Category Archives: Mediumwave

Ron is impressed with the PK Loop Mini (A-LOOP-MTAM)

Many thanks to SWLing Post contributor, Ron, who shares the following review of the PK Loop Mini (A-LOOP-MTAM):

Standard PK Loose-Coupled Loops (the “A” series) are 14 inches in diameter…they are
for use with a receiver having a built-in ferrite bar antenna.

Don’t think they’re not capable of serious DX…a few years ago a friend in Texas
snagged and recorded France Inter (162 kHz) on a 14 inch standard PK LW
loop using a Sony 7600GR.

But this is about the PK Mini 10 inch loop for Medium Wave (there are none for
other ranges).

The build quality is superb as with all PK loops. The band has two ranges: 525 to
710 and 710 to about 1720 kHz. Paul Karlstrand uses a unique design consisting
of flat computer cable and a custom made circuit board to connect the turns
end-to-end.

The low end simply switches in a fixed capacitor across the variable to lower the
frequency.

The Mini has 25% less sensitivity than the standard 14 inch loop according to the website.
Currently it can be had for $66 USD delivered to your door from Melbourne…this one
was ordered on a Monday and showed up a week later,which is outstanding considering
it had to clear customs in NYC.

Performance is virtually identical with the Tecsun or Terk loops, which are 9 inch loops.
So why buy a PK?

You get what you pay for, or not…the PK is fairly robust compared to the Tecsun or Terk.
It’s made to last and it’s a PK Loop.

Here are some links for comparison purposes:

If you wish to enhance your loop try co-coupling it to your receiver with a Q-Stick :

http://dxtools.com/QStick.htm

Thank you, Ron, for sharing your experience with the PK Loop Mini. It certainly sounds like an excellent option for travelers and, like you, I agree that the construction quality is superb!

Click here to check out the PK Loop website.

Spread the radio love

Radio World: History of Directional AM Broadcast Antennas

Many thanks to SWLing Post contributor, Marty, who shares the following article by John Schneider in Radio World:

In the early years of AM radio broadcasting, all stations utilized non-directional antennas. Most all of these were wire antennas suspended between towers or buildings. Interference, especially at night, was severe. An interfering signal of 5% or less in signal strength was enough to disrupt reception of the desired station, and if the frequencies of the two stations were slightly separated, there would be a heterodyne beat note. As a result, only a few widely-spaced stations could operate on each of the AM broadcast channels in the entire country at night. This limited the number of stations that could coexist to about 500 nationwide, with many of them sharing time on a single frequency.

As antenna technologies were developed and improved in the early 1930s, a few progressive stations began experimenting with multi-element directional arrays. This approach offered two attractive benefits: 1) It could reduce radiation towards other stations on the same or adjacent frequencies, permitting more stations to share a frequency; and 2) a broadcaster could direct more signal towards the desired coverage area, and away from wasted areas such as open water in the case of coastal stations.

WFLA-WSUN

The first known use of a directional antenna was by a pair of stations in Tampa/St. Petersburg, Fla. In 1927, the Clearwater Chamber of Commerce acquired station WGHB and changed the call sign to WFLA. A companion station, WSUN, was operated by the St. Petersburg Chamber of Commerce. The two stations shared the frequency of 900 kHz, broadcasting on alternate evenings to promote tourism and business opportunities in their respective communities. In reality, they operated with two station licenses, but there was only one transmitter and one antenna.[…]

Click here to to continue reading the full article in Radio World.

Spread the radio love

August 2019 Rockwork DXpedition

Many thanks to SWLing Post contributor, Gary DeBock, who shares the following guest post and update from the August 2019 Rockwork DXpedition:


Gary DeBock DXing with Craig Barnes at the Rockwork 4 ocean cliff near Manzanita, Oregon, USA

Once again the largest FSL antenna collection on the planet made its way across the Columbia River bridge during an overnight trip to NW Oregon, finally being deployed at the original Highway 101 plunging cliff turnoff– Rockwork 4. There has been a drastic decrease in the squatter population, so that Craig Barnes and I were able to easily set up all four PVC bases for all-out DU-DXing at the dream site this morning (see photo). Unfortunately Chris Black came down with a health issue at the last minute, and needed to cancel out.

