Category Archives: Accessories

Mike’s low and high pass filter deals

SWLing Post contributor, Mike Ladd, is an avid SDR enthusiast and an administrator of the SDRplay Facebook group. Mike contacted me about special pricing he has arranged for low and high pass filters through Rescue Electronics. Mike explains:

These filters retail for $70.00 each. I spoke to the builder. I told him who I was and what I do and got him to make a deal for anyone in the United States with these filters and a direct link to his site. I make zero dollars on this. I always try to give back to the hobby and the community any way possible.

You have 3 choices: a high pass filter, a low pass filter, or a combo package.

These are hand built one at a time by Paul W1VLF with your choice of SO-239 or BNC connections. Full details are below:

High pass filter $55 shipped anywhere in the USA

This filter will begin attacking the AM band at 1770 Khz and increase attenuation as frequency decreases.

You can see this in the screen capture of the swept filter below.

160 Meters and above is virtually left untouched, but below that is where the attenuation takes place.

The filter has attenuated 60 db by 960 KHz.

The AM band has some very large signals that can mix in the front end of your. A lot of these spurious frequencies can land in 160 meter band or above.

For instance, I have a big signal at 1080 Khz and another at 770 Khz, add these 2 together and you get a spur that falls at 1850 Khz

Picture this happening at multiple frequencies with multiple mixes and you have a raised noise floor in the 160 Meter band.

The filter is built into a 2″ x 4″ 1.25″ 1/8″ wall aluminum enclosure for excellent RF shielding

Low pass filter $55 shipped anywhere in the USA

The AM-2 filter has a cutoff at 520 KHz.

Then, and without a lot of fanfare it begins the attack on the MW band.

Purchase this filter if you are into NDB, DX’ing, Maritime Mobile, Navetex, FCC Part 5 600 Meter band.

Each filter is handmade and swept in my lab.

The AM -2 Low pass is equipped with BNC connectors.

The filter begins to roll off at 520 Khz and gives an ultimate rejection of around 80 Db.

The filter is built into a 2″ x 4″ 1.25″ 1/8″ wall aluminum enclosure for excellent RF shielding

Combo deal for both $100 shipped anywhere in the USA

Click here to view/purchase via Mike Ladd’s promotional page at Rescue Electronics.

Many thanks for sharing this Mike! During my presentation at the Winter SWL Fest last week, I spoke about the need for high/low pass filters for listeners who live in the presence of strong broadcasters and interference. Many of the inexpensive SDRs on the market do not have built-in filters and preselectors thus can overload under these conditions.

While filters can be homebrewed or built from kits, these filters seem to be a good deal for a quality shielded and tested product. Thanks for arranging this, Mike!

CountyComm: Free deluxe case with purchase of GP5/SSB

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Many thanks to SWLing Post contributor, Ron, who shares this deal from CountyComm:

http://www.countycomm.com/gp5ssb.html

MegaLoop ML052: Bonito’s new portable mag loop antenna

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(Source: Bonito Press Release)

At the beginning of the model year 2016, there is good news in the range of our MegaLoop Active Loop Antennas:

New Model: MegaLoop ML052

The new Active Loop MegaLoop ML052, which is available end of February, is the successor to our MegaLoop 060. Based on the proven technology of theMegaLoop 200 platform, an additional low pass filter with an extra FM-band-stop was integrated. Thus, the ML052 is especially suitable for operation near strong FM-stations and higher frequencies , where, because of its broadband capacity, the ML200 could be overloaded by strong signals.

Frequency range:
Low Gain: 9kHz – 52 MHz
High Gain: 9 kHz – 36 MHz
Suppression on FM (88 – 108 MHz): max. 40 dB

Intercept Point
IP:3: typ. +40dBm
IP2: typ. +84 dBm

The effect of the integrated filter can be seen very good on these two images:

ML052 in High Gain Mode

ML052 in Low Gain Mode

Like the ML 200, the amplification of the ML052 can be changed internally with a jumper:
a) High Gain: 0-36MHz
b) Low Gain: 0-52 MHz (-7dB)
Suppression of the FM band: (88-108MHz): max. 40dB

Outstanding intermodulation surpression, with only 5 volts!

