Q1) Why SF401 frequency counter always show frequency less than it's actual?  (      For example: installs on 433.000Mhz radio, counter shows 432.999Mhz)
A1) Please go to [System] and set [Freq Offset] to adjust the deviation
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Q2) It can check UHF, but cannot check HF
A2) Please try the followings
       * put the ATT button into left hand side 
       * Make sure that the antenna is HF, as the antenna that we provide us dual band  (VHF/UHF) only
       * please try to slant your radio to the frequency counter to make sure that the signal level in green area
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Q3) LCD display already show frequency or always receive signal before measuring will affect the device operation
A3) Please go to Menu "RF Detect Level" and set 5 or above to solve the problem
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Q4) How far effectively can i detect a signal ? Close range as in 1-5 feet or can it work further like 5-15 feet ?
A4) Radio cannot leave the frequency counter too far, make sure that the signal level in green area when you measuring.
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Q5) What is the small number after the CTCSS/CDCSS mean ? (see photo)









A5) These number is for our technical use only

Q6) Will the SF-401plus pick up Color Codes and Time Slots for DMR ham radio?
A6) SF-401plus cannot pick up color colde and time slots for DMR radio

Q7) What is the minimum digital pulse time required to register with the device?
A7) ​digital mode for DMR radio only, not for other digital device

Q8) How to close the attenuator?
A8) switch the antenuator button to left hand side 

Q9) How to close " * " before Digital [SF-103]
A9) Press [F2 Stop] and then press [F4 Ent] to close the *, device will back to normal

Q10) What is the function of " * "
A10) it is a lock function, which mean you can't adjust the gate digital

Q11) Hi there how to I calibrate my SF-103 frequency counter it's off
A11) *Power On/Off:     
Power on ,press and Hold down the [Red key] by 3 second
Power off ,press and Hold down the [Red key] by 3 second of number count down to 0
https://www.youtube.com/watch?v=3ODZKwtI98U

Q12) How can i increase the signal detection range of my SF-401plus?
A12) SF-401 design for check strong signal from walkie-talkie. switch to 0 dB  is increase the signal. 

Q13) What is the distance of receive for this SF-103?
A13) About 1-3M 

Q14) Does SF-401plus measure the CB band / I know it states not accurate but what does that mean? I am looking for a wireless frequency counter that is wireless
A14) Sorry , We have no idea for choose other brand , frequency counter  for 27MHz and AM mode cb radio.

Q15) SF-103 works on analog and dmr digital?
A15) SF-103 works on analouge and dmr digital. But the DMR mode only for frequency , e.g. 430.025 . without colour code and group detail

Q16) Could SF-401plus be used to point a directional cellular antenna
A16) it can't 

Q17) Can SF-401plus /SF-103 test key fob car remote / RF welding machine?
A17) It can't , as our frequency counter is design for walkie talkie use only

Q18) Hello, this Counter worked then would "not count" when it was powered up again?
How do I Factory Reset this Counter?  It just stays up in the 2GHz range.
A18) power on and hold on

Q19) How do you use the CTCCSS/DCS Decoder to deactivate a chip?
A19) SF-401plus is design for walkie talkie use only