Review Of The RCI 2950DX
The RCI 2950 has been around for many years. The
first radio of this type from Ranger Communications was the RCI 2900. The
2900 radio was a CPU type radio with an analog S/RF meter. Comparing the
2900 to the 2950, the meter was the only redeeming quality of the 2900. The 2900 radio was a complete failure.
There were modifications on top of modifications to attempt to make these radios
work. One was so extensive, it required numerous parts and circuitry
changes, taking a couple of hours to complete. After all the
upgrades, the radio was still not very good. In fact as soon as the 2950
was released they no longer recommended the upgrade, they suggested radio
replacement. I imagine some 2900 owners received a free 2950 as a
replacement if they complained loud enough.
Ranger Communications has continued to improve their
engineering and manufacturing techniques over the years. They manufacture
most of the 10 Meter radios on the market today. Their factories
manufacture radios for many other US based companies including Galaxy. They have been known to copy or clone radios like the
President Jackson and Grant, this information is only included to inform,
not to praise them for doing so. In fact, the 10 Meter chassis used in all
their radios have evolved from that original Uniden design. The dual
final, AM modulator/regulator, mixer, receiver stages are all variations
of that original 120 channel Grant radio. The designs quickly included
circuitry to increase bandwidth to cover the increasing frequency range. Other variations were to adapt for obsolete components as years
Now Ranger Communications has improved the 2950 with
completely redesigned CPU and main circuit boards. From the outside, you
may think itís the same old 2950. All the controls and buttons are in
the same location as in its predecessor. The face is gray instead of black
and of course, itís labeled 2950DX. Many operators thought the only
difference was the dual band coverage. This wouldnít have taken a
complete redesign; there were Mirage 2950s that covered 24.0000 MHz to
30.0000MHz. The only difference between the RCI and the Mirage was the
CPU. The main board was pretty much the same. However, the real news is
that the 2950DX is improved in many areas. Not too many people are aware of
why the 2950 radio was really redesigned. The driving force was Sony
discontinuing the PLL chip used in this radio. The chip was discontinued
some years ago. RCI must have made one last large purchase of the chips to
keep them going as long as they did.
SMT or surface mount technology is used in this new
generation Ranger. Many radio shops havenít been receptive to the
surface mount technology used in these radios. They are more difficult to
repair, if not impossible for some shops. To combat this Ranger changed
the warranty period from one year to two years, in order to show their
faith in this newer technology. It seems to be working, sales of these
radios has increased in recent months.
RCI is using this CPU and main board combo in a
number of radios. The 2950DX-30 Watt mobile, 2970DX-150 Watt mobile,
2985DX-30 Watt base station, the 2990DX-150 Watt base station, and Iíve
been told the 5054DX 6 Meter mobile. The board even has provisions for
producing an AM/FM only version, which has caused this issue of CB World
Informer to run
late. This will be explained later in the review.
The first look inside is memorable. This doesnít
look like any of the other RCI HF radios. There is RF shielding on the main PC
board for VCO circuits, TX mixer circuit, and RX front end, mixer and initial
IF stages. All the tin shields are punched for adjustment access and are
stamped with the adjustment designators. Quite impressive, this hasnít
been done since the late 1970s. Two radios come to mind that had this
level of shielding, the CPI CB radio line and the Stoner PRO-40 SSB rig. These of
course were CB radios, but they were top of the line rigs and operated in
the sister band of 11 Meters.
A look at the 2950DX schematic revealed a double balanced
mixer stage in the receiver. This is found in HF rigs costing many times
the price of the radio. This design is used for better intermodulation
rejection. RCI claims other receiver enhancements that improve the
receiver sensitivity. Also revealed, the schematic contains a
seven-transistor noise blanker. Weíll put that baby to the test at the
shopís noisy location.
The Ranger specification sheet indicates that the
meter is capable of reading modulation, no function found to perform this
measurement. This is a misprint. The frequency stability is
listed as .001%. If this specification is true, this makes it one of the
most frequency-stable 10 Meter radios available.
Itís now time for the stock radio bench test. The
first results are with the RF power control set to the full power
clockwise rotation. The AM
and FM output is at 9-Watts. The AM modulation swing is 22-Watts peak. The
sideband power is 27-Watts PEP. Now the output readings with the RF power
control in the low power counter-clockwise rotation. The AM/FM power
dropped to 1-Watt. The AM modulation swing is 2.5-Watts PEP. The sideband
power dropped to 4 ĖWatts PEP.
Testing the receiver indicated that the sensitivity
was quite good on all modes. Even very weak signals on AM and sideband
were cleaner than on the old 2950 and on most 10 Meter radios for that
satisfied with the sensitivity of the receiver, the selectivity was then
checked. My crude method is to crank up the signal generator to full RF
output, modulated to 100% with a 1KHz tone. This registers 30 dB on a
calibrated ďSĒ meter, or is equivalent to a signal of someone less than a ľ mile away.
