Category Archives: Antennas

One week of Hamvention, Air Force Museum, Wright Brothers and National Parks On The Air

I returned home last night from my week-log Dayton Hamvention trip around 8:30 PM.

The Hamvention actually ended at 1:00 PM on Sunday, May 22, but my buddy Eric McFadden (WD8RIF), his son Miles (KD8KNC) and I stayed Sunday night in Dayton, and Monday night at Eric’s home in Athens, Ohio.

After packing up our Hamvention booth (for Ears To Our World) on Sunday, we made our way to the nearby National Museum of the USAF–the largest aviation museum in the world. We visit the museum every year–and every year I discover something new.

This BC-348 can be found in one of the museum’s B-29 displays.

In June, the Air Force museum is actually opening a fourth building which will house an additional 70 aircraft in four new galleries.

If you’re an aviation buff–trust me–the National Museum of the USAF is worth a pilgrimage to Dayton, Ohio.

NPOTA activations

Monday morning, Eric, Miles and I packed up, ran a few errands on Wright Patterson Air Force Base, then made our way to our first National Parks On The Air activation: the Dayton Aviation Heritage National Historical Park (HP11) and North Country National Scenic Trail (TR04) “two-fer” at Huffman Prairie Flying Field Interpretive Center in Dayton, Ohio.

Eric worked CW on 20 meters and I worked SSB on 40 meters using the LNR Precision LD-11 transceiver (which I’m currently reviewing) and my recently-purchased Hardened Power Systems QRP Ranger.

For all of my Monday NPOTA activations, I used the EFT Trail Friendly antenna I purchased at the Hamvention:

The EFT Trail Friendly Antenna made set-up a breeze: simply throw a line into a tree, hang the end of the antenna, then hook up the other end to the feedline/transceiver. No antenna tuner is needed for 40, 20 or 10 meters once the antenna is tuned for resonance. It packs up into a small bundle that easily fits in my radio go-kit (see photo above).

The LD-11/QRP Ranger/EFT antenna combo worked amazingly well and made for very quick deployment.

I can easily fit the LD-11 transceiver and QRP Ranger on a foldable metal chair (my make-shift field table!).

My buddy Eric, I should mention, is typically on the leaderboard for NPOTA as he’s an avid QRP field operator.

Eric (WD8RIF) operating NPOTA with his field-portable vertical HF antenna.

You can follow Eric’s activations on QRZ.com or his website.

Eric’s field-portable HF vertical packs up into this small canvas bag.

We had a tight NPOTA activation schedule to meet Monday, but after packing up from our first sites, we took 30 minutes to stop by the Wright-Dunbar Interpretive Center and The Wright Cycle Co. museum in downtown Dayton.

Well worth the short visit! Next year, I’ll plan to revisit both museums when I have more time.

Next, we made our way to the second scheduled NPOTA activation site: the Charles Young Buffalo Soldiers National Monument (MN18).

Despite not having my antenna very far off the ground (my antenna line fell down one branch in the process of hanging) I still managed to work a pile-up of stations from Georgia, North Carolina, Ohio, Illinois, Connecticut, Michigan and Indiana. After Eric and I racked up a number of QSOs, we packed up our site in haste and made our way to the final activation of the day: the Hopewell Culture National Historical Park (HP15). We arrived as the Park Ranger was getting in his car to leave for the day!

At Hopewell, I managed to deploy the EFT antenna much higher off the ground. I worked a small pile up of stations from all over the region which, to my surprise, included two radio friends (Ed and Eileen) in Franklin, NC. Eric also worked blogging buddy John Harper, AE5X on 20 meters CW (got your message, John!).

All in all, it was a fantastic day to be outdoors and on the air.

Of course, a side benefit of doing National Parks On The Air activations is that you get to check out all of these amazing park sites.

Without a doubt, this was one fun-filled and radio-centric Hamvention week! It couldn’t have been better.

Part of my log sheet for NPOTA HP11 and TRO4 “Two-Fer” activations. Not bad for such a tight schedule!

Thank you

Many thanks to my friends Eric (WD8RIF), Miles (KD8KNC), Mike (K8RAT) and Christine (KM4PDS) for volunteering to manage our Hamvention booth for Ears To Our World. It was a record year for collecting donations. Many thanks to all of you for the support!

I’d also like to thank the SWLing Post readers who stopped by to visit our new location in the Silver Arena–it was great seeing everyone!

