Albrecht_AE-485S_review_2001.pdf

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1、40RadCom January 2001 ReviewReviewReviewReviewReview Reviewed by Chris Lorek, G4HCL* The Albrecht AE485S 10m * PO Box 400, Eastleigh, Hants SO53 4ZF. W ITH THE SUNSPOT cycle at its present high state the 10m band is often open, with world-wide QSOs possible even if youre just using low power and sim

2、ple antennas. Several years ago, converted multimode CB rigs were very popular for this purpose, al- though you needed to have the required formal documentation from the Radiocommunications Agency to own and use one legally. Recent changes in the UK law now mean that we can freely purchase single-ba

3、nd 10m rigs again. Because of this, transceivers such as the Albrecht AE485S have become available. The AE485S is a lightweight and easily transportable single-band 10m rig, weigh- ing just 1.2kg and measuring 52 x 165 x 194mm. It has transceive modes of USB, LSB, FM and AM, with a maximum power out

4、put of 25W on SSB and FM, and 6W on AM. A variable power control lets you reduce this to a couple of watts for QRP work. Being originally derived from a multimode CB transceiver design, it does not have CW transmit capabilities, and just tunes using the front panel click-step control in 10kHz increm

5、ents. All isnt lost though, as a press of the front panel step button also lets you select the 1kHz digit for frequency selection, so you can interpolate between the 10kHz steps. A variable clarifier also lets you tune in between the 1kHz steps, albeit only on receive. For 10m FM operation it useful

6、ly has selectable plus and minus repeater shifts. Theres even a 1750Hz toneburst button on the supplied fist microphone for use with repeaters which need this for access. Five programmable memory channels are avail- able in which to store your operating fre- quencies, and a scan facility can search

7、through the entire tuning range in 10kHz steps, pausing whenever the receive squelch opens. CONTROLS THE FIST microphone also comes with up / down buttons for frequency / channel change, which operate in parallel with the front panel click-step control. A combined power on / off and rotary volume kn

8、ob is mounted just above the 6-pin microphone socket, and to the right of this are concentric controls for mic gain and receive RF gain, a further concentric control being fitted for variable transmit power and receive squelch adjustments. Each of the rotary controls has an orange backlit outer ring

9、 to help you locate them in the dark. The orange backlit front panel LCD shows the operating frequency to within 1kHz in large easily-read digits, with a further smaller digit to the right indicating the selected memory channel if youve recalled one of these. Along the bottom is a five-section bargr

10、aph giving you an S-meter reading on receive and relative output power level on transmit. Smaller icons show the operation mode, shift status, scan, audio low filter selection and noise blanker status. Six large push buttons below the display act together with a push-button facility on the clarifier

11、 control to give multi-function capability. These let you control the 100kHz, 10kHz or 1kHz frequency digit selection, noise blanker on / off, operation mode (USB / LSB / FM / AM), a low pass audio filter to cut out high-frequency noise, transmit repeater shift, last channel recall, scan, and memory

12、 save and recall functions. The repeater shift can be varied between 0 and 999kHz, I programmed this for 100kHz to suit 10m operation but other shifts (eg 600kHz) could be useful if youre using, say, a 2m transverter with the rig. The transceiver comes supplied with an adjustable mobile mounting bra

13、cket, mic clip, a fused DC power lead and a 17-page user instruction booklet. An internal speaker is fitted to the lower case lid of the trans- ceiver, and a 3.5mm jack socket is also fitted at the rear which lets you plug in an external speaker if you wish. Thats it, a no- nonsense, easy to use, ri

14、g to get you on to 10m. So lets see how it performed on-air. IN USE THE OPERATION OF the trans- ceiver was very simple, as long as I kept to the pre-set 10kHz steps and within minutes of connecting it up to my power supply and antenna I was having my first contact on 29.600MHz FM. Over the review pe

15、riod, 10m was certainly lively dur- ing the daytime, with plenty of European, Russian, and both North and South Ameri- can stations coming in. One such station was Ray, DL2GG/YV5, in Caracas, Ven- ezuela, romping in at exceptional strength on FM one lunchtime working G stations. As well as direct FM

16、 operation, I was able to operate through a number of 10m FM repeaters across 29.610 to 29.690MHz. Some of these, typically North American ones, require a CTCSS tone for access, which the AE485 isnt equipped with. How- ever, I did successfully operate through a number of repeaters in areas around th

17、e world. I must say, though, that I often pre- ferred simplex, as the overall multipath dis- tortion was rather less. If youve ever oper- ated HF FM in an ionospheric fading environ- ment youll know that signals often become quite distorted as a result of this. The traditional DX modes are of course

18、, CW and SSB and, together with various data modes such as PSK31, these are the mainstay of most HF operation (the AM mode included instead of CW on the AE485 revealing its design origins as a mass-user CB rig). This mass-production does, how- ever, make it economic enough to be placed on to the ama

19、teur market, which we cant argue with! The transceiver did, in fact, operate reasonably well on SSB, with re- ports on my transmit audio being well up to those of a top-flight amateur transceiver costing much more - no wide transmit splat- ter here! I felt the receive bandwidth was a little on the w

20、ide side, with the occasional adjacent SSB signal sometimes splitching through. But then 10m isnt usually an overcrowded band, and I never found this to be a problem in use on SSB. A slight limitation I did find was that I couldnt always accurately net on to a station calling CQ, or call in at the e

21、nd of an existing contact, without sometimes be- ing up to a few hundred Hertz off-frequency 41RadCom January 2001 ReviewReviewReviewReviewReview Multimode Transceiver due to the 1kHz minimum transmit steps. But even with this, calling in- variably brought a response from the other station and I fou

