{"id":17219,"date":"2016-02-05T08:20:54","date_gmt":"2016-02-05T12:20:54","guid":{"rendered":"http:\/\/swling.com\/blog\/?p=17219"},"modified":"2016-02-05T13:23:51","modified_gmt":"2016-02-05T17:23:51","slug":"dx-fiend-gary-debocks-guide-to-building-the-pl-380-pest-control-fsl-antenna","status":"publish","type":"post","link":"https:\/\/swling.com\/blog\/2016\/02\/dx-fiend-gary-debocks-guide-to-building-the-pl-380-pest-control-fsl-antenna\/","title":{"rendered":"DX Fiend: Gary DeBock\u2019s guide to building the PL-380 “Pest Control” FSL antenna"},"content":{"rendered":"

\"Gary-Debock-Pest<\/a>SWLing Post contributor,\u00a0Gary DeBock<\/a>,\u00a0is\u00a0an acclaimed\u00a0innovator in the realm of Ultralight DXing<\/em>\u2013he\u2019s well-known for\u00a0constantly pushing the envelop on these inexpensive DX receivers<\/a>.<\/p>\n

Gary has published yet another detailed home-brew project that can turn your stock\u00a0Tecsun PL-380<\/a> into a Mediumwave DX Fiend<\/em>!<\/p>\n

Many thanks to Gary for the following\u00a0guest post:<\/p>\n

\n

\u201cPest Control\u201d 4.25\u201d FSL Tecsun PL-380<\/strong><\/p>\n

Put Your Local Noisemakers Down for the Count with this Breakthrough Model<\/strong><\/p>\n

By Gary DeBock, Puyallup, WA, USA<\/p>\n

February 2016<\/p>\n

Introduction \u00a0<\/strong><\/p>\n

The first portable radio with a transplanted FSL antenna was introduced last month (click here to read)<\/a>, providing breakthrough MW-DXing performance in the pocket radio class. Although this 3\u201d Bar FSL Tecsun PL-380 exceeded expectations in every way, its 100mm ferrite bars were in very short supply.<\/p>\n

By coincidence the final eBay seller of these 100mm x 20mm x 3mm Russian surplus bars (in Romania) stopped selling them on the day that the first model was finished, creating an instant rush in demand. After providing twelve sets (of 8 bars each) to various DXers my own stock of these bars was rapidly dwindling, and it became an urgent matter to design a similar model using the plentiful 62mm x 12mm x 4mm ferrite bars. Sensitivity of the new FSL antenna would need to be fully competitive with the original model, and I was hopeful of a design that would offer at least one new DXing advantage.<\/p>\n

\"Gary-Debock-Pest<\/a><\/p>\n

With the shorter (62mm bars) it would require a larger diameter FSL antenna to come close to the original model in sensitivity, so by necessity this alternative model would need to have a \u201cshort and stubby\u201d FSL coil design. After considering this I recalled that most of the antennas with a reputation for exceptional nulling performance (and direction finding) seemed to have such a \u201cshort and stubby\u201d coil design\u2014so why not take this opportunity to design and create a portable radio with breakthrough nulling performance, in addition to its superior sensitivity? Such a combination would hopefully make the new model an innovative performer in urban areas\u2014a portable radio that could not only silence multiple MW \u201cpest\u201d stations, but also provide unusual sensitivity to receive competing stations right on the same frequencies. As the model was developed several technical discoveries were made to improve nulling performance, such as the use of grounded shield foil for the Litz wires, and an ultra-symmetrical FSL coil. But even if you live in a rural area far from any MW stations, you will find that this modified radio has a great deal of performance to offer\u2014 a combination of sensitivity, selectivity and nulling ability that has never existed in portable form.<\/p>\n

Project Overview\u00a0\u00a0 <\/strong><\/p>\n

This modification procedure will convert the Tecsun PL-380 AM-LW-FM-SW portable from a modest-performing Medium Wave receiver into an exceptional one, with a significant enhancement of Longwave performance as well. The process involves some close-order soldering on a crowded PL-380 circuit board, and should only be attempted by those will good close-up eyesight, steady hand coordination and some soldering experience. The process also involves the winding of a highly symmetrical antenna coil, which is essential for optimal nulling performance. Because of this, careful attention to the instructions and the use of the recommended ferrite bars and Litz wire is important for the best performance. Certain component parts may be in short supply depending upon current demand, and it is recommended that all these be collected prior to starting the modification procedure.<\/p>\n

Since major portions of this project involve duplication of procedures contained in the PL-380 7.5\u201d Loopstick Transplant article, reference is made to various steps and instructions in that article (posted here<\/a>). As such, hobbyists who have successfully completed the 7.5\u201d loopstick transplant project on a PL-380 will find this procedure relatively simple, with only the 4.25\u201d Bar FSL construction as a new challenge. The resulting FSL-enhanced PL-380 truly provides a quantum leap in MW-DXing performance over the stock model, but reasonable care is necessary to protect the modified portable from sudden drops or mechanical shocks. Completion of the finished radio should provide a great level of satisfaction and hobby enjoyment, especially during travel opportunities where external antennas are impractical or forbidden.<\/p>\n

\"Gary-Debock-Pest<\/a><\/p>\n

Construction Parts Required<\/h2>\n

A.) Tecsun PL-380 AM-LW-FM-SW Receiver (available from multiple sources on eBay<\/a>)<\/p>\n

B.) Precut section of Ace Hardware 48″ orange plastic carpenter’s level (dimensions to follow)<\/p>\n

C.) 2.6″ long section of the 3.5″ diameter “Big Boss Noodle<\/a>“<\/p>\n

D.)\u00a022 Russian surplus 62mm x 12mm x 4mm ferrite bars<\/a><\/p>\n

E.) Tube of Duro Super Glue, .07 ounce (or equivalent)<\/p>\n

F.) Two 1″ x 1\/2″ strips of 1″ I.D. rubber heater hose<\/p>\n

G.) 7 1\/2″ of 1\/8″ diameter shrink tubing<\/p>\n

H.) Two 18″ long plastic tie wraps, 125 lb. test<\/p>\n

I.) Oatey 4″ x 4″ foam closet spacer pack<\/p>\n

J.) Roll of Rite Aid 1″ wide waterproof tape<\/p>\n

K.)\u00a040 feet of 250\/46 Litz wire<\/a><\/p>\n

L.) Roll of Scotch “Extreme” shipping tape (any size)<\/p>\n

Miscellanious:<\/strong><\/p>\n