This page is about software version 1.02 Download here
Software date: 15. Jan 2002.
Use a PIC16F876 programmer to copy the unpacked HEX file into the PIC.
If no attenuator is used, the dBm readout goes from -63 (noicefloor) to +30 dBm (1W)
The status readout show the selected frequency band, and attenuator mode
Use the band dail to change between LF, HF, VHF, UHF and SHF calibration memories
I have calibrated my wattmeter 0 dBm at: LF=3.5MHz, HF=14MHz, VHF=145MHz, UHF=430MHz, SHF=440MHz
But you can calibrate at your own favorite frequencies for best performance.
In the RF-powermeter screen, use the SELECT button the enter RELATIVE mode.
In this mode dBm and bar-graf is shown, when entering this mode the dB read out is zero'ed.
To enter the menu / settings use the MENU button
when in menu, use the band dail to get the desired setting,
at the right setting use SELECT to activate, this is also shown in the display.
Here is all the menu points:
0: 0dB, no attenuator is mounted 1W max. !
1: -10dB attenuator is mounted, 10W max. !
2: -20dB attenuator is mounted, 100W max. !
3: -30dB attenuator is mounted, 1kW max. !
4: -40dB attenuator is mounted, 10kW max. !
5: -50dB attenuator is mounted, 100kW max. !
6: DC Voltmeter, actual and min. and max.
7: RF Powermeter, the default startup screen.
8: SSB PEP Wattmeter, with peak hold and variable decay
9: Return loss with SWR readout, usable with a SWR bridge
10: Calibrate 0 dBm at the selected band
11: Read all calibration values
12: Zero all calibration memories
13: Display update delay 2-80mS, and Peak hold and decay speed
14: About Info, shows software version and so on.
The DC voltmeter can measure from 0 to 20 volt only positive, with a resolution of 20mV.
Nothing is burned if input is reversed, it just can not measure !
Calibration is done in hardware: use one or two 10meg resistors to parallel R28 or R18 until correct voltage is shown.
In the DC voltmeter screen, actual voltage, minimum and maximum is displayed. To reset min and max press select button
The voltmeter can be used to monitor the battery voltage if a battery supply is used, or what ever you want to measure,
but remember the input impedance is about 80 kOhm.
New in this version:
SSB PEP wattmeter, the peak hold and decay time is controlled by the display update delay
Change to lower update delay for shorter hold time and faster decay.
The attenuator settings is now stored in the EEPROM,
the digital wattmeter will now remember all attenuator settings, also after power off.