Inhaltsverzeichnis
Drake R - 8 A
Manufactured by R. L. Drake.
In April 1991, Drake returned with the announcement of the R - 8 to the shortwave receiver market after an absence of many years, the set was subsequently improved several times:
- R-8: initial version: the different operation modes or IF filters could not be selected directly, by pressing a „carousel“ button the set went from one operation mode to the next, but without a „step back“ option, so that it was possible to switch from USB to LSB by pressing a button, but the way back to USB required the button pressd five times. The discontent of many DXers was increased because of the R-8 changed the IF filter bandwidth to a pre-programmed value simultaneously when the operation mode was changed…
- R-8A: with six buttons each, direct access to all filters and operation modes was possible, 440 frequency memories with alphanumeric labelling
- R-8B: Synchronous detector with independently selectable sidebands, 1000 frequency memories.
- R-8E : European version of the original R-8
The R-8A is a double conversion tabletop receiver from US production, which was in the middle price segment in its country of origin. Due to the microprocessor control, an alphanumeric labelling of the memories is possible in addition to the usual memory and scan functions, which makes the receiver stand out from the crowd. The receiver is operated entirely from the front panel, but it also is equipped with an RS-232C PC interface and can be controlled from a windows terminal or special control software. A monitor speaker is built-in, and an auxiliary speaker is available as an option. The only other option available is a VHF converter covering 35 - 55 and 108 - 174 MHz.
Technical data
- Frequency range: 10 KHz - 30 MHz
- Frequency display: Digital display 10 Hz
- Frequency memory: 440 memories (alphanumeric)
- Features: Numeric keypad for direct frequency input, RS232 interface
- Sensitivity: AM (A3) <1 μV, SSB <0.25 μV / Selectivity: 0.5/1.5 kHz, 1.8/3.6 kHz, 2.3/4.5 kHz, 4/8 kHz, 6/12 kHz (-6/-60 dB)
Power supply
- Mains operation: 110, 220 V
Dimensions
- 335 x 133 x 330 mm, weight 6.0 kg
Accessories
- MS-8: external loudspeaker
- VHF - converter
- Software for PC control of the receiver
Operation
The front panel of the black set has a clearl structure, although the front panel of the predecessor model R-8, on which all controls were located below the centre trim in the middle of the front panel, was even more impressive. The fact that the IF filters and operation modes could not be accessed directly was the big disadvantage of this set.
In the upper part of the front panel, you find from the left the S-meter, which is an analogue instrument and displays the signal strength adequately. Next to it, on the green backlit liquid crystal display, the time is continuously displayed in either local time or UTC when the set is turned off. After switching on, the operation frequency is displayed with an accuracy of up to 10 Hz depending on the selected tuning step, next to it the IF filter bandwidth and the operation mode. Below this, the state of the 6 menu buttons is displayed, VFO A/B, preamplifier / attenuator, AGC, noise blanker, antenna input, and notch filter. To the right, there are two blocks of six buttons that allow direct access to one of the five filter bandwidths and an automatic bandwidth selection mode as well as to one of the six operation modes. Next to the six menu buttons, you find the recessed power switch.
In the lower part of the front panel, you find at the left a double potentiometer to operate the notch filter and tone control, and next to it a numeric keypad for direct frequency entry. The numeric keys are arranged in a block of nine like on the telephones. To the right of this are four buttons which control the VFO / memory functions and next to them the UP/DOWN keys and the tuning knob. The latter is relatively small and light, but it is easy to operate thanks to a finger recess. It has an electronic flywheel effect, and the tuning step width can be varied between 1 kHz, 100 Hz and 10 Hz. Since two menu buttons are located just above the tuning knob, it cannot be easily replaced with a bigger model. At the bottom right are two concentric pots for passband tuning and squelch, and for the AF and RF gain adjustment.
The rubberised keys with a soft pressure point take some time to get used to, after you have operated the hard keys of the NRD receivers, at the beginning I often missed a digit when entering a frequency. Of course, I have inactivated the confirmation beep for each keystroke when I got the set.
