TRC-459 help needed

[press1280]

Playing around with one of these: Radio Shack Realistic TRC-459 CB Radio Overview | CB Radio Magazine

Not sure what's going on with it. It seems like it's way off frequency or something. My separate SWR/power meter is showing similar transmit power numbers to my other radios that are working. It's also picking up several bars of background noise (similar to my other working radios). SWR of the antenna is under 1.1. But when I transmit to or from my test walkie talkie you can't make out voice and you can barely tell there's "something" there. I tried on all frequencies and same thing. All LEDs and all controls seem to be working otherwise. Any ideas?

 

[KB4MSZ]

I read that PLL modification for channel expansion was complicated on these rigs and hopefully that isn't what happened to yours. Would you possibly have access to a SDR type radio so that you could see the rig's output across the entire CB band at one time?

 

[press1280]

Would a superstar 4900 qualify?

 

[KB4MSZ]

I was thinking more like a spectrum scope type radio where you can "see" the entire CB band at one time. Maybe someone you know has one? Here is a screen shot of my SDRPlay RSPdx radio control software. When you key the TRC-459, the resulting signal would show up someplace between 26.965 and 27.405 MHz. Then you would know where it is transmitting. Hopefully it hasn't been modded to the point that it isn't within that range. Unfortunately it is a possibility.

 

[press1280]

Nothing like that. I saw some frequency counters on Amazon, would something like this do the trick?

 

[press1280]

As far as it being modded, I opened it up and don't see anything pointing to that. But, I could be wrong.

 

[KB4MSZ]

You could use a frequency counter. The trick would be getting it safely coupled to the radio during transmission. I used to use a very poorly shielded short length of coaxial cable that was externally wrapped with a bare wire lead from a frequency counter, the other end was terminated with a 50 ohm load. Crude but did work. It would at least give you some idea where the radio is tuned.

 

[DaveJacobsen]

You do have both radios on the same modulation? (AM USB LSB)

 

[press1280]

Yep on AM. Didn’t show signal for side band channels either

 

[press1280]

Would bad capacitors cause something like this?

I do see one or 2 that look like they have brown glue around them. One seems to have zero continuity as well.

 

[KB4MSZ]

A capacitor will look like an open circuit to a ohm/continuity meter. It will be hard to determine what that transmitter is doing without some sort of frequency measuring instrument with a broad range. The "glue" around the capacitors was common back when radios had monolithic components, it helped protect the capacitor from possible damage from vibration or shock as they tended to be large and top heavy.

 

[press1280]

Is there a cheapie frequency counter?

 

[KB4MSZ]

At this point I would have to ask if it is worth the effort in reviving such and old CB radio. If it is the nostalgia of this particular model then I guess the expense and effort is worth it. At this age, there are bound to be components that are bad or weak and trouble may show itself in the near future. Depending on what needs to be replaced, a complete alignment may be also required for operation. Otherwise a newer radio may be in order.

As for a low priced frequency counter the link below is an example of what came up on EBay. Its not a recommendation, it's just an example of what I found. It claims capacity up to 2.4 GHz (info found on another site, EBay site says nothing). There are both cheaper and, of course, more expensive units.

 

[KEWB-N1EXA]

Playing around with one of these: Radio Shack Realistic TRC-459 CB Radio Overview | CB Radio Magazine

Not sure what's going on with it. It seems like it's way off frequency or something. My separate SWR/power meter is showing similar transmit power numbers to my other radios that are working. It's also picking up several bars of background noise (similar to my other working radios). SWR of the antenna is under 1.1. But when I transmit to or from my test walkie talkie you can't make out voice and you can barely tell there's "something" there. I tried on all frequencies and same thing. All LEDs and all controls seem to be working otherwise. Any ideas?

How far away is this Walkie Talkie ?
If your keying up the mic in one hand and hold the walkie in the other your most likley blowing the doors off the hand held .

Send somebody down the street with the walkie ad see if it works then.

Peter N1EXA

 

[press1280]

In the same room (antenna is outside about 50-75 feet away).
The signal on the walkie is barely indicating something is transmitting. When I key the walkie back to the base the signal meter on the base goes down. I saw this happen before when transmitting from a wrong frequency.

 

[KEWB-N1EXA]

In the same room (antenna is outside about 50-75 feet away).
The signal on the walkie is barely indicating something is transmitting. When I key the walkie back to the base the signal meter on the base goes down. I saw this happen before when transmitting from a wrong frequency.

Id go with what was mentioned above in the comments ... Run an SDR Dongle and some software and look where the carrier is.

Pete N1EXA

 

[press1280]

I’ve never seen those before. So this sort of turns your computer into a scanner?
Are you able to actually scan around to find your signal? (The CB isn’t transmitting or receiving in the frequency range it’s supposed to)

 

[KB4MSZ]

So this sort of turns your computer into a scanner?

It's better than a scanner. In the view shown below is the entire voice portion of the 20 meter ham band. It's quite a bit smaller than the entire CB band is but the effect is the same. Each column of colors is a voice conversation taking place. So, as you can see, all activity going on in a certain band of frequencies is visible at once. The software used in this case is capable of showing a group of channels 20 times wider than the CB band so you could easily find the output from your radio at a glance.

 

[press1280]

Ok I’ve ordered a cheap dongle from Amazon and will see exactly what frequency this thing is on. I flip all the channels and they all sound the exact same....normal static but can’t hear any distinguishable signals.
tone changes for usb and lsb so I think that’s working but still wrong frequencies.

 

[KB4MSZ]

I found this information on the PLL modification for the TRC-459. Maybe you could look at it along with this information and tell if yours has been modified.

secret_cb_vol_10_pg32_35.pdf (cbtricks.com)