Two Way Radio Receivers

RF amplification can be very effective.

2007-11-11 00:36:33 by oops

I have a two-tuner directv dish that I had wired up to a dual-tuner Directv/Tivo box, as well as a single tuner box in another room. When I moved, I lost the splitter the install guy used. I want to say that he ran the two coax cables out of the dish into a splitter that had two inputs and then ran from that to the dual receiver as well as the single input receiver. However, when I went to radio shack, I didn't see any dual input splitters. Does this sound right? Do I need a special-order splitter -- I swear it looked like a five dollar 1 to 4 splitter. Any help?

You need a 3x4 multiswitch. A splitter is not made for satellite tv (and by the way will not fry your receivers)
If you do not have capability to run a separate cable from the dish to each receiver, call DIRECTV they will do a dish upgrade for you for free. And, by the way, the installer who responded was referring to a multi-sat dish (which are now pretty much standard unless you have hdtv & live in specific areas) not all areas of the US get programming from more than one satellite. I don't, all my programs come from the 101 satellite even locals. Now if I upgraded to high def for my area I would still use my multi-sat dish w/3 LNB's but in some areas of the country you would need a 5 LNB dish in order to get high def locals.
So, when in doubt go to the experts, call DTV its free trouble shooting & advice.

2006-10-08 18:29:29 by holjim

Price: $149.99 $119.95

Ideal for work, shooting events, races or professional landscaping
Audio jack for both radio and scanner connections
Noise reduction level of 24dBA
All-purpose noise-reduction headset with AM/FM radio receiver
Electronic listening capability; listen to favorite station without being isolated

we are required by our professor to construct a single transmitter that can send a signal either amplitude or frequency modulated that can be simultaneously received by two receivers tuned to different frequencies. The scenario would be like this; during transmission, one receiver(radio) is tuned to 20Mhz(for example) and the other receiver is tuned to100Mhz(for example), still both receives the information being transmitted all at the same time. He told us to make use of harmonics. If anyone has a schematic of such a circuit, it'll be more helpful. I hope yahoo answers has the solution to our problem. Thank you so much!

The following link shows a project schematic that can probably be modified to suit your purposes.

What you are trying to do is really quite fundamental to radio transmission. "All" radio transmitters transmit "harmonic" components of the fundamental frequency. But, because of obvious interference consequences caused by broadcast harmonics, there are gov't rules and regulations requiring all transmitters to "filter" all harmonic components of an RF signal to levels that are deemed to be insignificant.

Refering to the schematic in the link below, you can probably tune the output filter to pass the fundamental and a harmonic of your choice. (good learning project for you).

One legitimate use of multi-frequency, multi-band, harmonically related broadcasts are the NIST Time Standards broadcasts by radio station WWV in Boulder, Colorado. If you tune a shortwave receiver to 5.0, 10.0, and 15.0 Mhz, you will hear the same time-tick broadcast by the same WWV transmitter. You may not hear all three broadcasts at the same time of day because of radio wave propagation characteristics that change between summer, winter, night and day. Which is why they broadcast on multiple frequencies simultaneously.

2007-12-17 08:11:45 by bhoghart_ako

Price: $200.00 $89.95

128 groups channels storage
Channel Step: 2.5/5/6.25/10/12.5/25KHz
Dual-Band Display, Dual Freq. Display, Dual-Standby;A/B band independent operation

1. UHF 5W
output power
2.128 memory channels
3.Built-in 50 CTCSS
and 104 DCS
4.Wide (25kHz) and Narrow(12.5kHz) channel spacing
programmable in separate channels
5.Come with 1200mAh Li-ion battery
6.Input Frequency directly by keypad
7.VOX built-in
8.Frequency Scan & CTCSS Scan
9.Three different scan type: TO/CO/SE
10.Three color LCD backlight display
11.Sound Alarm
12.Programmable by PC software
13.Bell ring when receiving signal
14.Priority Scan Function
15.Adjust power High/Low
16.Switching between Channel/VFO
17.Display Channel+ Frequency mode.
18.Adjust squelch level (0-9)
19.Busy channel lockout
20.Keypad lock
21.Reverse Frequency Function
22.Channel step 5k,10k,6.25k,12.5k,25k
23.Optional Frequency range: 136-174Mhz/400-470Mhz/240-260Mhz/465-520Mhz
24.Program alphanumeric channels name
25.DTMF encode
26.Self-program
27.VFO/MR key to store and delete channel
28.CE Approved

