BHF echecs16.info Date/1/9 Hits 【Click to download】. Prev:BHF echecs16.info Next:GP 1/4 Wave GP Antenna Manual. This is the latest BH FM Transmitter design from RHOM that includes a lot of features in one small package. It comes with pre-emphasis, limiter so that. Gods Transmitters pdf download This FM Transmitter is stable and has output booster for all low power FM transmitters such as BA, BH, BH
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The BHF is a FM stereo transmitter IC that transmits simple configuration. The IC consists of a stereo modulator for generating stereo composite signals and. The circuit is based on BH PLL stereo transmitter IC from Rhom semiconductors. The IC has separate audio processing sections for the left and right. Fig block diagram of the Rohm BHF stereo FM transmitter IC. The text As shown, the BHF includes two separate audio processing sections, for the left and right channels. .. Click to download . Micromitter Front Panel (PDF) · Micromitter PCB (PDF) · Micromitter Front Panel (ZIP) · Micromitter PCB (ZIP).
You are on page 1of 5 Search inside document This small power FM transmitter can transmit more than 1 km in good conditions. The modulation can be made so much with a microphone or audio source. Circuit of power fm transmitter is built around 2n transistor. Transmitter coil is 5 turns of enameled 22 AWG wire, with diameter of 1 cm without nucleus. Look at the capacitors that it should be ceramic. The antenna should possess from 15 to 40 cm.
Each part is installed by holding it in place with the tweezers and then soldering one lead or pin first. That done, check that the component is correctly positioned before carefully soldering the remaining lead s. In the case of the IC, it's best to first lightly tin the underside of each of its pins before placing it onto the PC board.
It's then just a matter of heating each lead with the soldering iron tip to solder it in place. Be sure to use a strong light and a magnifying glass for this work. This will not only make the job easier but will also allow you to check each connection as it is made.
In particular, make sure that there are no shorts between adjacent tracks or IC pins.
Finally, use your multimeter to check that each pin is indeed connected to its respective track on the PC board. The remaining parts are all mounted on the top side of the PC board in the usual manner.
If you are building the plugpack-powered version, follow the overlay diagram shown in Fig. Top assembly Begin the top assembly by installing the resistors and wire links. Table 3 shows the resistor colour codes but we also recommend that you use a digital multimeter to check the values.
Note that most of the resistors are mounted end-on to save space.
This will make it much easier to connect to these points later on. The capacitors can go in next, taking care to install the electrolytic types with the correct polarity. The NP non-polarised or bipolar BP electrolytic types can be installed either way. Push them all the way down into their mounting holes, so that they sit no more than 13mm above the PC board this is to allow the lid to fit correctly when the AAA batteries are mounted under the PC board inside the box.
The ceramic capacitors can also be installed at this stage. Table 2 shows their marking codes, to make it easy for you to identify the values. Coil L1 Fig. It comprises 2. Alternatively, you may also use any commercially made 2.
Two types of formers are available - one with a 2-pin base which can be soldered directly to the PC board and one that comes without a base. If the former has a base, it will first have to be shortened by about 2mm, so that its overall height including the base is 13mm.
This can be done using a fine-toothed hacksaw. That done, wind the coil, terminate the ends directly on the pins and solder the coil into position. Note that the turns are adjacent to each other ie, the coil is close wound.
This photo shows how the case is drilled to take the RCA sockets, the power socket and the antenna lead. Alternatively, if the former doesn't have a base, cut off the collar at one end, then drill a hole in the PC board at the L1 position so that the former is a tight fit. That done, push the former into its hole, then wind the coil so that the lowest winding sits on the top surface of board. Be sure to strip away the insulation from the wire ends before soldering the leads to the PC board.
A few dabs of silicone sealant can then be used to ensure that the coil former stays in place. Finally, the ferrite slug can be inserted into the former and screwed in so that its top is about flush with the top of the former.
Use a suitable plastic or brass alignment tool to screw in the slug - an ordinary screwdriver may crack the ferrite. Crystal X1 can now be installed.
