Anyone already using the so called Donut Antennas?

[Dirk_SDR]

At Amazon so called "Donut Antennas" are offered recently for SDR RX.

4PCS UV UHF und VHF FM AM MW SW Mini Ringe Transceiver Tragbare Loop Antenne für UV und VHF: Amazon.de: Elektronik & Foto

4PCS UV UHF und VHF FM AM MW SW Mini Ringe Transceiver Tragbare Loop Antenne für UV und VHF bei Amazon. Große Auswahl an Aufsteckantennen in Elektronik & Foto zu günstigen Preisen.

www.amazon.de

There seem to be 4 types:
1. AM: 0,5 - 1 MHz and 1 - 2 MHz
2. SW: 4 - 12 MHz and 12 - 24 MHz
3. VHF: 80 - 150 MHz
4. UHF: 400 - 470 MHz
What do you think? Useful or junk?

 

[dlwtrunked]

At Amazon so called "Donut Antennas" are offered recently for SDR RX.

4PCS UV UHF und VHF FM AM MW SW Mini Ringe Transceiver Tragbare Loop Antenne für UV und VHF: Amazon.de: Elektronik & Foto

4PCS UV UHF und VHF FM AM MW SW Mini Ringe Transceiver Tragbare Loop Antenne für UV und VHF bei Amazon. Große Auswahl an Aufsteckantennen in Elektronik & Foto zu günstigen Preisen.

www.amazon.de

There seem to be 4 types:
1. AM: 0,5 - 1 MHz and 1 - 2 MHz
2. SW: 4 - 12 MHz and 12 - 24 MHz
3. VHF: 80 - 150 MHz
4. UHF: 400 - 470 MHz
What do you think? Useful or junk?

It looks like an unshielded loop in a flat configuration with a tuning capacitor. Depending on your SDR and money, you can likely find better (something shielded), but if size is a strong consideration these "donut" (really loop) might be considered. (If you have an AirSpy HF+ Discovery, the Airspy Youloop is great but other SDR will not have enough gain for it).

 

[krokus]

The VHF & UHF loops might be fun to play with, but the loops for AM BCB & HF/SW are questionable. If loops that small were effective, for those freq ranges, there would be more of them.

 

[dlwtrunked]

The VHF & UHF loops might be fun to play with, but the loops for AM BCB & HF/SW are questionable. If loops that small were effective, for those freq ranges, there would be more of them.

I think they may have been primarily intended for direction finding. For direction finding, small size is often desired and too much sensitivity can be a problem.

 

[krokus]

I think they may have been primarily intended for direction finding. For direction finding, small size is often desired and too much sensitivity can be a problem.

I had not thought about that aspect. It does seem odd they would try that with a SW specific antenna.

 

[dlwtrunked]

I had not thought about that aspect. It does seem odd they would try that with a SW specific antenna.

I have a commercial HF (SW) loop antenna that I have used for direction finding to locate a mysterious beacon. It was only a little larger.

 

[johnmblack]

They are not bad. The MW loop works pretty well and has sharp tuning. The SW one is so-so. Both are useful and at least outperform a telescopic antenna on my Malahit radio.

 

[dave524]

I like the SW one , as said it works better than the telescopic, pirate Wolverine Radio

 

[Dirk_SDR]

Now so called "Hi-Z Amplifiers" appeared on Amazon also as a bundle with donut antennas:

https://www.amazon.de/LYEAA-Rundantenne-Impedanzverst%C3%A4rker-800-mAh-Akku-Donut-Kurzwellenantenne-StyleA/dp/B0CHZRZ8MV?th=1

They are advertised with using them also with the donut antennas and other high impedance output antennas.

These "amplifiers" have 0 dB gain and an input impedance of 1 MOhm.
Advantage is the built-in Li-Ion battery.
I will report as soon as I get mine.

 

[wtp]

i would figure it is directional, but it might help with simulcast.

 

[surfacemount]

If loops that small were effective, for those freq ranges, there would be more of them.

You mean, like a squalo?

'Effective' in radios is a ratio between sensitive and footprint in my opinion...

 

[wtp]

like this, but cheaper ?

 

[wobble8]

Like are found in thousands of 40's - 60's tabletop AM radios? Just sayin'........

The VHF & UHF loops might be fun to play with, but the loops for AM BCB & HF/SW are questionable. If loops that small were effective, for those freq ranges, there would be more of them.

 

[wtp]

 

[ratboy]

I have one of the blue SW ones, and it works pretty well. Just the fact that it doesn't flop around or fold up like the whip does on a couple of my radios is a huge plus. It was like $5, so why not?

 

[satellite909]

At Amazon so called "Donut Antennas" are offered recently for SDR RX.

4PCS UV UHF und VHF FM AM MW SW Mini Ringe Transceiver Tragbare Loop Antenne für UV und VHF: Amazon.de: Elektronik & Foto

4PCS UV UHF und VHF FM AM MW SW Mini Ringe Transceiver Tragbare Loop Antenne für UV und VHF bei Amazon. Große Auswahl an Aufsteckantennen in Elektronik & Foto zu günstigen Preisen.

www.amazon.de

There seem to be 4 types:
1. AM: 0,5 - 1 MHz and 1 - 2 MHz
2. SW: 4 - 12 MHz and 12 - 24 MHz
3. VHF: 80 - 150 MHz
4. UHF: 400 - 470 MHz
What do you think? Useful or junk?

I just received one today via Amazon. Not bad at all, the photos of them may appear to be cheaply made, but that’s not the case. Installed it on my Icom ICR6 receiver and seems to work very well. I will experiment more at night with better propagation. So far so good, and also noticed strong signal levels and clarity on the UHF FM 800mHz frequencies.

 

[Voltaire]

They are not bad. The MW loop works pretty well and has sharp tuning. The SW one is so-so. Both are useful and at least outperform a telescopic antenna on my Malahit radio.

This is my experience with the antennas as well. They are not as good as my SV2CZF PL250C as they are not seemingly directional (which is odd for a loop) but they are much quiet and pick up signals much better than the telescopic.

My cons are: They are not seemingly "Directional" like a traditional loop(I do not know why at this time, possibly the design itself.) And the high/low switches and knob tuning seem to be "off," 4Mhz setting on the SW "donut" tuned up all of the 80m band without any issue. Very strange, but it does work.

I agree that a larger loop is better(MLA-30, etc,) but for the money and size these are definitely worth having in your kit.

 

[Dirk_SDR]

..,

My cons are: ... And the high/low switches and knob tuning seem to be "off," 4Mhz setting on the SW "donut" tuned up all of the 80m band without any issue. Very strange, but it does work.

Possibly the receiver input adds some capacitance to the LC circuit (= the donut antenna).

 

[Dirk_SDR]

Another design?

https://www.amazon.de/GOOZEEZOO-5pcs-Antenne-Kurzwelle-Radio-Schwarz/dp/B0CKSVQZGT/