| 5B4AIY |
Rating:  |
2024-02-07 | |
| Expensive, but worth it! |
Time Owned: more than 12 months. |
When I retired I moved to Cyprus and initially rented a house which unfortunately did not have sufficient room for anything like a full-size antenna, not even a vertical. After much deliberation I purchased a Ciro-Mazzoni 'Baby' loop from Martin Lynch & Sons in the UK in 2015. At that time the control unit for the antenna, which C-M call an ATU, was the original manual Mk-I. I subsequently replaced it with the Mk-II version, and this review is based on this later unit.
The problem with electrically short loop antennas, whose length is of the order of 1/8 lambda to 1/10 lambda is that their radiation resistance is very low, about 0.01 Ohm. Consequently in order to be efficient the sum total of all the other ohmic losses has to be much smaller than that, which is difficult to achieve. To minimise skin effect losses the C-M loop is constructed of 50mm diameter aluminium tubing with a wall thickness of 2mm. The variable capacitor required to tune the loop is an integrated assembly TIG welded to the ends of the loop to minimise contact resistance. In order to ensure that RF currents do not flow through the pivot pin at the bottom of the loop it is bypassed with a substantial stainless steel 'U'-loop secured to each half of the loop with three screws with a generous application of anti-seize conductive grease. As a result, the losses are low, and the 'Q' very high, about 1,100 @ 7MHz. This means that even small frequency changes will require the loop to be re-tuned. It also means that it is a good harmonic filter and front-end pre-selector.
The loop is tuned by opening and closing it with a Hywin linear actuator driven by an L298 integrated circuit H-bridge motor drive IC in the ATU.
The antenna system can have three modes of operation. Manual, where you enter the desired frequency between 6,600kHz and 29,800kHz on a keypad; Full Auto where the ATU's RS-232 port is connected to your transceiver and the ATU queries it once a second and follows your tuning; and Semi-Auto where again the ATU is connected to the transceiver but this time the ATU will blink a red LED if the transceiver's frequency differs from the antenna, and to correct you merely press the ENTER key. There is also a TEST mode whereby you can open and close the loop manually at low, medium or high speed and continuously monitor the SWR, as well as a SETUP mode to determine the 'sense' of the linear actuator's motor connections as well as the type of antenna and the serial port mode and speed.
The ATU contains its own signal generator, an Analog Devices AD9851 DDS driving a 10mW power amplifier. During tuning operations the transceiver is disconnected from the antenna by means of a RF changeover switch and the DDS output is sent through a SWR bridge to the antenna. The SWR is continuously measured as the actuator is moved and when it decreases the actuator is driven in small steps in the fine tune mode until the minimum SWR is found, whereupon the tuning is stopped, and the transceiver re-connected to the antenna. Note that because of this you will hear the tuning signal in the connected transceiver at a fairly high level, around S9+40dB. The entire operation is under the control of a 32-bit Microchip PIC32MX4xx series microprocessor.
The ATU requires 24V for operation, primarily to drive the Hywin actuator's DC motor. Internally the supply voltage is reduced to the necessary logic voltages by means of a LM2594 switching converter. In my case the power supply provided was a switching 24V 'wall-wart' device which unfortunately was a hash generator. I made a simple unregulated linear 24V/2A PSU to replace it which has proven to be entirely satisfactory. The linear actuator can operate with as little as 15V so a regulated motor supply is unnecessary. When driving the actuator at high speed the current consumption is about 450mA, the standby consumption is about 75mA from a nominal 24V supply. Note however that when starting the motor the peak current can be more than 1A, hence there should be a large reservoir capacitor in the power supply to cater for this starting transient, and in my PSU I used 4,700uF. Note also that if the ATU is switched off using the front panel switch, there is still about 50mA being drawn from the supply.
When mounting this antenna it is important to recognise that height is of no advantage. Ciro-Mazzoni recommend that the base of the antenna is between 1.5m/5 feet and 2.5m/8 feet from the ground, any higher and the SWR suffers. As an experiment I mounted my loop on the flat roof of my present steel frame house and whilst the SWR was reasonable, the ATU would no longer auto-detect the type of antenna in the SETUP mode. It is currently mounted up at 1.5m on a pole high up on the bank behind my house with a clear view of the horizon all around. In this position the SWR is between 1.1:1 and no worse than 1.8:1 on all bands.
The ATU firmware is regularly updated and the update is easy to do. You simply copy the new firmware file to the root directory of a USB stick, remove the USB keypad cable and plug the memory stick in and turn the power supply on. The ATU will detect the memory stick and will rewrite the firmware. At the conclusion you will be prompted to replace the keypad cable. The latest firmware, version 4.11, is now much more tolerant of keypads, and will even accept a wireless keypad obviating the need for a connecting cable.
