Re: Cape Perpetua (Oregon Cliff) DXpedition- Top Ten Signals from the South Pacific


Mark/airchecklover
 

Hi Gary - An armchair question/observation abt broadband FSL vs tunable, very narrow passband FSL. What makes UL-DU DX possible for you, with an admittedly 'lesser' receiver and what does the Perseus crowd not have? Assuming they can setup on the same cliff, the difference is the FSL. Doesn't the tunable FSL provide, besides intense gain, two other key functions: Both a very narrow passband which helps reject local 10Khz 'pests' and perhaps also more side image rejection?

I do not immediately see how how the "signal pre-conditioning" function provided by the tunable FSL can be achieved by a broadband FSL plus Perseus electronics. What are your thoughts on how you can mimic the signal conditioning provided by a narrow band manually tuned antenna?

I can image - in theory - an electronic tuning circuit which modulates FSL tuning such that the antenna is swept repeatedly at a rate higher than human hearing can detect. Much like the effect of a 60hz fluorescent bulb appearing to be steady state.

Ah this early morning coffee sure does work to get the ideas flowing :)

Mark
++++++++++++++++++++++++++

--- In ultralightdx@yahoogroups.com, D1028Gary@... wrote:


Hi Guy,

Thanks for your comments on the 'Top Ten" DU recordings from the Cape!

<<< After listening to your recordings from the Cape Perpetua cliff, I was left shaking my head in amazement. As you know, I was DXing at the very same spot one morning during the "Deja-Vu" Yachats DXpedition in July, using one of your 12-inch FSL antennas, but in "broadband" mode. I noted the presence of signals on most of the frequencies you recorded, but-- as Nick Hall-Patch would describe them-- they were "not so reasonable audio, occasional words or phrases in splash or noise that could be understood by a native speaker" or simply "burbles in the splatter and noise". Only a couple frequencies occasionally reached the level of even your poorest recordings. >>>

Well, it's pretty clear that if we want to make real progress on an effective Broadband FSL model, we need to try some completely different approaches than simply connecting the FLG100LN-2 amp across the Litz wire coil. Last winter my main focus was on the mechanical challenge of building the new 12" FSL's with materials that could survive a rough DXpedition environment, and the Broadband FSL experimentation was pretty much an afterthought. There is now quite a lot of interest among Perseus-SDR DXers in the project, though, so I think that by next winter it will be a main focus of experimentation. The potential benefit of combining the FSL's proven cliff-side DXing prowess with the Perseus-SDR's spectrum recording capability is too awesome to ignore.

<<< Unfortunately, the "freakish" DU signal boost at the ocean cliffs isn't enough to compensate for the broadband FSL's apparent deafness on the weakest of signals-- DUs coming from thousands of miles away. The effective gain of the tuned, resonant "circuit" of the single frequency (capacitor tuned) FSL is really incredible, as your recordings prove. >>>

Well, strictly from the standpoint of the Perseus-SDR DXer, one of the tunable 12" FSL's could be taken up to an ocean cliff site like Cape Perpetua (or Rockwork 4) right now and awesome live DXing could be conducted (with far superior sensitivity and filtering, in comparison to the PL-380 that was used last week). This would presumably allow reception of extremely weak and obscure DU's, at an all-new sensitivity level unprecedented on the west coast. The challenge is to somehow package this new capability up in an antenna that spreads such performance out on all the MW frequencies at the same time... not exactly an easy mission to accomplish!

<<< I look forward to working with you this fall and winter to try and solve this dilemma. Whether FSL-based or not, the goal is to find a very compact antenna that will have the gain and S/N needed to allow a SDR radio to record the entire band at the Oregon cliffs, where reception is "repeatedly amazing". >>>

Well, I'll be happy to work together with you on the project, Guy. You have full permission to modify or rework the existing 12" Broadband FSL in any way you wish, until I have more free time to join you (which might not be for a few months :-)

73, Gary DeBock (in Puyallup, WA, USA)





-----Original Message-----
From: thinkdx <dx@...>
To: ultralightdx <ultralightdx@yahoogroups.com>
Sent: Thu, Aug 22, 2013 10:59 am
Subject: [ultralightdx] Re: Cape Perpetua (Oregon Cliff) DXpedition- Top Ten Signals from the South Pacific







Hi Gary,


After listening to your recordings from the Cape Perpetua cliff, I was left shaking my head in amazement. As you know, I was DXing at the very same spot one morning during the "Deja-Vu" Yachats DXpedition in July, using one of your 12-inch FSL antennas, but in "broadband" mode. I noted the presence of signals on most of the frequencies you recorded, but-- as Nick Hall-Patch would describe them-- they were "not so reasonable audio, occasional words or phrases in splash or noise that could be understood by a native speaker" or simply "burbles in the splatter and noise". Only a couple frequencies occasionally reached the level of even your poorest recordings.


Unfortunately, the "freakish" DU signal boost at the ocean cliffs isn't enough to compensate for the broadband FSL's apparent deafness on the weakest of signals-- DUs coming from thousands of miles away. The effective gain of the tuned, resonant "circuit" of the single frequency (capacitor tuned) FSL is really incredible, as your recordings prove.


I look forward to working with you this fall and winter to try and solve this dilemma. Whether FSL-based or not, the goal is to find a very compact antenna that will have the gain and S/N needed to allow a SDR radio to record the entire band at the Oregon cliffs, where reception is "repeatedly amazing".


73,


Guy Atkins
Puyallup, WA





--- In ultralightdx@yahoogroups.com, D1028Gary@ wrote:

Hello All,

Posted below are MP3 recordings links for the ten strongest South Pacific AM-DX signals received during the 4 days-- 6 of which pegged the S/N readout of the Tecsun PL-380 Ultralight radio at the 25 maximum. Twisted and wild ropagation continued throughout the trip, with many bizarre snarls on frequencies across the band. Signals which pegged the PL-380's S/N readout at the time of reception are identified with a double asterisk (**). For those interested, a photo of the Cape Perpetua DXing si te, the new 12" FSL antenna, the new-design 7.5" loopstick PL-380 and not-so-new, sleep deprived DXer is posted at http://www.mediafire.com/view/cw5uw5egiwclrqc/CapePerpetuaSetup.jpg

<SNIP>

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