Now that I’m back home, I essentially have one week of emails and comments in my backlog to sort before hitting the road again rather soon. I appreciate your patience as I catch up. If you don’t hear back from me soon, it’s okay to give me a nudge! 🙂

CountyComm: A note of caution about the high-gain ferrite bar antenna

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After our post this morning regarding the high-gain ferrite bar antenna (available via eBay), I received a message from Nick at CountyComm.

Nick notes:

“[The high-gain antenna is] very cool however we wanted to let you know that we found out it [can] actually destroy the antenna input to the GP5/SSB or GP5/DSP because of its heavy weight. [W]e had at least five radios come back [after] customers had purchased the large ferrite antenna from an eBay seller.”

Many thanks, Nick, for the feedback. It is important to note that the high-gain bar antenna is not an OEM product, so CountyComm isn’t responsible if it harms the radio’s antenna jack.

While still relatively lightweight, the high-gain bar antenna is substantially heavier and longer than the GP5’s supplied MW antenna.

I’ve been concerned about dropping the GP5/SSB with the larger bar antenna inserted–fearing the jack could break off–so I’ve been very careful using it. I’ll probably continue using the larger ferrite bar, understanding that I’ll have to handle it with care.

If you’re concerned about damaging your radio, I would suggest using an inductively coupled AN200 loop antenna instead.

Again, Nick, thanks for the heads-up!

Have you ever installed a covert shortwave radio antenna?

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The Hammarlund RBG CHC-46140 (Photo by Rich Post, KB8TAD)

Yesterday, in a comment thread, SWLing Post reader Dan described a covert antenna he once installed in a student apartment:

I’m waxing nostalgic now, but I had a great set-up for a couple of years back in the ’70s. The receiver was a black WW2 Navy surplus Hammarlund RBG CHC-46140. (I still have it).

I was a student living in an apartment on top of a two story, wood-framed apartment building. The attic access for that building was from the ceiling of the wardrobe closet.

During a Christmas break I was probably the only occupant of the building. I snuck into the attic and installed a set of five switchable dipoles. I had a good 60′ of space to work with and the antennas were broadside to the southwest. This was quite a memorable listening post.

When I moved out, I cut the coax to the dipoles and used toothpaste and borrowed pieces of “cottage cheese” to fill the five holes in the ceiling. Those antennas are probably still there.

Indeed, I bet they are still there, Dan!

In reply to Dan’s comment, Walt Salmaniw, noted:

Dan, reminds me when I was stationed in Germany in the early 80’s.

We lived in old French officer’s quarters. Basically, 4 story buildings with the upper floor/attic uninhabited.

The Kenwood R-2000 (Photo: Universal Radio)

I put up some nice 60 m dipoles in that space, with a goal of hearing a lot of tropical band DX, which I did using my Kenwood R2000 receiver.

Those were the glory days of dxing!

Thanks, Dan and Walter, for sharing those stories. The thread reminds me of a post we published sometime back where one young listener installed a wire antenna in his home while his parents were away. (I can’t seem to locate that post at the moment for a link!).

Though not nearly as elaborate as Dan and Walter’s antennas, I did install a small covert antenna once myself.

In the early 90s, I lived in Grenoble, France, in a four bedroom house in which three bedrooms were occupied by university students. The landlord was a rather fussy elderly woman who lived on the ground floor. I never dared ask her if I could string a random wire outside my top floor bedroom window. Though she was mostly fair and even sweet at times, I knew what the response would be if I asked for permission: a firm “Non.”

One night, I opened the bedroom window and carefully connected a short wire antenna to a nail on the side of the house, above and slightly to the side of the window. I had to stand on the window and hang out of the house to do it.

The Realistic DX-440

The antenna dangled there the whole year I lived in that room and served me quite well. I’d simply open the window and clip it to my Realistic DX-440. I did remove the antenna before before I moved back to the States, but it was virtually undetectable against the exterior wall of the house.

Other covert antenna installations?

Please comment if you’ve ever installed a hidden antenna as well. (I love this stuff!) Besides…who knows…your antenna might benefit someone in need of a hidden antenna today!

Nothing to hear on shortwave? Jacques disagrees…

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Many thanks to SWLing Post reader, Jacques Catherine, who left the following comment on our post from 2012: Is there anything to listen to on shortwave?

“I live in Mauritius Island in the Indian Ocean and I’ve been listening to Shortwave since I was a kid (I’m 58 today) on my dad’s good old Phillips wooden valve radio.

