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Many thanks to Jon Hudson with SDRplay who shares the following announcement:
Introducing a new series of videos comparing the performance of wideband active loop amplifier/antennas for HF frequencies and below. In this introductory video, Mike Harwood shows how an RSPduo enables a real-time comparison of two antennas – in this demo, he uses a Wellbrook 1530AN and one of his own compact loop creations. You can see that he has lined up several other active loop antennas/amplifiers to try in future videos, including the Bonito Megaloop FX, the LZ1AQ amp and the Cross Country Wireless amp.
This is one of many videos from SDRplay – makers of the RSP family of SDR radios. See the full list of SDRplay videos and applications documents on: https://www.sdrplay.com/apps-catalogue/
The RSP family of SDRs from SDRplay cover 1kHz to 2 GHz with no gaps and give up to 10MHz spectrum visibility.
SDRplay is a UK company. The RSP SDR receivers are made in the UK and can be purchased for worldwide delivery directly from http://www.sdrplay.com/ (click on purchase and select your country to view shipping costs) or you can buy from any of our worldwide resellers listed here: http://www.sdrplay.com/distributors/ Many of the resellers offer local free shipping and/or local language technical support.
Many thanks to SWLing Post contributor, Paul, who recently shared a link to this Craigslist listing and asked if anyone in the SWLing Post community might be familiar with this Beam Box Electronically Directable FM Antenna.
The Cragslist post actually included the following images of the owner’s manual:
I’ll admit that I’m not at all familiar with this antenna, but I see how it might have been ideal for a component system. I’m curious if it was FM DX-worthy!
Many thanks to SWLing Post contributor, Frank Sturzaker, who writes:
I am a new SW listener in the UK and am using an elderly Sony ICF SW100E picked up from selling website here in the UK fairly cheaply as a starter. It gets excellent reviews and seems to do what is required very well. A couple of weeks ago I also picked up a non-working Sony AN-100A external antenna at a charity / thrift store here in the UK. Cheap because not working.
The antenna section simply pulled out of the plastic case so I opened it up to have a poke about inside to try to solve the problem.
The antenna has been “ripped” from however it was mounted and has taken the thin metallic shaped piece / strip that somehow connects it to the circuit board and twisted it. I would guess that this has happened when trying to rotate the extended antenna when the extending sections had become too stiff to rotate – the pieces visible from outside the unit would not rotate inside the fixed section that sits in the unit.
Photos
1 – This is what I bought (although the antenna itself was in the correct place in the case):
2 – This is a close up of the base of the antenna when first bought:
3 – The two halves of the case with the antenna in place but about 0.5″ short of where it should be:
4 – A close up of the ‘loose pieces’ from inside the case and the bottom of the antenna – on the right are the pieces that were left on the antenna and on the left is the this metal piece that makes contact with the circuit board from the antenna
5 – Photo of antenna screw hole in rear of case from inside – the broken plastic is obvious round the screw hole:
6 – Photo of underside of circuit board showing the flat metallic area where the metallic strip from the antenna makes contact:
My questions about how it all fits together (as a starter) are:
Is it ONLY the screw from the outside holds the whole antenna assembly in place or is it fixed with glue etc. when originally shipped? It looks to have been ONLY the screw because there are no traces of any adhesive etc.
Should the antenna be able to rotate at its lowest section – like on the SW100E?
Is the thin metal strip fixed to the circuit board by anything (solder??) or does it just ‘brush against’ the metallic surface?
If I simply fix the antenna in place with epoxy or similar and run a connector between the bottom of the antenna and the circuit board will this work or are there other things that should be done or done in a specific way?
If someone can help then great. I repeat, I am not an electronics wizard – a master with a soldering wand I am not!!!
I could go at this like a bull at a gate but advice would be appreciated if there is any out there.
Post readers: if you can offer Frank some advice, please comment. Also, if you own an AN-100E and could share some internal photos, that might help him sort out how it was originally attached inside.
Many thanks to SWLing Post contributor, Carlos Latuff, who shares the photo above of the
radio beacon at the Brazilian Navy in Tramandai, Rio Grande do Sul, Brazil.
Many thanks to SWLing Post contributor, Jock Elliott, who shares the following guest post:
There’s a 50-foot antenna in this room. Can you spot it?
Got reception issues? An idea worth considering: the “Horizontal Room Loop.”
by Jock Elliott (KB2GOM)
When my radio room was in the front of the house (on the east side), it was easy to run a feedline to a large RF-hungry SWL dipole with various stubs and feeders.
