Category Archives: Antennas

Can someone ID this Singer Eaton magnetic loop antenna found on eBay?

Many thanks to SWLing Post contributor, Dan Robinson, who shares a link to this 31″ Singer Eaton loop antenna found on eBay.

The seller knows nothing about this antenna, but did provide some detailed photos of the connector and product information sticker:

This loop obviously came from US government inventory based on the sticker. It looks to be quite robust and sports one of the balanced antenna connectors found on rigs like the Hammarlund SP-600. I’m guessing this loop might be fixed-frequency as I see no tuning section with a variable capacitor.

Can any SWLing Post readers shed a little light on this loop?  Have you ever used one? Please comment! 

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Using amplified loop antennas with portable radios?

SWLing Post contributor, Klaus Boecker, sports a homebrew magnetic loop antenna on his balcony in Germany.

Many thanks to SWLing Post contributor, Marty, who writes:

I have a question about loop antennas; specifically which type is “better,” passive magnetic loops or active electric loops?

I know, “It depends.”–?

I live in a ground-floor apartment, with a small porch, lots of RFI and restrictions against visible antennas. Also there are no trees within 75 ft of my porch, which faces on a parking lot. My radio is a Tecsun PL-660, which works okay inside with my 10-ft bare wire antenna hidden on the porch.

With a loop antenna, I’d like to mount the antenna on the porch at night and have a remote tuner/control inside because it’s very hot n humid here in Louisiana even after dark.

No doubt there are a number of magnetic loop antennas that could serve you well in your situation, Marty.

To answer your first question, though, you should search for a wideband amplified loop antenna since you’re only concerned with receiving.

Passive loops are great antennas on the shortwave bands–and easy to build–but they best serve ham radio operators who wish to transmit. Passive loops typically have a very narrow bandwidth that requires the operator to constantly tune the antenna when they tune the radio a few kHz. Most amplified wideband loops need no separate tuning mechanism.

Last year, I posted an article about choosing the right loop antenna for situations like yours where one has limited installation options.

Click here to read : Shortwave antenna options for apartments, flats and condos

Portables and amplified loops?

I do hesitate to encourage you to invest in an amplified loop antenna when your only receiver is a Tecsun PL-660. Some portables don’t handle amplified antennas well–they can easily overload and I imagine you can even damage the front end of the receiver.

I’m well aware, however, that there are a number of readers here who do couple their portable radio to an amplified loop. I have connected a number of portables to large wire antennas and found they could easily handle the extra gain, so I imagine an amplified loop would perform as well; the Sony ICF-SW7600GR, Tecsun S-8800, and Sangean ATS-909X come to mind.

But the PL-660 is a hot little receiver even with the built-in telescopic antenna–I’m not sure if amplification would help or hinder.

Please share your experience

This is where I hope the amazing SWLing Post community can pitch in and help us out here!

Does anyone here regularly connect their PL-660 to an amplified loop antenna? If so, what model of antenna are you using? Are there other portables out there that you regularly connect to amplified loops? Please share your notes, thoughts and experience in the comments section.

Thank you in advance!


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Test the Bonito MegaLoop FX and MegaDipol live on the air

Many thanks to Dennis Walter with Bonito, who shares the following for anyone interested in the Megaloop FX or MegaDipol::

If anyone like to test the MegaLoop FX live on the air, you can do it here:

http://emeraldsdr.ddns.net:8073/

The MegaDipol can be tested on the same location here:

http://emeraldsdr.ddns.net:8074/

The location of both KiwiSDR receivers is Carlow, Ireland. Both receivers exhibit excellent low noise characteristics.

Indeed, as I publish this post I’m listening to near perfect copy of Radio France International–using the MegaDipol–on 17850 kHz as they report the results of the FIFA Women’s World Cup. (Congratulations team USA!)

Thanks for sharing these links, Dennis!

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Inexpensive wideband amplified mag loop receiving antenna on eBay

Many thanks to SWLing Post contributor, Ola, who shares a link to this inexpensive mag loop antenna on eBay.

I have no clue if this antenna performs as well at all, but the price is certainly much lower than its competition at $47.99 US.

It appears you’ll need to supply your own dielectric center support  for this loop–a length of PVC would do the trick.

Copycat–?

I don’t like the fact this manufacturer has chosen the name “Mega Loop Active” for their antenna as the name is too similar to Bonito’s “MegaLoop FX Active.” I don’t like the confusion that could create, so I would hope this Chinese manufacturer would change this in time.

To be very clear, this product has no affiliation with Bonito and I certainly would not expect the quality or performance you would get from a Bonito product. Bonito products are pricey, but they’re design and manufactured in Germany and set benchmarks in terms of performance and quality. I’m a big believer in “you pay for what you get.”

