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HF box

Hello !

I want to talk about one of my homemade. I made it twenty years ago and still use it.


It is needed when setting up receivers, transmitters, radio stations, televisions, radio microphones, and other devices where high-frequency oscillations are used.

I did not always have a high-frequency voltmeter on hand. I decided the Ts20 avometer is adaptable for this purpose. And he made a high-frequency prefix to it.

As a basis, I took the detector circuit with voltage doubling.

There was a very important question, which diodes to put there. Looked in reference books.

I understood that diodes must be high frequency, with small capacitance and germanium, in order to detect weak signals.

I checked the work of a lot of diodes. It was D2, D9, D10 and others. They worked, but up to fifty megahertz frequencies. And then I found the military-industrial 1D507A. Germanium, pulse, low-signal. They were also used in civilian equipment, called GD507A, with a capacity of 0.8 pF. Operating frequency not indicated.

I had a military-industrial generator. I gave him a 500 MHz signal. Got excellent detection.

Now I’ll tell you in detail how this prefix is ​​arranged.
Consider a circuit diagram.


The signal from the WA1 antenna, the role of which is played by a small piece of wire, 50 mm long, enters the housing through the bushing. I soldered the case from silver-plated brass.

Through the isolation capacitor C1, the signal is fed to the detector with voltage doubling.

The rectified signal through the feed-through capacitor C2 is output from the housing and is measured by the Ts20 avometer, included in the measurement of direct voltage. Later I began to use a digital multimeter.

On the output, I added a load in the form of a resistor R1.
At one time I made low-power transmitters for television centers. Connecting the oscilloscope to the output of the console, I watched the demodulated video signal, its shape. This helped in setting up the transmitter.

The prefix provides two types of work - contact and non-contact.

Sometimes it’s enough to bring the prefix antenna to the circuit of the instrument under study. And sometimes, when the signal is low-power, you need to touch the antenna circuit.

Despite the absence of amplification cascades and a power source in the console, its sensitivity turned out to be very high. At a distance of 15 cm takes the receiver local oscillator.

The prefix is ​​broadband, frequency range up to 500 MHz minimum.

In addition to diodes 1D507A, good results were obtained with diodes GD507A, 1D508A, GD508A and D312.

I hope you find this article useful.

Sincerely, author.

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45 comments
Author
feonor12 , You are not mistaken. Yes, these are the same KM. At one time there was a boom on them. Everyone who was in the subject (the main thing is who had these capacitors then in sufficient quantity), turned in. I'm not an exception xaxa The content of PGMs (platinum group metals) is high for these Conders. Hucksters said they were buying cars for exhaust catalyst processing. GOOD BUSINESS! Perhaps the truth. In dashing 90 we went insolent with cardboard signs on my chest, I WILL BUYANDENSATORS EXPENSIVE! Pharmacy scales were at everyone’s place, and they took exclusively capacitors with bitten conclusions, there was no time to do this. And who, I apologize, Suckers, brought to hand over with normal conclusions. And either left the radio market, or gave it at a bargain price. Indeed, now almost no such capacitors are found. But I still have some reserves. I’m not going to sell them now, they’ll come in handy for serious work. boss
KM probably (Conder). It is already possible to record them in the red book of radio components, the barbarians will soon melt them all down to one. They will see such a thing - they will gnaw directly out of a working board with their teeth.
Author
impuls , thank you for appreciating the simplicity and versatility of my RF set-top box. Well, there’s nothing to make noise from there. No transistors, chips. And the noise of the diodes is insignificant, so that they can be fixed with a conventional oscilloscope.
There was a case, I was sent to an exhibition to present a transistor noise meter (for military reception, noise selection from a batch of transistors). I did not develop this box and had no idea what and how. But, I managed to understand that the level of his sensitivity is such that he claps his hands. And he didn’t screw up before the military representatives. The developers put ceramic condos at the entrances, who remembers such green ones, then we shoved them into all military equipment, and sometimes into civilian equipment. For such capacitors, the microphone effect is present. Told developers about this effect, checked together. The jamb has been eliminated. They drank all night until morning in the laboratory. The award was written to me later, like 4 of my salaries. xaxa drinks
impuls
Before the stunned, a simple solution, though a wide range here would be better to limit, in order to avoid unnecessary noise. Although all the simplicity here will already disappear. Respect to the author!
V. Popov.
Most likely you are a fifth grader once got involved in this "Shit"! What makes you think that he (the Author) should show you his advanced brains? What do you care what he writes? Or are there no longer teenagers and those who are slowly getting used to electronics? For them, he wrote all this and you are rather a little bit more literate in the lesson and does it bother you?
Apparently, not Vaseline, but the evening process of the formation of acetaldehyde in the body. ;)
Dmitry, it’s necessary to do upbringing too. But do not state a bad thing ... yes
mine also has DR, though not today, 1.5 years old, on the 5th ... As they say, a good freelancer will insert the key everywhere xaxa

