3.5 Inch (89mm) "Baby FSL" Antenna Demonstration
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- Опубліковано 26 гру 2016
- One of the smallest MW-DXing portable antennas provides a powerful gain boost to a stock Eton Traveler III pocket radio, increasing the daytime DX signal level of 750-KXTG (50 kW at 160 miles) from inaudible up to around S7. Includes construction details and basic operating information (by Gary DeBock, N7EKX)
- Наука та технологія
The best longwave/shortwave antenna for the money that I've seen is a 5 foot box loop with an air variable tuning capacitor and a small coupling loop located within the field of the large one, and it's dirt cheap, just some wire for the loops and a couple of tuning caps. It's what serious radio listeners used from the dawn of radio on, basically until the invention of the transistor. A ferrite-based loop such as the one in the video is a second-best option for when you want to pack the antenna around with you for the day. And of course, that much ferrite isn't light.
Awesome information. thank you very much Gary. (and I agree, the content of the broadcast added laughter to the video - but, not our type of conversation, ha) great !!
Great video - the performance of your antenna from effectively zero to S7 is incredible. 73! Clint
Thanks very much, Clint. Your comment is appreciated, and Happy New Year to you and your family!
My pleasure - a Happy New year to you and your family also. 73!
Another amazing video Gary, DX Sensei. Happy New Year for you and family 73 from ca3pdb
Thank you very much for your comment, Patoborq. Happy New Year to you also! 73, N7EKX
Very interesting piece of kit. Thanks and all the best Gary.
Thanks very much for your comment, Lee. Good DX to you!
Could this type antenna be used for a part 15 am broadcast antenna tuner ?
Hello 1620, I'm sorry, but this antenna was only designed for long range MW reception, and not for handling any level of transmitted RF power as an antenna tuner.
FSL = Ferrite Sleeve Loop (I just learnt, passing it on here for any other newbies)
Thank you
Gary, very impressive! I'd love to see/hear the difference between this sweet little honey, and progressively larger FSLs. One drawback I've encountered is the limited usefulness inside a RF unfriendly room with laptops, noisy lights, etc. I.e. My radio shack. The FSL really amplifies all of the crud. It shines away from noise sources, though!
Hi Walt, Thanks for your comment! You are certainly right that the FSL antennas really shine outdoors, away from sources of indoor RF pollution. Ocean cliffs without any AC power lines are ideal :-) And yes, I would also like to do a comparison video of one of these tiny new FSL's and a 15" or 17" ocean cliff DXpedition model. Or maybe track down a DU on both, at the Rockwork 4 cliff?
Hi Gary, great stuff you are doing. could you help me with a question? in the Uk here there is Radio Caroline using 1kw around 160 miles away, 24hr station. i cannot use an outdoor antenna because i am in a 2nd floor condo. what size FSL do you think would necessary to stand a chance of bringing in the station strong?
That's another sweet design of yours, Gary! I'll bet there is not a linear progression of sensitivity versus diameter X rod length. For instance, I doubt the 7" / 8" FSLs pick up twice the weak signals of this 3.5" version. The law of diminishing returns seems to apply here, but I doubt you'll be exchanging your monster FSLs for the small, easy-to-carry models any time soon on DXpeditions at the Rockworks cliff! 73- Guy
Hi Guy, There is indeed a tradeoff between antenna gain and convenience, and this model is certainly slanted toward the "convenience" group. Despite this the new 1162/46 Litz wire does provide a major boost in sensitivity over 660/46 Litz wire, making this tiny thriller something that could pull off a DXing surprise (or two) on the ocean coast.
A demonstration of the SDR antenna version would be nice too. I intend to build the 7 inch version during January. 73 de Ivan.
Hello Ivan, Work on the SDR version of the FSL antenna stopped around 2013, when I gave all my experimental broadband FSL antenna material to the local SDR DXers. Recently only the standard (inductively coupled, with a single optimized frequency) FSL antennas are being developed. 73- Gary
What happens when you get the radio closer and then retune the FSL cap, ie, is the radio detuning the FSL and retuning would allow you to hear the station again.
Gary
What's best am radio antenna for dx
5 inch fsl
4 ft box loop
Or 100 ft long wire ?
Anyone ?
Nice antenna... add to Fet TRF radio... and receive longwaves...
I think your camera is injecting a little noise into the stock radio. I can hear traces of KXTG before you pick up the radio.
Hi Stephen, My Galaxy S5 cell phone does indeed inject some noise into a radio when it's too close, but the slight pickup of KXTG on the stock radio (when the radio is down on the same level as the FSL, but widely separated) is more likely because of the FSL's ability to radiate a slight gain boost at distances of up to 2 feet. When the stock radio has neither the cell phone nor the FSL in its immediate vicinity, it manages only noise on 750 kHz around local noon.
Ahh, that's plausible.
Also I think you might have lower ground conductivity than some places in CA. At home, KLAA-830 at ~85 miles is ~32/25 or so, & KNX-1070 at ~111 miles is ~47/25. Both are 50kW ND, and KNX has some saltwater enhancement. Also near Bakersfield, I think KNBR-680 is probably in the teens to low 20s, at ~240 miles. Iirc, in Gila Bend, AZ, a couple years ago, KFI-640 was readable at ~320 miles, and in Quartzsite, KNX-1070 was I think detectable at ~240 miles, all barefoot.
can you pls sell this one to me? i would like to try this with my sony crf v21
well done..this is my ferrite loop antenna
ua-cam.com/video/Nm1wIhEFkrg/v-deo.html
Howdy. Nice presentation. A few comments.
Ferrite rods work only up to maybe 2 MHz.
I don't quite agree with the technique to assemble the rods in parallel. In my mind they should be in series. The longer the ferrite array the larger the effective aperture or catching area.
Check tis site : caves.org/section/commelect/mm/mm04.html
I believe there is no fear of ferrite saturation. The flux density capability of ferrite is way way more than that of free air.
Regards.
While a longer rod improves the effective aperture, the larger core improves the Q, since this antenna is essentially a tuned coil, and the inductor coil dimension ratios point to a maximum Q being provided by a coil with a slightly greater diameter than length, (i.e.) a greater inductance vs the resistance of the wire used to wind it.
I've played around with and researched a wide variety of low frequency antennas for decades, ever since reading of the work of Ralph Burhans in the 1980's.
@@johnwest7993 Howdy.
Aha ok. Good information. Thanks.
Also I see I have made a false statement. The ferrite material 4B1 actually reaches up to about 30 MHz though best performance is under 4 MHz..
Regards.
Arrrggghhhh! So much qrm! Can You wright the video out of buildings?