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RADIG ~ Ham Radio's new Tsunami Wave Issue 10

Some New Data ~ Data Points


Here is some setup and reference data for the RADIG. Today I looked at both the design of the J310 Amp stage and the drive levels from the Si570 on all bands. 

Starting first with the drive levels. I put a scope on the output from the pot as it connects to the LO Port on the  ADE-1 and the results are a bit surprising. Keep in mind that the actual frequency being generated is 4X the operating frequency. So at 10 Meters the RF from the Si570 is around 120 MHz. 


  • 160M ~ 544 MV PTP
  • 80M ~ 544 MV PTP
  • 60M ~ 544 MV PTP
  • 40M ~ 544 MV PTP
  • 30M ~ 544 MV PTP
  • 20M ~ 544 MV PTP
  • 17M ~ 512 MV PTP
  • 15M ~ 472 MV PTP
  • 12M ~ 377 MV PTP
  • 10M ~ 320 MV PTP
The outputs below 15 Meters were nice square waves and the surprise was that the lack of sensitivity would most likely only occur on 12 and 10 Meters. Thus my observation of lack of sensitivity previously on 20 Meters was more likely driven by the J310 Amp stage and not the LO drive level.

 [This is where the EMRFD illuminati  are supposed to jump in a decry the results. Actually you must look a little more closely at the 12 and 10 Meter numbers as there may be other factors that are skewing the data. There are variants of the 74AC74 that are good to 300 MHz; but this old plain garden variety is only good to 95 MHz which of course is a bit below the 4X for 12 and 10 Meters. So I think what I am saying is that the Si570 is not the bad apple in the barrel. But the lesser drive (resulting from the 74AC74) would impact 12 and 10 Meter sensitivity.]

Back to the J310 stage. Sure enough when I went back and looked at the simulation-- there was about 3 to 4 dB less gain at 14 MHz than 7 MHz. I will now look at a redesign of the J310 amp stage. It may involve just three components. Once I get it potted I will share it on the blog. 

More contacts with the RADIG including a 40M coast to coast with the RADIG and 600 watt amp last night. I got a very nice report. [ At 1630 left coast time today I worked the same east coast station -- that is early for the path. But once again a great signal report. The RADIG Rocks!]

73's
Pete N6QW



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