Unterschiede

Hier werden die Unterschiede zwischen zwei Versionen angezeigt.

--- en:dr-22 [2021/05/08 11:35] – angelegt mb
+++ en:dr-22 [2021/05/08 19:58] (aktuell) – mb
@@ Zeile 50: / Zeile 50: @@
 Searching stations with the DR-22 /RF-2200 is unproblematic: the telescopic antenna extended, the radio is set to a medium volume hiss and the RF gain control fully turned up. The band switch is used to select MW or FM broadcast band; in the SW position, a red marker below the coarse dial marks the selected shortwave band. When the main tuning control is turned, some shortwave stations are briefly audible, for a slow station search, the Panasonic radio has a slow tuning speed setting.
-{{ :images:panasonic-rf2200-dial.jpg?400|Scale National Panasonic DR-22}} The task becomes somewhat more complex when a station on a known frequency should be tuned. For this you have to calibrate the film dial with the help of a crystal calibrator and then move to the correct frequency with the linear fine tuning dial:\\
+{{ :images:panasonic-rf2200-dial.jpg?400|Dial National Panasonic DR-22}} The task becomes somewhat more complex when a station on a known frequency should be tuned. For this you have to calibrate the film dial with the help of a crystal calibrator and then move to the correct frequency with the linear fine tuning dial:\\
-The internal **crystal calibrator** generates a crystal calibration signal every 500 kHz. First, the next 500 kHz calibration point below the desired reception frequency (i.e. for reception of the ROI on 6155 kHz the mark 6000 kHz, for reception of 11805 kHz the mark 11,500 kHz) is tuned to. With the 500 kHz marker switch pressed, a strong whistle should be audible near the dial position. Now tune to "zero beat" with the main tuning, i.e. turn slowly until the whistle becomes deeper and deeper and then disappears completely. The pointer of the S-meter must move to the left stop. The fine tuning dial has to remain at the 000 setting during this manoeuvre.
+The internal **crystal calibrator** generates a crystal calibration signal every 500 kHz. First, the next 500 kHz calibration point below the desired reception frequency (i.e. for reception of the ROI on 6155 kHz the mark 6000 kHz, for reception of 11805 kHz the mark 11,500 kHz) is tuned to. With the 500 kHz marker switch pressed, a strong whistle should be audible near the dial position. Now tune to "zero beat" with the main tuning, i.e. turn slowly until the whistle becomes deeper and deeper and then disappears completely. The pointer of the S-meter must move to the left stop. The fine tuning dial remains at the 000 setting during this manoeuvre.
-After switching off the calibration marker, the dial moves again and can be set to 195 kHz - et voilà: the BBC should become audible on 6195 kHz. With the switch 125 kHz - Marker, calibration marks can be switched every 125 kHz to check the scale linearity, the receiver is muted.
+After switching off the calibration marker, the dial moves again and can be set to 155 kHz - et voilà: the Austrian Radio Programme should become audible on 6155 kHz. With the 125 kHz marker, calibration marks can be activated every 125 kHz to check the dial linearity, the receiver is muted.
-A BFO is provided for receiving CW (A1) signals and SSB transmissions. When switched on, a whistling sound is audible; with the tuning knob set to "slow", the optimum pitch of the Morse code transmission can be set for CW signals; for SSB transmissions, the pitch must be varied until the speaker's voice sounds reasonably natural; ECSS reception (i.e. reception of a sideband of a normal AM broadcast) is possible with difficulty, but usually does not bring any further improvement in reception with this receiver - the BFO for single sideband reception remains an emergency solution.
-In case of adjacent channel interference, the bandwidth switch can be set to narrow, whereby both IF filters are not - in keeping with the times - among the narrowest.
-The receiver works as a [[Double conversion]], the signal from the telescopic or MW ferrite antenna is amplified, converted to the first IF in a first mixer and amplified again. In a second mixer the signal is converted to the second IF, here the bandwidth filters are switched, the S-meter voltage is tapped and the signal is passed on to the AM demodulator or the BFO/SSB demodulator. The calibration marker works with a 4 MHz crystal and 1/4 or 1/8 dividers.
+A [[BFO]] is available for receiving [[CW]] (A1) signals and [[SSB]] transmissions. When its activated, a whistle is audible; with the tuning knob set to "slow", the optimum pitch of the Morse code transmission can be set for [[CW]] signals. For [[SSB]] transmissions, the pitch must be varied until the speaker's voice sounds natural; ECSS reception (i.e. reception of a single sideband of a normal AM broadcast) is possible with difficulty, but usually lead to any further improvement with this receiver.
-In the FM range, the DR-22 / RF-2200 operates as a single conversion.
-In terms of reception, the set reflects the technology of the mid-seventies: reception on medium wave is good, but on VHF the adjacent channel separation is insufficient by Central European standards; the Americans are more generous in this respect with a less dense VHF network. On shortwave, the concept with the built-in calibration marker and the calibratable kHz scale allowed quite good return accuracy and thus the finding of a station, which usually meant great difficulties with the German receiver concepts in those years (a dial on the drum tuner for each shortwave band, a wide scale pointer and only widely spaced coarse marks).
+In case of adjacent channel interference, the bandwidth switch can be set to narrow, but both IF filters are not really narrow.
+The receiver works as a [[Double conversion heterodyne]]. The RF signal from the telescopic or MW ferrite antenna is amplified, converted to the first IF in a first mixer and amplified again. In a second mixer the signal is converted to the second [[IF]], here the bandwidth filters are active, the S-meter voltage is tapped and the signal is fed to the AM demodulator or the BFO/SSB demodulator. The crystal calibrator works with a 4 MHz crystal and 1/4 or 1/8 dividers.
+In the FM range, the DR-22 / RF-2200 operates as a single conversion set.
+In terms of reception, the set reflects the technology of the late seventies: reception on mediumwave is good, but in the FM broadcast band, the adjacent channel separation is insufficient by Central European standards; in America with a less dense FM network, this is usually no problem.\\
+On shortwaves, the receiver concept with the built-in crystal calibrator and the calibrated fine tuning dial results in a quite good return accuracy and thus the capability to find a station on a known frequency, what usually was quite difficult with the German receiver concepts in those years (a dial on the turret tuner for each shortwave band, a quite wide dial pointer and only sparse coarse frequency marks).
 ===== Technical principle =====
+Double conversion set, calibrated fine tuning dial and crystal calibrator.
-==== Equipment ====
+==== Components ====
 The set is equipped with semiconductors.
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 {{gallery>:images?panasonic-rf2200*.jpg&0&80x80&lightbox&showtitle&titlesort}}
 ==== Further information ====
-  * [[https://www.radiomuseum.org/r/panasonic_dr_22.html|National Panasonic DR-22 / RF-2200LB on the website of www.radiomuseum.org]]
+  * [[https://www.radiomuseum.org/r/panasonic_dr_22.html|National Panasonic DR-22 / RF-2200LB on www.radiomuseum.org]]