Tag Archives: Portable Radio

Loop-On-Ground Antenna Part 2: Tom upgrades his low profile, low noise, portable DXing antenna

Many thanks to SWLing Post contributor, TomL, who shares the following guest post:


Loop on Ground Part 2

by TomL

My previous Loop on Ground (LoG) experiment was useful which entailed connecting my Wellbrook loop amplifier to a 100 foot loop of speaker wire in the field at my favorite local Forest Preserve. It really brought in stations I had never heard before or strong stations in a more powerful way that made the audio really pleasant to listen to.  This report will describe more experiments with smaller wire loops to see what the limitations are.  100 feet of wire is quite a lot of wire to mess around with especially in the cold weather or public places that do not have as much private space.

I don’t understand all the electrical interrelationships but a long posting at RadioReference.com had  a great discussion about creating a 160-20 meters LoG receive-only antenna. It is 11 pages long but is worth reading how “nanZor” experimented with various parameters for general use. Kudos to him for documenting the findings as the design changed over time. You can find it here:

https://forums.radioreference.com/threads/160-20m-log-loop-on-ground.370110/

nanZor basically boils it down to a few guidelines.

  1. Keep it on the ground. Lifting the wire more than an inch or two decreased the lower angle signal reception greatly.
  2. Calculate the optimal length for one full wavelength of wire at the highest target frequency, say for example, the top of the 20 meter band (14350 kHz). 936/14.350 MHz * 0.9 velocity factor of simple insulated wire = 58.7 feet.  You can round up to 60 feet, no big deal since this is broadband.  The antenna should have a predictable reception pattern from 1/10th wavelength up to 1 full wavelength. Outside that range, the pattern gets “squirrely”.
  3. Using a 9:1 balun seemed to be a little better than a 4:1 balun at the antenna feedpoint. This gets into things I cannot measure and has to do with rising impedance as a loop gets closer to ground level. I am not sure but I think my Wellbrook amp has a built in 4:1 balun and it seems to work just fine.
  4. Make sure to use an RF Choke at BOTH sides of the feedline coax cable. He was adamant that the loop can get easily unbalanced and allow noise into the antenna and/or feedline and so it must be isolated and the ground allowed to “float” in his words.

Personally, I also wanted to use less wire and happened to have a length of 42 feet of landscape wire which should work well below 5 MHz with the Wellbrook amp engaged.  Results were not bad even though on hard frozen ground. Signal levels were down a little compared to the 100 foot of wire.  Here are a couple of examples, first one in a fast food parking lot with a grass field next to it and second at the usual Forest Preserve parking lot on a grass field.  I made sure that my car blocked the view of the wire so people would not get nervous!

La Voz Missionaria, Brazil:

Voice of Welt from Issoudun France in Kurdish:

These are not necessarily “DX” but definitely good for SWLing. I like the signal strength with the amplifier inline at the antenna feedpoint and I did not have to use an RF Choke at the receiver side as was suggested.

I had a 75 foot long insulated wire and used that at the Forest Preserve parking lot on a couple of different days.  Lower frequency signal strength and signal/noise ratio improved a little bit to be noticeable.

US Air Force HFGCS “numbers” station. Remote controlled from Andrews or Grand Forks bases (https://en.wikipedia.org/wiki/High_Frequency_Global_Communications_System), there was no way for me to know which of the 6 transmitters it was coming from:

BBC from Tinang Philippines in Korean:

Then, as nanZor suggested in his postings, I purchased a 9:1 balun/RF choke (it has both a balun and an RF choke built-in) from Ham Radio Outlet and put that in place of the Wellbrook amplifier.

I have not worked with it, but it is reported that the Nooelec.com v2 model is cheaper and works just as well – https://swling.com/blog/2019/10/the-nooelec-balun-19-v2/

Examples below with the 42 foot loop and 9:1 balun/choke, no amplifier:

KSDA, Agat Guam in English

WB8U doing a POTA activation of Leavenworth State Fishing Lake

VOLMET weather, Shannon Ireland

HCJB Quito Ecuador, probably in Quechua

As a side note, there is a posting that mentions low-angle DX is better with regions that have better “ground conductivity”, salt water being the best. I have no way of verifying this.  See post# 126 by KK5JY Matt.

