433Mhz MHz Notch_Tiny filter

433 / 435 MHz Notch_Tiny Filter

Keep strong 433 MHz signals away from your receiver

The Notch_Tiny 433/435 MHz is a small, precision-tuned RF filter designed to remove strong unwanted signals around 433 MHz or 435 MHz before they reach a sensitive radio receiver.

This type of interference can be surprisingly difficult to diagnose. Your receiver may be perfectly tuned and the antennas may have a good SWR, yet the system can still suffer from reduced range, increased noise or unstable reception when a nearby high-power transmitter is active.

The reason is often not interference inside the receiver's operating channel. Instead, the receiver is simply being exposed to a very strong signal outside its intended frequency range.

A sensitive receiver has to deal with that signal before it can even start doing its normal job.

This is where a properly designed notch filter helps.

Remove the problem frequency

Rather than filtering a large part of the RF spectrum, the Notch_Tiny targets one specific frequency.

The filter can be tuned for either:

433 MHz or 435 MHz

At the selected frequency, it creates a deep attenuation notch with at least 38 dB of rejection.

Outside the notch, the filter is designed to introduce as little additional loss as possible.

This makes it useful when you want to protect a receiver from a particularly strong nearby transmitter without unnecessarily degrading the wanted RF signal.

38 dB is much more than it sounds

Decibels are logarithmic, so the numbers can be deceptive.

A jump from 30 dB to 38 dB may not look impressive on paper, but it represents a substantial reduction in RF power.

With 38 dB attenuation, only around 0.016% of the original RF power remains at the notch frequency.

As a simple example, a 1 W unwanted signal would be reduced to roughly 0.16 mW.

This does not mean that every receiver problem will automatically disappear — the final result depends on transmitter power, antenna separation, antenna orientation, frequency spacing and the receiver itself. But it gives a good idea of the amount of RF energy the filter can remove.

Made for real RF environments

The 433 MHz band is used by a wide range of radio equipment, and in many installations there can be more than one transmitter operating in the same area.

This can become particularly important in systems where a high-power 433 MHz transmitter is installed close to another RF receiver.

Typical applications include:

• 433 MHz RC and long-range control systems

• 433 MHz telemetry

• UAV and FPV equipment

• radio modems

• ground stations

• SDR receivers

• measurement and monitoring equipment

• custom RF systems

• installations where transmitter-to-receiver isolation is limited

The Notch_Tiny is connected between the receiver input and the antenna. It attenuates the unwanted frequency before that signal reaches the receiver's RF front end.

Individually tuned instead of simply assembled

Every filter is tuned to the frequency selected by the customer.

The difference between a nominal component value and an actually tuned RF filter can be significant, especially when working with a narrow notch.

For this reason, every Notch_Tiny is checked using a Vector Network Analyzer (VNA) after tuning.

The production specification guarantees at least 38 dB rejection at the selected notch frequency.

You therefore receive a filter that has been measured after assembly and tuning, rather than relying only on theoretical component values.

Compact enough to install almost anywhere

The Notch_Tiny weighs just 7 g and uses SMA connectors.

Its small size makes it suitable for installations where there is little room for additional RF hardware — including compact UAVs, FPV ground equipment and portable radio systems.

There is no need to add a large external filter when a small, frequency-specific solution is enough.

Technical specifications

When is this filter worth using?

The Notch_Tiny is most useful when you already have a good receiver and antenna system, but a strong nearby 433/435 MHz transmitter is causing unexpected RF problems.

If reception deteriorates when the transmitter is switched on, range changes significantly with transmitter power, or the receiver becomes noticeably less sensitive in the presence of a nearby RF source, reducing that unwanted signal at the antenna input is often a much better solution than trying to compensate for the problem elsewhere in the system.

A notch filter does one thing, and does it very well:

it takes a very specific unwanted frequency out of the RF environment seen by your receiver.

The Notch_Tiny combines that targeted filtering with ≥38 dB rejection, individual VNA tuning and a 7 g form factor, making it a practical solution for demanding 433 MHz and 435 MHz radio installations.