Ranger_RCI-2970DX_review_2001.pdf

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1、Product Review all-mode op- eration: AM, FM, USB, LSB and CW; memory and VFO scan capabilities; and built-in SWR metering. The General Configuration The RCI-2970DXs front panel is domi- nated by a large LCD display. Frequency digits, a vertical bargraph S/RF/SWR meter and over a dozen small feature

2、icons appear as black segments on a light green field. Background illumination can be set to one of three different levels or shut off completely. The small main tuning knob is located on the left edge of faceplate, and has a detented tuning action. Just below this knob is a six-pin microphone conne

3、c- tor. A hand mike is provided. Four more knobs are located on the far right of the front panel. Three of these are concentric pairs that handle the volume and squelch; RF power and mike gain; and RIT (labeled CLR) and RF gain. The fourth is the mode switch, which includes posi- tions for AM, USB,

4、LSB, CW and PA (public address). These four controls are grouped close together. It can be difficult to change the settings of their outer rings without inadvertently disturbing the set- tings of their immediate neighbors. Two rows of seven backlit translucent buttons are located just below the disp

5、lay window. Their assignments are printed directly on the surface of each key. Nearly all of these keys perform just one particu- lar task. This makes operating the trans- ceiver fairly easy and intuitive. No “func- tion key” combinations are required to access secondary key operations, so you wont

6、find yourself straining to read un- lit secondary assignment labels (which are typically printed directly on the face- plate of most other transceivers). The rear panel is the epitome of sim- plicity. There are three 1/8-inch phone jacksfor a CW key, external speaker Bottom Line With a higher level

7、of RF output power and real all-mode capabilities on both 10 and 12 meters, the RCI-2970DX packs in lots more fun than the typical 10-meter mobile. From October 2001 QST ARRL Table 2 Ranger Communications RCI-2970DX, serial number T1M00426 Manufacturers Claimed SpecificationsMeasured in the ARRL Lab

8、 Frequency coverage: receive and transmit, 24.89-24.99, 28-29.7 MHz.Receive and transmit, as specified. Modes of operation: CW, USB, LSB, FM, AM.As specified. Power requirements: 13.8 V dc; current consumption not specified.Receive, 0.35 A; transmit, 18 A, tested at 13.8 V. Size (HWD): 3.97.89.3 inc

9、hes; weight, 7.4 lb. ReceiverReceiver Dynamic Testing SSB/CW/AM Sensitivity, 10 dB (S+N)/N: 0.5 V.Noise floor (MDS)1: 24.9 MHz136 dBm 28 MHz132 dBm AM, 10 dB (S+N)/N, 1-kHz tone, 30% modulation: 29 MHz0.42 V FM sensitivity, 12 dB (S+N)/N: 0.25 V.For 12-dB SINAD: 29 MHz0.31 V Blocking dynamic range:

10、Not specified.Blocking dynamic range, 20-kHz spacing:1 24.9 MHz81 dB 28 MHz75 dB Two-tone, third-order IMD dynamic range: Not specified.Two-tone, third-order IMD dynamic range:1 24.9 MHz66 dB 28 MHz61 dB Third-order intercept: Not specified.Intercept: 24.9 MHz, 37 dBm; 28 MHz, 41 dBm.2 FM adjacent c

11、hannel rejection: Not specified.20-kHz offset from 29 MHz, 77 dB. FM two-tone, third-order IMD dynamic range: Not specified.20-kHz channel spacing, 29 MHz, 53 dB. Spurious response: IF rejection, 65 dB, imageIF rejection: 105 dB; image rejection, 72 dB. rejection: Not specified. Squelch sensitivity:

12、 Not specified.0.12 V at threshold. Audio power output: 2.5 W, THD and load unspecified.3.0 W at 10% THD into 8 . TransmitterTransmitter Dynamic Testing Power output: CW, FM, AM, 50 W; SSB, 150 W.AM, CW, typically 51 W; FM, typically 60 W; SSB, typically 115 W.3 Spurious signal and harmonic suppress

13、ion: 50 dB.53 dB. Meets FCC requirements for spectral purity. SSB carrier suppression: 50 dB.46 dB. Undesired sideband suppression: Not specified.39 dB. Third-order intermodulation distortion (IMD) products:See Figures 6 and 7. CW keying characteristics: Not specified.See Figure 8. Transmit-receive

14、turn-around time (PTTSquelch on, S9 signal, 200 ms. release to 50% of full audio output): Not specified. Unit is not suitable for use on AMTOR. Receive-transmit turn-around time (“tx delay”): Not specified.SSB, 1 ms; FM, 1 ms. Composite transmitted noise: Not specified.See Figures 9 and 10. All dyna