So, bottom line is that a Loop on Ground can be useful for pleasant SWLing and portable.  Best to use it on grass, not asphalt.  The loop amplifier is useful to get signal levels up if you have to use a smaller loop size but the signal/noise ratio will suffer due to its smaller aperture.  And, warning, the public will find a way to trip over the wire no matter where you set it up (I may try putting the wire around my car if I can park on a grass surface and/or use the gaudiest, brightest neon green or orange wire I can find – they can’t trip over THAT, can they?).

TomL


Thanks, Tom, for sharing your update. Obviously, the LoG is working brilliantly. It’s amazing that you got such clear reception from the parking lot of a fast food restaurant.  If you were using a vertical instead, I bet signals would have been buried in the noise. 

I can also relate to people tripping over antenna wires. I remember one POTA activation recently (the first activation in this three park run) where I intentionally laid my counterpoise on the ground, off a foot path, in the brush and where I couldn’t imagine anyone ever stepping. Ten minutes into the activation and for no reason, someone walked off the path, into the brush, and it snagged them. Maybe I’m just a Ninja level trapper and never realized it!?

Thanks again for sharing the results of your LoG, Tom. Inspiring! 

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Tom builds a portable Loop-On-Ground antenna

Many thanks to SWLing Post contributor, TomL, who shares the following guest post:


My First Loop-On-Ground antenna

A number of people have mentioned the Loop On Ground (LOG) antenna in the past as a good receive-only antenna.  I did some research but could only find a few examples by amateur radio operators.

Matt Roberts (KK5JY) has a good article including some antenna theory and measurements, you can find it here:

http://www.kk5jy.net/LoG/ 

Someone named Tom (KG3V) has a write up on it but it is a little short on details:

https://kg3v.com/2020/01/04/loop-on-ground-the-simplest-receive-antenna-you-will-ever-build-and-it-works/

Stana Horzepa (WA1LOU) has something similar:

https://tapr.org/loop-on-ground-log-antenna/

I also read somewhere that for transmitting, a LOG antenna is useless as it radiates much of the energy right into the ground!  But I didn’t care about that.  I needed something for receive I can deploy easily without supports and take down just as easily.  As you may recall, my home condo is literally saturated with noise and I cannot null it out.  So a wire looped on the ground is supposed to work?  You bet it does!

Of course, there are some conditions to meet.  There has to be enough flat ground away from people or pets (or lawn mowers!) who would get tangled in the wire on the ground.  The wire should be as close to the ground as possible (although I had good results laying the wire on top of cut grass).  The loop of wire can vary in circumference from about 20 feet to 150 feet (the shorter length will stay in an omnidirectional pattern higher in frequency but lower in signal pickup and vice-versa for the longer length).  The wire needs to be insulated.  That’s about it!

So, off to the hardware store to buy a cheap spool of 100 foot 18 gauge speaker wire.  But, the articles mention using a balun and they all made their own.  I did not feel like doing that (I am not that good at making things from scratch) and I did not want to spend money ordering one. More reading somewhere informed me that my existing Wellbrook Medium Aperture loop amplifier has a built-in balun at the antenna side of the device.  Hallelujah!

I bundled together the wire, Wellbrook parts and battery supply, small laptop and Airspy HF+ to my favorite Lake Nelson Forest Preserve.  The shelter there is little used and is adjacent to the prairie with cut grass.  It did take a good 15 minutes to lay out the 100 feet of wire on the ground while trying to keep it as flat as possible. And I did not have enough space for a circle, so I ended up with an oblong shape.  The long sides are facing directly north-south, so in theory (I think) this gives me an oblong shaped reception pattern east-west.  The photo shows half of the wire laying on the grass.

I ended up with this setup on a picnic table at the rear end of the shelter.  The coax wire goes from the Wellbrook amp into its power module, then to a Cross Country Wireless preselector, then to the Apirspy HF+ and laptop.

I was really impressed by the signal strength of the usual suspects like Radio Nacional da Amazonia.  I could see that the Wellbrook amp was boosting signals across the board with only a little extra noise.

I use the preselector to try to keep the Airspy radio from overloading, especially mediumwave broadcast signals which can sound like a small amount of extra “hash” type noise in the background.  I have since added into the accessory chain an old Kiwa Electronics BCB filter that does a great job of knocking down the frequencies below 2 MHz.

I have also since added a water resistant box to enclose the Wellbrook amp to keep it safe from getting stepped on or too wet.

Also, a couple of weeks later I was able to go to a campgound and try out 60 feet of wire but the result was noisier since I was surrounded by RV vehicles in a crowded campsite.  It was not horrible and I was able to listen to some good radio stations but location can matter with any antenna.