I’m sorry, but shortwave is certainly not dead. After having read all the comments above, I come to the conclusion that reception definitely depends on your location.

The Tecsun PL-660.

I have two Tecsun receivers ( Tecsun S 2000 and PL 660) hooked to a Windom antenna and an ATU. I receive dozens of stations from all over the world here as well as a lot of stuff on ssb, including – in the morning – New York MWARA (8825.0 usb), Gander (8831.0 usb) or, in the evening, Brisbane (5634.0 usb).

Broadcast stations from Japan, Taiwan, India, Iran, Australia, Singapore, China, Africa and even the US, come in here loud and clear with very little static, depending on the season and time of the day. I think I’m privileged to be located where I am !

And I bought some years back a pair of cheap small wooden amplified speakers in Hong Kong that reproduce exactly the sound of my dad’s old valve radio!”

Thank you for your comment, Jacques. You’re right: it’s all about your location…and you certainly live in a prime spot!

I’m most fortunate that I live where I do–quite far away from sources of noise that plague our urban readers/listeners (and that have plagued me in the past). My location is not ideal (from a radio/receiving standpoint) because my ground conductivity is very poor and I’m in North America where very few broadcasts are targeted these days. I do, however, have the space for a rather large horizontal delta loop antenna that serves me well across the HF bands. I might have invested $50 in the antenna wire and components five years ago.

When propagation is good, some broadcast bands are actually packed tightly with signals. Indeed, Thursday last week, I could’ve easily logged two dozen stations on the 31 meter band alone. Here’s a screen capture from the spectrum display of my SDR:

If you live in an urban area and feel that you’re missing out on the action, consider taking your receiver outdoors and away from interference. Take your receiver on hikes, camping trips or to the beach. You might be surprised by the number of stations you’ll log!

Recently, our friend London Shortwave has been posting an amazing array of broadcast recordings he’s made in a park in the middle of London, England. He’s the guru of mitigating urban interference.

When I have time to curate the recordings, I hope to do a 2016 update of “Is there anything to listen to on shortwave?“–it’s been on my to-do list for a while now.

Jacques, thanks again for your comment and reminding us to keep listening!

Aluminum foil: Larry’s simple AN200 antenna modification

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Many thanks to SWLing Post reader, Larry Caracciolo, who comments:

I bought the AN-200 in the spring of 2015 off of eBay. I was favorably impressed with the product. Comparing it to my old 9′ diameter tuned/shielded loop from 1992, there are some similarities and differences.

The Hallicrafters SX-96 (Image: Universal Radio)

I live in an apartment complex so plenty of radiated electromagnetic noise is present. I use a modified [Hallicrafters] SX-96 (AVC ckt was modified for improved modulation acceptance). The AN-200 does null out local static sources, somewhat, but not well enough to dig out weak stations. The tuning range for the loop is just at the bottom of the AM band (about 535 khz) to just over 1700 kcs.

On a whim, I wrapped aluminum foil around the loop and grounded it to the SX-96 chassis – in wistful hope of achieving some shielding from the RF has. As soon as I connected the aluminum foil ground clip to the rx chassis, all RF noise ceased and signals appeared from the mud. However, the tuning range is attenuated above 1200 kcs.

My favorite frequency on the AM band is 590 kcs. During the night, as many as seven different stations rose from the noise and provided station IDs at just the right moment. My best catch here in Everett, WA is KCSJ, a 1KW station in Colorado Springs.

From time to time, stations on the low portion of the AM band are accompanied with echoes – what I took for two stations and a small time delay between the same broadcast was actually multi-path to the degree that nearly 1/2 second separated the arriving signals. Short-delayed echoes, anyone? I’ve not observed this on frequencies above 1000 kcs.

Other sources of RF noise can come from the laptop, the cable modem, and even CFBs in other rooms. For truly noise-free listening environment, I place the laptop in sleep mode and unplug the cable modem. I’m quite happy with the AN-200 loop. Affordable, easy to use, easy to tune.

Thanks so much for sharing your experience with the AN200 loop antenna, Larry!

As anyone who grew up in the era of TV rabbit ears knows, aluminum foil can simply work magic in a pinch! There is no easier material to work with either!

