Post by sennikovkiy on Jan 20, 2022 10:43:19 GMT -6
Hello to all! I do not know English. I will use a translator. I've never done reviews, so don't judge too harshly. Better ask questions, if I can answer them, I will answer. Bought on aliexpress for $580.
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Back view: ibb.co/XDV1gc7 I got this option, i expected that I would get the old version with RCA inputs, left and right audio channels(version where, 2 XLR, 2 RCA and BNC(MPX) How did I get out of this situation: ibb.co/vq7BPX0, ibb.co/gMfxDFH
ibb.co/nkbzTqM, Amplifier, the cooling system is disabled because it is constantly running and noisy, I do not use the full power of the transmitter
ibb.co/vZGK1Yn, Board for connecting audio sources. Chip markings are erased. Have click when switching from STEREO(EXT) to MONO-MIX(LEFT,RIGHT), relay switching
ibb.co/ZH6HQd7, FM exciter, I have not seen the BH1414K board anywhere. Inside the metal box are 3 transistors (or varicaps, I'm not sure)
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MENU 1 Freguency setting: Choice 0.01MHz, can install Freguency 93,47MHz example.
MENU 2 RF power settting: An important point, when setting this parameter, it is important that a compatible antenna is connected, because this parameter is applied immediately, and the SWR protection does not work when you are in the menu RF setting. That is, if you want to set 25 watts, then these 25 watts are applied immediately when you turn the encoder, when you turn the encoder, the SWR protection does not work until you exit the menu.
MENU 3 Signal mode setting: STEREO (RCA,XLR) MONO-MIX(AES/EBU?) MONO-LEFT MONO-RIGHT MONO-RIGHT & EXT MONO-LEFT & EXT MONO-MIX & EXT STEREO & EXT (audio signal XLR and only RDS(SCA) signals. There is no low-pass filter here, so it is important to only send the RDS signal) EXT MOD (MPX,BNC) if you want use fm audio proccessor (i use Stereo Tool)
MENU 4 Audio pre-emphasis setting: Only works with XLR connected audio, i'm from Russia, we use 50us, if you switch to 75us, the high frequencies increase 0us 50us 75us
MENU 5 Audio gain siglan(only XLR): Gain setting +- 15db max, choice +- 0.5 db, signal level can be set for each channel, if set below 15 decibels, "MUTE" will appear LEFT+RIGHT LEFT RIGHT
MENU 6 External modulation gain setting (MPX,BNC): Gain setting Aslo +- 15 db max and choine 0.5 db
MENU 7 Network setting: It's just an inscription on the display in 2 lines "Network option not installed. Network option not installed."
MENU 8 Exit
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I don’t have a power measuring device, so I will measure the consumption of the amplifier, with different RF power settings. There is an interesting point, if you set 0.1 watts, then they are not real. I have had 100 milliwatt transmitters and I remember from memory how far they can transmit. This transmitter transmits the signal much further. The transmitter display has a line called DRIVE in %, when you set 0.1 watts without leaving the RF setup menu, the DRIVE parameter smoothly increases to ~13%, this percentage is frozen if you exit the settings menu, also gradually increases the RF power, But if you set the power setting from 0.2 watts, then there is a sharp increase in power, Drive immediately shows 13% Video:
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Sound: I liked everything here, at 20 Hz the square on the MPX Tool oscilloscope shows even rectangles. I calibrated the frequency response of the MPX FM exciter bh1417f, if it is fed into a quadrature sine wave at a frequency of 20 Hz, everything is bad. In this video you can see the shape of the quadrature sine wave at the output of bh1417f
Test sound MPX Stereo Tool to Warner RF FMT5.0 (and comparison with RCA)
I decided to have some more fun, I recorded the mpx of my local radio station using the MPXTool program, I sent this recording to Warner RF this radio station had some problems, I decided to record.