And today my daughter wrote to me on a chair, and then she put on a bed just in the place where my head was, although this had never happened before. These are the signs. xaxa

But in general, such signs are just an excuse to see a negative in life.
Sorry ... Do you, an hour, not Vaseline in knuckles interfere with writing? )))) ... Well, nothing is clear! ...))))
Thank you ... I also remember today, as "yesterday" took away from the hospital ....
Only now, she is now a "little girl", and then I was a "grown man" .... but, after all, she was older than her current one year))))
Valery
that day a black cat ... a happy date for me
Definitely, that cat in the shower was white and fluffy! But seriously, let me sincerely congratulate you wholeheartedly! I remembered the birth of my elder ... drinks
And somehow, on this day, a black cat broke an mirror with an empty bucket, while sprinkling salt .... and nothing! )))))))
Well I say - a happy date for me.
Ivan_Pokhmelev
Friday the thirteenth, bainki time!
There is only one stopudovy sign that works if on Friday the thirteenth a black cat crosses your road (not a cat !!!) with empty buckets! Separately does not work! xaxa
My daughter has a birthday ... When she was born (23 years ago), it was also Friday.)))))
Friday the thirteenth, bainki time! ;)
Author
We sang who lives in Kusk and Voronezh. Whoever launches a few rockets will be unequal at the stage of Puksk
Andrey-750
Still, MHz, not MHz (do not consider it an attempt to be smart) ...
Author
I remembered our ZIL with a shielded ignition system. In case of a nuclear war.
Quote: R555
Protection against natural background exposure.
This is protection against static, and not against background radiation. D603 and the like were used by the warriors, but in principle they cannot have anything that dies from the natural background. Yes, and civilians do not need this.
There are domestic 10 A at 800 V.
R555
frail voltage reverse breakdown 40 Volt
STPS3150U, Schottky Diode 150V 3A [SMB]
STPS30150CT, 2 Schottky diodes 30A 150V [TO-220AB]
VS-10CTQ150SPBF (VS-10CTQ150S-M3), Schottky diode, 2 x 5A, 150V, common cathode [D2PAK / TO-263AB]
BAT240AE6327HTSA1, Schottky Diode, Dual Serial, 240V, 400mA, AEC-Q101, [SOT-23]
smile
If you need the opposite, take other Schottky diodes. How many volts and what current do you need?
Author
I am very concerned about the subject of Schottky diodes.
They have a fast, but frail reverse voltage breakdown of 40 Volts.
They put on the output of the PSU.
Author
Speak correctly about humps. But when I managed to catch the moment, I received generation with a power supply of only 0.8 Volts.
They are definitely not suitable for detection.
Quote: R555
Along the way, I remembered about tunnel diodes