I hope you like the recordings below.  Because of some serious health issues this summer, these May 31 2020 recordings & report are just being published now (I am recovering slowly but surely!).  My small laptop is under-powered, so I was only able to record MP3 files one at a time.  It kept me busy as I went from one frequency to the next and kept recording anything I heard.  I was able to hear a couple of stations I never heard before and that is a success in my book.

It remains to be seen if this antenna is as good as my 19 foot vertical antenna attached to the top of the car roof, especially low-angle DX signals.  Maybe you will have the chance to experiment as well and share your experience, too.  Now, will a small loop-on-ground antenna around my car parked late at night at a far corner of the grocery store work OK???  I will have to try it!

Recordings (crank up the volume if it is too weak):

22:00 UTC, Radio Saudi (Arabic) 11915 kHz

22:04 UTC, KDSA Adventist Radio (Indonesian) 11955 kHz

22:14 UTC, KDSA Adventist Radio (English) 12040 kHz

22:20 UTC, Voice of Korea (Japanese) 11865 kHz

22:23 UTC, Yemen Radio (heavily jammed) 11860 kHz

22:35 UTC, Radio Brazil Central (Portuguese) 11815 kHz

22:50 UTC, WWV booming in 10000 kHz

23:11 UTC, UnKnown (might be FEBC) 9795 kHz

23:15 UTC, China Radio Int’l (Spanish teaching Chinese, from Kashi) 9800 kHz

23:17 UTC, China Radio Int’l Business Radio (from Xianyang) 9820 kHz

23:19 UTC, China Radio Int’l (Chinese from Urumqi) 9865 kHz

23:21 UTC, Voice of Korea (Korean) 9875 kHz

23:23 UTC, Maybe Radio Taiwan without jamming from CNR 9900 kHz

23:34 UTC, China Radio Int’l (Chinese from Bamako Mali) 7295 kHz

23:43 UTC, Radio Nacional da Amazonia 6180 kHz (& 11780 kHz around 40 seconds)

23:50 UTC, MAYBE China PBS from Xinjiang in Kazakh (nothing else listed on schedules) 6015 kHz

23:56 UTC, Radio Mali (French announcer humming to music and acting crazy) 5995 kHz

00:07 UTC, Radio Rebelde (Spanish w/clear signal, Bauta, Cuba) 5025 kHz

00:15 UTC, 75 meter Amateur Radio 3913 kHz (LSB)

00:27 UTC, CHU Ottawa 3330 kHz

00:30 UTC, XEPPM Radio Educacion (Spanish Mexico City) 6185 kHz


This is brilliant Tom! Thank you for sharing. 

Our antenna guru contributor, Grayhat, has been encouraging me (understatement!) to build a Loop-On-Ground antenna but I haven’t done this yet because, at home, our driveway would interfere with its deployment. That and I have no RFI to speak of in my rural/remote home so my skyloop antenna is tough to beat. But having one available for portable use would make a lot of sense.  I’m going to put this on my 2021 project list!

Post Readers: Do you use a LoG antenna at home or in the field? Please comment!

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BELKA-DX: A Pocket-Sized Radio for Pocket Change

Well, not pocket change for most people, but I couldn’t pass up a clever headline!

I want to alert SWLing Post readers to a lower cost option for the new BELKA-DX than the Mobimax source: the ecommerce web site of Alex Buevky (EU1ME) who designed the radio.

In early February I bought the original BELKA DSP from the designer’s site, for a total of $117 USD. It arrived safely in 10 days to my Washington State address, with free tracked shipping included.

Yesterday I ordered the new BELKA-DX from the same web site, and the grand total was 340 BYN, or in US Dollars, $128, tracked shipping included.

If I had ordered from Mobimax, the total would have been 176.91 Euro, or $205.76 USD. That price includes FedEx shipping, the only available option to the USA.

Purchasing from the BELKA-DX designer’s web site in Belarus saved me nearly $78, and I’m confident I’ll receive this new model in about a week and a half as before (hopefully no COVID-19 related delays).

I had no issues this time or previously with my payment being “flagged” for security concerns. I used my PayPal VISA card and the transaction completed without issues.

For more information on this tiny powerhouse receiver, see Georges Ringotte’s (F6DFZ) brief review here on the SWLing Post.

Guy Atkins is a Sr. Graphic Designer for T-Mobile and lives near Seattle, Washington.  He’s a regular contributor to the SWLing Post.

 

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Proper Radio Prepping: Keep a kit that is always ready to hit the field!

