Motive

Some Chinese wireless products sell 433/315 MHz. Enoki wants to know the frequency is either, and bought a Chinese 1 ~ 1200 MHz counter.

Summary

Enoki tried it for 433 MHz transmitter. The counter has been junk. But, it seems that Enoki has to test it feeding more air power, because the transmitter range is 15m only.

経緯目的

中国製ワイヤレス製品は 433/315 MHz と称し，どちらの周波数なのか不明である。発信周波数を知りたい。

要約

200 MHz 以上の感度は極めて低いと思われる。433MHz の測定はできなかった。広告画像表示の 450.000 MHz にだまされた 感じ。供試トランスミッタのレンジは短いので，大電力で確かめてみる必要はある。 AliExpress 取扱品だと 測れるかもしれない。

Enoki bought it at amazon.co.jp. The specification is as follows at amazon.com in English,

Use 8 bit Microchip PIC16F648A, up to 1.1GHz

Gate time: 0.64 seconds

Test sensitivity
1 MHz ~ 10 MHz: superior 60mVpp
10 MHz ~ 60 MHz: superior 60mVpp
60 MHz ~ 1.1 GHz: not tested

Frequency reference
5032 package 13.000 MHz Warming voltage controlled crystal oscillator ( VC - TCXO) , frequency stability is ¡À 2.5 ppm

IF settings
The minimum frequency is adjustable in steps of 100 Hz, frequency range 0 ~ 999.9999 MHz, can be set to plus or minus IF mode

Working voltage
DC input: DC 9V ~ 12V

Working current
The backlight is enabled: ¡Ü 55 mA backlight disabling: ¡Ü 55 mA

Display
maximum of 8 digit display

Physical dimensions
Length * width * height: 58mm ¡Á 32mm ¡Á 27mm

Board interface
RF INPUT ( measuring signal input ): XH2.54-2P side outlet port
ICSP INPUT (MCU programming interface ): XH2.54-6P pins
POWER INPUT ( Power Interface ): XH2.54-2P side outlet port

Package included:
1 x Frequency Counter Tester Measurement For Ham Radio(If the number of products received is incorrect, please contact us . we will refund or give you a replacement)

At first, I elongated the power line 24cm. Power supply DM-310MV supplies 9V.

The counter picks up noise, as shown in Photo1. The counter shows 0.000 MHz, when input shorten, as shown in Photo2.

I have 433 MHz transmitter and receiver. I tried to measure the 433 MHz, but failed. So I attached some resistor (1, 3.3, 10k) as shown in Photo2. The frequencies are 107, 99, 134 MHz. They are always varying.

It seems that the counter cannot detect 433 MHz at all.

I have a DSO which generates precise 1kHz at 5V. Although the counter range is 1MHz minimum, I made a attenuator with 4.7k and 100 Ω resistors. Naturally the counter showed a meaningless value, as shown in Photo3.

I soldered 3.3 kΩ with the ends of detecting lead wires. The status has not changed.

The counter can select the minimum digit scale 1 or 0.1 kHz. I have set up IF (offset) frequency 4.3 MHz.

I missed the specifications untested sensitivity more than 60 MHz. The counter may not be sensitive for high frequency.

But AliExpress shows the sensitivity:
Channel sensitivity: (HM8134-2 data)
Test frequency (MHz): 5 10 30 60 100 150 200 300 450
Sensitivity (mV RMS): 35 20 10 3 3 4 8 15 12

Test frequency (MHz): 500 550 600 700 800 900 1000 1100 1200
Sensitivity (mV RMS): 14 30 65 80 80 35 175 270 310

It has a sensitivity 12mV RMS for 450 MHz. Does the new version improve RF amplifier? Amazon.com sells portable RF counter, but Amazon says, "Currently, there are no sellers that can deliver this item to your location"

Enoki has Tektronix 60 MHz DSO. I have no chance to measure 6 digits of 60 MHz frequency. Simply Enoki would like to detect 433 MHz frequency.

An Amazon.co.jp seller shows "450.000 MHz" display photo. I was cheated by the photo.