Desk study of opportunity to improve linearity. At Chinese AD8307 power measurement module #2 I showed measurement of the linearity of an AD8307 based RF power meter. The specification linearity is +/-1dB, which is poorer than one might like in a power measuring instrument. The diagram above from the AD8307 datasheet shows the internal architecture, including … Continue reading Chinese AD8307 power measurement module #4
At Chinese AD8307 power measurement module #2 I concluded that the modified AD8307 was useful on HF, and through to 54MHz depending on accuracy requirements. This article looks at combining the AD8307 module with a display option based on an Arduino Nano. Above is a demonstration of the display prototype. The module in the foreground … Continue reading Chinese AD8307 power measurement module #3
At Chinese AD8307 power measurement module #1 I documented the first phase of checkout of a low cost AD8307 module. There are two requirements for accurate power measurement: input impedance of the power meter must be very close to 50+j0Ω (say input VSWR<1.2); and then gain from the SMA terminals to the AD8307 input terminals … Continue reading Chinese AD8307 power measurement module #2
I purchased a ‘ready to use’ AD8307 RF power measurement module on eBay for a project to develop a HF common mode current meter sensor for use with the RFPM1 (Duffy 2014). Price was A$22 incl post. Above, the AD8307 module on a small PCB with shield enclosure. Note the prominent labeling DC-500MHz, but the … Continue reading Chinese AD8307 power measurement module #1
The VK-AMPS 2kW directional coupler is available at modest cost. The coupler was purchased as an assembled module as pictured above. It is a Sontheimer coupler and uses AD8307 logarithmic detectors in the FWD and REF channels. Last update: 14th June, 2022, 5:56 PM
RF Power Meter 2 is a logging RF power meter based on AD8307 and ESP8266. This article describes its calibration and use with a 40dB 50Ω 20W attenuator to make a 20W or 43dBm RF power meter. Above is a pic of the system under test on a nominal 5W transmitter, indicating 37.4dBm, equivalent to … Continue reading RF Power Meter 2 (RFPM2) – 40dB external attenuator calibration and integration
RF Power Meter 2 is a logging RF power meter based on AD8307 and ESP8266. The original LCD display was white on blue, but was very difficult to read at some viewing angles, so it had to go. Unfortunately I could not find more displays with that hole pattern, it seems to have been discarded … Continue reading RF Power Meter 2 (RFPM2) – display update
RF Power Meter 2 is a logging RF power meter based on AD8307 and ESP8266. The project was used as the basis for a new project, and during that development work some improvements were made and ported back to RFPM2. Last update: 25th April, 2021, 7:45 AM
This article documents a review of the magnetics of the ‘voltage’ transformer in the VK3AMP Sontheimer directional coupler. It is typically the most important component in determining InsertionVSWR and ReturnLoss at the lowest frequencies. The transformer of interest is the one to the left, and if you follow the tracks, the multiturn winding is connected … Continue reading A magnetics review of the VK3AMP Sontheimer directional coupler
This article documents measurement and analysis of a VK3AMP Sontheimer directional coupler in an implementation of a 400W wattmeter design by N2PK (Kiciack nd). I purchased one of the couplers for use with a DIY digital display, and although I have had it longer, it isn’t yet realised! A common failing of almost all hammy … Continue reading Basic measurements of the VK3AMP Sontheimer directional coupler for a N2PK wattmeter