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The Shortwave Antenna Portable Magnetic QRP Loop Antenna is designed for optimal performance across a wide frequency range, ensuring excellent signal gain and clarity. With user-friendly knob operations for precise tuning and impedance matching, this compact antenna is perfect for both amateur and professional radio enthusiasts. The package includes all essential components, making it a convenient choice for on-the-go communication.
Impedance | 50 Ohm |
Number of Channels | 4 |
Item Dimensions L x W x H | 9.8"L x 9.4"W x 3.3"H |
Color | White |
O**T
An excellent starter-loop antenna
The media could not be loaded. Loop antennas are a little more complex in operation than dipoles, but I found this to be an excellent antenna for getting to know this important antenna technology. The build quality is outstanding for the price, and the design works well - especially as an indoor receiving antenna. Should work for the frequencies and uses implied in the description.No it doesn't have the theoretical super-high Q possible at 10 MHz with a 2 meter loop circumference and massive components, but the Q is probably between 50 and 100 (based on some calculations and a receive comparison with a telescoping whip of length equal to the diameter of this loop), so it works better than a short monopole. Of course it won't beat a full half-wave dipole outside for sensitivity and efficiency, but loops are good for other things like rejecting near-field noise on receive.I have not used it for transmitting and I doubt the variable capacitors have a high enough breakdown voltage for more than lower power "QRP" mode. But on receive, it does work very nicely. And it seems to reject some noise as loops are supposed to do at lower frequencies.Here are a few "pros and cons", and associated pictures:Very nice "hardline" coax as main loop. Keeps it's shape without a support when main tuning box is on a tripod. See photo. It can be reshaped to be round, but I just left it in an oval. No significant difference in performance either way.No feeder loop needed. The impedance matching is done in the main tuning box.The main tuning box is a bit easier to use than I expected from looking at the ad - but still requires thought and understanding, which is helped if you have a "NanoVNA". I tuned it to 10 MHz as shown in the photo and the return loss was able to reach -26 dB (VSWR of 1.1:1).After I understood what the switch and knobs do, I could generally tune it without the NanoVNA by listening to the signal and noise levels coming from the receiver. The switch wants to be up for the lower bands and down for the upper (kinda backwards, but OK). The upper knob is the main tuning one, and the lower one is mostly for matching (better notch depth). But of course there's a little interaction. Not real critical for receive use...I could generally get better than 10 dB return loss (< 2:1 VSWR) from 7 to 29 MHz. Lowest I could get resonance was 5 MHz. Highest I tried was 148 MHz - where I could also get a good notch. I couldn't get it to notch inside the FM broadcast band, but that's not very important and I can re-engineer it if I want to. I didn't try the 440 band.Solder joints on mine were all extremely well made. (I had to open the box since there was a rattle, and I wanted to see inside anyway ;-) The cases are nice plastic housings and the connectors are well mounted. Tuning caps are AM/FM receiver type, so they're small, with limited Q and limited breakdown voltage.The balun is excellent. I examined it and tested it and whatever core is being used seems to work nicely.Below the VHF bands, the tuning seems completely insensitive to proximity of me taking measurements on it. I did not find that to be the case with a Hustler mag-mount loaded vertical antenna on my car. Perhaps this is due to either the well-performing balun, the nature of the small loop, or both. But its nice.In summary, I am extremely satisfied and feel the designers, builders, and seller did a great job.I would definitely recommend this product to anyone interested in a compact indoor or portable antenna and for gaining experience with these sorts of antennas in general. And maybe for low-power QRP operation at 14 MHz and above where the efficiency is reasonable. (Would be nice to have a max power spec)
M**N
False advertisement
Do not waste your time buying this antenna. On all bands I had a 3+SWR. This product is a terrible for transmitting. Receiving it does great. If you want to listen in and have a Rx only antenna then sure this is good. However, to work QRP and transmit, this is not the answer.If you take anything from this review, DO NOT DO NOT DO NOT BUY THIS! You will waste your time and waste more of it by returning it. I wish I took the other reviews seriously. It’s not a good antenna. I hate I could only leave one star…. If I could do less I would. Whoever is reading I hope this helps you. Don’t waste your time/money like I did.
A**N
Nice to look at, not so nice in operation
The loop antenna arrived quickly. Appears nicely designed using Hardline for the loop. There were no instructions but I quickly learned that the red switch was up for 5-10 and down for 10-28. The top knob is to tune the loop to desired frequency and the bottom knob is to match the transceiver to Loop. The frequency range stated is incorrect. It goes from around 5.5 Mhz upward limit is below 10 meter band at Around 28 Mhz. It’s difficult to tune the 10 meter band. So any talk about above 28 mhz is nonsense. The controls are touchy… very touchy. That is usual for a loop but in order to get good swr it takes a steady hand. The loop receives okay and is of course directional. TRANSMISSION: I’m an extra class ham operator. To test performance I loaded up WSPR a digital mode that tells you how your antenna is working and provides propagation information. I tried this loop on 40-10m and received NO responses. I knew my radio was transmitting because I could hear transmissions nearby with my portable radio. I tried over several days on multiple bands and modes with no return contacts whatsoever. My conclusion is this antenna is probably okay for receiving signals but you will be disappointed using it as a transmitting antenna. The overall design isn’t bad but the capacitors inside are similar to those used in AM/FM receivers not transmitters. The included balun is cheaply made. I expect that the loop will match but doesn’t radiate very well. I am going to keep this loop and add some better capacitors and increase the size of the loop. I will wind another balun as well. You may do better without even hooking the balun up. So, for $88 I got basic parts to construct a better loop. but my loop (a least) did not work as advertised. Did not operate in the frequency range states and was unable to make one contact although I was able to receive stations.
Trustpilot
1 day ago
2 weeks ago