TECHNICAL SPECIFICATION

GENERAL:
Frequency Range:136―174MHz，245-246MHz，400—470MHz
Working Temperate －20℃―＋50℃
Operating Voltage DC 7.2V
Operate Mode:Simplex or Semi-duplex
Dimension 100mm×55mm×32mm (Not included Antenna)
Weight 220g (Including battery)
Antenna impedance 50Ω

TECHNICAL:
Frequency Range 136―174MHz，245-246MHz，400—470MHz
Working Temperate －20℃―＋50℃
Operating Voltage DC 7.2V
Operate Mode Simplex or Semi-duplex
Dimension 100mm×55mm×32mm (Not included Antenna)
Weight 220g (Including battery)
Antenna impedance 50Ω

Transmitter
Frequency Stability ±2.5PPM
Output Power ≦5W
Max Frequency Deviation ≦5KHz
Audio Distortion ≦3%
Modulation Character +3dB—-3dB
Adjacent Channel Power ≥65dB
Spurious Radiation ≤7.5UW(-36db for CE)
Occupied Bandwidth ≤16KHz

Receiver
RF Sensitivity ＜0.2UV(12DB SINAD)
Audio Distortion ≦3%
Audio Response +2dB—-10dB
Adjacent Channel Selectivity ≥60dB
Intermodulation Rejection ≥60dB
Blocking ≥80dB

Simple! All depends on the terrain or the location of your transmitter.
In a big city, we can talk from 3 to 6 Km. In a city with a repeater on a high mountain, we can put our signal at more than 20 Km. And in a flat terrain without any obstacles, but at the normal human heigth, no more than 6 to 10 Km.

2008-10-24 08:31:24 by yousef67765

in this manner ...i have FCC license


General

Frequency Coverage

(unit: MHz)

Version IC-V82 IC-U82
USA

Tx 144-148

Rx 136-174*1


Tx 420-450*2

Rx 400-479*2
Europe 144–146 430–440
Guaranteed Range *1 144-148MHz, *2 440-450MHz
Mode F3E, F2D, F7W*
*Optional UT-118 Required
Number of memory Ch. 207 (incl. 6 scan edges and 1 call)
Operating Temp. Range -10°C to +60°C; +14°F to +140°F
Frequency stability ±2.5 ppm (-10°C to 60°C)
Power supply requirement

7.2V DC

(6.0-10.3V DC aceptable; Icom's battery pack only)

Current drain

(at 7.2V DC)

IC-V82 IC-U82
Tx High (7W/5W) 2.6A 2.0A
Rx Max. audio Standby
Power Save

250mA

80mA

30mA


250mA

80mA

30mA
Antenna impedance 50Ω (BNC)
Dimensions (W×H×D) (Projections not included)

54 × 139 × 37.5 mm;

21/8 × 515/32 × 17/16 in
Weight (approx.) 390g; 13.8oz (w/ant. and BP-222N)
Transmitter
Output power (at 7.2V DC)

IC-V82

IC-U82



7.0/4.0/0.5W (High/mid/low)

5.0/2.0/0.5W (High/mid/low)
Spurious emissions Less than -60dBc
Max. freq. deviation ±5.0/±2.5kHz (Wide/narrow)
External Microphone connector 3-conductor 2.5(d)mm (1/10") / 2.2kΩ
Receiver
Receive system Double conversion superheterodyne
Intermediate freq. 46.35MHz/450kHz (1st/2nd)
Sensitivity (typical) 0.16µV (typ.; at 12dB SINAD)
Squelch sensitivity 0.11µV (typ.; threshold)
Selectivity More than 55/50dB (wide/narrow)
Intermodulation 65dB (typ.)
Spurious and image rejection

80dB (typ.; VHF)

70dB (typ.; UHF)
Audio output power 300mW with an 8Ω load
Ext. speaker connector 3-connector 3.5(d) mm (1/8”) / 8Ω
Ext. Data connector 3-connector 2.5(d) mm (1/10”)

Pardon me if I sound skeptical about your license, but how did you pass you license exam if you can't estimate the range of this radio?

2008-10-25 06:29:51 by reza3267876