Is a .1MHz RF Choke Necessary for the Itty Bitty Radio Telescope?

In summary, the conversation was about building the Itty Bitty Radio Telescope and the confusion over the required RF Choke. Suggestions were made to try a 1kHz choke or to look for designs for homemade chokes. It was also suggested to use a shielded enclosure for the batteries instead of a choke. The conversation also mentioned the purpose of the choke and someone expressed interest in building the telescope. Finally, a physics teacher shared their reason for wanting to build the telescope.
  • #1
I'm putting together the Itty Bitty Radio Telescope. In the instructions (see:, it says to use a .1Mhz RF Choke. I have been unable to locate this particular frequency, as the only one I have been able to locate has been a 1kHz RF Choke? Can anyone help me? Was it a typo or do I actually need a .1MHz RF Choke?
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  • #2
I can make the following suggestions:
*Try the 1kHz choke... it should filter all frequencies above 1kHz so may be even more efficient then the suggested .1Mhz choke.

*Check around the web for designs for home-made RF Chokes.

The point of the choke is to prevent the battery clips from acting as an antenna picking up ambient microwaves (i.e. nearby cell phones etc). So...

*You may be able to replace the choke with a shielded enclosure for the batteries. In fact this may work even better but I'm not up to speed on microwave circuit issues (only broad theory) so can't say for certain. Try finding an aluminum enclosure with a coax junction which will hold your batteries.
  • #3
Thanks, have you built this type of radio telescope already?
  • #4
redguy12 said:
Thanks, have you built this type of radio telescope already?

No but it looks interesting. I've bookmarked the link and may try it this summer.
  • #5
you need an adjustable choke [tuning coil]. i haven't built one of these things either, but, it is little more than a low frequency ham radio with a funny antenna and extra shielding.
  • #6
I'm new to the forum having I stumbled upon it looking for add'l info on the IBT. I believe the choke you are looking for is a 0.1mH or 100uH choke. I think the information published on the 'How to build' sheet was in error.

I'm a physics teacher looking for some new ways to excite the students. I think working with a radio telescope will help in the understanding of the EM spectrum and provide a different way of doing physics in this area We'll see.

Take care,


1. What is an Itty Bitty Radio Telescope?

An Itty Bitty Radio Telescope (IBRT) is a small and inexpensive radio telescope designed for amateur astronomers and students to observe radio emissions from celestial objects.

2. How does an IBRT work?

IBRTs use a small satellite TV dish, a low-noise amplifier, and a software-defined radio receiver to detect and process radio signals from space. The dish collects the signals and the amplifier amplifies them before they are sent to the receiver for processing.

3. What can an IBRT observe?

IBRTs can observe a variety of celestial objects, including the Sun, planets, stars, galaxies, and even supernovas. They can also detect radio emissions from sources such as pulsars and quasars.

4. How accurate is an IBRT?

An IBRT can achieve an accuracy of about 1 degree in its observations, which is sufficient for amateur and educational purposes. However, for more precise measurements, a larger and more expensive radio telescope would be needed.

5. Can an IBRT be used for research purposes?

While IBRTs are primarily designed for amateur and educational use, they can also be used for basic research and data collection. However, they may not have the sensitivity and precision required for more advanced research projects.

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