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RCI-2950DX 10 Meter AM/FM/SSB Export Radio Review

The 2950DX from RCI has become an icon in the radio world. The radio has proved itself to be solid, reliable, and offer excellent performance.

Its older version, the standard 2950, was a very popular radio in its day, but it did have its faults. RCI sought to improve upon that radio with the DX version, and the end result is a very nice radio with surface mount technology.

The 2950DX purchased for this review was picked up on eBay and came with the original box and the included accessories. Used 2950DX’s can usually be found in the $180 - $250 range depending on condition.

The 2950DX is advertised as a 10 & 12 meter radio with AM, FM, LSB, USB and CW capabilities. The radio can be converted for 11 meter use (although there are a couple of models floating around that are rumored to not be convertible).

This radio uses a digital display with a digital signal/SWR/RF bar meter. The digital display also shows the frequency in six digits or it can switch to a channel display mode.

The radio is roughly the size of a Cobra 148 or similar type radio and has a heatsink on the back with cooling fins for heat dissipation. This is a dual final radio and will get warm with use but the cooling fins do an excellent job in keeping the radio at an ideal operating temperature.

When looking for a quality SSB radio for 11 meters the RCI-2950DX is really at the top of the class. It has any number of features and designs only found on more expensive ham rigs such as a double balanced mixer stage and RF shielding over key components inside the radio. A quick look inside and you’ll immediately see what I’m talking about. On the left hand side of the radio is a large portion of the circuit board covered with a metal shield. There are holes in the shield so you can still access the tuning points.

Picture from http://www.cbworldinformer.com/

The other nice thing about the inside of these radios is that the common adjustment points are actually marked with a text description rather than just a number. This means it’s very easy for your average radio owner to open up the radio and make a quick adjustment here and there.

This radio uses surface mount technology which means very very small parts. In most cases the average CBer’s will not want to try to work on surface mount technology as it requires a very fine tipped soldering iron and a good magnifying glass if you don’t have 20/20 eyesight. Luckily these radios are well made and most people will never have to touch the inside of the radio.

Features on this radio are abundant, from split frequency operation, frequency scanning, internal SWR function, to a roger beep, it has everything an operator needs. In some cases its many features scare off the standard CBer’s who prefers the look and feel of the more traditional face CB radio. Don’t let this be the case for you - if you are looking for a solid SSB radio the 2950DX is easy to use and it only takes a couple of minutes to familiarize yourself with the basic operation.

Performance

Let’s be straightforward in discussing the abilities of this radio – if you are a big AM’er this is not the radio for you. I’ve heard some of the 2950DX’s that have had extensive work and mods done to them for loud AM audio and they sound okay, but it’s wasted money if you want to be a big strapping AM audio hog.

These radios have amazing frequency stability and clean audio quality making them perfect for SSB. If you are tired of CB’s or export radios that constantly drift around than you need a try a 2950DX. The only other radios I’ve come across that are on the same level as the 2950DX for SSB stability are the HR2510 and the Magnum 257.

Not a whole lot is needed to tune up these radios for good results. The addition of a good power microphone such as a D104M6B can help bring a bit more punch to the audio. Inside the radio adjusting the modulation pot and SSB ALC will help yield good swing and audio performance. I do not suggest doing the NPC mod to these radios or removing the limiter. These radios have clean solid audio and post good numbers without excessive modification.

On AM the variable power control can be set from 1 watt up to 8 watts on most radios (adjustments to the AM power controls will allow for different settings on the RF control). Make sure not to set your max AM deadkey higher than 10 watts as the radio is not designed to run in such a manner. In most cases in the high power RF setting you’ll see swing in the 20 – 30 watt range. The last 2950DX I had would swing to 35 watts on AM and SSB. With the RF power in the low position deadkey will be around 1 watt with swing to around 12-15 watts. Some people will do NPC type swing modifications to this radio to allow for higher swing from the low 1 watt deadkey.

Receive

These radios have a great receiver and can pull in the far off stations without difficulty. Tuning in SSB stations is easy and the clarifier has smooth movement.

RCI-2950DX’s are known for one issue and that is white noise. Although some dealers will perform a modification for around $30 to help correct the issue, the fact is that most 2950DX’s you run into will have a lot of white noise in the receive.

While this white noise doesn’t really have a negative effect on the receiving of signals from other stations, for those who keep the squelch down and RF gain up you may find the noise on the annoying side.