As ergonomy is concerned, the pushbuttons on the front panel are problematic to reach - but it's a contrast to the keys on the NRD, which are located slightly too high. The concentric pots have raised criticism, although only the inner buttons are actually assigned to important functions.
The green backlight display can be dimmed in several steps and is readable without fatigue even over longer hours of listening time. The liquid crystal display has not spectacularly brilliant colours like the one on the competing NRD sets, but in a test, it caused only minimal RF interference.
The antenna connectors are located at the unit's rear panel. The socket Ant 1 accepts a PL 259 plug, a second antenna with low impedance or a high-impedance long wire can be connected to the Ant 2 terminals; both antennas can be selected from the front panel. Next to the external DC 12 V connector, there is the voltage selector and the plug-in socket for the mains cable. The internal as well as the external loudspeaker can be switched off separately. As a special feature, the Drake R-8A has two line output sockets, so a cassette recorder and a RTTY decoder can be connected at the same time. Finally, the 9-pin RS-232 interface is to be mentioned. A serial cable to the PC can be connected without any special interfaces (although today, most computers do not have a serial / COM1 port anymore).
A small built-in monitor speaker radiates upwards, the MS-8 is an external 2.5 watt loudspeaker matching the R-8, it sounds quite decent.
Operating concepts: I cannot comment on all details about the operation of the R-8A here, I don't want to quote the entire 40-page operating manual here, I will keep it to the steps important for practical use and would present you some possible operating scenarios:
Conservative: Some older communication receivers were equipped with a VFO. These receivers, which were technically based on the receiver section of an amateur radio shortwave transceiver, had a connector for an external VFO or had two individual internal VFO's, so that it was possible to switch between two „memory“ frequencies.
The Drake R-8A can be operated this way: The power switch turns it on, the first menu button selects VFO A or B, and then the tuning knob can be used to set the desired frequency. Select one of 5 IF filters and the operation mode (AM, LSB, USB, etc.) directly. A peculiarity of older Drake receivers was retained, each operation mode is coupled to the IF filter that is optimal in the eyes of the manufacturer: even the classic R-4C was modified by many owners, the coupling was often criticised in the original R-8. In the R-8A it is at least an option that can be switched off and even the filter assignments are freely programmable, so that when changing from AM to USB the receiver changes from the 6 kHz to the 2.3 kHz IF filter and the tuning step as changed to 10 Hz. When the button AM/SYNC is activated, the sync detector is activated, it engages with a short whistle even with weak signals and, together with the passband tuning, which shifts the filter passband to the side of only one sideband, can the intelligibility of a signal affected by interference can be greatly improved. Slow or fast AGC time constants can be selected, and their response and decay times are well designed. When the AGC is switched off, the RF gain can be adjusted with the RF gain control, which is a concentric knob behind the volume pot and is a bit difficult to access. The notch filter is used to fade out an unwanted interfering whistle; in contrast to earlier Drake sets, it acts on the AF level and has to be tweaked manually. In VFO mode, it is possible to switch back and forth between the two VFO channels A and B and to copy the memory contents - some listeners like the easy way, and you can catch up rare DX only with with two memory channels.