The antenna is simply a half-wave dipole type. It consists of a 1. This should give good results as far as transmission range is concerned. Preparing the case Attention can now be turned to the plastic case. This requires holes at one end to accommodate the RCA sockets, plus holes at the other end for the antenna lead and the DC power socket if used. In addition, a hole must be drilled in the lid for the power switch.
The circuit can be powered from 4 x 1. Note that the battery holder requires some modification in order to fit everything inside the case see text. It's also necessary to remove the internal side mouldings along the walls of the case to a depth of 15mm below the top edge of the box, in order to fit the PC board.
We used a sharp chisel to remove these but a small grinder could be used instead. That done, you also need to remove the end ribs under the lid in order to clear the tops of the RCA and DC sockets. The front-panel label can then be attached to the lid.
The battery-powered version has a AAA cell-holder mounted upside down in the box, with the base of the holder in contact with the copper side of the PC board. There is just sufficient room for this holder and the PC board to mount inside the case with the following provisos: 1. All parts except for power switch S5 must not protrude above the surface of the PC board by more than 13mm.
This means that the electrolytic capacitors must sit close to the PC board and that L1's former must be cut to the correct length.
The AAA cell holder is about 1mm too thick and should be filed down at each end, so that the cells protrude slightly over the top of the holder. The tops of the RCA sockets may also require shaving slightly, so that there is no gap between the box and the lid after assembly.
The transmission must not be on the same frequency as a radio broadcasting station or repeater or translator station operating within the licence area.
Further information can be found on the www. The class licence information for LIPDs can be downloaded from: www.
The first job is to tune L1 so that the RF oscillator operates over the correct range. To do that, follow this the step-by-step procedure: 1.
Set the transmission frequency using the DIP switches, as shown in Table 1. Note that you need to select a frequency that is not used as a commercial station in your area, otherwise interference will be a problem. Select a DC volts range on the meter, apply power to the Micromitter and check that you get a reading that's close to 5V if you're using a DC plugpack.
Alternatively, the meter should show the battery voltage if you're using AAA cells. Move the positive multimeter lead to TP1 and adjust the slug in L1 for a reading of about 2V.
The battery holder sits in the bottom of the case, beneath the PC board. The oscillator is now correctly tuned. No further adjustments to L1 should be required if you subsequently switch to another frequency within the selected band.
From this i can determine how much amplifying in need. If i convert this to milliwatts converter i gives me So this is the RF power going out of pin Is my logic correct? And how sensitive are cheap car radio, and how does it relate? Question 2: Can a passive or inexpensive active antenna amplify the BHF signal to the level required?
The order in which the bhf were numbered on the silkscreen did not appear to be logical in some cases, resulting in hunting around the board for the right point to bhf components. Learn More — opens in a new window or tab Any international shipping and import bhf are paid in part to Pitney Bowes Inc.
Bhf new Japan has BH is one of the most simple and practical integrated circuits, which combines phase-locked loop circuit, stereo encoder circuit, transmitter circuit, as well as other additions. Top Rated Plus Sellers with highest buyer ratings Returns, money back Ships in a business day with tracking — opens in a new window or tab Learn more. Interest will bhf charged to your account from bhf purchase date if the balance is not paid in bhf within 6 months.
Subject bhf credit approval. Learn more — opens in a bhf window or tab. Learn More bhf opens in a new window or tab International shipping and import charges paid to Pitney Bnf Inc. Report item — opens in a new window or tab. It can be connected to any type of stereo audio source such as buf, Computer, Laptop, CD Player, Walkman, Television, Satellite Receiver, Tape Deck or other stereo system to transmit stereo sound with excellent clarity bhf bhf home, office, yard or camp ground.
Other offers may also bhf available. Bhf enamelled copper bhf proved hard to strip with a knife and difficult to solder, and its value appears to be critical to achieving successful high and low band operation as a result, I was only able to achieve high-band operation.
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