Nitpicking points

I really like these radios and so there isn’t a whole lot for me to complain about, but nothing is perfect.

-         I don’t like the dual control setup on these radios. I tend to find that often when adjusting one of the knobs (especially in the mobile) it’s easy to knock the lower control out of position.

-         The display is great when looking straight on, but at an angle or on a really sunny day it can often be very hard to see the frequency or meter.

Overall

I can’t say enough about how great these radios are for the SSB’er. Both the 2970DX I’ve tried and the 2950DX’s have performed flawlessly with excellent stability. They aren’t the loudest radios out there and they aren’t the easiest to use in terms of simplicity, but they are far and above a better SSB export radio than the majority of radios on the market.

As someone who uses SSB every day of the year I can be very picky about wanting a radio that doesn’t drift and stays on frequency. This radio meets my requirements. And if that doesn’t tell you enough, take into consideration that while most Ham radio operators despise “CB capable exports” almost all of them will admit that the 2950DX is a great 10 meter radio for the price.

If you're interested in more information, an excellent review was done by cbworldinformer a couple of years ago - Review: RCI 2950DX Dual Band Amateur Radio

 

FEATURES ( WWW.RANGERUSA.COM)

 

TECHNICAL SUPPORT
Alignment Procedures

RCI-2950DX
12 & 10 Meter Mobile

( Note: For non-DX Series, see 2950 Series )

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Equipment required for Alignment procedure:

• DC Power Supply ( 13.8 Vdc, 20A )
• Oscilloscope (50 MHz), with X10 probe
• 50
W dummy load
• Frequency Counter - 100 MHz
• Digital voltmeter or Multimeter
• RF Signal Generator

• Audio Generator
• Automatic Distortion Meter
• SINAD Meter
• RF Wattmetter ( 25~60 MHz, 100W )
• Automatic Modulation Meter

To view Main PCB Adjustment for location of adjustment points, please see this drawing -  2950DX Main PCB.  After viewing, press "back" to return to this page.

The following steps are required to re-align the RCI-2950DX:
Caution:   Alignment should only be attempted by personnel trained in RF product testing and alignment.

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PLL Synthesizer / Oscillator Frequency Alignment:

1. PLL2 - VCO Voltage:
A. Set radio to 24.890 MHz, AM RX mode, connect multimeter to TP10.
Adjust L14 for 1.0 Vdc ± 0.1.
B. Set frequency to 29.699 MHz, AM RX mode, connect multimeter to TP10.
Adjust L14 for 4.5 Vdc ± 0.1.

2. PLL1 - VCO Voltage:
A. Set radio to 24.890 MHz, AM RX mode, connect multimeter to TP10.
Adjust L13 for 1.0 Vdc ± 0.1.
B. Set frequency to 32.000 MHz, AM RX mode, connect multimeter to TP10.
Adjust L13 for 6.5 Vdc ± 0.1.

2. AM Frequency:
Set radio to AM RX mode, clarifier to
12 o'clock,. Connect frequency counter to TP16.
Adjust VC2 to 10.1 MHz ± 10Hz.

3. VCO Output:
Set radio to 28.000 MHz, AM RX mode, connect oscilloscope to TP3.
Adjust L17 to 38.6950 MHz (maximum output).

4. AM OSC:
Set radio to AM TX mode, modulation off, connect frequency counter to TP5.
Adjust L18 to obtain 10.6950 MHz ± 10Hz.

5. USB OSC:
Set radio to
USB TX mode, modulation off, short TP6 to ground, connect frequency counter the TP5.
Adjust L20 to 10.6975 MHz ± 10Hz.

6. LSB OSC:
Set radio to
LSB TX mode, modulation off, connect frequency counter to TP5.
Adjust L19 to 10.6925 MHz ± 10Hz.


This completes this stage of the alignment procedure.

 

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Receiver Alignment:

1. Receiver Setup: Put the mode selector on AM, the RF gain fully clockwise (maximum gain), squelch to minimum (unsquelched), volume at 2 o'clock, set frequency to 28.295 MHz, and NB/ANL to OFF. Connect signal generator set at RF carrier frequency of 28.295 MHz, AM modulated with a 1 KHz audio tone at 30% modulation level.