On AM & FM, the radio performed much better than expected. The old
2950 didnít do very well with this test. Sideband however, displayed a
signal of approximately 4 bars on the LCD meter 200KHz on ether side of
the center frequency before the strength started to decrease. This is to
say, if someone was coming in at 30dB on channel 20, the signal from that
transmission would still be received at four bars on channels 1 and 40.
Being puzzled and thinking this must be a defective
radio; a second 2950DX was pulled from its box and tested. The results
were identical. To confirm the test equipment was operating properly, two
radios were tested, a Uniden Grant and a Galaxy 88. Both radios tested
fine. Now the story gets more interesting, a call to JR at Ranger service
didnít resolve the issue. JR said they could not reproduce the results
at their service lab. He went further to say the ARRL tested the RCI
2970DX and found no problem of this type. As concern grew, a decision to
contact the author of the RCI 2970DX review in QST magazine was made.
Contacting Wayne Irwin was a pleasant experience. After explaining that he
wasnít responsible for the lab testing, he offered to find what he could
and reply. Wayne agreed the transmitter unwanted sideband figure of 39dB
(50dB is a minimum figure one would expect) could be due to the design
issue findings. Here is the response from Wayne:
just checked with Joe Bottiglieri in the editorial office.
It appears that the problem you found with the Ranger was not
apparent in our lab tests. Since you have seen it in a couple different
radios, he suggests that you consider submitting a little piece for
possible publication in Hints and Kinks.
many thanks for your feedback.
K. Irwin, W1KI
to the ARRL VEC Manager
The E-mail states the problem wasnít apparent in
their lab tests, but they donít deny a potential problem. Looking at the
receiver test results, a test for selectivity was done on FM, but no SSB
selectivity test results were published. The assumption may have been
made, that if FM were tight SSB would be better. I wrongly made this
assumption myself on all the radios tested prior to this article. I will
cover what I feel is a design flaw and what is needed to correct the
potential problem in the next article, titled Image Rejection
I have also tried to contact Gordon West about his
findings while reviewing the RCI 2970DX for Popular Communications. I
haven't received a response yet.
Continuing the review with a modified IF stage showed
the 2950DX to achieve excellent results on the sideband selectivity test.
Compared to other 10 Meter radios, the RCI 2950DX performance was
outstanding, and this one covers 24 MHz to 32 Mhz. Until now, radios
selectivity suffered more as frequency coverage increased.
The RF power control works well and tracks well with
the modulation and output limiter circuits very well as long as the
limiter isnít removed altogether. This radio sounds so good, I donít
recommend eliminating the limiter circuit. Great results can be had by
turning up the SSB power, SSB limits, and AM modulation controls up fully. If
you were looking for a radio to make a lot of noise with, many other
radios would be a better choice. This is a great all mode radio, for
operatorís who are looking for good clean communications, donít spoil
it with the old tricks to get every last milli-watt out of it. Square wave
audio isnít becoming of this one.
Testing the receiver on the air dramatically
demonstrated the difference between the RCI 2950DX and its predecessor.
All modes sounded clear and crisp. Even very weak signals were easy to
understand. Single sideband is especially natural sounding, with greater
sensitivity and lower noise than any other 10 Meter radios Iíve tested
to date. The only fault with the radio is the meter. It flickers on AM and
SSB not holding long enough to achieve accurate readings. This was
corrected by the addition of a 4.7uf capacitor connecting the positive
lead to the MT signal or the band side of D14 and the negative side of the
capacitor to ground. This only effects the meter portion of the radio,
both incoming signal and outgoing power
Frequency stability is super. The radio tested
drifted only 30 Hz from power on to one hour of running. The clarifier is
very easy to tune whether itís unlocked or not.
The display is unchanged with its large six-digit
frequency readout. The backlighting has changed from amber to green. This
green lighting is very evenly distributed and it almost appears to be of
the electro luminescent type used in the Cherokee and Cobra faceplates,
but itís not. The schematic indicates two incandescent lamps, but the
lamps are in a sealed unit and an ohmmeter reading leads me to believe
there may be banks of LED in the light panel. I hope this to be true, LEDs
will last much longer.
If youíre familiar with the old 2950, youíll know
how all the functions work, they havenít changed much. The following
figure indicates the front panel controls, switches, and indicators.
- FREQUENCY SELECTOR
This control is used to select a desired transmit and receive frequency.
- RF POWER CONTROL
This control allows the user to adjust RF power output.
- MIC GAIN CONTROL
Adjusts the microphone gain in the transmit and PA modes. This controls the gain to the extent that full talk power is available several inches away from the microphone. In the Public Address (PA) mode, the control functions as the volume control.
- ON/OFF VOLUME CONTROL
This knob controls the volume and the power to the radio. To turn the radio on, rotate knob clockwise. Turning the knob further will increase the volume of the receiver.