Craig and I had some excellent signals from the regulars (including 531-More FM, 558-Fiji and 1017-Tonga), although it wasn’t quite a stellar morning for rare DX. We were kind of spoiled last year with 1017-Tonga staying a S9 practically throughout the session, but this morning it was “only” at S9 for a few minutes at a time. This meant that as soon as I notified Craig of 1017’s potent status, the signal tended to nosedive. Maybe the cumulative effects of humidity and salt water exposure are beginning to take their toll on the Tongan big gun? 558-Fiji showed up with decent signals for a couple minutes at a time, which meant that Craig got the short end of the stick after I notified him of the potent signal. 531-More FM hit an awesome S9 peak around 1312 (including the usual split-second female ID), making it once again seem totally bizarre that no trace of the 2 kW modern rock station has ever been received at Grayland for the duration. The Rockwork Cliff is typically focused in like a laser on New Zealand, and this was a typical morning!

531 More FM Alexandra, NZ 2 kW Potent S9 modern rock signal from this Rockwork regular, with female “More FM” ID at 19 seconds:

Click here to download.

558 Radio Fiji One Suva, Fiji 10 kW Island music at temporary potent level at 1257; typically hit the skids after reaching this level:

Click here to download.

1017 A3Z Nuku’alofa, Tonga 20 kW Female Tongan speech at S9+ level at 1317:

Click here to download.

1017 Newstalk ZB Christchurch, NZ 10 kW Presumed the one under A3Z’s meltdown-level signal:

Click here to download.

73 and Good DX,
Gary DeBock (DXing with Craig Barnes at the Rockwork 4 ocean cliff near Manzanita, Oregon, USA)

DXpedition equipment:

7.5″ loopstick CC Skywave SSB and XHDATA D-808 Portables
15″, 15″ and 17″ Airport Unfriendly FSL antennas (see photos above)


Again, thank you so much for sharing your DX, Gary! I’m so amazed by the signals you snag each year with your homebrew loopstick antennas!

To read more of our posts by Gary DeBock, click here.

Spread the radio love

Video Demonstration of Gary DeBock’s 3″ Baby FSL Antenna

Many thanks to SWLing Post contributor, Gary DeBock, who shares a video of his latest Ferrite Sleeve Loop (FSL) antenna: the 3″ Baby FSL.

Gary Notes:

The new design 3 Inch (76mm) Baby FSL antenna is the smallest, most compact and lightweight of the “airport friendly” FSL’s developed here recently, but it provides a very potent inductive coupling boost for weak AM-DX signals.

This demonstration video shows its huge boost to a weak daytime DX signal from 1070-CFAX (10 kW in Victoria, BC, Canada) here in Puyallup, WA, USA:

Click here to view on YouTube.

Most impressive, Gary! You’re right: that design is compact enough that it should even fit the bill for my one-bag travel philosophy. I think I might have to build one of these!

Check out more of Gary’s adventures in Ultralight DXing, by browsing our archive.

Spread the radio love

RNZ: No plans to replace AM radio mast in the Cook Islands

(Source: RNZ via Michael Bird)

The Cook Islands Investment Corporation says there are no plans to replace an AM radio mast that is to be dismantled on Rarotonga.

The mast at Matavera, built with New Zealand aid money many years ago to provide a signal to the outer islands, is rusted through in places and in danger of collapsing.

Pupils from an adjacent school have been moved to ensure their safety, while plans are made for the dismantling.

In a statement the CIIC says with the rollout of FM radio and the ability to digitally stream events of national importance, the AM signal is no longer required.[…]

Click here to download the audio.

Spread the radio love