What is the RF output power, in watts

Check your antenna, cable and all connectors. It is common for power to fluctuate if you have any short anywhere in the radio to antenna system. Do not test your radio without an antenna attached or what is called a "dummy load", you may fry your transmitter. Do not trust cheap cables that are pre assembled, I've had many bad out of the box.
John L.

The FT-840 uses a die-cast RF power amp with thermally switched fan to ensure full power output (up to 100 watts). The digitally synthesized local signals ensure clean, low-noise transmitter output on all HF amateur band. There might be no AC line interference. it has strong Rf output. any AC line intersect does not affect its radio performance. Check and adjust RF power so to maintain proper output. some times more RF power generated at the output may cause interference. adjust Rf power..Even some unfiltered Noise getting the other end of the end may calso cause interference. Check for any Ripple voltages present at the output. Contact authorised service station for further Rectification. thank you shanth

Yes you can turn up VR pot inside to recieve max level but will cause noise to be max too. I don't rightfully remember which one does it but I'll refer you to Defcom cb radio mods for a spec sheet
or Snakedoctors cb radio mods google site. Go to these radio mods sites on Google search and type in radio model. It will tell you what Vr inside to turn up RX of RF gain. Turn up modulation and written instruction if you are handy with solder gun how to change a resistor or cap to make it more sensitive recieve. How to replace final stage and resistors to 1/2 watt size for 6 more watts output and spread coils 1/8 inch apart like a comb for 100% microphone loudness or swing output. say 3 watts to 40 watts output. More windshield wiper swing in meter makes loud voice and extends range with Power final boost. Most people prefer to keep a mobile at around 11 watts swing to 45 watts.(but on generic radio meter will show 2 to 5 watts-its not accurate just a cheap indicator you are forward swing). Even though factory says 4 watts FCC hogwash. They come tuned from Cobra with 11 watts to 14-22 watts.Cobra really peaks them babies so competition doesn't beat them out like new louder radios made by Galaxy 55. Even though law says blah blah (corporations bend it)sales pitch Galaxy very heated with Cobra on the game(rich can do what they want)Galaxy is 20 watts factory with big promise to 40 watts dual finals. So Cobra updated and said "screw it we will break the law too" Now Cobra is loud as ever and offering their own super mod versions and dual final radios with 45 to 65 watts output with ranges on SSB & USB of 1500 miles on a strong good outdoor antenna.

it is just because your cable is loose, try it after tightning it up

Hi Joe,

If you're putting out 7 watts of RF power, you shouldn't need more to hit a repeater within 15 miles of your location, however, if there are no repeaters within range, then you must be in a rural location.

If this is so, then unless there is a repeater within reasonable range, you're not going to have much luck no mater the RF power your radio put out.

The more RF power your radio chuffs out, the shorter the battery life can be expected, 7 watts is enough to drain the battery quickly as it is.

If on the other hand this is a base set, I doubt it, then with a properly installed out door antenna, you should be making contacts with ease on 7 watts, depending on location as I've stated.

I hope this has answered your query.

Cheers,
Peter

The rule is the taller the antenna the better the reception and power output. Of course it is not always convenient to mount a 102" whip.

• 4 watts into a 102-inch whip antenna, it is the same output as if you put 11 watts into a 3-foot whip.

• 4 watts into a 102-inch whip antenna,, it is the same as if you put 14 watts into a 28-inch antenna.

• 4 watts into a 102-inch whip antenna, it is the same as if you put 54 watts into a 7.5-inch antenna.

You did not mention the signal on their meter and how close they are. This may be a modulation issue. Wattage increases can go unnoticed volume wise but small modulation increase can make dramatic changes in volume to the receiving radio. Check that your dynamike or mike gain control is turned up clockwies increases it. The radio itself may need the modulation increased internally. If you have a powermike with adjustments on back it may be way to low. Hope this was of some help

The antenna is your problem not much gain. Height is everything tx and rx. Although it would not compare to a conventional cb size negates performance. Seeing is believing in this case hearing get adapter to connect to standard coax of antenna. (PL259) to BNC Coax Adapter Radio Shack sells them. And dont ask or buy any radios there. They are hardly the radioshack of choice anymore.

• If you put 4 watts into a four-foot antenna, you will get the same power out of that antenna as if you were putting 2 watts into a 102-inch whip.
  
• If you put 4 watts into a 3-foot antenna you will get the same power out as if you were putting about 1.5 watts into a 102-inch whip.
  
• If you put 4 watts into a 7.5 inch antenna on a hand held CB, it would put out as much power as a third of a watt into a 102-whip.
  
• If you put 4 watts into a 102-inch whip antenna, it is the same output as if you put 11 watts into a 3-foot whip.
  
• If you put 4 watts into a 102-inch whip antenna,, it is the same as if you put 14 watts into a 28-inch antenna.
  
• If you put 4 watts into a 102-inch whip antenna, it is the same as if you put 54 watts into a 7.5 antenna.

RF output power is 4 watts

Yes, you need an amplifier, since the "levels" of the sound-output from each device (TV, CD-player, cassette-player, Sony mini-disk player, turntable) are not sufficient to physically move the "cones" inside your speakers, to push air around, to produce sounds.
You need "watts" of power to push air, while the devices produce milli-watts (watts/1000) of power.

Also, the amplifier is also a "decoder", electronically processing the input to produce "5-channel" (left, front, right, back-left, back-right) surround-sound output.

Hello jacknichols,

This means that you have an RF output problem. What you need to do is connect the antenna jack to a power output meter (with antenna loading) and measure the power out put when the mic is keyed. The power readfing you should be expecting is 4 watts (Peak Envelope Power) PEP.

I believe that you will read a lot less. If this is the case you will have to get a schematic of your CB radio and using a multimeter measure the voltages around the RF power output section of your radio and the sections leading to the output stage. This is assuming that you have a background in electronics. If not, I would suggest that you take your CB to a repair shop to have them find the problem and repair it.

I hope this helps,

Thank you,

Shuttle83

http://www.electron-age-technologies-llc.com