Now, however, with my “shack” moved to the SW corner of the house, any attempt to mount an outdoor antenna of any significant length raised potential safety issues because of nearby electrical lines.
Monitoring VHF/UHF is no big deal because of high-performance scanner antennas. HF, however, presents challenges.
My main SWL receiver is a Satellit 800, which has the guts of a Drake R8 and also has a large telescoping vertical antenna. It works okay, but I wanted more signal. I had been looking at small loops and got some great recommendations on Radio Reference, but then I had a thought: what if I turned the 8′ x 12′ room into a giant horizontal passive loop?
Here’s a hint.
So I called a ham friend and ran the idea by him. “Sure,” he said, “give it a try.” He gave me 25 feet of 4-conductor phone wire. Before I could use it, I had to strip off the outer insulation so I could get at the four separate insulated wires inside. The better half helped. Once I had the four wires, I connected two of them together and ran the resultant 50-foot strand around the perimeter of the room by taping the wire to the top of window frames and hiding the wire on the top shelves of book cases. As a result, the horizontal room loop is near the ceiling, about 7 feet in the air, and the room itself is on the first floor.
With the loop in place, I hooked the ends to the clip-in terminals on the back of the Satellit 800.
There’s a switch on the back of the 800 that allows me to quickly compare the loop with the radio’s built-in vertical antenna. And . . . it works! It pulls in more signal than the vertical (as measured on the signal strength meter), but I have not noticed a dramatic reduction in noise. On some stations, the horizontal room loop brings the signal up to full scale, and then the sound is very agreeable indeed.
In all, I am pleased with the results.
For anyone who wants squeeze more performance out of their shortwave receiver, I can recommend giving the horizontal room loop a try. It’s not expensive; it’s relatively easy to do (and undo if you don’t like the results), and just might improve your shortwave reception.
If you are not blessed with a bunch of window frames on which you could tape the wire for your room loop, you’ll have to get creative, but with lightweight wire, you don’t need a massive support structure. Tape, map tacks, or even self-adhesive Velcro segments might work for putting your room loop in place.
I don’t claim that this is the “ultimate” SWL DX antenna, but it certainly improved my situation. Perhaps others have suggestions for improving it.
A few weeks ago, Chameleon Antenna sent me a pre-production model of their new wideband magnetic loop antenna called the Chameleon CHA RXL.
I’ve evaluated and reviewed a number of Chameleon’s ham radio antennas (primarily on QRPer.com). I find that the quality of their products are second to none. Price-wise, they tend to be at the top of the market, but keep in mind they machine and manufacture all of their antennas here in the US and they’re incredibly rugged; indeed, military-grade. And in the spirit of full disclosure, I’m proud Chameleon has been a sponsor the SWLing Post and QRPer.com since last year. My sponsors are by invite only and focus on companies I trust with our radio community’s business.
When Chameleon shipped the CHA RXL to me, it wasn’t from their factory, it was directly from the field: Fort Irwin, to be exact.
(Source: NTC Operations Group, Ft. Irwin)
This CHA RXL sample had been used by NTC Operations Group Fort Irwin (who, incidentally, won QRPX this year–click here to read the PDF report).
I was told that the condition of the antenna could be very rough after the QRPX because it had essentially been sandblasted in the desert winds. I was also told that someone accidently transmitted 5 watts into it at some point but it didn’t seem to harm it (for the record, like all amplified receive-only loops, it’s not designed to take RF).
Tony (W0NTC), who was one of the Ft. Irwin radio ops, sent me this note as he dropped off the shipment at Fort Irwin’s FedEx:
“Had a blast with [the CHA RXL], and it was absolutely critical while I was operating in the Army HF Low Power Competition (think tons of high powered MARS stations piling up and drowning out the 20W or less competitors). It absolutely crushed some localized RFI from a huge building I operated behind, and the receive on it I can only describe as “layered” in that I could hear stations somewhat clearer than usual if they transmitted simultaneously. Receiver I used was the IC-705 with default Auto Notch and Noise Reduction.”
Tony volunteered all of this info–I never asked him how it performed.
A few days later, I wasn’t sure what to expect when I opened the box although I knew that my operating locations were nowhere near as cool as its position next to a Humvee at Fort Irwin in the photo above!
I pulled the CHA RXL out of the box and it looked cosmetically flawless to me.
Frankly, there’s not a lot to get damaged. The 36 inch diameter loop is made of rigid aluminum and has a Navy gray powder coating. The preamplifier unit is completely sealed and made of a high-impact plastic/PVC type material. The steel loop is attached to the preamplifier loop flanges with wing nut connectors.