22、nd that a quick explanation of the rigs 1kHz incre- ments was always understood and acknowledged by the other station. They typically just continued to keep their RIT switched in for the remain- der of the contact. The step button let me alter the 1kHz setting of the frequency display, but this didn

23、t mean the transceiver tuned across the band in 1kHz steps - after 10kHz it rolled round again, ie 8 kHz, 9 kHz, 0 kHz, 1 kHz etc, without incrementing the 10kHz digit when 0 kHz digit was reached. This meant that finding SSB signals over a range of, say, 100kHz or so was a bit of a two-handed affai

24、r in looking around 10 segments of 10kHz each, but I quickly got used to this. FM was no problem whatsoever, with stations typically using 10kHz steps as op- erating channels. Potential CW operation does suffer from this step limitation though, and naturally theres no CW key input jack. The memory c

25、hannels store the frequency but not the operating mode or repeater off- set. But in use I tended to use these as handy scratch pad memories when tuning around, particularly on SSB, making QSYing back an easy job. The last used frequency button was also quite handy, this remem- bered the frequency wh

26、ich Id either last transmitted on or listened to for at least a few seconds, again letting me QSY back very quickly. The user manual doesnt give circuit or mic connection details and so I didnt test the transceiver on CW or data modes as this would need a bit of circuitry experimen- tation. But usin

27、g a program such as DigiPan on PSK31 overcomes 1kHz step size and receive filter bandwidth limitations, and the transceiver would certainly be a powerful QRP tool using this mode. LABORATORY TESTS THESE SHOW THE receiver to be ad- equately sensitive as well as quite sensitive given its intended use

28、in terms of blocking and other strong-signal rejection. The re- ceive intermodulation rejection (where off- frequency signals combine internally to form an on-frequency interfering signal) wasnt up to that of an expensive top-flight purpose- built amateur transceiver, also the SSB re- ceive bandwidt

29、h which was, as I found on air, a little wider than usual. But one would expect this and once again, 10m isnt usually the busiest of bands strong-signal wise. On transmit, just over 25W maximum was produced on both FM and SSB modes, the operat- ing frequency being accurate to within a few tens of He

30、rtz. Trans- mit harmonics were nicely sup- pressed, something which sur- prised me at first, showing the internal filtering to be very effec- tive. The transmit IMD (ie the amount of splatter youre likely to cause) again wasnt that of a rather more expensive top-flight rig, but it certainly wasnt as

31、 bad as Ive seen on some transmitters! CONCLUSIONS THE ALBRECHT AE485S is an easy-to- use transceiver for 10m FM and SSB, its also very lightweight and ideal for taking along with you on holiday for a spell of DX operation. The 1kHz minimum transmit steps are a slight limitation for SSB working, and

32、 no CW mode is available, but the re- ceive clarifier allows received stations to be tuned in correctly. The transceiver has recently been re- duced in price to 169.95. Our thanks go to Martin Lynch and Sons (tel: 0208 566 1120) for the loan of the transceiver for review. If you order from ML&S befo

33、re the end of January 2001 and quote RadCom, you can claim free carriage. SSB IMD Performance Measured with a two-tone AF signal at onset of Tx ALC, results given as dB below PEP level. 3rd Order5th Order7th Order9th Order11th Order +ve:-31dB-33dB-41dB-39dB-38dB -ve:-31dB-41dB-50dB-43dB-47dB Harmoni

34、cs 2nd:-67dBc 3rd:-75dBc 4th:-77dBc 5th:-72dBc 6th:-90dBc 7th:-90dBc TX Power / Current Consumption Connected to stabilised 13.8V DC using supplied DC lead Max Power:26.3W (5.6A) Min Power:1.85W (2.85A) S-Meter Linearity SSB AM FM Sig LevelRel LevelSig LevelRel LevelSig LevelRel Level S11.40 V pd-38

35、.6dB2.18 V pd-36.0dB1.68 V pd-28.9dB S32.83 V pd-30.8dB4.18 V pd-30.4dB3.08 V pd-23.7dB S57.59 V pd-22.2dB10.6 V pd-22.2dB6.56 V pd-17.1dB S997.3 V pd-0dB ref64.3 V pd0dB ref48.5 V pd0dB ref S9+30825 V pd+18.7dB1.31 V pd+19.7dB738 V pd+23.9dB Image Rejection 1st image: 92.5dB 2nd image: 78.7dB 3rd O

36、rder Intermodulation Rejection Increase over 12dB SINAD level of two interfering signals giving identical 12dB SINAD on-channel 3rd order intermodulation product, measured at 21.4MHz. SSBAMFM 20kHz spaced signals:54.9dB53.8dB55.8dB 40kHz spaced signals:55.1dB53.9dB55.9dB Blocking Measured as increas

37、e over 12dB SINAD level of interfer- ing signal, unmodulated carrier, causing 6dB degrada- tion in 12dB SINAD on-channel signal. SSBAMFM +100kHz:85.9dB74.2dB87.5dB +1MHz:93.5dB81.8dB92.6dB +10MHz:104.4dB98.6dB98.1dB SSB Selectivity -3dB:3.58kHz -6dB:3.78kHz -10dB:4.36kHz -20dB:5.00kHz -40dB:6.05kHz -60dB:7.14kHz Sensitivity Input level in V pd required to give 12dB SINAD FreqSSBAMFM 28.000.190.250.23 29.000.210.250.23 29.690.220.260.23 TRANSMITTER RECEIVER All measurements carried out on 29.000MHz in USB mode unless stated. LABORATORY RESULTS