Top quality shortwave communications receivers have been in use to monitor
External services of foreign countries on shortwaves, one of the receivers
in use was the Telefunken E-1501, military designation E-657.
The PLL synthesized communnications receiver has a high frequency stability
and a very good accuracy of the frequency display as well as a good choice
of I.F. filters ordered to individual requirements of the user.
The receiver has been replaced by the Rohde & Schwarz EK070 and the AEG-Telefunken
E-1800 both offering electronic frequency memories.
The Telefunken E 1500 / 1501 is a commercial quality communications receiver,
it is intended for 19" rack mount, it's dimensions are 54,4 x 14 x 40 cm and
it's weight arount 17 kg.
The complete receiver has a modular construction behind the front panel.
the receiver E 1500 is the main component, optional components are the DE 1500
(this second demodulator is used for independant side band / ISB reception modes A3B/A7B),
the radio teletype decoder TD 1500 (F1/F4/F6A) and the AD 1500 dual antenny diversity
option, which make a complete E1501.
The standard mains power supply module is the NS 1500 to power the radio from
110 / 220 V, for mobile use, a battery power option BS 1500 running from 24 V DC
has been available.
The frontpanel design is very straightforward: in the top row all indicators,
in the bottom row of controls at the left the main tuning knob, all other receiver
controls and below the internal monitor speaker the mains switch.
The analog signal strength meter can be switched to display the A.F. level,
in radioteletype modes, it can display the current and audio level of the
signal driving the teletypewriter.
The big red LED display will indicate the reception frequency with a resolution
of 10 Hz, two LEDs on both sides indicate the selected antenna when antenna
diversity is active (the more powerful signal of two distant shortwave receiving
antennas will be fed to the demodulator).
A row of LED's are used for signal analysis: for a correctly tuned AM signal, the
middle red LED indicates carrier center, rows of green LEDs both sidebands.
In single sideband mode, only the respective LEDs are active, in radioteletype
transmissions F1, the LEDs are used to display the Mark and Space signals.
At the right, next to the LED display, You find an internal monitoring speaker,
just below the mains switch and the headphones jacks.
The main tuning knob at the left hand is equipped with an electronic flywheel
effect, one turn will tune the set 1,8 kHz, the tuning speed will increase to
18 kHz / revolution when the tuning knob is rotated quickly. Two UP/DOWN tuning
knobs with a speed of 300 kHz and 3 MHz per second will give You access to the complete
shortwave range within a few seconds. For a straight landing in the desired
boradcast or amateur band, You need some practice. The following knobs at the right
activate / lock the tuning mechanism and select one of the two antennas or set to
automatic antenna diversity operation.
The following switches are used to select the sidebands in ISB mode A3B,
to select automatic or manual gain control, to switch between normal and inverted mode
and wide and narrow shift in radioteletype mode and to activate the noise limiter
and the internal monitor speaker.
In the row of rotary controls, the leftmost is used as A.F. gain / volume control,
next is the BFO, the manual R.F. gain control and the I.F. filter switch and
modes switch at the right.
The receiver offers a great choice of high quality intermediate frequency filters:
the 50, 150 and 750 Hertz filters are used for CW reception, 750 Hz for radioteletype
operation, 3 and 7 kHz for AM reception. +3 is the filter for the upper sideband
(in the manual, You will find OSB for Oberes Seitenband) and -3 for the lower
sideband (USB stands for Unteres Seitenband, remember, this is a german set...).
To use the modes switch, You need some minimal knowledge about the international
designations of transmission modes: A1 stands for CW / morse code reception,
A2/A3 for normal AM reception (the wider dark bar indicates the AM position
with a slower AGC decay time), A3J is for reception of single sideband transmissions
and signal with reduced carrier, A3B is for independant side band telephony,
A7B stands for ISB telegraphy with two independant teletype/telegraphy channels,
F1 and F4 are for radioteletype reception.
Apart from the cryptic frontpanel lettering with it's many different symbols,
as typically found on commercial shortwave receivers, the operation scheme of
the E 1500 is straightforward and simple. Switch on the receiver with the
mains switch below the monitor speaker grill and make sure, the speaker is active.
To tune in a signal in the 49 m broadcast shortwave band, set the modes switch
to A2/A3, the filter to "7" and use the fast UP/DOWN tuning buttons to tune
to a frequency near and the tuning knob to the exact frequency that is desired -
when the receiver is tuned to 6155.00, You should hear the signal coming from Vienna.
The red LED active in the signal analysis panel tells You, that the technicians
in vienna have tuned their transmitter exactly on the correct frequency.
To tune in to an amateur radio station or a volmet weather report in single
sideband mode, use A3J as reception mode and the -3 filter and slowly tune up
and down until the speakers voice does not sound like Mickey Mouse anymore.
The Telefunken E 1500 / E-657 is a premium grade communications receiver
offering You stable reception of AM and single sideband signals with a wide
choice of I.F. filters; in comparison to amateur radio receivers, the set
is lacking some possibilities of "postprocessing" a disturbed shortwave
signal, You have to do without passband tuning and notch filter - these
features are usually not present in commercial shortwave receivers and the
Telefunken E 1500 makes no exception.
© Martin Bösch 15.1.2005 / transl. 4.9.2010