2. AM Sensitivity:
Connect a SINAD meter to the external speaker jack.
Adjust L3, L4, L6, L7, L8, L10, L11 and L12 for best SINAD.
Increase the RF generator to 1mV RF carrier level.
Adjust L3, and L4 for minimum distortion.
Verify that the receiver AM sensitivity is better than 0.5µV for 10 db SINAD.


3. FM Distortion:
Change the RF generator to the FM mode, 1mV RF carrier level, FM modulated with a 1 KHz audio tone ± 3 KHz modulation level.
Adjust L5 for minimum distortion.

4. USB Sensitivity:
Turn off the audio modulation of the RF generator, and change it's frequency to 28.296 at an RF carrier level of .5 µV. Set radio to USB RX mode.
Adjust L11 and L12 for audio output greater than 2V.

5. LSB Sensitivity:
Keep the audio modulation of the RF generator off, change frequency to 28.294 at an RF carrier level of 1mV, set radio to LSB mode.
Adjust L11, and L12 for audio output greater then 2V.

6. NB Adjust:
Set radio to 28.305 MHz AM RX mode, NB-ANL/OFF switch to ON, adjust RF generator to 28.305 MHz with an RF carrier level of 1mV, AM modulated with a 1 KHz audio signal at 30% modulation. Connect a digital voltmeter to TP1 (R11).
Adjust L1 and L2 for DC Voltage to max ( 1.3V ).

7. AM Scale Meter:
Turn NB-ANL switch to OFF, SWR/S/RF switch to S/RF position, set radio frequency to 28.305 AM RX mode, RF signal generator setting 28.305 MHz with a carrier level of 100 µV, AM modulated with a 1KHz audio signal at 30%.
Adjust VR1 so that bar graph reads 6 bars.

8. USB Scale Meter:
SWR/S/RF switch to S/RF position, set radio frequency to 28.495 MHz USB RX mode, RF signal generator setting 28.496 MHz with a carrier level of 100 µV, no audio modulation.
Adjust VR2 so that bar graph reads 6 bars.

9. AM Squelch:
Set radio frequency to 28.495 MHz AM RX mode, SQ control fully clockwise, RF signal generator setting to 28.495 MHz , RF carrier level at 1 mV, AM modulated with a 1 KHz audio signal at 30%.
Adjust VR4 very slowly until squelch noise just goes off.

10. SSB Squelch:
Set radio to 28.495 MHz USB RX mode, SQ control fully clockwise, RF signal generator setting to 28.496 MHz , RF carrier level at 1 mV, with audio modulation.
Adjust VR3 very slowly until squelch just goes off.


This completes the Receiver stage of the alignment procedure.
 

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Transmitter Alignment:


1. Driver BIAS:
Remove the "Shorting PCB" from TP7, TP8, and TP9. Set radio to USB mode, connect current meter to TP9 (+) and TP8 (-).
Adjust VR11 to obtain 50 mA.

2. DRIVER BIAS:
Set radio to USB mode, connect current meter to TP9 (-) and TP7 (+).
Adjust VR13 to obtain 10 mA.

3. SSB & AM RF Power:
Reconnect the "Shorting PCB" from TP7, TP8, and TP9. Connect a watt meter and a 50 Ohm load to the antenna connector, set radio to 28.495 MHz, USB mode, mic gain to maximum. Inject 30 milivolts of 1 KHz audio into the audio input pin of the mic jack (pin 2). Set SSB power control (VR12) to full counter clockwise position (maximum power position).
Adjust L18, L33, L40, L42, L43, and L44 to obtain maximum power output.
Adjust SSB power control (VR12) to 21 watts peak RF power output.

Change mode to AM
Adjust VR15 to obtain 10 watts RF power output.

4. Power Meter:
Set radio to 28.495 MHz, AM mode, mic gain control to maximum, meter switch to S/RF and key the transmitter.
Adjust VR10 until the RF meter reads 10 watts

5. TX AM Modulation:
Set radio to 28.495 MHz, AM mode, mic gain control to maximum, key the transmitter. Inject 30 milivolts of 1 KHz audio into the audio input pin of the mic jack (pin 2).
Adjust VR17 to 100% modulation.

6. CW Side-Tone Signal:
Connect a voltmeter directly across the speaker, key the transmitter using the CW jack in the rear of the radio.
Adjust VR9 to obtain 200mV across the speaker.


This completes the Transmitter stage of the alignment procedure.

 

 

 




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