It is also important that the RF path from the ATU to the antenna should be direct with no joins or splices in the coaxial cable. In my case when I moved QTH I had to add 5m to the RF cable, and I used a SO-239 bullet to join the cables together. This worked for a while but then one day it would no longer tune. A check with my time domain reflectometer showed a cable fault 25m from the shack - you guessed, the SO-239 bullet!
So, how well does it work? After some 9 years of use I would say it works very well. I have run several WSPRLite tests using a SOTA Beams WSPR transmitter and with 200mW I am regularly copied on 20m in Australia, North America, Canada, even as far as Puerto Rico, and similarly on the other bands. On 40m a few weeks ago the furthest was 14,372km with 5 spots by VK7JJ, and an average distance of the top 10 spots of 9,216km. On the same weekend on 10m, again 8 spots by VK7JJ and the top 10 average spots distance was 11,950km. This compares favourably with my other antenna, a Hexbeam. Typically on SSB the C-M loop averages about 1 S-point down, but bear in mind that the Hexbeam has about 1 S-point of forward gain.
I have had some odd quirks, on one occasion the antenna would not tune with a low SWR and when I examined I found that mice had made a home in the box base of the antenna. After clearing them out I placed a small aluminium plate over the gap, and had no further problems. I found that if I filled the space with some packing material that adversely affected the SWR.
I can only say in conclusion that if this loop were to be destroyed I would HAVE to replace it with another, I am very happy with the quality of construction as well as the operation of this loop, and if you have a similar antenna size problem, then this loop should certainly be on your short list. It's not cheap, but you do get what you pay for. I have also had excellent support from Ciro-Mazzoni, and if you are having a problem, then you can contact me on their website support page.
Adrian, 5B4AIY |
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| K0INN |
Rating: |
2023-07-20 | |
| Industrial strength construction and handles power! |
Time Owned: 0 to 3 months. |
I purchased the antenna second-hand. The antenna was already out of the warranty period (2 years) so that is not a concern for me.
I already own an MFJ1788 Magnetic loop so my expectations are tempered. I am familiar with loop tuning. The MFJ looks like a toy compared to the Baby Loop.
The Baby Loop looks like it was built for the commercial/industrial market. I've read several reviews where hams operated the antenna for 10 years with no maintenance (which I can believe). No shortcuts were taken in the materials and construction. You won't be disappointed feeling that the product was cheaply made with trouble prone components.
I have my MFJ mounted on my roof and I'm able to tune pretty much 1:1 SWR throughout it's tuning range. I plan to replace the MFJ with the Baby Loop. I'm expecting that the Baby Loop will be able to achieve the same SWR ratios in the same location.
After getting the loop I tested the manufacturer recommended mounting height (minimum 5 feet) on a tripod. It was a solid performer. As with most HF antennas, they perform better when mounted higher. The MFJ loop performed better at height and I believe the Ciro will also.
The tuner on the Ciro has 3 operating modes. Automatic mode - a cable (not supplied) connects to your radio abd the tuner automatically tracks the radio VFO. Semi-automatic mode - you punch a frequency into the keypad and the antenna tunes to that frequency. And then there is manual mode - you punch a frequency into the keypad and use up/down assigned buttons on the keypad to manually tune. The current SWR is displayed.
The tuner on the Ciro is a dream compared to the MFJ (which compares to manual mode on the Ciro).
The antenna is a bit of an investment. It definitely looks like it is built to last. It allows you to have an effective, low maintenance HF station in a minimum amount of real estate. I'm really looking forward to using it. |
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| HB9ZHK |
Rating: |
2022-10-11 | |
| Good antenna, lousy customer support |
Time Owned: 3 to 6 months. |
First things first, the good: the antenna performs very well when properly tuned with the included tuner. I made QRP contacts further than I have ever before (I do have quite strict limitations on the antennas I can use where I live).
The bad: the tuner does not tune very well and I often have to tune multiple times to get an optimal SWR - I might be fussy here, but if I can get an SWR of 1:1.3 instead of 1:1.6 after the first tune I'll retune.
The ugly: customer support is lousy to absent. Out of three requests sent to them by e-mail, only one was answered and the answer was completely useless (I asked if the pinout and voltage levels on the serial port were standard RS-232 - all I got was "just buy our (overprized) cable and be fine with it).
Overall I'm a bit unsure if I took the right decision to buy this antenna. It performs very well and seems to be a near-perfect solution for the limitations I have here. On the other hand, it is exposed to wind and weather and will need maintenance and repair after a few year. After the disappointing experiences I had with customer support I'm not sure if I'll get this. |
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| N2ZD |
Rating: |
2022-01-12 | |
| Performance is seldom cheap! |
Time Owned: 3 to 6 months. |
I picked this up a few months ago with the tripod. It tunes fast, the tuning unit and keypad are intuitive, it takes some extra power if needed.