Contemporary: the more playful listener is spoiled by the R-8A with its 440 memories arranged in blocks of ten 00-09, 10-19, etc. The memory number is shown in the display below the frequency. With the two keys MEM and V>M it is possible to change from a stored frequency to VFO mode, by pressing V>M the active frequency can be stored in one of the 440 memory channels. In MEM mode, the main tuning knob or the up/down keys are used to jump from one frequency memory channel to the next, something useful to compare several stored BBC frequencies or the Brazilian locals in the 25 m band… The receiver has the usual scanning methods: all memory frequencies can be scanned, only the frequencies not previously blocked are scanned or a specific frequency range between two corner frequencies is scanned. Furthermore, the reaction of the R-8A after reaching a signal can be selected, i.e. to stay on the frequency, to play it only briefly or to continue searching after the carrier signal drops. The scanning possibilities are similar to those of the Sony ICF-2001D or the NRD receivers, but in one point the Drake R - 8 differs fundamentally from the above-mentioned receivers:
The memory channels can be assigned alphanumerical labels with 7 letters or numbers, when the NAME function is activated. However, the station name is not only displayed when a specific memory location is called up, but also when one comes close (+/- 1 kHz) to a previously stored station when sweeping a frequency band. For example, my receiver reports KADUNA when scanning the 60 m band at 4770 kHz, GABON is displayed when approaching 4777 kHz and MALI lights up at 4783. If good reception conditions prevail at the time, the text KADUNA is accompanied by the news from Radio Nigeria coming from the speaker. Of course, this magic only works when a frequency is typically used by only one station, the receiver is not yet able, like the DXer's ear, to identify a station by its programme.
This alphanumeric text memory function gives sense to the large memory capacity of a receiver for the first time. I can use the Drake set like a notebook for „interesting frequencies“ and then, for example, check the 90 m band in an evening to check whether signals on interesting frequencies can be heard. Linking alphanumeric memory channel labels with frequencies that are tuned to, could put an end to the endless discussions about the sense of hundreds of memory channels of a receiver. My handwritten notes on the contents of my NRD 525's 200 memories just lay on my desk unused.
memory intensive: In the first 6 months of operating my R-8A, I was quite happy with its memory possibilities, but - there was still this socket labelled „RS-232“ on the rear of the radio. After enquiries in Europe had yielded no results and I still lacked the necessary knowledge to become a PC programmer, although the commands for PC control of the R-8A are explained in detail in the manual. I finally found the right software came from Mark Fine, USA - Remington, Virginia: His Smart R-8 -Control programme not only allows complete control of the Drake receiver but also has a logbook and a database function. The first thing to do was to get a supplementary serial interface card and a serial modem cable with suitable plugs for my PC. Everything was plugged in, a „green plug“ lit up in the corresponding field to indicate successful contact, and my „darling“ was already responding to mouse clicks. From the screen, not only frequency entries can be made, but also the filters, operation modes, AGC, the attenuator and the antenna input can be selected; only the analogue controls (volume, tone, passband tuning and notch) still have to be operated by hand, but that can be done without a computer. The Drake's 440 memories can be read out, edited on the screen and stored as different files on the computers hard disk. Depending on the requirements, different memory assignments can be transferred to the R-8, which simplifies radio listening even after the computer causing RF noise has been switched off. The active settings can be transferred to an electronic logbook at the touch of a button, the time can be transferred from the computer to the Radio (or vice versa). From the station database, the programme can display the stations that are currently active on a frequency with their target areas, for example, if 9950 is entered at 21.20, „AIR Delhi, eu“. A click on the frequency display leads to the display of a list of the stations active on the frequency during the course of the day with their transmission times. It should be noted that the programme only includes English-language broadcasts and utility stations, and that the frequency selection is tailored to the US.
I compared my Drake R-8A with my NRD receivers 525 / 535, connected to a 40 m longwire antenna via a magnetic longwire balun from RF Systems, and with various classic tube receivers connected to a second 20 m longwire antenna.
The sensitivity seems to me to be slightly lower than that of the NRD competitors. This is only significant for stations with an extremely weak signal in a free frequency range without adjacent channel interference. Operated on a long-wire antenna, the sensitivity of all modern communications receivers is sufficient to reproduce weak stations. As a rule, the intelligibility limit is not set by the sensitivity but by the ability of a receiver to separate the wanted signal from interference. For example, depending on the propagation conditions, the R-8 reached its limits with the faint signal of Radio Republik Indonesia in the evening in the 19 m band, on other days the reception was perfect with a slightly stronger signal. In poor propagation conditions, the NRD-525 was once ahead reproducing the German language service of RAE Buenos Aires in the evening, also with the SSB signal of HCJB on 21455 kHz. As soon as the signal strength exceeded a minimum threshold, the reception was regularly more understandable and more pleasant to follow with the Drake. My Drake radio only had to give up when trying to receive Radio St. Helena in SSB in November 97, which only came through during signal peaks. With the NRD it was a little better, but it was not possible to follow the programme. The EKD500 with its superior SSB performance had to be used to follow the programme content.
