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8" FSL vs. 4' Air Core Loop MP3 Impressions
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<<< I could not hear the media clips, and explaining to me how to do
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that would probably be a challenge. Could you briefly describe the results or post the RSSI numbers if you recorded them? I am guessing the FSL did very well, but wonder if it would be able to be used anywhere near a computer or other home electronics? With my 4 foot air core loop or even my 2 footer, I can usually null out electronics in the room, and still hear some signals, but of course the ones the antenna pattern points to are much better than the ones in the null for interference. The ferrite rod antennas you made for my PL 360 have a much tighter pattern than the air cores. -FARMERIK >>> Hello Farmerik, The four fringe-station MP3's posted from the antenna testing are fairly convincing, but for those who can't open the recordings, I'll share my personal impressions. The 8" FSL's reception advantage on the weaker stations is almost entirely related to its lower noise pickup, and not superior signal strength. On a couple of the fringe stations (1040-CKST and 1070-CFAX) there was a fairly great difference between the FSL's relatively quiet, noise-free reception and the 4' air-core loop's pickup of electrical or atmospheric noise. The FSL's low-noise advantage is greater when receiving the weaker stations, and it becomes less noticeable as the DX station's signal strength increases. In rare cases the 8" FSL will provide a slightly stronger DX signal than the 4' air-core loop, but this is unusual, and the DX station signal levels are generally equivalent on the two antenna systems. The 8" FSL does have a few other advantages over the 4' air-core loop, such as greater bandwidth (450-1700 kHz, as opposed to 530-1600 kHz) and superior nulling performance. The FSL design also uses a high-Q tuning system providing sharper selectivity, and can typically cut down local station slop better than any air-core loop (this does requires more careful tuning, however, making optimum signal peaking more of a challenge) . Balanced against these advantages is the fact that the FSL design has side effects of concentrated cost and weight, and requires some protective padding for the ferrite components. In general the FSL design does provide a high-gain DXing breakthrough for extremely compact antennas, though, and is perfectly suited for the Ultralight radio DXer who has only a picnic table for setup space. 73 and Good DX, Gary DeBock (in Puyallup, WA)
-----Original Message-----
From: farmerik <farmerik@...> To: ultralightdx <ultralightdx@...> Sent: Thu, Jul 7, 2011 11:10 am Subject: [ultralightdx] Re: 8" Diameter FSL vs. 4' Sided PVC Air-core Loop Runoff Gary - Thanks for all your experimenting and reporting of test results. You and several others are doing a huge service to improve ULR DXing results for all members. Because I am a computer idiot, I could not hear the media clips, and explaining to me how to do that would probably be a challenge. Could you briefly describe the results or post the RSSI numbers if you recorded them? I am guessing the FSL did very well, but wonder if it would be able to be used anywhere near a computer or other home electronics? With my 4 foot air core loop or even my 2 footer, I can usually null out electronics in the room, and still hear some signals, but of course the ones the antenna pattern points to are much better than the ones in the null for interference. The ferrite rod antennas you made for my PL 360 have a much tighter pattern than the air cores. -FARMERIK --- In ultralightdx@..., D1028Gary@... wrote: week (with the family) and only enough space to pack a relativelycompact antenna, it was time to choose the best performer for DU-chasingthis summer.August 20-22 DXpedition to Lincoln City last year, receiving over 30 SouthSlider model (as described in the article posted at> been a lot of experimentation with Ferrite Sleeve Loop antennas, indicating that these compact ferrite-based antennas provide a realsuch, it was time to see if one of the new FSL's could really compete on MWwith a proven DXpedition performer like the 4' portable PVC Loop.10mm ferrite rods, purchased on eBay from an Eastern European seller(who, presumably, is amazed at his recent financial bonanza). Theferrite rod > assembly was secured on soft rubber form filled with padding material, > then wrapped with 18 turns of 660/46 Litz wire from the eBay seller > "Mingmak222." A 381 pf variable capacitor from Crystal Radio Supply (part # N50P) was used to tune the compact loop, providingfrequency coverage from 450-1700 kHz. The design and construction of thisFSL was > chosen based on extensive A/B testing with another 8" diameter FSL control model, and a photo of the FSL twins is posted atmodel on the right, before MW frequency conversion).chosen to test the two compact loop systems, most of which were well over 100station in Vancouver, BC. 1070-CFAX is in Victoria, BC, and 1110-KWDB is inreception on the 4' sided PVC air core loop is first (about 15 seconds),then the reception on the 8" diameter FSL:it soon became quite clear which antenna provided a low-noise signalwere all made on a stock PL-606 model, which was inductively coupled toboth loop antennas at the optimum range. The new 8" FSL can easily bepf of capacitance in parallel with the N50P variable cap, providing thebest of both DXing worlds in a compact system taking up only one cubicfoot of space. A photo of the relative size of these two antennasystems is also posted at http://www.mediafire.com/i/?yr7grir83488ii3 , which
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Rik
Thank you very much. I do hope the FSL antennas will become available to purchase. Until then I will keep using what I have.