As I pointed out in previous posts, the AN200 loop antenna is quite affordable. I just did a quick price search:

The Tecsun equivalent of this antenna (the AN100) is available from various sellers on eBay from about $15 – $30 US.
The Kaito AN200 (Kaito’s branded version) is available on Amazon for $30 shipped.
With the purchase of the Eton-Grundig Traveler III, Eton-Grundig Field, or Eton-Grundig Satellit, Universal Radio will include a free AN200 with your purchase.

Guest Post: Building a magnetic loop antenna & broadband amplifier for your SDR

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Many thanks to SWLing Post contributor, Dave Gahimer (K9ZCE) for the following guest post:

Small Magnetic Loop Antenna with Broadband Amplifier for SDR Reception

by Dave Gahimer (K9ZCE)

Those with limited space, or antenna restrictions, might find a small 1 meter loop antenna a solution.

My son lives in an apartment. One Loop leaning against a wall gives him acceptable reception with the SDRPlay RSP on the ground floor–2nd or 3rd level flats should have very good reception.

Ten meters off the ground outside should give reception equal to any SWL antenna. We all with SDRs fight the image problem. Normal resonate ham band antennas show too strong reception of unwanted bands/stations. Did I mention noise? Loops are well known for –6 db noise reduction.

Then there is the possibility of SDR chip damage from your 1.5 KW station! In researching Loops we came across LZ1AQ. A Brilliant design /engineer (http://www.lz1aq.signacor.com/). Deep reading sometimes, but a great understanding of what makes a good receiving loop antenna.

Those who chase DX know that sometimes fading is caused by the signals’ polarization changing in the Ionosphere. Having both vertical and horizontal loops, and the ability to combine both signals diminishes this fading problem. Being able to filter the powerful, commercial FM transmitters diminishes image problems. Clipping strong signals at the antenna from very near powerful antennas/transmitters could save the SDR receiver from damage.

The LZ1AQ broad band Amp solves all these problems. http://active-antenna.eu/amplifier-kit/.

My son Ted and I built three, one meter loops from soft ½ inch copper plumbing tubing. One for his apartment, two for my crossed loops antenna. We weather proofed the Copper from corrosion by coating with outdoor clear spar varnish. We shaped the circle by drawing the tubing around a round glass top patio table.

The soft copper loop in held by white PCV plastic plumbing pipe. 1” or 1.25 inch schedule 40. Be careful to check that the PVC is schedule 40, thick wall. The thin wall pipe is not strong in the wind and will crack when you try to drill it.

Drill up to a 3/8 hole for the ½” copper tube to go through, then file out to fit. Here are some photos (click to enlarge):

Check out these links (all courtesy of LZ1AQ) to acquaint yourself with the loop construction and amplifier installation:

http://active-antenna.eu/tech-docs/2_ActiveAA_Mount_20.pdf

http://active-antenna.eu/tech-docs/1_ActiveAA_DandS_20.pdf

http://active-antenna.eu/tech-docs/3_ActiveAA_Antena_11.pdf

Many SDR receiver owners have seen improved noise and Image reduction by placing the plastic cased SDR unit on a small shielded/ grounded case.

The Amp needs 12VDC from in the shack. The Amp has two relays that you can switch, from in the shack, to select Vertical or Horizontal loops, or a dipole. The loop amp connects back to the shack via a shielded Cat 5 cable, Make sure you get shielded CAT 5 to reduce noise pickup. Make sure you provide an adequate good Ground below the antenna, less noise pickup and lightening protection.

Have fun!
Dave, K9ZCE
Retired from EE Dept @ Rose-Hulman Institute of Technology
Terre Haute, Indiana

Thank you so much, Dave!

Readers: yesterday I saw Dave’s loop antenna photos on the SDRplay RSP Facebook page. I was fascinated by his horizontally/vertically oriented loops and asked if he would write up a short guest post. He kindly obliged in a matter of hours!

If you have an antenna project you’d like to share, please contact me. So many SWLs and ham radio operators live in areas with restrictions and pervasive RFI–projects like Dave’s can revive one’s radio life!

GODAR antennas

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Many thanks to SWLing Post contributor, Mario Filippi (N2HUN), who writes:

[Check out] this site I came by accidentally, small company, USA made antennas, most are OTA TV but he has a few shortwave antennas, quite reasonable. […] Also has old vintage pics. A little of this and that on the website, quite interesting company. He sells on Ebay too.

GODAR USA

Thanks for the tip, Mario. I love supporting mom-and-pop manufacturers like Godar. It appears–based on his eBay rating–that Michael Godar has very satisfied customers and produces quality antennas.

Thanks for the tip!