Flamingo AM - Broadcast AM Bandstop Filter (AM Notch Filter) for Software Defined Radio (SDR) Applications

Blocks harmonics from AM bands on the 3-5 MHz shortwave bands. Cleans up the 80m band quite nicely. Price was descent, well packaged, and arrived on time.

First, this Flamingo AM notch filter is very well constructed and I appreciate they include a male-to-male SMA adapter so it can be easily placed inline right out of the box.My application is shortwave listening and DXing. Using a portable Tecsun AM/FM/SW radio and now also an SDR, both in conjunction with an MLA-30+ active magnetic loop antenna.My problem: Even with reduced antenna gain, I would pick up higher harmonics from a couple of VERY strong local AM towers all the way up to >3000 kHz on the MLA-30+. Through the antenna rig, the stations are many tens of dB stronger than weak SW signals at the fundamental and several dB higher at the harmonics. Thought I'd try an AM band stop filter and see if that would suppress the harmonics ringing through the low-noise amp.Success!Installed this between the antenna bias tee output and the radio. On my Tecsun I no longer hear AM stations echoing through multiple 2000-3000 kHz frequencies. On my SDR I still pick up the AM stations at a much lower level, and the harmonics vanished. (By default, the Tecsun uses the internal ferrite for direct AM reception.)I see no discernible loss of SW signals either, though there's not a lot to find in the 2-3 MHz band here. This is with it inserted after the bias tee, as noted above, so as to not eat out-of-band insertion loss from the filter before amplification, though I've not yet tried placing it between the antenna and tee.Perfect! For my needs, at least empirically, this did the trick right out of the box. Will probably leave as a permanent part of my setup to keep the blowtorch AM stations quiet for SW DXing.

If you need a filter for the AM broadcast band either for SDR purposes or test and measurement purposes… This is a nice inexpensive option.You can do better but you will spend 5 to 10 times as much money to get better performance.This is a nice inexpensive product and a nice package with a common connector style that you can work with.Things you need to know about this unit:The SMA connectors are a little fragile. If you want to install some adapters on them to convert them to type-N or TNC or install a DC block you may need to be careful. I managed to snap one off and have to solder it back on. I successfully repaired my filter with little effort and it swept fine after the fact so no harm done.The performance of my filter was in line with what the manufacture specified according to my VNA. I would like the shelf to be a little sharper, but as I said to get that you have to pay a lot more money.This filter is easily good enough to take harmonic measurements for AM Broadcast if you have a good spectrum analyzer, and it will work well to protect your receiver if that’s what you’re looking for.You should not transmit through this filter, and it does not voltage pass, so you should install a DC block to protect the filter.

The media could not be loaded. My stations are way cleaner now, I can honestly say it’s a HUGE DIFFERENCE!!! Very very well worth the money! You’ll see a difference in your reception the moment you turn it on! Thank you for an amazing product 😁😁☺️☺️🫶🏾🫶🏾🫶🏾

Yep, that AM band is gone.

And yes, I tried it both directions, it doesn't matter, same result both ways.I bought this because I live fairly close to an AM tower and it has a tendency to overpower everything. I wanted to just filter out the whole AM band to allow me to get into HF/SW and such. This looked to be like the kind of device I needed, but in practice it seemed to do the exact opposite. Not only did it not filter out AM, it seems to make AM less noisy. Broadcasts are even more cleanly defined in sdr programs, it's really got me scratching my head.To be thorough, I ordered the AM filter from rtl-sdr-blog (also available here on Amazon) and that one does exactly what I was expecting. So I guess if I have to choose between the two, I'd go with that one, but knowing my experience seems to be completely anecdotal.I'm going to keep the flamingo in case I ever get into AM stuff, it'll be fun to run some experiments with. At the price point it doesn't break the bank, just disappointed it didn't do what I was led to believe it would.

This item will not completely eliminate offended Broadcast yay-em QRM from your receiver, however it absolutely attenuates Broadcast yay-em enough to reduce the burden on the receiver's front end and built in filters. I'm using this in conjunction with an 'Uno' and I can now use the RF gain at any level without overloading the front end and I no longer hear/see the nearby biblestation every 20khz, every band. Good bang for the buck and worth the extra couple dollars for the aluminum enclosure over the "bare bones" listing.

My SDRplay RSP2PRO was un-usable for NDB beacon search.(209 to 520 KHz) Local AM stations were killing me. My SDRplay can now hear everything my ICOM IC7300 hears. Bought a second filter for my Malahit-DSP SDR radio. The Flamingo filter is in a nice aluminum case. Solid construction and clean design. Insertion loss is about 1 dB above and below the AM band. Great little filter.