Miniature Af Generator

Thanks to transistors and printed circuits you can hold- this complete Jab in one hand. Not long ago this would have been a whole shelf fui! of test equipment, 455 khz generator for aligning if's, 400 hz generator for audio circuits. Plus a normal VOM and R&C substitution. Field Strength meter for tuning transmitters. Everything in one small box!

Model SE-400 Mini-Lab ONLY $25.00

Mtni-AF Generator for the laboratory or ham work bench. 10 to 100,000 hz in four bands sine or square wave. World's smallest. 7ft" x 3V x 4" 2 lbs! Built-in AC power supply stabilized to 0,1% The output is maintained at minimum distortion and constant level with FET oscillator and thermis-ter and heavy ¬°inverse feedback.

Model 6803 AF Generator

ONLY $59,95

52 Ohm 1 KW SWR Meter

Simple Inexpensive Effective $14.95 Mode) SE-405

Call

This is by far the single most valuable piece of test equipment. Built in meter for measuring gain of each stage under test. Easy to find weak or defective stages. Output speaker buift in or to VTVM or scope. No line cord since it is self powered, ONLY

Model SE 350 Signal Tracer $22.50

350a Sansei

RF Field Strength

Meter 1-400 mhz

Sansei Field Strength Meter

Comes with 5-section antenna and earphone for modulation checking, invaluable for tuning any transmitter. Magnetic base for mobile use.

Model FL-30 ONLY $8.95

Worth its weight in, batteries, tnvaluab/e for testing transistorized or IC gear. Saves its price in batteries for long range operation of radios cassette tape recorders, etc, 0-20 VDC @ 150-200 ma. Metered and regulated.

Model SE-100 Power Supply ONLY $16,95

in an effort to increase the gain of the receiver so that the volume control could be operated at a lower level, it was desired to have more if gain and audio gain. The collector load resistor of Q5 was changed from IK ohm to 3.3K ohm, which SBE does in the SB-34, Q7? the receiver if amplifier transistor, was replaced with a 2N1224 which provided more gain at the same volume setting than the 2N2672 used originally. Now with the greater amplification in if and audio stages the volume control does not have to be advanced as far for a specified audio output. By operating the volume control at a lower setting the amplification of the hf mixer, Q11 is held to as low a value as possible which helps to prevent overload of the vfo mixer and if amplifier.

The proof of the pudding is in the testing so the receiver was subjected to the following tests in both the modified and unmodified condition: in the original configuration it took a cw signal level of ,7 microvolt to produce an audio output at the speaker terminals 10 db above noise. After modification a ,35 microvolt signal produced an output 10 db above noise..This test was performed on 1 5 meters and the rf stage was repeaked for each configuration.

To test overload characteristics, a cw signal of 5 microvolts was fed into the receiver at 21,3 mhz, another generator was set at 21.35 mhz and the output increased until the audio output from the 5 microvolt signal decreased by 6 db. In the unmodified state a signal level of 9.5 millivolts at 21.35 mhz was required to reduce the desired 21,3 mhz signal output by 6 db. After modifica-

Was this article helpful?

0 0

Post a comment