- SQUELCH CONTROL
This switch is used to eliminate background noise being heard through the receiver which can be disturbing when no transmissions are being received. To use this feature, turn the
control fully counterclockwise and then turn clockwise slowly until the background noise is just eliminate. Further clockwise rotation will increase the threshold level, which a signal must overcome in order to be heard. Only
very strong signals will be heard at a maximum clockwise setting.
- RF GAIN CONTROL
This control is used to reduce the gain of the RF receiver amplifier under strong signal
- CLARIFIER CONTROL
Allows tuning of the receive frequency above or below the assigned frequency by up to 500 Hz. Although this control is intended primarily to tune in SSB/CW signals, it may be used to optimize AM/FM signals.
- MODE (FM/AM/USB/LSB/CW/PA) SWITCH
This switch allows you to select one of the following operating modes:
- NB/ANL BUTTON (NB/ANL)
In the NB/ANL position, the RF Noise Blanker and Automatic Noise Limiter in the audio circuits are also activated. The Noise Blanker is very effective in eliminating repetitive impulse noise such as ignition interference.
- ROGER BEEP BUTTON (R.BEEP)
In the Roger Beep position, the radio transmits an audio tone at the end of your transmission to indicate that transmission has ended. As a courtesy to others, use the Roger Beep only when necessary.
- SPLIT BUTTON (SPLIT)
This control activates the offset frequency function. It causes the transmit frequency to be offset either above or below the receive frequency by a user programmable amount to allow operation of an FM
- PROGRAM BUTTON (PRG)
This button is used to program operating or scanning frequencies into memory. See the OPERATION section of the manual for further details.
- MANUAL BUTTON (MAN)
This is used to return the unit to manual mode.
- SHIFT BUTTON (SHF)
This is used to select 100 Hz, 1 KHz, 1O KHz, 100 KHz or 1 MHz frequency steps.
- DIM BUTTON (DIM)
This button adjusts the display backlighting in four different steps to best match the ambient light.
- SWR BUTTON (SWR)
This control is used to check SWR.
- SCAN BUTTON (SCAN)
This is used to scan frequencies in each band segment. The OPERATION segment of
the user manual provides detailed information on using the SCAN control.
- MEMORY BUTTON (MEM)
This button is used to program memory channels. Detailed information on how to use this control is provided in the OPERATION section of
the user manual.
- ENTER BUTTON (ENT)
This is used to program frequencies in memory. See the OPERATION section of this manual for more information on using this control.
- LOCK BUTTON (LOCK)
This button is used to lock a selected frequency. Press it to activate the switch. In this position, it disables the Frequency Selector Control, up/down buttons on the front control panel and remote up/down buttons on the microphone. Repressing the switch will unlock the frequency.
- UP/DOWN SELECTOR
These buttons are used in conjunction with the shift key to move the frequency upward or downward to select a desired frequency.
This meter indicates received signal strength, transmitter RF output power and SWR level.
- LCD DISPLAY
The LCD displays the frequency selected, functions and memory channel.
- MIC JACK
Accepts 6 pin female connector with a type Philmore T616C or Calrad 30445 style connector.
Press PRG, then press MEM, then enter frequency, then press ENT.
To select any of the 0-9 memories, press MEM each time to step
to the next desired memory channel.
Press PRG, then press SCAN (SCAN+ will appear on the display),
then enter frequency for the high scan limit, then press ENT,
then press SCAN (SCAN- will appear on the display), then enter
the frequency for the low scan limit, then press ENT. Unlike
the 2950, setting the scan limit doesn't limit the frequency
operation outside the scan mode, even though the DX user manual
states it will.
Press PRG, then press SPLIT, enter the desired frequency split,
then press ENT.
Memory channels are accessed by pressing the MEM
button. Each time the MEM button is pressed, the memory advances one
channel. To exit the memory channels, press the MAN button.
Two scan options are available, memory scan and
frequency scan. Frequency scan will scan between the high and low limits programmed.
If no limits are programmed, the radio will scan the entire frequency
range of the radio. Squelching the radio starts the radio
scanning. Once a signal breaks through the squelch, the radio pauses until
the signal no longer breaks the squelch for about a second. Pressing the SCAN button once
indicates a SCAN(+) on the display and causes the radio to scan up.
Pressing the SCAN button again indicates SCAN(-) on the display and causes
the radio to scan down.
The split frequency is selected by pressing the SPLIT
button. Pressing the SPLIT button once indicates SPLIT(+) on the display
and causes the amount of frequency split programmed to be added to the
receiver frequency during transmission. Pressing the SPLIT button again
indicates SPLIT(-) on the display and causes the amount of frequency split
programmed to be subtracted from the receiver frequency. Pressing the
SPLIT button a third time shuts off the split feature.
If you've never used a 2950 before, it comes with a user
manual that Wayne from QST correctly regards as adequate that will help
you master the functions. If you liked the
2950, youíll love the 2950DX. This is a great dual band radio for the
money; I recommend it for anyone that takes radio seriously. If you
werenít impressed with the old 2950, like myself, I think youíll have
a different outlook on Ranger Communications Inc. after trying one of these! Bob
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