The antenna is well constructed, a bit heavy but that’s to its advantage. Signals heard are very good and low noise by the loops very nature.
My Hats off to Ciro on a job well done. Right out I worked Belize and Michigan with the loop 10 feet from the front of the house in my driveway and I was heard on the first call.
It’s an expensive antenna, but I’m in an HOA and this looked like a good solution, so far so good as it has me on the air. |
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| DL7SDI |
Rating: |
2021-04-09 | |
| Great Job of the Baby Loop |
Time Owned: 3 to 6 months. |
My Baby Loop is now installed since Nov 2020 and it's really a phantastic new experience for me. First trial was 2 m above ground on a tripod, autodetection works great and Baby Loop was identified without problems. First QSO's in all directions on 40m SSB with 100 W result in 59 in EU and booming signal comments - wooow. After 2 weeks mounted on the final destination 3 m above ground and 1,5 m above the roof. This is not optimal but works. Autodetection doesn't work anymore but manual detection was ok. Again - oustanding signal reports through EU, US CN and Southamerica on 40m(!) SSB. Never had that worked before on 40 m.
And - compared to my Vertical and Wire Antenna works ways better and i worked countries which I never did before.
A really outstanding antenna and worth every Euro. To be honest - I'm really impressed by that performance.
You can see it on QRZ.com.... |
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| N7JFF |
Rating: |
2021-02-17 | |
| Master of Compromize |
Time Owned: 6 to 12 months. |
I won't go on and on in detail, but did notice that most of the reviews here are very old, and wondering if these users have the update ATU 2.0? I have put several hours on the Baby Loop since receiving it a week ago, and just over 400 contacts, mostly on FT8.
I am making contacts with countries I would only get when the stars are in alignment, like Australia. I have been making contacts in Australia everyday since the install. I also am getting countries I have never had, and seeing countries on the screen that I have never seen. I am working DX everyday.
This antenna is certainly not compromised where it comes to build quality, and based on my experience with long wire antennas, I don't feel like it's compromising.
Matter of fact, I like it so much I will most likely be purchasing the Midi Loop at some point as well.
Good luck! Good DX!!!
Update: 06-23-2020
I wanted to make a short update. The DX still pouring in as I am now continuing to log new countries on FT8. Last Sunday evening, I logged OD5KU in Lebanon. Okay, I was pretty excited! Last night I saw a station on Easter Island. It was already fading deep into the grey line, but know know when to watch for him now. I don't see much in change of the propagation reports, so it must be the antenna, and of course a bit of help from the big guns out there in Europe. I am also assuming that with COVID-19, "Stay At Home", there are many more operators on the HF bands. Heaven knows you can't reg chew or tie up talk group 91 World Wide on DMR... hi hi
Hey, I am not the only Ham working DX in Montana, however it seems that way as I get many operators needing MT to complete WAS. Bring em on! I am happy to be your Montana confirmed contact! I have sat on the fence about this antenna for over a year. I in now way regret it, and am surprised every day that I fire up the rig the stations that I am making contacts with. I will keep more updates going! So far I am up to 772 logged contacts for June, 2020 since installing this antenna. By the way, I still have a day job, so I only get in a couple of hours a day.
February 17th, 2021 Update
Still enjoying the loop, and making many DX contacts. Band conditions are still not that great, but seem to still work Aussie stations, Russian, and stations in Europe. I want to mention, that my antenna is ground mounted, and the closest object is the back of the house at 30 feet from the antenna. Any other objects/ structures are three times that. I have a lot of clear space. I will editing and updating this review would allow me to add a photo of the install and you could clearly see what I mean. We have had just last week temps at -30 without the wind. I leave the loop on 20 during those temps. The antenna is still running strong, and preforming well. |
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| AG6EM |
Rating: |
2020-07-01 | |
| Great but you may need an expensive accessory |
Time Owned: 3 to 6 months. |
I purchased the Baby Loop for my HOA regulated home. I also purchased the tripod so I could experiment with locations in the yard for hiding it as much as possible from the neighbors. I am impressed by the performance of the Baby Loop to pull in signals with relatively low noise. While this is an expensive antenna it is probably the best solution for my situation.
I did have a couple of problems. At first the actuator that tunes the antenna would not work. I checked the wiring and found a bad crimp on one of the wires in the upper junction box of the antenna. After fixing that I checked the actuator with a meter and found an extremely high resistance value, far too high for the DC motor that is internal to the actuator. I tried reversing the polarity of the wiring but that didn’t work. After contacting DX Engineering they offered to send either an actuator or an entire new antenna. The next day I moved the antenna to a different location and the actuator started working. The actuator has internal limit switches and I suspect one of them might have been stuck and the vibration from moving it may have freed it up. I have had no further problems to date.