The selectivity depends mainly on the filters used. With the R-8A, Drake returned to the technique of the L-C filter and provides the DXer with a wide selection of five bandwidths as standard, the skirts of these filters cannot not reach those of mechanical filters or sets with digital signal processing. However, the passband of these filters may be responsible for the fact that the intelligibility and the sound of the R-8 are so convincing to the DXer's ears. In my eyes, the bandwidth choice meets most listeners demands. In situation with an undisturbed signal, the 6 kHz filter can be used in AM, when things get tighter the 4 kHz filter is optimal and in the tropical bands the 2.3 kHz filter together with the passband tuning is of great value. In SSB, 4 kHz is sufficient for undisturbed situations and 2.3 and 1.8 kHz for adjacent channel interference, and the 500 Hz filter helps in CW.
The R-8 has a full and yet present sound in AM reception, even with narrower filter bandwidths. Listening to the Drake for longer periods of time with a narrow filter to me seems less tiring than with the NRD. In addition, the Drake lacks the high-frequency hiss that accompanies reproduction on the NRD 525. The sound of the Drake R-8 comes probably most near to the hollow state receivers, which is confirmed by several US American „hollow state DXers“. In difficult interference situations, the 2.3 kHz filter as well as the passband tuning, which has a large range and must be operated sensitively, especially with narrow filters, are particularly helpful. Only one interfering station, either above or below the 5 kHz channel spacing, can be handled well either with the passband tuning or by switching to USB / LSB reception. In a „sandwich“ situation with 2 interfering stations in the 5 kHz channel grid, e.g. the evening broadcast of Radio Korea Intl. on 3970 kHz, squeezed between RFI and Budapest with high signal levels, could be received moderately well with the passband shifted towards the weaker interfering signal from RFI by means of PBT shifting.
The reception of moderately jammed stations can usually be optimised with the available means in such a way that the programmes of Radio Thailand, All India Radio, Pakistan, R. Australia or today Radio New Zealand International can be followed for a longer time without geting tired. Even the weaker signals of the Christian US-American private stations such as WINB, WGTG or WJCR under average conditions are received quite stable so that the gospel music can still be enjoyed.
In contrast to the excellent sync detector of the Sony 2001D, the sideband of the R-8A is not selectable in sync mode, only the latest model, the Drake R-8B has this possibility. The sync detector of the R-8A helps with selective fading, but rarely improved the reception in my tests. The sidebands are only selectable by means of passband tuning, often the receiver has to resynchronise when adjusting the PBT, which is noticeable by a shorter or longer howl. The AGC times seem to be chosen well, with the fast time constant there is fortunately no long „muting“ of the receiver after a crackle….
In summary, the Drake R-8A and certainly its successor R-8B is a station receiver with many features, without any additional costs for the options, that fully meets my needs, especially as a radio listener with preferences for the tropical band. I can read and set all parameters directly on the front panel, I can use the memories thanks to the ingenious alphanumeric label function, my receiver also gives me „tips“ about the usual assignment when cranking through a band, the PC control allows me, thanks to the electronic program schedule, te hear stations, that I had a tendency to forget (there was a note about RNZL in some magazine….).
A negative point was the availability of the receiver in Europe: the Drake R-8A / B is available in the USA around 1100 US$ and costs 500 US$ less than the fully equipped NRD-535. In Germany the receiver was offered by one importer at 2440.- DM, at nearly the double price.
Technical principle
Solid state double conversion superhet.
Components
The set is equipped with semiconductors.