Re: [IRCA] Rockwork 4 DXpedition-- Top Ten Signals from the South Pacific

[d1028gary@xxxxxxx]

Hi Guy,

<<<  Your recordings from the Rockworks cliff are amazing! It's hard for me to
believe I was DXing at another Kiwi DX producing cliff to the south of you
on one of the same mornings, yet all my reception with the same 12-inch FSL
design was low-level and poor S/N ratio. The capacitor-tuned, single
frequency FSL just blows away the same antenna used in a broadband fashion.   >>>

Of course, the results of the current 12" Broadband FSL at Cape Perpetua were not what we had hoped for. You guys devoted some serious time and effort in transporting and testing out the antenna, and I'm sorry that your hard work did not result in more DXing success. Of course, I ran a few A/B tests here in Puyallup with the Standard and Broadband FSL's in the reception of fringe DX on Ultralight radios, and the Standard FSL version blew away the inductively-coupled "Flag Amp" version of the Broadband FSL here, as well. I was hoping that the additional sensitivity of the Perseus-SDR and the cliff-side enhancement boost at Cape Perpetua would somehow compensate for the Broadband FSL's lack of weak-signal sensitivity, but it's obvious that we need to try a different approach.

<<<    I look forward to further discussions with you about the "hybrid' FSL
tuning idea I proposed. This will make use of the broadband mode for signal
spotting, and then switching to the single frequency tuning approach for
actual DXing and recording of the station with Perseus. There's also the
subject of small, 7 to 8 ft. amplified Flag loops to pursue, such as Chuck
was trying at the top of the Cape Perpetua Lookout.   >>>

Guy, I received your detailed suggestions (and those from Bill) about reworking the Broadband FSL configuration, and they were all innovative and interesting. Because of a serious time crunch here related to a remodeling project (and being in between DXpeditions to Rockwork and Cape Perpetua), I'm sorry that I haven't yet been able to respond to you both regarding each individual suggestion. You have my full permission to modify the current 12" Broadband FSL in any way you wish, and try any or all of the changes that you and Bill propose. After this month, I should have more free time to work closely with you (and Bill) in a determined effort to make the Broadband FSL more competitive in relation to the Standard FSL. By the way, thanks very much for your comments on the Standard FSL's performance at Rockwork 4 last week, which are much appreciated!

73, Gary DeBock (in Puyallup, WA)
  

     
 




-----Original Message-----
From: Guy Atkins <dx@xxxxxxxxxxxxx>
To: irca <irca@xxxxxxxxxxxxxxxx>
Sent: Wed, Jul 31, 2013 10:41 am
Subject: Re: [IRCA] Rockwork 4 DXpedition-- Top Ten Signals from the South Pacific


Gary,

Your recordings from the Rockworks cliff are amazing! It's hard for me to
believe I was DXing at another Kiwi DX producing cliff to the south of you
on one of the same mornings, yet all my reception with the same 12-inch FSL
design was low-level and poor S/N ratio. The capacitor-tuned, single
frequency FSL just blows away the same antenna used in a broadband fashion.

It was disappointing to discover such a vast discrepancy, because at home
and on a camping trip/mini DXpedition my comparisons between the two hookup
methods indicated comparable reception except for slightly higher noise on
the broadband version. However, I wasn't testing on the DU signals, which
normally are much, much weaker than domestic North American signals (weaker
even than the foreign TPs in winter). The "Q" and sensitivity boost given
by the resonant tank circuit of the FSL's coil coupled with the tuning
capacitor evidently makes all the difference.

I look forward to further discussions with you about the "hybrid' FSL
tuning idea I proposed. This will make use of the broadband mode for signal
spotting, and then switching to the single frequency tuning approach for
actual DXing and recording of the station with Perseus. There's also the
subject of small, 7 to 8 ft. amplified Flag loops to pursue, such as Chuck
was trying at the top of the Cape Perpetua Lookout.

If you can ever get to the Rockworks cliffs during the fall/winter TP
season you may need to tie yourself and the FSL to the guard rails to avoid
being blown away! I can only imagine the quality of the 3rd tier, weak
Japanese stations you might catch. I think you said that one of the
Rockworks cliffs was situated better for TP signals coming from the
northwest direction.

73,

Guy Atkins
Puyallup, WA
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