My Red Oxx Micro Manager packed with a full radio field kit

Yesterday, my family packed a picnic lunch and took a drive through Madison County, North Carolina. It was an impromptu trip. Weather was forecast to be pretty miserable that afternoon, but we took the risk because we all wanted to get out of the house for a bit.

Although that morning I had no intention of performing a Parks On The Air (POTA) activation, my family was supportive of fitting in a little radio-activity, so I jumped on the opportunity!

A quick glance at the POTA map and I determined that the Sandy Mush State Game Land (K-6949) was on our travel route. Better yet, the timing worked out to be ideal for a lunch picnic and before most of the rain would move into the area.

Ready for radio adventure

I had no time to prepare, but that didn’t matter because I always have a radio kit packed, fully-charged, and ready for the field.

My Red Oxx Micro Manager EDC pack (mine is an early version without pleated side pockets) holds an Elecraft KX2 field and antenna kit with room to spare (see photo at top of page).

The Micro Manager pack easily accommodates the entire kit

This 20 year old blue stuff sack is dedicated to antenna-hanging. It holds a reel of fishing line and a weight that I use to hang my end-fed antenna in a tree or on my Jackite telescoping fiberglass pole. The sack also accommodates a 10′ coax cable.

The Elecraft KX2 transceiver, EFT Trail-Friendly Antenna, hand mic, CW paddles, C.Crane earphones, and wide variety of connectors and cables all fit in this padded Lowe Pro pack:

The advantage to having a simple, organized radio kit at the ready is that everything inside has its own dedicated space, so there’s no digging or hunting for items when I’m ready to set up and get on the air.

This level of organization also makes it easy to visually inspect the kit–missing items stand out.

Yesterday I parked our car at one of the Sandy Mush Game Land parking areas, deployed my field antenna, and was on the air in a matter of seven minutes at the most.

Hunter Parking Area Sign

Technically, this should read “Activator” parking area! (A questionable inside joke for POTA folks!)

We planned for heavy rain showers, so I fed the antenna line through the back of my car so that I could operate from the passenger seat up front.

I also brought my Heil Proset – K2 Boom Headset which not only produces better transmitted audio than the KX2 hand mic, but it frees up my hands to log stations with ease. This is especially important when operating in the front seat of a car!

The great thing about the KX2 is that it’s so compact, it can sit on my clipboard as I operate the radio (although typically I have an elastic strap securing it better). Since all of the KX2 controls are top-mounted, it makes operation a breeze even in winter weather while wearing gloves.

Since I routinely use the KX2 for shortwave radio broadcast listening as well, I know I always have a radio “locked and loaded” and ready to hit the air. My 40/20/10 meter band end-fed antenna works well for the broadcast bands, as long as there is no strong local radio interference (RFI). When I’m faced with noisy conditions, I pack a mag loop antenna as well.

What’s in your radio go-kit?

Having a radio kit stocked and ready to go on a moment’s notice gives me a great sense of security, and not just for recreational ham and shortwave radio listening reasons.

Sometimes I travel in remote areas by car where I’m more than an hour away from the nearest town and where there is no mobile phone coverage.

If my car breaks down, I know I can always deploy my radio kit and get help from the ham radio community in a pinch. Herein lies the power of HF radio!

If you haven’t built a radio go-kit, I’d highly recommend doing so. Although I’m a bit of a pack geek, keep in mind that you don’t need to purchase special packs or bags for the job. Use what you already have first.

I’m plotting a detailed post about the anatomy of an HF radio field kit. In the meantime, I’m very curious how many of you in the SWLing Post community also have a radio kit at the ready–one based on a transceiver or receiver.  Please comment!

Better yet, feel free to send me details and photos about your kit and I’ll share them here on the Post!


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Let’s take a deep dive into a list of our favorite radios!

Over the past week, I asked the SWLing Post community if they’ve ever regretting parting with a radio, and then what radios they’ve owned that had the most “fun” factor.

The response from these two posts was pretty overwhelming.

I don’t actually check the SWLing Post viewer stats that often, but I was too curious: together, those two posts amounted to well over 20,000 unique pageviews in two days!

Obviously, I’m not the only radio nostalgic person around here!

These posts resonated so well, I didn’t want readers’ favorite models to be lost in the comments section. I decided to comb through the comments, make a list of all of the models, and link to sites and pages with more information and photos.

This is an interesting collection of radios since some are benchmark performers, while others much less so. Many were listeners’ first radios–the ones we cut our teeth on.