15、mic range measurements are taken at the ARRL Lab standard spacing of 20 kHz. 1500-Hz bandwidth filter not available. Bandwidth on CW is approximately 1900 Hz. See text. 2Intercept points calculated using noise floor method. 3See text. and public address speakera chassis mounted SO-239 antenna jack a

16、nd a six-pin rectangular dc power jack. A headphone jack is not provided. The dc power connector is physically the same as the one found on the vast majority of modern HF transceivers, but beware: the wiring configuration is different. The in- cluded dc power cable is about 10 feet long and is fused

17、 in both leads. A massive heat sink is fastened to the underside of the enclosure. The radio does not employ a cooling fan. My oper- ating experiences indicate that the cool- ing system is sufficient; I didnt encoun- ter any instances where the heat sink became particularly hot. The U-shaped mobile

18、mounting bracket thats packed with the rig can only be attached toward the upper side of the enclosure. This allows you to mount the radio under a dashboard or shelfnot above. An extended bracket that fits be- low the radio is available as an optional accessory. Four thumbscrews are pro- vided for s

19、ecuring the mobile mounting bracket to the chassis. Some additional mounting hardware and a microphone hanger are also included. Documentation The small 18-page Owners Manual is adequate, though not overflowing with From October 2001 QST ARRL 1086420246810 80 70 60 50 40 30 20 10 0 Frequency Offset

20、(kHz) Reference Level: 0 dB PEP information. A brief description of each of the controls and jacks is provided. Most operators should have little, if any, diffi- culty with installation and proper opera- tion using the information provided, how- ever. The majority of the control functions are appare

21、nt from the labels on or near the controls. After I negotiated the short learn- ing curve, I found the radio to be relatively user friendly. Stern warnings about the consequences of unlicensed operation on the Amateur Bands are included on the carton, in the manual and on a label af- fixed to the to

22、p cover of the radio. No schematic or other service infor- mation is included in the manual, but a diagram of the mike connector pin out is presented for those that want to use a microphone other than the supplied hand mike or to wire the rig up for digital mode operation. Factory service manuals ar

23、e available. Figure 6Spectral display of the RCI-2970DX transmitter during two-tone intermodulation distortion (IMD) testing on 10 meters. The worst-case third-order product is approximately 21 dB below PEP output, and the worst-case fifth- order product is down approximately 32 dB. The transceiver

24、was being operated at 100 W PEP output at 28.35 MHz. Figure 7Spectral display of the RCI-2970DX transmitter during two-tone intermodulation distortion (IMD) testing on 12 meters. The worst-case third-order product is approximately 27 dB below PEP output, and the worst-case fifth-order product is dow

25、n approximately 37 dB. The transceiver was being operated at 100 W PEP output at 24.95 MHz. Figure 8CW keying waveform for the RCI-2970DX showing the first two dits using external keying. Equivalent keying speed is 60 WPM. The upper trace is the actual key closure; the lower trace is the RF envelope

26、. The transceiver was being operated at 50 W output at 28.02 MHz. Figure 10Spectral display of the RCI-2970DX transmitter output during composite-noise testing at 24.92 MHz. Power output is 50 W. The carrier, off the left edge of the plot, is not shown. This plot shows composite transmitted noise 2

27、to 22 kHz from the carrier. Figure 9Spectral display of the RCI-2970DX transmitter output during composite-noise testing at 28.02 MHz. Power output is 50 W. The carrier, off the left edge of the plot, is not shown. This plot shows composite transmitted noise 2 to 22 kHz from the carrier. Tuning Ther

28、e are several different ways to set the operating frequency. The main tun- ing knob is perhaps the most obvious method, but you can also employ a pair of CHANNEL buttons located on the top of the microphone or L and M buttons on the front panel. The smallest tuning step is 10 Hz. Finer receive tunin

29、g is ac- complished by use of the receive incre- mental tuning knoblabeled CLR (for “clarifier”)on the front panel. The main tuning knob or buttons can be used to change the frequencies in 10 Hz; 1, 10 or 100 kHz; or 1 MHz steps. This feat is accomplished by using the radios SHF button to move the p

30、osition a small arrow icon under the digit that you wish to change. The tuning knob or keys are then employed to tune by the se- lected digit. Band changing is a bit unusual. While you can move from 12 meters to 10 meters by placing the arrow under the 1 MHz digit and tuning, in order to move from 1

31、0 to 12, youve got to place the arrow under the 100 kHz digit and tune above or below the 10-meter band limits. When the radio is in the memory mode, a MEMORY icon and the channel number appear in the display just to the left of the operating frequency. Ten memories are available and are selected us

32、ing any of the same three controls that are used for VFO tuning. The memories are not “tuneable.” SSB Operation The majority of operators will prob- ably use this radio for single sideband operation. Lets take a look at this type of operation first. The 2970DX supports both upper and lower sideband

