SRF-39FP, some notes

Horacio Nigro <hanigrodx@...>

Talking about loops and ferrite boosters, after the first weeks using the SRF-39FP I've noted that if I put my hands covering the receiver, in its upper side (near the antenna coils and the tuning capacitor) the signals tend to increase a bit. I've already noted some capacitance effects in the SRF 59, and read about that in this group.

Also with the SRF-39F I've experienced some nulling enhancements that I hadn't seen with the silvered case brother. I'm talking about taking it near a metallic curtain. At some distances or positions the nulling is better. Also as I've noted that the SRF-39FP's  reception is enhanced near the end side of my random wire, where the wire falls down at that point and I can bring it closer. Here the wire imposes its influence and the enhancement is mainly from the wire's direction (in my case from the North, i.e. Brazil). With a loop or ferrite booster, which is in my plan to build, I am certain expecting to increase the quality of DX reception, as most of us already have experimented

Horacio A. Nigro

--- El mar, 12/5/09, D1028Gary@... escribió:

De: D1028Gary@...
Asunto: Re: [ultralightdx] Re: Brazilian DXers recent Lorena DX camp
Para: ultralightdx@...
Fecha: martes, 12 mayo, 2009 1:20

Hello John and Horacio,
Although I'm nothing like a NAm Mossback :>) , I would certainly agree with John that MW loops, both of the ferrite and air core type, are pretty much overlooked in traditional DXpeditions here. For Ultralight radio DXers, however, these loops have great potential to provide absolutely thrilling DX for very little investment.
Both the Slider-tuned ferrite loops and the huge passive air core loops are ideal for ULR DXers, providing a cheap, easy way to make pocket radios extremely sensitive. Bringing these loops to an ocean beach almost always results in a thrilling experience. The figure-8 reception pattern is not ideal in some situations, but with extremely selective DSP-enhanced ULR's now being marketed, the challenge of overcoming domestic splatter may be easier.
One of the unique attributes of the larger PVC loops being tested here is the ability to make even relatively "deaf" ultralights perform like ultra-sensitive wonders, with only inductive coupling. DSP-enhanced radios like the new Degen DE1123 are typically not very sensitive on AM, but when coupled up to a 9 or 10 foot PVC loop, they run wild over any stock portable on the planet, even overloading on stations that a Slider E100 can barely receive. The combination of great DSP selectivity, a built-in MP3 recorder, and a massive sensitivity boost from a 10-foot PVC loop is tough to beat-- all for a total investment of about $150.
73, Gary         
In a message dated 5/12/2009 7:23:51 A.M. Pacific Daylight Time, bjohnorcas@rockisla writes:


Thanks very much for posting the link to the Lorena DX camp. I've gone back there three times and find the differences between this Brazilian group and typical North American DX camps startling!  First, the size.... in North America, most of the MW/SW DX Camps or DXpeditions tend to be rather small. Say 4 to 6 DXers... tops 8 DXers.  The only real exception to this that I can think of is the long-running Ontario DX Association (ODXA) annual camp.  It has been about the size of the Lorena group at times.

The even bigger difference, though, is the huge number of loops, both ferrite and small air core.  Although there has been a minority use of small loops up here in recent years, they are absolutely not the norm... hobby-wide, especially at DX camps. At camps, normally they are selected for remote locations and large wire antennas, usually beverages, are the norm. Although we have seen the full range of antennas up here in recent years, the more popular antennas by decades would be something like:

40s-50s: Long Random Wires

60s and 70s Large Box loops and Random Wires

80s and 90s Beverages and Random Wires

00s Large Single-turn Loops and Beverages

There has been a MWDX sub-group (at times a large one) up here that focuses on DXing with portables since at least the 1970s... maybe going as far back as far as the early transistorized Trans-Oceanics around 1960...

Anyway, if the Lorena camp represents the current general practice of MW DXing in Latin America, they seem far better set up to do Ultralighting in the Unlimited Class than many of us up here. BRAVO!

Thanks for the report, Horacio.

John B.
I'd love to see some of the other NAm Mossbacks comment on the By Decade list above.

At 04:40 AM 5/12/2009 +0000, you wrote:

--- In ultralightdx@ yahoogroups. com, Horacio Nigro wrote:
> Despite there are no ULR at sight, here are interesting pics from Brazilian DXers recent gathering. Note that several use loops and ferrite boosters.
> http://www.sarmento 09.htm
> Horacio A. Nigro
> Montevideo
> Uruguay

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