Now on to the ATU. I have an Icom IC-7600 and I purchased the adapter cable for the CI-V interface. Upon setting it up for Automatic tune the ATU tries to tune the antenna to 6.6 mHz, the lower limit of the antenna. This failed with the ATU continuously waiting for the antenna to tune. The actuator had hit the limit switch and the motor was no longer running but the air capacitor was not fully closed so the antenna couldn’t tune down that far. This was corrected by loosing the mounting bracket for the actuator and adjusting it so the capacitor was fully closed when the limit was reached. Now everything was working fine until I tried to start Ham Radio Deluxe which was connected to the radio by its USB port. Any tuning of the radio either by HRD or the tuning dial would cause HRD rig control to stop functioning. I tried WSJT-X and got error messages. Apparently the ATU continuously polls the radio for frequency changes and these were colliding with the rig control software. After several emails to HRD, DX Engineering, and Icom, no solution was in sight. I also emailed Ciro Mazzoni but it took several days for them to reply that I needed to buy their “Serial Switch” which would correct this issue. This was an expensive fix at $500 US but it did work to solve the problem. I suspect anyone with an Icom transceiver will have this issue and probably with other makes as well. In addition, the ATU will not now function in automatic mode unless HRD or some other rig control software is in operation. If I want to operate without the computer I need to remove the Serial Switch or change the ATU to Manual mode.
I did find one other possible software solution for Icom radios after the fact which I have not tested but should work. The Win4IcomSuite ($60 US) along with Com0Com (free) should work for those of you with an Icom that don’t want the expense of the Serial Switch. The software provides rig control and virtual serial ports which can be configured with Com0Com to link other software application to the radio. There are some good setup videos for this on the Win4IcomSuite web site.
One caution when reading about the linear actuator provide on the antenna. It has a 10% duty cycle rating and the manufacturer’s documentation says exceeding this may shorten its life. Those who like to search and pounce should be aware of this.
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| KH4AB |
Rating: |
2018-10-12 | |
| Stealthy & Best Mag Loop Antenna Ever |
Time Owned: 0 to 3 months. |
Stealthy Baby Loop Antenna:
Hello fellow Hams and Baby Loop enthusiast. I just wanted to share the new look of my stealthy and camouflage Baby Loop antenna. I was actually pleasantly surprised how my paint job turned out after about five paint spray cans from the Home Depot’s Rust-Oleum camouflage series set.
I was a little bit worried that the paint may impact the performance, but to my second surprise, not one bit of SWR changed from bare to painted metal. This antenna just continues to impress me every time I turn on ICOM 7300 as I am getting a very impressive SWR from 1.1 to 1.6 across the entire 6600 to 29800 band…simply amazing.
With regard to DX, farthest contact has been Chile and Argentina on the southern end and US east coast to the East, and Hawaii to the west. I heard Guam and Saipan Islands last week, but they could barely hear me on 40 meters SSB. Antenna is only about 8ft above ground at my backyard at this time on a Yeasu 450A rotator.
The goal it to mount it on the roof one of these days to improve DX performance and hopefully the HOA will not notice…lol…I also think the paint will be able to extend and protect the bare metal from the natural elements, although, the construction, fit, and finish is top notch industrial grade quality.
So far so good, I am very satisfied and very pleased with this magnetic loop antenna system, the tuning with the ATU2.0 can automatically tune from the IC7300 and it can follow my rig’s VFO via the CI-V serial RS-232 interface.
Thank you Cirro Mazonni.
Cheers & 73s,
Dan – KM6VMR
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| 2E0JWW |
Rating: |
2016-10-10 | |
| Great antenna |
Time Owned: 3 to 6 months. |
Just thought i would update since my last review on this great antenna.
Since the last review i have now installed a rotator and the difference is just incredible,since then i have had some nice DX,sure its not going to compete with a big Yagi,but for me it is the best Antenna i have had in my limited space. |
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| GW4UWD |
Rating: |
2016-09-13 | |
| Brilliant quality in build and performance |
Time Owned: 0 to 3 months. |
| Have used the loop consistently since January this year with an Icom 7200, elderly ft747gx and ts430s for ssb and an Elecraft K2 for cw.The first results show how quiet the loop is for noise.perfect for cw at qrp and higher levels. Working Kuwait,Saudi etc with good results.My baseline is the other antenna being a perfect Hi End fed antenna from the Netherlands whilst using an Icom 718, FT450D for ssb and a K1 for CW.The hi end fed is 1.1.1 on all bands except top band with the auto atu, but so much noisier than the loop.The loop seems to have the edge on the end fed. It is very well made, easy to set up and does the job perfectly. A lot of money for the kit, but you get what you pay for. I would strongly recommend it. Love mine and enjoy the dx. 73. Peter GW4UWD |
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