I would encourage you to read through the comments on our first and our second posts. Many great memories in there!

Below, you’ll find the full list of radios in alphabetical order, starting with receivers then moving to transceivers:


Receivers

AOR 7030

AOR AR8000

Drake 2-C (Photo: Eric McFadden)

Drake 2-C

Drake R8B

Eddystone 750

EH Scott SLR12B

Eton S350DL

Globetrotter V01

Grundig YB400

Hallicrafters SX-100 (Photo: Rick Post)

Hallicrafters SX-100

Hammarlund HQ-140

Heathkit GR-64

Heathkit GR-78

Heathkit SB-310

Icom IC-R2

Icom IC-R75

JRC NRD-515

JRC NRD-515

JRC NRD-345

Kaito KA1103/Degen DE1103

Kenwood R-1000

Knight Star Roamer

Palladium 949/469

Panasonic RF-2200

Panasonic RF-2200

Panasonic RF-2800

RCA AR-88

Realistic Astonaut 8

Rheinland 4953W

Realistic DX-160

Realistic DX-200

Realistic DX-300

Realistic DX-394 (Photo: RigPix)

Realistic DX-394

Realistic Patrolman 6

Realistic Patrolman 9

Sangean 803A/Realistic DX-440

Siemens Radio E309

Sony Earth Orbiter (CRF-5090)

Sony ICF-2001D

Sony ICF-SW1000T (Photo: Universal Radio)

Sony ICF-2010

Sony ICF-SW1

Sony ICF-SW1000T

Sony ICF-7600D

Sony ICF-SW7600

Sony ICF-SW7600GR

Sony ICF-SW7600GR

Sony ICR-4800

Unelco 1914

Wireless Set No.19 Mk III

Yaesu FR-50B

Yaesu FR-101D

Yaesu FRG-7

Yaesu FRG-7700

Transceivers/Transmitters

Heathkit HW-8 (Photo: Eric McFadden)

The Icom IC-735

Drake 2-NT

Heathkit HW-8

Index Labs QRP+

Icom IC-735

Marconi C100

National NCX-3 (Photo: Universal Radio)

National NCX 3

Yaesu FT-77

Yaesu FT-101B

Yaesu FT-817ND

Yaesu FT-857D


Many thanks to everyone who shared their favorite radios! I truly enjoyed checking out each of these models as I listed and linked to them. There were a number of unique models I had never seen before and many I had completely forgotten (like the Sony ICF-SW1000T)!

If you have more favorite models to share, feel free to comment here or on the original posts!


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Please consider supporting us via Patreon or our Coffee Fund!

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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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Please consider supporting us via Patreon or our Coffee Fund!

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“Perfect Fit” Cases for the ATS-909X and D-808 Radios

I’m generally not a fan of slip-cover cases (or pouches) that are included with many portable radios. I like to have a little extra padding around radios, but I don’t like bulky cases either. My preference is to carry accessories separately and keep the case as small as possible while still offering some protection.

With that in mind, others may be interested in my choice of non-original cases for the Sangean ATS-909X and XHDATA D-808 receivers.

The Evecase brand of sleeve for the Apple iPad Mini 4 makes a close fitting case for the ATS-909X. After a day or two in this sleeve, the radio stretches the fabric a little and the result is a fit “like a glove”.

The Evecase sleeve leaves NO room for anything else, except perhaps a pair of earbuds loosely coiled on top of the radio before zipping the case shut. Protection of the ATS-909X is very good though, better than the stock Sangean slip case.

For the XHDATA D-808, I discovered that a model of the popular “Pelican” line of hard cases is an absolutely perfect fit. Model 1040 (Micro Case series) is the one to get, especially if you want the extreme protection this padded, hard-sided case provides. It’ll be right at home among your camping gear for instance, and if it happens to take a tumble from your backpack or car’s trunk, no problem!

It’s important to note that the solid color 1040 cases like mine have a sheet of thin protective foam in the lid, in addition to the molded padding in the bottom half. The clear lid versions of the 1040 case do not have this extra padding.

Let the description and photos of these two case solutions inspire you to consider other ideas for protecting your radio gear! A lot of possibilities exist, considering the wide array of protection available for tablets, laptops, GPS, hard drives, and so on. Many of these can be repurposed for portable receivers.


Guy Atkins is a Sr. Graphic Designer for T-Mobile and lives near Seattle, Washington.  He’s a regular contributor to the SWLing Post.

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