For those who are not interested in electronicsreview is useless. The rest - please under the cat. Overview of the two boards. One, as I hoped, on the RF detection diodes, the second on the AD8318 chip (a logarithmic detector with an operating frequency of up to 8 GHz).
I wanted to know how often my cellIt turns on the transfer when no one touches it. The final device, I will say right away, did not start yet. I just bought two detector boards, about which I decided to write a review.
The first board is an envelope detector (RF Envelope Detector Amplitude Detection) on two diodes connected by a voltage doubler circuit. Link - in the title.
The characteristics of the seller:
Maximum input signal: 20 dBM (I do not know)
Frequency range: 0.1–3200 MHz;
Dimensions: 15 × 23 mm (indeed, but without the connector);
RC filter: R = 10 kΩ, C = 1 nF (I did not check the capacitor, but it seems to be true);
Something is written about the high sensitivity -30 ... -40 dBm.
Also explicitly written, what is used two inverse? microwave diode. And that this is not the usual diodes 2AP9, 1N60.
In general, after reading all this and seeing atpictures of the seller marking the P2A diodes my imagination told me that these are HSMS-2852 diodes - a dual high-frequency diode optimized for operation without bias. What you need for this board.
Connector - SMA MOM. The seller is not stated but from the pictures obviously.
There are no complaints about the packaging. In addition to the usual pimples, the board came soldered into a small anti-static bag. Well done Chinese, I thought - HF diodes are afraid of static. I opened the anti-static bag, took out a fee. The fee from the flux is not washed off. Totally. Well, he laundered himself. Photo after washing:
Photo details, which should be a dual diode, close-up:
Marking is what you need. I connected an antenna to the input (at 430 MHz), and a multimeter to the output in the 200 mV range. Shows zero. Hm Strange. In Moscow, the broadcast is simply clogged and in such a wide frequency band something must be detected. Okay. I go from the tablet to the Internet via LTE at 30 cm from the antenna. Zero. I turn on the transfer of a radio station at 430 MHz (5 W). Already it becomes terrible to burn the diode, so I do it at a distance of 1 meter from the antenna - zero. The board is clearly not working. I prozvanivayu diode multimeter. In fact, it is possible to burn a diode with statics, on the board, it obviously does not work anymore.
After some time thinking and searching the Internet for information about the details in the SOT-23 package with P2A marking, I came to the conclusion that this is a P0102AL thyristor.
A-K does not ring in both directions. But if you connect to output A plus of a multimeter in the dialing mode of diodes, to K - minus and then briefly connect to output G plus the thyristor opens and the multimeter shows a voltage drop of ~ 0.6 Volt. Current multimeter enough to keep the thyristor in the open state. If you turn off the multimeter, and then again connect to the terminals A and K - again it does not ring. By all indications - thyristor. Work as an RF detector can not. This is a lie.
At the input is the capacitor 0.1 microfarad. In my opinion so much is not needed.
Delivery was adventurous. In 1.5 months from the date of order, I found in the tracking information that the parcel was delivered to the post office. But not in mine! Opened the dispute - the parcel was sent to the wrong address. The next day someone received that package. The seller asked to cancel the dispute. He said that the parcel sent, but it is without a track. And this track gave just to fill the field. I was somehow not impressed. In general, the dispute won, but promised the seller to pay if the parcel arrives. When the parcel arrived (70 days after the order!) - informed the seller about it. He said he was ready to pay 50%, but leave a negative review at the same time due to the fact that the fee does not work. This bad man said fine - pay by PayPal. How do I leave a negative review?
The second board is a logarithmic detector 1-8000 MHz on the AD8318 chip. Here is link to the store. Price $ 11.08. The package did not reach quickly. 45 days. A photo:
The characteristics declared by the seller:
Operating frequencies: 1-8000 MHz
Dynamic range: -65dBm to + 5dBm (less linear from -55 to 0 dBm)
Slope of the transfer characteristic: -25 mV / dB (typical)
Output voltage range: 0.5–2.1V
Power supply: 7-15 V (contains power supply stabilizer)
Input impedance: 50 ohm
RF Connector: SMA Mom
Stabilizer Chip 78L05 Installedhas a rather large voltage drop. It outputs 5 V at an input voltage of 6.5 V and above. I powered the board from 9 V. At the entrance of the VCC there is a red LED indicating the presence of power.
The wiring diagram almost coincides with the scheme from the description on AD8318:
At the input instead of 1 nF capacitors (C1 and C2)0.1 μF established. R1 is rated 51 ohms. The TADJ pin has a 510 ohm resistor connected instead of a 499 ohm resistor. The output of the CLPF provides for the connection of a capacitor, but the space for it is empty. The VSET and VOUT pins are connected somewhere under the chip. If you need to put the microchip into controller mode, this can be a problem. C6 and C7 are most likely at 0.1 μF. Condensers measured without watering. Possible error.
To check the board used generator Rohde &Schwarz. The range of its output frequencies is from 0.1 to 3.3 GHz. Calibration he did not pass a few years, but the device itself is not old. To connect the board, I used a coaxial cable from the instrument kit (semi-rigid, about 0.5 m) and an N-type adapter - SMA. The output voltage of the board was measured with a multimeter.
The resulting numbers - under the spoiler
Signal at the input, dBm: 0 -10 -20 -30 -40 -50 -55 -55 Generator off
At the output, Volt (100 MHz): 0.617 0.844 1.103 1.353 1.601 1.840 1.952 2.171
At the output, Volt (500 MHz): 0.608 0.836 1.092 1.342 1.591 1.837 1.953 2.162
At the output, Volt (1.0 GHz): 0.601 0.816 1.072 1.321 1.568 1.817 1.938 2.161
At the output, Volt (2.0 GHz): 0.562 0.749 1.008 1.256 1.501 1.748 1.872 2.159
At the output, Volt (3.3 GHz): 0.604 0.820 1.074 1.322 1.567 1.816 1.946 2.158
As a result, we got the following schedule:
For some reason, at a frequency of 2 GHz, the line has passed below. As if the input signal was 3 dB more than what I set on the generator. Why?
I measured the dependence of the output voltage on the input frequency at a constant input level of -20 dBm.
Numbers - under the spoiler
Frequency dependence, of course, is far from ideal. What kind of trouble happened at a frequency of 2.3 GHz? SWR, unfortunately nothing to measure. However, for my purposes it will come down well. But to use this handkerchief to measure the level of the RF signal is not very good.