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I am curious how my rook and diamond weave 12 inch antenna coils would work with ferrite bars or rods arranged inside the coils. Would that dramatically change the inductance? I had them made for both AM and LW use on DSP URLs. Any speculation? -FARMERIK
--- In ultralightdx@..., D1028Gary@... wrote:
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Pollock,Raphael E <rpollock@...>
It might be very interesting—slightly off topic—to see how the FSL vs Box Loop inductively coupled comparison holds up when using radios w/ stronger “front ends” and/or ability to modulate RF gain such as the Sony 2010 or the Satellit 750???
From:
ultralightdx@... [mailto:ultralightdx@...] On Behalf
Of farmerik
Thank you very much. I do hope the FSL antennas
will become available to purchase. Until then I will keep using what I have.
> -----Original Message-----
> From: farmerik > To: ultralightdx <ultralightdx@...> > Sent: Thu, Jul 7, 2011 11:10 am > Subject: [ultralightdx] Re: 8" Diameter FSL vs. 4' Sided PVC Air-core > Loop Runoff > > Â > Gary - Thanks for all your experimenting and reporting of test > results. You and several others are doing a huge service to improve ULR > DXing results for all members. > > Because I am a computer idiot, I could not hear the media clips, and > explaining to me how to do that would probably be a challenge. Could > you briefly describe the results or post the RSSI numbers if you > recorded them? > > I am guessing the FSL did very well, but wonder if it would be able to > be used anywhere near a computer or other home electronics? With my 4 > foot air core loop or even my 2 footer, I can usually null out > electronics in the room, and still hear some signals, but of course the > ones the antenna pattern points to are much better than the ones in the > null for interference. The ferrite rod antennas you made for my PL 360 > have a much tighter pattern than the air cores. > > -FARMERIK > > --- In ultralightdx@..., D1028Gary@ wrote: > > > > Hello All, > > > > With a DXpedition trip scheduled to the Oregon coast in about a > week > > (with the family) and only enough space to pack a relatively > compact > > antenna, it was time to choose the best performer for DU-chasing > this > > summer. > > > > The 4' sided portable PVC Loop had performed very well in the > August > > 20-22 DXpedition to Lincoln City last year, receiving over 30 South > > Pacific stations when inductively coupled to to a C.Crane SWP > Slider > > model (as described in the article posted at > > http://www.mediafire.com/?9tjd0pqpa4ld2f0 ). But recently there has > > been a lot of experimentation with Ferrite Sleeve Loop antennas, > > indicating that these compact ferrite-based antennas provide a real > > DXing breakthrough for hobbyists with limited setup space. As > such, it > > was time to see if one of the new FSL's could really compete on MW > with > > a proven DXpedition performer like the 4' portable PVC Loop. > > > > An 8" diameter FSL was constructed w/ 63 Russian surplus 100mm x > 10mm > > ferrite rods, purchased on eBay from an Eastern European seller > (who, > > presumably, is amazed at his recent financial bonanza). The > ferrite rod > > assembly was secured on soft rubber form filled with padding > material, > > then wrapped with 18 turns of 660/46 Litz wire from the eBay seller > > "Mingmak222." A 381 pf variable capacitor from Crystal Radio Supply > > (part # N50P) was used to tune the compact loop, providing > frequency > > coverage from 450-1700 kHz. The design and construction of this > FSL was > > chosen based on extensive A/B testing with another 8" diameter FSL > > control model, and a photo of the FSL twins is posted at > > http://www.mediafire.com/i/?pp9sa4pl56dm4kf (with the DXpedition > model > > on the right, before MW frequency conversion). > > > > At local noon here in Puyallup, WA four fringe stations were > chosen to > > test the two compact loop systems, most of which were well over 100 > > miles distant. 550-KARI and 550-KOAC are fringe stations in the > > Vancouver, BC and Portland, Oregon market, while 1040-CKST is a > station > > in Vancouver, BC. 1070-CFAX is in Victoria, BC, and 1110-KWDB is in > > Whitbey Island, northwest of Seattle. In all four MP3's the > reception > > on the 4' sided PVC air core loop is first (about 15 seconds), > then the > > reception on the 8" diameter FSL: > > > > 550-KARI-KOAC mix http://www.mediafire.com/?akf4xkx3sjwlwp3 > > 1040-CKST http://www.mediafire.com/?jvcps6shc99i0q7 > > 1070-CFAX http://www.mediafire.com/?bn16gdvoa2bdcnn > > 1110-KWDB http://www.mediafire.com/?ea3zczjet3mw1cj > > > > Although the antenna testing was done with a completely open mind, > it > > soon became quite clear which antenna provided a low-noise signal > > advantage, especially on the weaker stations! The above recordings > were > > all made on a stock PL-606 model, which was inductively coupled to > both > > loop antennas at the optimum range. The new 8" FSL can easily be > > converted to an "LW Optimized" antenna by switching in about 700 > pf of > > capacitance in parallel with the N50P variable cap, providing the > best > > of both DXing worlds in a compact system taking up only one cubic > foot > > of space. A photo of the relative size of these two antenna > systems is > > also posted at http://www.mediafire.com/i/?yr7grir83488ii3 , which > > hopefully will be of interest to picnic-table DXers like me! > > > > 73 and Good DX, > > Gary DeBock (in Puyallup, WA, USA) > > >
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