0
$\begingroup$

Hey I'm new to using CBs I have a classic Cobra 29 I had it peaked and tuned supposed to be pushing about 60 watts also supposed to have everything set as far as my SWR however I am still only getting out about as far as I did with the stock radio at 15 watts I was told I needed to run in s/RF mode when I do and I key up I transmit at about 1.5 but sometimes while receiving the meter goes up past two and three while people are talking is that normal?

$\endgroup$
4
  • 2
    $\begingroup$ Not sure I can help much, but you might want to check the manual. Often the meter has dual functions: when sending, it shows your SWR, during receive is shows your received signal strength. Does the meter have a seconds scale besides SWR? $\endgroup$ May 25, 2023 at 20:05
  • $\begingroup$ Highly unlikely your Cobra 29 can output 60 watts without serious modification to the final section. According to what I find, the final transistor is an ERF-2030 which in the updated version can output ~25 watts datasheetspdf.com/pdf/713512/EKLComponents/ERF-2030/1 Also, even if you can output 60 watts from the 15 you had earlier, that is only 1 S-unit difference to the folks who can hear you anyway. The question is, what are the signal reports now compared to before, from the people you contacted before the modification? $\endgroup$
    – Lou-in-USA
    May 26, 2023 at 23:10
  • $\begingroup$ 60 watts is illegal on CB. $\endgroup$
    – Pete NU9W
    May 27, 2023 at 18:32
  • $\begingroup$ Please edit your question so that it is not a run-on sentence. $\endgroup$ May 28, 2023 at 0:48

2 Answers 2

1
$\begingroup$

The process is a bit more complex - first you need to calibrate the internal SWR meter, then you need to read it on the antenna.

the manual says:

Calibrate for SWR (Standing Wave Ratio) SWR calibration is done to properly adjust the length of the antenna and to monitor the quality of the coaxial cable and all RF connections. This calibration is critical to achieve optimum performance.

  1. Select Channel 20.
  2. Switch to the CAL position. NOTE: Antenna Indicator LED will illuminate when transmitting if the SWR is high.
  3. Push and hold the mic button.
  4. While holding the mic button adjust the SWR CAL knob so the meter swings to the CAL mark on the right side of the meter. NOTE: Calibration must be made in an open area (never in a garage). The vehicle’s doors must be closed. No one should be standing near the antenna. (See your antenna directions for more complete information.)
  5. While still holding down the mic button, set the S/RF SWR CAL SWR position, to read the SWR reading.
  6. Repeat the same steps two through five on Channel 1 and 40. This will check SWR for all channels.

NOTE: When switched to SWR position the meter needle should ideally be as far to the left as possible. Anything over 3 is not acceptable. The antenna indicator will light. A slight antenna height adjustment (higher or lower) may be required. Repeat recalibration steps

It also says:

S-Meter

The S-Meter swings proportionately to the strength of the incoming signal when receiving. The S/RF-SWR-CAL switch must be in the S/RF position to read the meter

so this makes sense when you are receiving.

I think it's very unlikely that the radio can produce 60 watts without an external amplifier. It's specified for 4 W and some tweaking might double that, though it would overheat more quickly. And if you have an external amplifier, the SWR meter won't show you whether the antenna is working or not.

There is a fair amount you can do to improve the antenna performance on a vehicle, with the antenna position, improved grounding, panel bonding, etc. Search the internet for "HF Moble Antenna Installation" for a lot more suggestions.

$\endgroup$
0
$\begingroup$

Joe Lee, it's nice to see your first question on this web site !

Someone may have told you that your Classic Cobra 29 pushes out 60 W, but i believe some wishful thinking or just plain exaggeration was involved there, this radio is only capable of 5 - 10 W max.

Then, despite what may seem, in reality the difference in getting out between 10 W and 15 W will be hardly noticeable. If you increase the power of a CB from 10 to 15 W, at the other end the person listening to you will only notice a tiny amount of improvement.

To answer your question, the S/RF meter in your CB radio has two functions, it shows the received signal strength of stations or people you can hear when you are listening, and then it shows the output power of the CB when you are talking or transmitting.

When you are listening or receiving, the meter reads the signal strength of the people you can hear, this is the "S" part of the S/RF meter.

Then, when you are talking or transmitting, the S/RF meter will read the output power of your CB, this is the "RF" part of the S/RF meter. It should normally go up to about 2/3 of the way when you are talking.

You just have to make sure that the left most 3 position switch on the front of the radio is set to S/RF. The other settings for that switch are for checking if the antenna is tuned correctly, i would just leave that for now. This switch has no effect on how you get out, regardless of what it's set to, it only affects what the meter is showing.

When listening or receiving, it is normal for the meter to go from zero all the way to the end, or anywhere in between, depending on how strong the people or signals are that you are listening to.

Hope that all makes some sense !

$\endgroup$

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .