Edgar wrote:

Hello,
I've purchased an 1962 tube HF receiver. Well the problem is I don't know
exact antenna input impendence value of it. I use simple 40m. dipole on a
regular TV cable of 75 ohm. I would like to do some experiments with random
wire, and 50 Ohm coax or 300 Ohm ladder line for dipole. Is there any
circuit that can help me to mach the impendence?

Edgar,

Since I can understand and read Russian I looked at the site you
mentioned. They say that the antenna input has been forseen for a
symmetrical twin-lead 200 ohms impedance. They also add that any longer
wire would do. They also mention that the receiver has poor stability;
however it is a double mixing superhet, and the second IF is 85 kHz
which gives rather good selectivity. The Russian amateurs used to use it
as an IF amplifier at 2 MHz, so they standardly built a converter with a
crystal XO in it and got a very usable amateur receiver. If you need
some more translation, just send me an e-mail. Best wishes,
Bozidar, 9a2hl

Edgar wrote:

Hello,
I've purchased an 1962 tube HF receiver. Well the problem is I don't know
exact antenna input impendence value of it. I use simple 40m. dipole on a
regular TV cable of 75 ohm. I would like to do some experiments with random
wire, and 50 Ohm coax or 300 Ohm ladder line for dipole. Is there any
circuit that can help me to mach the impendence?

Edgar,
Since I can read and understand Russian I looked at the site you gave in
your post. They say that the antenna input us provided for a symmetrical
twin lead 200 ohms impedance. They aso say that it is a double
conversion receiver; the second If is 85 kHz giving rether good
selectivity. The stability of the receiver is rather poor, and the
anateurs used to use it as an IF amplifier of 2 MHz first IF. If you
want me to translate for you some more data, send me an e-mail. They
also say that any longer wire as an antenna will do. Best wishes,
Bozidar, 9a2hl

Thank you all,
I can do understand Russian very little too:-( The problem is I am new to
all this technical radio stuff. I am an ordinary SWL for two years from LY
country:-), I started interesting in ham bands so I bought this radio to
explore them. Well as for AM listening the receiver do quite well, but for
ham band is worse. I decided to experiment with antenna to expand my
listening capabilities. So I came up to impedance question. I thought it is
very important. After your replies I try to do some random wire antenna test
first:-).

Thanks for your replies.
Your sincerely,
Edgar
73!