Tunnel diodes have an N-shaped characteristic. Use them as ordinary diodes will not work. They collect generators or switching devices (instead of relays). I made several designs on them. Very moody :). In addition, the voltage difference between the humps is very small, it is difficult with them.
Author
Pronin that you mentioned AA, gallium aride, if not confuse. Along the way, I remembered about tunnel diodes. I have them piled up. I want to try to collect something on them, although my friendship with the tunnels did not work out because of their negative resistance (the tunnel transition effect is fantastic).
Author
Pronin, I used this diode in a ceramic case in the device to search for bugs (it got on the picture). It is also visible that I was scared to solder it, put it in the fuse block. The military intimidated. When the diode fell into my hands, it was in lead foil. Protection against natural background exposure. It will be necessary to see how much a diode costs today. To buy from the Chinese ...
I did a slightly different scheme with the D603 diode (and with AA112A)
Guest Vladimir
I made such a prefix in a can of coffee and inserted the miniature head of a milliammeter there. An excellent high-frequency indicator, it’s been working for 20 years already ...
Guest serge
do you think you contradict him with this answer ... no, only agreed with him ... if you collected this prefix 20 years ago, then you are at least 30 years old ... or are you still a fifth grader ?!
I did not collect such things. There was no need. Measuring instruments of all stripes for all ranges were always available. And RF voltmeters with remote heads, and selective microvoltmeters, and much more. He just worked in his youth on the railway at the PKK (control and repair center). He repaired radio stations of all ranges.
73! UA9SFA
You should not have answered me, but Guest Eugene.
Author
Guest Alexander, contours can be shielded, but wires or paths to them are not always. With them, the prefix catches the radiation. Another receiver emits a local oscillator signal with its antenna. This is especially evident in super-regenerative receivers.
Genadiy
Yes, I also did such probes, 35 years ago! ))) True, at the input I set a very small capacitance of 0.5 pF, so that if you touch the circuit, do not introduce the capacitance. I also did it with one transistor, a bipolar or a field device ... Implementation options depend on the frequency and level of the signals of interest ...
Another guest who does not read further than the title. ((The author writes:
The prefix provides two types of work - contact and non-contact .... And sometimes, when the signal is low-power, you need to touch the antenna circuit.
Naturally, at the same time, the frequency gets a little confused, but as a rule, this is usually enough to establish the fact of generation and preliminary adjustment of the level in a first approximation.
Guest Alexander
in essence, it is a detector broadband receiver without an input circuit ... but how does it “hear” the local oscillators, the same circuit in the screens, if we are talking about industrial receivers?
Author
Guest Vladimir! I worked in this range. I don’t have a call sign, otherwise I would have talked. Also worked and work in most other ranges, so this prefix is ​​needed. So do not boast that you have done this before 30 MHz. This is not an achievement.
Author
Guest Sergey! What kind of degrading youth did you blurt out? I'm not very young, I wrote at the beginning of the article that I collected this prefix about twenty years ago, and it is clear that this is not the first thing that I collected. This is now in grade 4-5, as you put it, they collect robots from ready-made blocks, the program only needs to be written (rewritten). Great mind is not necessary. And this constructor, dad and mom bought it. And dad collected and wrote. And at this age, we collected radio components from landfills and garbage dumps, and there was no mention of Ineta. From now on, think to whom and what to write.
Author
Ivan_Pokhmelev, the prefix does not catch the network interference, due to the fact that I guessed at the input to put the capacitor C1, which represents a significant resistance for a low frequency of 50 Hz. And I set the load resistor R1. And the RF signals pass well and are detected. By the way, few people know that a voltage-doubling detector demodulates not only AM and IM, but also to some extent FM. I mean, by connecting a bass amplifier or just high-impedance headphones to the output of this set-top box, you can listen to the walkie-talkie for transmission.
Author
Guest Eugene, I usually do not put extra details. Capacitor C1 is needed to suppress mains interference of 50 Hz.
To catch a network tip?
Guest Eugene
I think that capacitor C1 is not needed.
Quote: Guest Sergey
Youth is degrading.
PMSM, not young people are degrading. Some have not even mastered the first line, which says:
I made her twenty years ago and still use it.
Guest Sergey
Youth is degrading. In my childhood, this was done by pioneers in the 4-5 grade.
Guest Vladimir
I have done this for a long time. True, I have frequencies up to 30 MHz. Mainly for transmitter control. I am a shortwave and only up to 30 and no more.
73 !!! UA1TCR

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