CPI1000 with a standard Powerbank

The MegaLoop ML052 achieved outstanding values regarding intermodulation suppression even at a low supply voltage from only 5V. It can be powered either by a conventional plug power supply or even via USB. Powering via USB has the advantage that no external power supply is needed and that the antenna can be used autonomously and noise-free with a separate USB power bank. A appropriate dual power input adapter (CPI1000) is already included in the standard package.

The MegaLoop ML052 can now be pre-ordered in our eShop underwww.hamradioshop.net. In the UK at Taylor Made RF.

A simple homebrew high pass filter

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Many thanks to Jon Hudson, of SDRplay, who posted the image above along with the following note on Facebook:

David, WA7JHZ has designed and assembled this neat 2.6 MHz high-pass filter (HPF) for use with SDRs. He says that this simple input band-pass filter (BPF) might be of interest to anyone suffering from strong AM broadcast stations that are causing overloads…..David suffers from three nearby AM radio broadcast stations that overload the front ends of several of his receivers, including the SDRplay RSP and this is an ideal, low cost solution. He built this circuit from junk parts and commented that Amidon T44-2 iron powder cores would have made a better design, but that he decided to keep costs down with this design.

This design is simple enough for almost anyone to build and could help your receiver’s front end from overloading. Many thanks to David for the design/schematic and to Jon for sharing!

Radio Go Bag: JC recommends this affordable shoulder pack

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Speaking of backpacks and protective cases for radios, SWLing Post reader, JC, recommends an inexpensive tactical shoulder pack available via eBay.

JC writes:

I tend to want a little more protection and space so I use a tactical military type shoulder bag for my portable radio kit. It hangs nicely off the back of the passenger’s seat in my car and allows me to keep my PL-660, spare batteries, portable wire antenna, earphones, frequency lists, and other gear all together in a handy pack.

JC’s shoulder pack

The price is about $13.60 w/ free shipping. It’s a great bag for my portable kit, and it’s built pretty sturdy. Any extra protection is better than none for a radio used out in the field.

Click here to view on eBay.

Thanks for the recommendation! That is incredibly affordable and a great looking bag.

I’m very partial to Spec Ops Brand packs, but they’re quite pricey in comparison.

Protecting your investment: Troy’s radio case recommendations

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Many thanks to SWLing Post contributor, Troy Riedel (the Amateur Astronomer), who writes:

I’m rather – uh – call it OCD re: equipment cases (and bags/packs).

All of my […]astronomy equipment is well secured & cataloged in several dozen cases.

I [also] wanted to protect my shortwave radios. I like the neoprene cases that Tecsun ships with their radios as they have a bit of shock absorbing capacity. I went online at Amazon & eBay and I bought “neoprene” cases of various sizes made for GPS units, external hard drives, and tablets.

Upon receiving them I’ve found the 3.5-4″ GPS cases are perfect for the Grundig G6 and similar sized radios.

Belkin “Grip” tablet cases are perfect for the Grundig G3/G5. And the larger “iLuv Gaudi” case is prefect for the YB400 & Sony ICF-SW7600GR. The iLuv even has memory foam. I feel I could drop any radio in this iLuv case from a reasonable height and the contents would be perfectly fine.

Including shipping, I spent $6 for the most expensive case and as little as $3.95 for the least expensive.

The iLuv memory foam case, in silver, was only $4.99 and free shipping via Amazon Prime. Some of the cases have exterior zipped pockets perfect for ear buds and a USB cable. The neoprene has the capacity to stretch a bit, so all of them are a snug fit. Though there is an extra 1/2″ on the iLuv case, the memory foam quality ensures a nice, tight fit.

I’ve attached a few pictures to illustrate my finds.

BTW, I also noticed today that The Worldwide Listening Guide is priced at $21.62 on Amazon. That’s down from $24.95 and a good deal with Prime.

Thanks so much for sharing your research, Troy. I have just added the iLuv case to my Amazon cart. Like you, I have a Sony ICF-SW7600GR and it gets taken to the field a lot. The 7600GR comes with a nice custom case/cover, but it offers little in the way of protection–$4.99 is a reasonable cost to protect one of my favorite portables.

Like you, Troy, I have a serious addiction to quality bags and cases. I hope you know that you’re only enabling me! Ha!

Readers: Please share your radio case/bag recommendations as well!