The only potentially vulnerable part of the antenna system is the Bias-T box which would normally be located in your shack close to your receiver.
If I mounted the CHA RXL permanently outdoors, I would use Coax Seal around the BNC connection point, of course.
Although the CHA RXL has a supplied mounting bracket for permanent installations, I love the fact that the preamp box has a 1/4” x 20 threaded camera socket on the bottom. This makes for a brilliant portable loop because it can so easily be mounted on a standard heavier-weight tripod! All antenna manufacturers should give us tripod mount options when possible.
On the air
One of the reasons amplified receive loop antennas have become so incredibly popular over the past couple of decades is because they do an amazing job mitigating radio frequency interference (RFI) a.k.a. “QRM.” If you live in a neighborhood with significant radio interference, you really should consider some form of loop in your antenna arsenal.
Ironically, at home, I live in pretty much an RFI-free zone. I’m surrounded by tens of thousands of acres of national forest, so I’ve only used amplified loop antennas in the past for mediumwave DXing–mainly, when I wanted to take advantage of their amazing ability to null out unwanted signals.
Many years ago, I purchased a Pixel Loop Pro antenna (now under a different name via DX Engineering), mounted it outside where it lasted almost a year before a bear decided to pull it down and chew through the coaxial feedline. He/she did so with enough energy that it ripped down the loop and damaged the connector end of the Pixel’s pre-amp. This all happened when our family was travelling for two months in Canada. Why bear, why?!? But I digress…
The CHA RXL version I was shipped has one single rigid loop–the “EU” version’s loop comes in two pieces (for easier shipping/transport)–but I had no problem fitting the entire assembled loop in the back seat of my Subaru or my truck (as long as no one was sitting back there at the time). If you plan to travel with your loop a lot, consider the “EU” version!
I’ve taken the CHA RXL to my parent’s home a couple of times and enjoyed doing a little mediumwave and shortwave listening. Inside the house, the loop would attenuate RFI nicely, but when outside it would all but eliminate many sources of RFI.
At their house, I primarily used my Icom IC-705 for cruising the bands (being careful, of course, to disengage the transmit function).
Listening time in my hometown, though, was very limited. Since the CHA RXL is so portable, I decided to set it up at home on our porch for a few days, giving me an opportunity to test both the Sangean ATS-909X2 and Tecsun H-501x with an external antenna.
I’ve especially appreciated using the CHA RXL on mediumwave. Even from our screened-in porch, I can rotate the loop and use its excellent nulling properties to pick out multiple station IDs on crowded frequencies.
I’ve spent time on shortwave, too, and found that it certainly gave these two portables a signal boost.
In fact, it was by using the CHA RXL that I discovered the audio level difference between AM and SSB on my ATS-909X2 is very minimal when an external antenna is connected.
I’m sure you’ll hear the CHA RXL in action when I post audio clips and recordings in upcoming reviews.
Summary
If I owned a CHA RXL loop, one of the first things I’d do is build a power cord for it with an in-line fuse and terminated with an Anderson Powerpole connector. Since the operating voltage of the Bias-T is 12-14 VDC, it would pair perfectly with one of my Bioenno LiFePo4 batteries, offering a power source with longevity in the field–ideal for a group LW/MW/SWL DXpedition.
It’s difficult for me to truly comment on the loop’s performance because I don’t have another loop at present for comparison. I can say that it’s amazing on mediumwave, where I’ve spent much of my listening time this past week. I believe shortwave reception has been at least on par with my former Pixel Loop, if not better. It’s hard to say, in truth, because propagation conditions have been so poor lately. The CHA RXL loop does effectively mitigate noise!
I’m not sure if the CHA RXL is currently on backorder or not, but I would suggest you check out the product page on Chameleon’s website and possibly contact them if you’re interested. They’ve a number of options and accessories to consider.
One thing for sure: this must be one of the most rugged and durable RX loop antennas on the market. In addition, that Navy gray powder coating helps this rigid aluminum loop disappear against the sky. I believe you could strategically mount this loop and the friendly neighborhood association may never notice–it’s pretty stealthy. Speaking of which…
Josh’s CHA RXL install and demo video
Josh over at Ham Radio Crash Course recently installed a CHA RXL on his house and tested it on several bands, comparing it with a number of his external antennas:
Many thanks to SWLing Post contributor, Grant Porter, who notes that Ham Radio Outlet has the Eton/Grundig AN200 loop antenna on a closeout sale for $15.00.
As Grant notes, this is an especially great deal if you live near an HRO retails store.
Many thanks to Jon Hudson with SDRplay who shares the following announcement:
