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Reviews Categories | Antennas: HF Portable (not mobile) | Kaito KA31 Shortwave Active Loop Antenna Help

Reviews Summary for Kaito KA31 Shortwave Active Loop Antenna
Kaito KA31 Shortwave Active Loop Antenna Reviews: 4 Average rating: 4.0/5 MSRP: $$39.99
Description: Receiver antenna for use with the Kaito KA1103 and other receivers
Product is in production.
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You can write your own review of the Kaito KA31 Shortwave Active Loop Antenna.

WA6IXI Rating: 5/5 May 28, 2013 20:10 Send this review to a friend
Really great for the price!  Time owned: 0 to 3 months
The only previous active SW antenna with which I am familiar is the old Radio Shack unit (from the late 1980's) that did what I think was a remarkable job for an inexpensive amp. This little antenna amp is right up there and earns its oats. It is difficult to be critical of an amp that does this good of a job at such an inexpensive price. She'll pull signals right up out of the weeds with no problem. I will be purchasing a couple of additional units soon to assist my other SW radios.
WB4U Rating: 5/5 Apr 6, 2013 14:57 Send this review to a friend
This review is for the Kaito KA33  Time owned: 0 to 3 months
I am as much a SWL and AM BCB Dxer as I am a ham radio operator. As a radio enthusiast, I am always on the lookout for a better antenna.
I decided to try the Kaito KA33 active loop antenna for medium wave and short wave. The antenna comes packaged in a box and a bubble pack
within the box. There is the control unit, a long connecting cable to go from the antenna to the control unit, a plastic clip and suction cup
to hang the antenna, a ferrite bar coupler, and an antenna/ground clip lead connector, the loop antenna with a telescoping rod to spread the
antenna into a diamond shape and attached to the loop is the amplifier/band selector. The antenna covers the medium wave broadcast band 520
to 1710 KHz and all shortwave bands from 3.9 to 22 MHz.

Does it work? Yes and surprisingly well I might add. I tested the antenna both outdoors and indoors and used my Grundig Satellit 750 and
a Tecsun PL-380 ultra light radio. I connected the output cable from the control unit directly to the Grundig 750 for BCB testing and could
easily A - B between the KA33 and the rotatable ferrite antenna on the Grundig. For the Tecsun I used the ferrite bar coupler. On the SW bands
I used the clip lead connector for both radios and clipped the loop antenna to each radios whip antenna.

Outdoors during daytime on the AM band the results were amazing on both radios. It was between just hearing a station right in the noise and
having very strong signal to listen to. I have a station about 75 miles away that can be heard at the noise and the loop brought it up to
an S-9 signal on the 750 and a 65 DBu and 40 DB SN level on the Tecsun. I could tune to a otherwise empty spot on the dial and tune the
loop and many times find a station there even if very weak. The loop was less impressive on short wave. It does work very well and pulled in
any station, but with the SW broadcasters blasting out thousands of kilowatts the difference between the loop and whip antennas most times
was not that great. The advantage of the loop on both the AM and SW bands is the ability to rotate the KA33 to null out noise
or a co-channel station allowing you to hear the desired station. This was very useful on SW and in the evenings on the medium wave band.

Testing indoors went as expected. Connections to both radios was the same. The loop performed very well, however indoors as many of you
know, it had to contend with noise from many sources as any indoor antenna. Performance was limited in that way on both SW and the
medium wave band, but again being able to rotate the loop could solve some noise issues and allow a station to be heard.

The bottom line.....This is a very useable antenna that performs as advertised, is low cost and well built and provides a good
value for the money. I was very impressed and pleased at how well it worked on AM, much better than I expected. Away from noise
sources this antenna will give you many hours of enjoyment. It is powered by two AAA batteries which should last a good while since
rated current draw is only 6 mAH. The only downside is the tuning control. It's a small wheel recessed in the control unit and
must be moved very slowly. It is easy to pass by a signal peak for a station and you'll have to jog back and forth to get maximum signal,
this can be tedious at times. It's not kind to guys with fat fingers.
ZS6KB Rating: 1/5 Aug 21, 2012 07:47 Send this review to a friend
Receive antenna transmits!  Time owned: 0 to 3 months
The antenna is designed to tune the loop by varying a voltage across the varicap. That in itself is bad because strong stations will be modulated. The worst is still to come. The Varying voltage is produced in the control unit by a DC-DC converter and the square wave produces harmonics across 2.54 to 30+ Mhz at 40 db. So no chance for a weak station in there! Worse yet, your neighbor can receive the signals to because the loop radiates the harmonics. How did the FCC allow this antenna onto our shores? Check the video
JETPILOT Rating: 5/5 Apr 2, 2008 08:44 Send this review to a friend
Kaito/ Degen KA31/KA33/TG33/TG34 Fun antenna, works @ discount  Time owned: 0 to 3 months
This is a fun little portable "active" amplified loop antenna. I purchased it at the same time as my DE1103 radio (which I'm impressed with) on eBay. It took +3 wks but worth it.

This antenna is sold under different names, Kaito (import) or Degen/generic (china version). The KA31, I believe now KA33, Kaito's latest version of this antenna. The ant tested was on the TG34 model (replacing the TG33 model). It does not say Degen but its their brand and I am sure the same as Kaito.

You get a lot of stuff with it. You get clip & suction cup to hang-up a "diamond" loop with a telescoping antenna, used as a "spreader". I have no idea the affect of this metal rod in the middle of the loop, but more on how it works below. At the feed line is a switch for SW or MW. That switch does do something and improved nose level when switched while on AM MW BC band. It comes with a long feed line (15'). The amplifier is the size of a large pack of gum. It takes two AAA's (not incl). It has an on/off switch, led on light and a small thumb tune dial, unmarked/no scale. I found dialing down biused more towards higher freqs. I opened the the amp up with three tiny screws and found the on/off switch, resistor, potentiometer/variable capacitor(?) and an IF Transformer. I did not look under the board, it was in there for good, so I did not push my luck. From the amp is a short pigtail with a 1/8" stereo plug. You get two attachments, a loop-stick booster and one two lead pigtail with alligator clips. The DE1103 has a 1/8" antenna jack and the loop plugs in direct for SW and FM. For AM MW BC you use the loop booster, which is fun to play with. If you have no leads or have dedicated antenna input, the third way to use is the pigtail and clip attachment, connecting to the external antenna or to the radios wires leads. I tried all three methods on 5 radios, 2 SW general band and 3 AM or AM/FM radios.

Radios I tried it on where the DE1103, RX320D for MW and SW. For MW AM BroadCast I tried three cheap AM or AM/FM radios, including: Panasonic portable black/white TV w/ an am/fm radio (analog), Sony (ICF-34) AM/FM/TV/WX portable with ac/bat power and a handheld AM/FM stereo digital tune "optimus" (aka radio shack, cat # 12-792), with a small 2" or 2.5" loop-stick towards to bottom (it's a small radio not much room for a loop-stick).

First about loops and amplified or active antennas. For you experts you probably know this, but from my novice experience and reading there is a plus/minus or Pro/com with any tunable active loop. It is said that you boost signal and noise equally. Well I found that true sometimes but not always. Bottom line it make un-listenable radio listenable. Some times it was still noisy and others it cut noise. The tuning is a pain of you are scanning, but if you are going to stay put on a station or a few favorite stations the tuning part is a minor issue. When you do tune it (with the little thumb dial on the amp) and the station comes in loud and clear its worth the effort.

The fact is loops are directional and tunable. That is good and bad. On a scale of 0-5 it can make 0 stations be a listenable 2-3's. It can make a 2-3 stations more enjoyable. I found on strong stations it even cut noise sometimes but did nothing for the signal (which did not need it). Sometimes it made the signal louder and more disginishable but also raised the noise equally. I did not play enough with moiving the antenna around. Also I am doing this around a bunch of computer stuff and AC stuff. Out in the open who knows.

The second good/bad is a fact of life, is that its tunable, a feature which brings in weak stations. The down side is you have to tune it each time you change radio stations. The tiny dial on the side of the amp is super sensitive. It's very small volume like control, but it is clear when you move this, it's an active loop, it does do something. If your active loop is connected and you have it badly mis-tuned, it can have the total opposite affect of bringing in stations, it can reject or block them, so you tune with it off or disconnected and than connect it and tune it. If you are listening to one station than this is not an issue.

**First using the Loop stick boost on AM MW BC band.

One note, you have to know where the loop stick is inside the radio. I either have had them apart or hunted for it using the loop stick booster. Also moving the booster around, switching the booster leads around 180degs can have big affects on signle. The down side is you can't hold it there forever, so some non-stick frig tape is a must for long term use. Some times it can just sit on top (about where may loop sticks are mostly) but other times you need to hold it to the back.

One real WOW moment was when I just dialed to static and put the loop-stick booster to the radio about where I knew the internal loop stick was. Leaving the radio alone I tuned the antenna and brought in a signal I could not hear other wise with the radio's antenna alone! Even moving the radio around with out the Active loop connected did not bring in that station. I repeated many tries on all radios and had improvement on all of them, in a similar fashion, but this one radio and station gave spicatcular results.

The directional part of the loop is a question; a few times I moved it and there was no change, but one tell-tale indication was tuning in a weak station, with the Optimus handheld am/fm radio. Moving the loop made a difference as described in the below par.

The second WOW moment using the loop-stick booster was when I tuned in a weak station, than put the booster up to the radio; tuning brought in a totally new station coming in stronger! The down side was this new station had heterodyne (squeal), no doubt from the other station that was now blocked. Moving the loop around (stuck to the window) made the heterodyne disappear. Moving the antenna had no affect on the signal strength (by my ear) but the squeal was gone. It was hanging vertically. It took only a small movement of the bottom to the side to do the trick. So instead of vertical it was angled slightly. Small change made a big difference. However with other tries moving it the loop had little or no affect.

The base of the loop where the feed line is a switch with SW/MW. It did make a small difference in noise.

Trying it on all radios there was no doubt improvement on a scale of 0-5 at least 2 some times more. Results varied but the signal amplification sometimes reduced noise and other times it amplified the signal and nose equally.

SHORT WAVE: I tried this on the Degen DE1103 and Ten Tec RX320D. It worked similarly to AM radio, but of course the method of connection was different. The Degen has an antenna jack. The RX320D has a RCA jack. I jury rigged a RCA jack and used the TG34 alligator clips to make the connection; not high tech but it seemed to work as good as the built in preamplified telescope provided with the RX320D. When you plug in an RCA jack it disables the telescope antenna.

Bottom Line: I am a novice and getting into DX'ing after a long absence, so warning I am easily amused or impressed, but fact, it does work. I am not naive enough to think it's better than a good outdoor antenna, it is not I am sure. However for something that can fold up (size of a pak of cigs), you can hang it up in your hotel room or on the road; it isn't bad. It's really ideally suited to bring in that one particular station you want to listen to, that's a tad too far to enjoy. It's OK for scanning but more work for sure due to tuning. This antenna can make a difference. I tried it with cheap radios and expensive radios, it worked to a degree on all. Some results were fair and a few where spectacular. Some stations where not heard with out the loop became listenable. No matter how I orientated the radio with out the active loop I could not get the station; connecting the loop brought it in. Nuff said, the active loop DOES WORK. On a scale of work I give 5 with all the limitations above. I am comparing it to the stock internal loop sticks, built in telescope antennas and other indoor antennas, with PRICE factored in. It is a bit of a Rube Goldberg deal, you have mount the loop (on clip or suction cup), feedline, amp and adapter. There are lots of parts.

To a real antenna or a real BIG loop it might disappoint the Pros out there. The only critical comment on quality is the wiring seems a tad delicate. You have to push/pull the plugs (which connect and disconnect good force) at the plug, not the wire or you'll break the wires, which are small gauge.

If you can get one at a discount, I paid $22, free shipping as a package deal, it is recommended. $39? Well than it would not be as good. If you just want it for an AM radio may be the Terk passive AM loop might be better (which I have not tried personally). The TG34 uses batteries, so keep that in mind; don't forget to turn it off. I have a bunch NiMH rechargeable so its no big deal if I forget. Have not used it enough to get a feel for battery life

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