Home |
Search |
Today's Posts |
#1
![]() |
|||
|
|||
![]()
You could try tuning in a broadcast station. They are generally very close
in freq. I use a GPS based 10 mhz reference. Calibration of deviation is more difficult but setting up known deviations with a good fm signal generator and a spectrum analyzer using bessel zero or carrier null method will produce very accurate deviations without the need foe another deviation meter to compare with Russ - WA4POD Richard W. Solomon, W1KSZ wrote in message ... How do you go about calibrating the frequency accuracy of your Service Monitor ? I know I could go to a local Cal Lab and pay the price, but I like the idea of doing it myself. I do not service and commercial or Public Service radios, only HAM so the critical nature of accuracy is not that severe. One idea a friend had was to set the Monitor to receive and pick a signal off the air. He suggested the Mass. State Police as they are locked to GPS (according to him) or one of several paging systems that he said were also locked to GPS. That seems to be a good idea, especially since you are looking at freqs in the 800-900 MHz region. Of course, one needs to know the absolute frequency, just being locked to GPS is meaningless unless they really are "on freq". Curious what other folks do. Thanks, Dick, W1KSZ |
#2
![]() |
|||
|
|||
![]()
Some service monitors will accept an external frequency reference, usually
10 MHz....my IFR 1500 has a port on the back that accepts a 10 MHz signal....I use a pair of HP Z3801A GPS frequency references to drive the IFR and several other pieces of test gear on the bench. Dino KLØS/4 |
#3
![]() |
|||
|
|||
![]()
I am the one who suggested using a broadcast station in lieu of a local std.
WWV or CHU would be considered such a station. Earlier today I was looking through n IFR 1200A maunal and they recommended just such a procedure by loosly coupling the 10 mhz time base outpot intp the ant port along withan antenna so as to pick up WWV and adjust the time base for zero beat. you would need a good stable signal free of fades for best results Russ - WA4POD C.L. wrote in message ... "Richard W. Solomon, W1KSZ" wrote in message ... How do you go about calibrating the frequency accuracy of your Service Monitor ? I know I could go to a local Cal Lab and pay the price, but I like the idea of doing it myself. I do not service and commercial or Public Service radios, only HAM so the critical nature of accuracy is not that severe. One idea a friend had was to set the Monitor to receive and pick a signal off the air. He suggested the Mass. State Police as they are locked to GPS (according to him) or one of several paging systems that he said were also locked to GPS. That seems to be a good idea, especially since you are looking at freqs in the 800-900 MHz region. Of course, one needs to know the absolute frequency, just being locked to GPS is meaningless unless they really are "on freq". Curious what other folks do. Thanks, Dick, W1KSZ As one other party suggested, Broadcast Radio Stations are pretty accurate. Used to be - they were referred to most in any literature for such things as Home Built Kits from Eico and so on, as to their Signal Generators to get them close to accurate. Also, another method no one pointed out, which can be done with an antenna on the unit, is to pick up the WWV signals on 5, 10, 15 MHz (the ones most easily picked up) also there are others. 7.335 CHU Canada is one. They are all very accurate and MANY places use them as Time Base Frequencies. So give them a whirl and see what happens. Personally - I would use them far quicker than any 2 way radio signal. C.L. |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
![]() |
||||
Thread | Forum | |||
Ham-radio is a hobby not a service | Policy | |||
Why You Don't Like The ARRL | Policy | |||
Broadcast Station Field Strengths.. | Antenna | |||
Low reenlistment rate | Policy | |||
Some comments on the NCVEC petition | Policy |