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Hmm - at 14.2 MHz with the gen set to -72dBm ( as low as it'll go without an external attenuator ), I'm seeing just a hair under S9. Not bad! 7.2Mhz - just a hair under S8. Well, on that band the BPF

Hi Jack- Joerg, DB2OO contributed code to T41EEE which allows calibration of the S meter. Here is a description: ---------------------------- dBm Signal Level Calibration ----------------------------

I didn't say that right. The calibration of the s-meter sets the ZERO point (well... -73 db point) on the meter. That is the intercept of the equation for "S" units. You also have to calibrate (eg

BTW, when doing something "sensitive" like this, if your computer is close by, turn it off. Eary in the T41 development, I was really disappointed in the noise it was picking up. Then in a "duh"

Yeah and make sure you do it with the attenuator at ZERO! THEN go ahead and calibrate the RX attenuation control. Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ

*** Makes sense. That's actually what I figured :). I think such calibration would need to be per-band. - Jerry, KF6VB

No. It is an approximation based on comparing S signals on commercial rigs with the T41 reading. At the time the S-meter was coded, its accuracy was pretty far down the list of things to do, so it was

Yeah… we need a calibration procedure for this too… Looks like you have volunteered Jerry! Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ Owner - Operator Big

I was just doing this for one of my other radios, and wondered: Is the S meter display on the T41 calibrated? S9 is defined as -73dBm, or 50 microvolts @ 50 ohms. I think I'll try it out with a signal

That is on the “TO DO” list. Since this is an open/ community project… I would ask that someone with a working radio… please step up… do this as a contribution to the project if… people

I’ve never had noise from an on-board source, but that doesn’t mean it couldn’t happen. There is probably a solder bridge somewhere that is causing this… but keep it simple… to hone in on

Should be 60db of attenuation

Thanks Bill, that sounds like a plan.? I just finished hooking up my sig gen to one of the antenna with an output of -40dbm and 60dbm of attenuation, 7MHz AM, RF gain set at 0 and I could see and

Mark…. You can unplug everything except the MAIN and RF boards (and the front panel and encoders) and the radio should work by just placing a receive antenna on the RX IN on the RF board. If you

Hey Tim, Not yet.? I was tracing all the paths on the LPF control board to make sure I didn't have a problem with one of those 0179's.? I found a problem with the SWR xfmr in the tx path, so I fixed

Put it into receive calibration mode and check a few things: 1) Do you see clock signals at the expected frequency on the clock lines? 2) Do you see the receive calibration tone at the RF in SMA

V12 board set 50.2 FW Jumper J4 in place I select RX calibration and never see the signal on display, tried lowering attenuation no help Press the menu button to show signal from oscillator and it

Mark did that help I am trying to calibrate and all I see on spectrum scope is noise Changing frequency does not change spectrum or water fall. Tim

Also for the 5" version... Regards Phil VK2KKZ

Hang tight… I still have kit parts coming in from overseas… and I want to send a couple of these out to folks I know will pound on them to see if there are any holes to fill. Dr. William J.