SU62128A1 - Device for parallel connection of several receivers in one antenna - Google Patents

Description

In the practice of receiving radio centers, it is often necessary to deal with parallel connection of several receivers into one antenna, for example, in the field of short-wave reception and in the area of directional reception of long waves with parallel connection of several field coils to the goniometer frame clamps.

A simple parallel connection of receivers is connected with two inconveniences: 1) the presence of parallel connected receivers changes the resistance at the terminals of the receiving antenna, like a generator, and thus makes it difficult for you to simply match the antenna and receiver input; 2) changes in the tuning of one of the receivers affect the operation of the others, which is especially evident in cardioid reception.

This proposal is intended to eliminate whether to weaken these drawbacks. It focuses on such 1 receiving devices, the input rollers of which do not change when changing partial ranges; This includes, in particular, shortwave receivers for backbone longwave receivers with a goniometric input.

When connecting multiple receivers in parallel to one antenna, the switching circuit must satisfy the following two basic requirements:

1. It is necessary to obtain the highest voltage on the capacitor of the receiver input circuit. This requirement is almost equivalent to obtaining the maximum power in the circuit.

2. It is necessary to make reciprocal effects when receivers change as little as possible.

In order to meet these requirements, a chain connection circuit of antenna receivers of receivers in the feeder line is proposed: the input coils receive cables according to the invention are interconnected by means of additional capacitors so that the whole circuit

No. 62128-2 forms a T-or U-shaped filter, which is equal to the characteristic resistance, and cut off:,:; and frequencies that lie below the operating range of the receivers.

The invention is explained in the accompanying FIG. -5, which depict electrical circuits made according to the invention or equivalent.

Depicted in FIG. 1 self-induction coils 4 are antenna coils of receiver input circuits.

At the ends of the circuit, special coils with self-induction 2L are included, one of which (located on the side opposite to the antenna) is shunted by active co-motivation fj equal to the characteristic impedance of the feeder line.

For the aliza- tion of the operation of the chain-switching circuit of the receivers, we will replace it with an equivalent catenary line (Fig. 2), consisting of U-shaped cells.

The selection of the inductance of z-coded coils L and capacitances C is made from the following considerations.

1. The chain line must have a characteristic impedance that is constant in range and equal to the characteristic impedance of the feeder line leading to the antenna.

2.In the input circuit of the tuned receiver, maximum power should be received.

The impedance of the U-shaped cell in the passband is determined by the formula.

/ L1

P 1 / (1)

one

Where

 2I / IC

In order to change the range, inequality must be fulfilled.

guaranteeing the simultaneous transmission of frequencies.

The last inequality will be satisfied if, for example, we put:

where is the minimum value of the received range.

Using formulas (1) and (3), it is easy to determine the desired pairs; meters:

Г 9-0 0, UZR., „„

 0.93 p 10

in deriving formulas (4), it was assumed: (i) i. (2)

The unconfigured receiver — practically does not receive power from the line and, therefore, does not add additional active resistance to its antenna coil. The latter circumstance ensures the absence of mutual influence of receivers operating on different waves.

You will see what should be the tuning of the receiver input circuit and its connection with the antenna coil in order for the second condition regarding the maximum power output to be fulfilled.

To do this, you must first know the resistance of the antenna.

We assume for the sake of definiteness that the antenna has a purely active resistance equal to the characteristic impedance of the feeder p. This corresponds to the most common use of antennas: Rhombic, Traveling Wave, Beverage, etc.

After adjusting the receiver's input circuit to a certain wave, the latter introduces some resistance 2b into the antenna coil, which can be represented as included in a line parallel to the antenna coil L. Since the catenary line (Fig. 1 and 2) is equivalent to an ordinary line with an impedance o, for wave 1, our system with receivers, one of which is tuned to wave Ki, can be represented as an equivalent circuit (Fig. 3). Using the Tevenen theorem, we determine the current in the resistance Z ,,, (see Fig. 3).

.(five)

It follows that the greatest power will be released in the resistance Zg, (i.e., in the input circuit), then

It remains to determine the detuning value of the input circuit.

A., (uZ, and the connection of K to his antenna coil in order to satisfy condition (6).

Remembering that the resistance Zj introduced into the antenna coil is considered to be connected parallel to the coil, and taking into account condition (6), we find the connection between Zu (p / 2) and the parameters Gz, LZ, Cz of the receiver input circuit. PG / - about

j -, -t5 () - g where

X and L, j :, (O, Qi -.

Department of real and imaginary parts, we find, after some transformations, formulas for detuning the circuit and the coupling coefficient:

/ 1 -; - to, od.

2 {-L I about 1 4

. -. (6)

/ g P

2

1 „(1) /. 2

coLOG 2

X, KQ.r,

g

In cases where the receivers are spaced apart and there is a significant segment of the feeder line between them, the switching circuit (Fig. 1) must be modified (see Fig. 4). The new scheme differs from that considered in that it represents a chain of T-shaped cells (and not U-shaped in Figs. 1 and 2); this allows switching feed lines of any length between individual cells. True, the number of capacitors doubled, but on the other hand, there are no terminal coils with an inductance of 2L. The coils L (Fig. 4), as before, are the antenna coils of the receivers.

The formulas for calculating the parameters of the circuit of FIG. 4 almost coincide with the previous data and have uid

0.93о, „„ „

The formulas for calculating the receiver loop configuration will take a slightly different form.

Indeed, when tuning one of the receivers to wave ii, the system for this wave is equivalent to the circuit shown in FIG. 5 (instead of Fig. 3 in the previous case, case), where Z is the resistance introduced into the antenna coil from the receiver circuit. The current flowing through the antenna coil is defined by the formula:

 + 0,5p- / Here, Ea-a, the voltage of the clamps, which would be on them with the coil disconnected.

From here, the conditions necessary for obtaining maximum power in the receiver circuit immediately follow;

H. -y 01L -

P 2

(Ze r, + jX,)

Using the well-known formulas for 2 ,, we find, after simple transformations, the value of the necessary "connection K and detuning of the input circuit Xz:

X, +

sch1d,

(7}

I-10 O.HZ

RFN

(eight)

about. ten

E

 0

(9)

2o)

(ten)

Subject invention

Device for parallel connection of several receivers. into one antenna, characterized in that, in order to weaken the effect of tuning one receiver on the tuning of others, the input terminals of the receivers are interconnected by means of additional capacitors so that the entire circuit forms a T or U-shaped filter, closed at characteristic, and cutting the frequencies that lie below the operating range of the receivers.

-5-№ 62128

 / 1 ife 1 f

P