author Topic: Repeater Shift Excel Formula  (Read 4075 times)
KF7ELU
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Posts: 23




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« on: March 13, 2011, 09:12:07 PM »

I am having a tough time with this one...... Trying to setup an excel spreadsheet that will automatically show a repeaters offset when you enter its frequency. WHAT is the formula i would use??
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W8JX
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Posts: 5904




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« Reply #1 on: March 13, 2011, 09:37:27 PM »

Depends on function here. Meaning if it simply dealing with one offset or if it is complex and must deal with several scenarios. In the later you will have to develop a long formula with "IF" statements to test input for correct output formula. It is not as hard as it sounds but you need to figure out EXACTLY you want it to do first. 
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KF7ELU
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Posts: 23




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« Reply #2 on: March 13, 2011, 09:52:24 PM »

Well I need is to output offsets for both 2m and 70cm.....
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W8JX
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Posts: 5904




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« Reply #3 on: March 14, 2011, 06:36:05 AM »

You will have to make a conditional IF statement to "test" or check for frequency and then point to macro that returns offset. Remember though that 2 meter will require a additional test (or a additional primary IF clause) because plus and minus offset are used in that band. 
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WB2EOD
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Posts: 219




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« Reply #4 on: March 14, 2011, 07:27:32 AM »

It has been a while since I have done any serious repeater work.
Others, please correct me if I am wrong. 
To the best of my knowledge:

For 2 meters
The offset is 600 KHz
At 145 and 146 MHz the transmit frequency is 600 KHz below the receive. 
For example, you listen on 146.865 and transmit on 146.265)
At 147 it is 600 KHz above. 
You listen on 147.180, and transmit on 147.780
On 145 the spacing between repeater channels is 20 KHz,  on 146 and 147 it is 15 KHz

For 70cm (440)
The reapeater sub-band is 440 to 449.975 (440 to 450)
The offset if 5 MHz, the direction (+ or -) is the one that keeps you in the band.
For example, you listen on 442.500 and transmit on 447.500.
The channel spacing on 440 is 25 KHz

You will probably want to build in some logic to keep the results in the repeater sub-band

Hope this helps
73
WB2EOD
 
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W8JX
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« Reply #5 on: March 14, 2011, 07:44:52 AM »

At 147.00 it can be a positive or negative offset and is a wild card.
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KF7ELU
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Posts: 23




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« Reply #6 on: March 14, 2011, 10:30:38 AM »

See thats the part i cant remember how to do... Its been many years since I wrote excel formulas, could someone give me good start?
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W8JX
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« Reply #7 on: March 14, 2011, 05:04:48 PM »

I will have to jog my memory to and look through some SS formulas I have written.
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N3OX
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« Reply #8 on: March 15, 2011, 06:40:50 AM »

Don't forget that on two meters there's another weird little band of 1MHz split repeaters:

http://www.eham.net/articles/9947
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73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
K4FV
Member

Posts: 2




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« Reply #9 on: March 22, 2011, 10:55:56 AM »

Assume that the repeater output frequency in MHz has been entered into cell A1. Placing the formula =IF(A1<148,IF(A1<147,B4-0.6,B4+0.6),A1+5) in any other cell will yield the repeater input frequency for either 2 meters or 70cm.

Note: This will produce a +600 KHz offset for a repeater on 147.00.  If the desired offset for 147.00 is -600 KHz replace the A1<147 with A1<=147.

--- Neil
« Last Edit: March 22, 2011, 06:31:49 PM by K4FV » Logged
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