RF preamplifier parts kit

Rated 4.00 out of 5 based on 4 customer ratings
(6 customer reviews)


SKU: RF-Preamp Category: Tag:


Broadband RF Preamplifier Active Antenna Booster

This is the same circuit as our prior RF Preamplifier Kit (RF-Preamp), but now comes with a circuit board.

Here is the schematic: RF Preamplifier Circuit

Here are the connection directions: Connecting Your RF Amplifier
The RF Broadband Preamplifier was designed mainly for Crystal Radio sets. However, it has a frequency response up to 25 – 30 Mhz allowing it to work well in other applications.

It is not as pretty as the $100.00+ Broadband RF Preamp units but with the addition of the optional ferrite antenna output coil it will work using the same coupling method as some of the more expensive RF Preamps.

These are made by us with our own circuit design. It has not been copied form another design and we have never seen one like it anywhere for RF.

A broadband preamp will have a little more noise than a narrow RF band preamplifier. However, unlike the over $100.00 Broadband RF Preamplifiers (Active Antenna Boosters) for a few dollars you can add a tuned input known as a pre tuner and make it a narrow band RF preamp as the input is accessible and not molded in a plastic case.

Frequency response 100Khz to 25-30Mhz.

Without the optional LED, the battery only draws about 2ma current. So a 9 Volt battery will last a very long time.

If your location or space limitation prevents you from having a 100ft or longer antenna then this Broadband RF Preamp Active Antenna Booster will allow you to use a 15ft or so antenna.

If you live in a rural area and need a long antenna to receive AM stations on your crystal or AM radio then this RF preamplifier is for you. I live about 20 miles from the nearest AM station and even with a 15ft antenna I can barley get one station on my crystal radio set. With this RF preamp and a 15ft antenna I get three stations on my crystal ( Xtal ) radio set.

Many people put audio amplifiers on their crystal ( Xtal ) radio sets. However it takes about .1 volt for the diode to conduct so stations not able to produce at least .1 volt from antenna do not pass into the audio amplifier so hundreds of times audio amplification times nothing equals nothing.

Comes with directions to connect with just about any crystal ( Xtal ) radio set or receiver with 50 to 300 Ohm inputs or to any receiver without these inputs with the optional ferrite output coil.

You need a 9 volt battery and wire for the antenna and ground.

If you have any questions email us before you purchase the RF preamp.

6 reviews for RF preamplifier parts kit

  1. Rated 5 out of 5

    (verified owner)

    I like this rf circuit/kt and tuning capacitors with shafts and knobs for use in my 80 Meter RDF device. The antenna and tuning circuit is from 1987 Radio Amateurs Handbook (pg 39-13) that uses 3 tuning capacitors.

  2. Rated 5 out of 5

    (verified owner)

    This works very well for bringing in the dx stations!

  3. Rated 1 out of 5

    Hello to all, the contents existing at this site are in fact remarkable for people knowledge, well, keep up the nice work fellows. bbcfckgfgceccddf

  4. Rated 5 out of 5

    (verified owner)

    Awesome kit, arrived fast, reasonable prices, works great with the MK484, which is a neat kit in itself, don’t think about it, order both!!!


    • I have not built one like this myself, but this should work fine. The pre-amp will cap out at ~30MHz. You may need to experiment some with the coupling. If you have any questions feel free to e-mail me the details of your build and I’ll see if I can help.

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Have a question or something to discuss?

December 10, 2015

Hi Mike,
can you let me know when the circuit board is out for the RF preamplifier?

Mike Lowe
December 10, 2015

Yes, I will shoot you an e-mail when they are available.

December 10, 2015

Thanks Mike! Merry Christmas!

January 25, 2016

Is there a circuit board available to purchase along with the parts? Thanks in advance.

Mike Lowe
January 26, 2016

Yes, we have just received the circuit boards for the RF Preamplifier kit. We will be doing some testing today. We should have an updated RF Preamplifier Kit with circuit board listed on the site in the next day or two. I will e-mail you when they’re available on the site.

Thank you.

Mike Lowe
January 28, 2016

The kit has been updated to include a circuit board!

August 23, 2017

hello, mike:
what are the approximate dimensions of the circuit board?

Mike Lowe
August 23, 2017

The circuit board is 2 3/8 inch square.

December 1, 2018

where in a crystal radio should i install this circuit, before the tuner or after?

Mike Lowe
December 2, 2018

This would go before the tuner. Between the antenna and the crystal radio’s tuning section. See page 3 of the linked document. It has a couple different ideas for ways to connect the preamp. https://www.mikeselectronicparts.com/wp-content/uploads/RF-Pre-Amplifier-Circuit.pdf

December 11, 2019

How much gain does this preamp have? dB?

Mike Lowe
December 12, 2019

I do not have an exact measure of the preamp gain. I do have the results from a simulation which closely match my own observations and measurements with this preamp. Your results may vary from this a little, but this should be fairly close. The gain slowly decreases with frequency. I hope this helps.

200K 20db
5Mhz 19db
10Mhz 17db
15Mhz 14db
20Mhz 12db
25Mhz 10db
30Mhz 9db
35Mhz 8db
40Mhz 6db