I suppose though if you’re just looking for a cheap antenna to test, this one is quite inexpensive. Just know that it is not a Bonito MegaLoop, despite the similarities in product name! 🙂

Click here to view on eBay.

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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.

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New indoor passive loop antenna for shortwave

Many thanks to SWLing Post contributor, Dave Zantow (N9EWO), who notes:

Here is an interesting looking indoor passive HF loop antenna [photo above] that Randy McIntosh just started selling in the US. Made in Greece. Model TLA500C. Sorry it’s not for MW.

Here’ are the specifications/description from the eBay page:

This sale is for an HF magnetic loop antenna that should be attractive to anyone living in an apartment, residence, or other location where it is not possible to erect an outside dipole antenna. If you can erect an outside antenna, this is always the best solution for reception as no inside antenna can compete with a good outside antenna for the very best signal reception. But erecting an outside antenna is not always possible for many people desiring to listen to amateur radio or shortwave signals. Thus, this antenna offers a solution to such hobbyists handicapped by personal physical limitations to mount an outside antenna, minimal yard space to erect such an antenna, apartment living, or HOA restrictions.

This antenna spans a tuning range spanning 3.5 MHz through 40 MHz and thus covers 80 – 10 meters on the amateur radio bands, all international shortwave bands plus the 11 meter CB bands. The antenna comes with a 3′ coaxial cable to attach the antenna BNC output to a SO-259/PL-259 input of your receiver (most receivers).

Simple assembly directions are also included and you may be view this information in the last picture at the top of this listing. If you have a different input on your receiver other than the PL-259, you will need to acquire the proper interconnect cable from another Ebay seller. Assembly takes 5-10 minutes using only a proper sized Phillips head screwdriver and the antenna can be disassembled to transport to a remote DX location or for convenience in your travel luggage…..or as our picture shows, located permanently at your home listening room or bedside. Depending upon your preference and the dimensions of your receiver, the antenna can be set on top of or next to your receiver (see pictures at the top of this listing) during operation. Please remember that this is a “receive only” antenna and cannot be used to transmit signals.

Features:

  • non amplified….no batteries required
  • works on wide variety of communications receivers both stationary or portable
  • light weight aluminum construction weighs about 1 lb with the interconnect cable
  • portable – can be disassembled and folded into a low stature for compact transport
  • sharp tuning helps filter strong non-desired out-of-band signals
  • low noise loop design helps filter RF noise often found inside a home or apartment from lighting or appliances
  • tuning range of 3.5 MHz – 40 MHz
  • small loop antenna assembles to 18″ diameter at the broadest point
  • great alternative for signal reception when an outside antenna is not possible
  • very easy set up and connection

Thanks for the tip, Dave! This looks like a practical design for portable and low-profile operation.

Since it is passive antenna design, I image you would have to re-tune the antenna for peak performance each time you shift frequencies. It looks like the control panel would make this a pretty simple process.

Click here to view this antenna on eBay (partner link).

Post readers: If anyone has used this antenna, please comment with your impressions or contact me with your review.

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Kev-Flex Stealth Kevlar Antenna Wire: an incredibly durable wire for field radio

My good friend David Cripe (NMOS) has recently informed me about a new product he’s offering to the radio community via his eBay store: Kev-Flex Stealth Kevlar Antenna Wire. Kev-Flex looks like a superb option for field antennas of all stripes especially since it has an incredibly high tensile strength. It’s available in 75′ bundles, but Dave can also cut custom lengths. NM0S is also a trusted retailer in the ham radio world, so you can purchase with confidence.

Here’s the product description and link:

Kev-Flex is a unique antenna wire manufactured exclusively for NM0S Electronics. The lightweight center core of the wire is made from Kevlar fiber, giving the wire its incredible strength. The Kevlar core is wrapped with six tinned strands of 30 AWG copper. The effective surface of the wire creates an effective skin area capable of handling well over 100W.

The cable is protected from the elements by a coating of UV-resistant black polyethylene. With a total diameter of only 1/16″ (incl. insulation) and a weight of just 16 feet per ounce, the tensile strength 125 lbs allows lengthy unsupported horizontal runs. Kev-Flex is ideal for extremely long LW-antennas and Beverages and is great for balloon or kite-supported antennas. Its low weight and high break-load makes it most suitable for SOTA activations and other field operations.

The outer insulation makes the wire kink-resistant, and its slippery finish makes it ideal for stealth antennas that must be passed through trees or other obstacles without snagging.

This antenna wire is sold in 75 foot long bundles, which is enough for a 40M dipole or EFHW. Two 75 foot bundles would make a great 80M dipole. Custom lengths are available on request.

Specification

– Kevlar fiber core wrapped with six 30 AWG copper strands
– Weather-proof black polyethylene (PE) insulation, 1/16″ O.D.
– Weight: 16 feet per ounce
– Breaking-load: 125 lbs
– Velocity factor 0.97

Click here to view on eBay.

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