What’s Inside a Mohu Leaf Antenna?

by | Last updated May 21, 2022

If you follow  my site, you know that I’m a big fan of the Mohu Leaf flat indoor antenna. It gives me over one hundred channels here in Los Angeles.

One day, reader Philip asked me what was inside the Mohu Leaf antenna. Hmmm, good question!

From all of my antenna testing, I happened to have an old Mohu Leaf Plus. This is an older amplified version of the Mohu Leaf. It’s ideal for a tear down because it was made of laminated paper instead of all plastic like they are now.

The Tear Down

The first thing I did was disassemble the module that attaches the cable to the antenna. This was held together with four custom screws.

Disassembling the original Mohu Leaf Plus antenna
Disassembling the original Mohu Leaf Plus antenna

Upon opening it, I was surprised to find a small printed circuit board! At first, I thought this was just a passive filter, but later I realized this was the actual amplifier, placed right against the antenna where it should be!

Mohu Leaf Plus amplifier circuit board
Mohu Leaf Plus amplifier circuit board

Remember, I disassembled the amplified Mohu Leaf.  The regular Mohu Leaf does not have this circuit board or the power module (just a passive balun), see below.

Regular Mohu Leaf with no amplifier
Regular Mohu Leaf with no amplifier

Power is supplied from the USB power module further down the cable. There are only two signal wires, so power is sent through these wires to power the amplifier at the antenna and the signal comes down these same wires via DC blocking capacitors.

Mohu Leaf Plus USB power module
Mohu Leaf Plus USB power module

The Antenna

Now for the part you’ve probably been waiting for. What does the Mohu Leaf antenna actually look like?

Since this was the older laminated version of the antenna, I could simply cut around the edges and split it open. The center of this antenna two sheets of paper stock with very thin foil for the antenna in between. Unfortunately, it was nearly impossible to peel the paper away from the antenna foil – they were glued tightly together, probably to hide the design.

Original Mohu Leaf antenna peeled open
Original Mohu Leaf antenna peeled open

But, you can see the faint outline of two bowtie antennas. I’ve outlined them below for clarity.

Mohu Leaf bowtie antennas
Mohu Leaf bowtie antennas

This type of antenna is known as a wide-band printed bowtie antenna. This is a traditional TV antenna style, although the dimensions were carefully chosen by Mohu for optimum reception.


A Comparison

Just to compare, here’s a photo of a Winegard FlatWave Amped antenna. It’s clear so you can easily see the design:

Winegard FlatWave Amped antenna
Winegard FlatWave Amped antenna

So, not all flat antennas are created equal.

Conclusion

So there you have it! The original Mohu Leaf is a dual wide band printed bowtie antenna!

The current all-plastic Mohu Leaf antenna  is much harder to dissect. I’ve get very similar reception with it, so I would assume it’s also a bowtie antenna, but that is just conjecture.

Was that a bit anticlimactic? Were you expecting a more exotic antenna design, perhaps a fractal antenna? Even though the design is very traditional, the Leaf is a great performer, probably due to subtle design tweaks by Mohu. Sometimes it’s best to go back to the basics! – Brian

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About Me

Brian Shim, DisableMyCable.com

I'm an electrical engineer (BSEE Caltech) with twenty years of experience designing industrial and consumer products, and now a web developer who loves to share ways to save money on TV content, Internet access, and cell phone plans! Read more about me here. You can also watch my videos on YouTube.

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Doggiemama5
5 years ago

so the amplified version will get better reception?

Brian
5 years ago
Reply to  Doggiemama5

Hi Doggiemama5,

Not necessarily. In fact, several readers have reported to me that they got worse reception when using an amplifier (I’ve seen this myself too). Unfortunately, experimentation (trial and error) is the only real way to know whether an amplifier will help, although if you are far from the transmitters or have long cable runs, it’s more likely that an amp will help.

Best,
Brian

Philip Cain
Philip Cain
5 years ago

Excellent breakdown of the Mohu Leaf antenna. Thanks Brian. It’s more or less what I expected. A primo design to be sure. The sealed “bow tie” elements bare a striking resemblance to what I’m already working with at home.

https://www.facebook.com/photo.php?fbid=2342843065962048&set=p.2342843065962048&type=3&theater

The little per-amplifier is a great idea, but only if it automatically bypasses itself when the DC power is not applied. And I question the combined phasing of the two bow ties when the output is taken from the bottom of the lead lines instead of the exact center where synchronization is assured across the entire band.

Brian
5 years ago
Reply to  Philip Cain

Hi Philip,

Yes, good points!

Best,
Brain

Steve
Steve
5 years ago

That’s probably a balun in the regular Leaf, not a filter. Thanks for the teardown.

Brian
5 years ago
Reply to  Steve

Hi Steve,

Thanks for the correction!

Brian

Ers Antenna
Ers Antenna
5 years ago

Thanks for the tear down, I found this helpful. Thank you.
https://www.ersantenna.com/about/

Patriot American
Patriot American
3 years ago

Thank You for The Enlightenment…!

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