33、(lower sideband is handy for those who might want to operate RTTY). There are separate controls for the microphone gain and RF power out- put. VOX operation is not supported. When I initially got on the air in this mode, I received a report from an opera- tor in the Midwest that my transmit au- dio

34、sounded distorted. After a minute or so of head scratching, I discovered that I had the microphone gain control set too high. Theres no ALC level indicator on the radio, so it takes some experimen- tation to find the setting that works best for your particular voice character- istics. I set the knob

35、 at about mid rota- tion, and subsequent reports verified that the audio sounded fine. Information on split frequency opera- tion in the SSB mode is not included in the manual, but the radio does have this capability. Rare DX and DXpeditions 1086420246810 80 70 60 50 40 30 20 10 0 Frequency Offset (

36、kHz) Reference Level: 0 dB PEP 246810121416182022 140 130 120 110 100 90 80 70 60 Frequency Sweep: 2 to 22 kHz from Carrier Reference Level: - 60 dBc/Hz Vertical Scale: dBc/Hz 246810121416182022 140 130 120 110 100 90 80 70 60 Frequency Sweep: 2 to 22 kHz from Carrier Reference Level: - 60 dBc/Hz Ve

37、rtical Scale: dBc/Hz From October 2001 QST ARRL will use split frequency operation as a pileup management tool, so this can be an important feature (see “Working Split: Whats the Secret?” by Duane Traver, WV2B, QST, May 2001). Set this up us- ing the instructions in the manual given for FM repeater

38、operation. Adjust the “repeater” offset value somewhere in the range that the DX is “listening up” typically 5 or 10 kHzand activate a positive split. On transmit, the radio should display the higher frequency. (This trick will also work in the CW mode.) While this arrangement is not as flexible as

39、split operation on a radio that features dual VFOs, it is most definitely workable! FM Operation In the FM mode, the 2970DX will generate about 50 W of RF power, and the transmit audio reports were univer- sally positive. The offset and split fea- tures that I just discussed are intended primarily f

40、or FM repeater operation. Most 10-meter FM repeaters are set up for a 100 kHz offset. One minor annoy- ance is that this offset information and the operating mode is not retained in the memories. If you choose to program FM repeater frequencies into the memories, youll have to remember to switch to

41、the FM mode and activate the split manually when you dial them up. The radio is not equipped with a CTCSS encoder. Internal provisions, however, are made to facilitate wiring in aftermarket tone boardssuch as those offered by Communications Specialists. Inclusion of this feature would have greatly e

42、nhanced the viability of this ra- dio for the 10-meter FM enthusiast. Due to the DX propagation characteristics of 10 meters, many of these repeaters are CTCSS tone protected so as to reduce interference between repeater systems that share the same frequency pairs. CW Operation Ranger Communications

43、 has not com- pletely forsaken the CW operator in the design of the RCI-2970DX (as was the case with one 10-meter monobander that we recently reviewed), although this transceiver would not be the radio of choice for a serious CW aficionado. A narrow CW filter is not provided nor is one available as

44、an optionand the receivers CW bandwidth is in the “barn door” category: about 1900 Hz. This can make copying a desired signal under even moderately busy band conditions an ex- ercise in concentration! A single CW signal will also appear on both sides of zero beat. (You can, how- ever, verify that yo

45、uve got a CW signal properly tuned by taking a quick listen for the signal in the LSB mode. If its there, youre tuned correctly.) A straight key or an external keyer connects via an 1/8-inch phone jack on the rear panel. Keying is semi break-in. The CW sidetone level and pitch is fixed, and sounds t

46、o be about 1200 Hz. Power out- put on CW is limited to about 50 W. So What are the Other Mode Switch Positions For? The RCI-2970DX is also capable of operation in the AM mode. Youll find a moderate amount of 10-meter AM activ- ity between 29.0 and 29.3 MHz. Maxi- mum RF output power in this mode is

47、around 50 W. The bandswitch also includes a PA position. This activates a “public ad- dress” system. In this “mode” the trans- mitter is disabled and amplified micro- phone audio is available at an independent external speaker jack on the rear panel. (Keep in mind that the use of public address syst

48、ems in vehicles may be subject to local restrictions.) This fea- ture might also come in handy as a means of checking the sound of the transmit audio when testing alternative micro- phones or setting levels for digital opera- tion. When testing microphones, keep careful tabs on the volume setting th

49、ough, or feedback will result. Lab Test Results When looking over the receiver per- formance data that appears in Table 2, its important to note that the numbers for the noise floor, blocking dynamic range and two-tone third-order IMD dynamic range are at the minimum CW bandwidth available (1900 Hz in this instance). Whenever possible, the Lab makes these measurements at 500-Hz bandwidth. Con- sequently, you shouldnt use these figures to make direct comparisons to the num- bers weve reported for others units that were taken at the 500-Hz bandwidth. While the radio does exhibit blo