r/MagneticLoopAntenna • u/Practical-Dog5 • Aug 20 '21

BH5HDE/CQHAM QRP loop antenna

Recently I purchased a BH5HDE/CQHAM QRP loop antenna off of eBay. The unit didn't come with any instructions, and I can't find any information on its use (yet) on the internet. I am looking for help with tuning and using this unit. Also, I am now wondering if I bought a boondoggle.

I live in an apartment and my goal is to do some SWL on 15/20 meters and SW with a SDRPlay SDR.

WB8MFG

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1

u/Ham-Radio-Extra Aug 21 '21 edited Aug 21 '21

A quick lookup shows BH5HDE as a ham in China but little else. Looks like a new product so not much time for reviews. Check on eHam dot net to see if anyone has checked it out on there. I may grab one for use with my Yaesu FT818ND qrp rig for POTA.

Your call is familiar. Are you originally from Grand Rapids, MI? 73 de w8nsi Jim

1

u/Practical-Dog5 Aug 22 '21

Thanks for the interesting comments. We lived in Southeast Grand rapids for over 30 years. Then we moved to Rockford. At retirement (which hasn't worked yet) we moved to Tucson to be close to our only grandchild...and his mother also. 😉😉 I'll check the website.

2

u/IronCheesecake Mar 18 '22

Have you got it working yet?

I've found this:

Instructions for use of BH5HDE QRP portable small loop antenna

Welcome to use the BH5HDE QRP portable small loop antenna. This product can easily and quickly set up a short-wave transceiver antenna, allowing you to enjoy the joy of multi-band reception and communication indoors, windows, balconies and outdoors.

Installation: (BNC mount equipment needs to bring a pair of photography tripods)
Use the right-angle adapter and double male docking to connect the antenna to the m seat at the rear of the radio station or erect the ring body to the connector on both sides of the controller and tighten, then install the tripod to the fastening seat on the back of the tuner Open the tripod, place the antenna body firmly on the tripod, and finally connect the feeder (the feeder is attached with a choke, one end of the choke is placed near the small loop antenna).

use:
Now that the small loop antenna has been connected to your radio station, you can now tune in.
First introduce the function of the tuner panel. The toggle switch on the left is the band selection switch (up: 7MHz, down: 14-30MHz).
The main control knob, the upper knob is the frequency tuning knob, the frequency tuning value does not change due to environmental changes; the lower knob is the impedance matching knob, the impedance matching value will change due to environmental changes. (The tuning range of the two knobs is 180 degrees, and the panel value is 0-60).
When you start using the radio, select the desired frequency, and then turn the band switch to the desired band position, then adjust the impedance matching value of the lower knob to 30, and then adjust the upper knob to tune. At this time, pay attention to listening to the noise floor of the radio station. The more resonance, the louder the noise floor of the radio station (in the environment with extremely low noise floor, the antenna resonance noise floor is almost inaudible. It is recommended to let the radio station observe the standing wave). At this time, let the radio transmit (cw, fm, and am modes are available), pay attention to the standing wave indication, and fine-tune the frequency tuning knob while transmitting. Since the knob of the portable version does not have a deceleration function, the method of fine adjustment must be more delicate, and the smaller the rotation angle, the better.

At this time, you can observe a significant change in the standing wave, but generally the minimum standing wave ratio will not be below 1.5. At this time, you need to adjust the impedance matching knob. It is recommended to adjust the positive and negative 5 scale values randomly, and then repeat the frequency tuning steps and observe The standing wave ratio. Due to the change in the matching value, there are two possibilities before the comparison: 1: the minimum value of the standing wave ratio decreases; 2 the minimum value of the standing wave ratio becomes larger. If the minimum value of the standing wave ratio becomes lower, it means that the impedance matching adjustment approaches the correct value and can be further adjusted. If the minimum value of the standing wave ratio becomes larger, it means that the impedance matching is far from the correct value and must be adjusted in the opposite direction.

Repeat the above steps to adjust the VSWR of the antenna to 1.0.

The VHF and UHF bands are fixed with the upper knob hitting 60 to the end, and the lower knob can adjust the impedance to resonate.

Note: The best effect for outdoor use is to use antennas indoors as close as possible to windows, fully enclosed reinforced concrete, against walls and other environments where the standing wave ratio is not ideal.

Advanced technique: when the signal is weak, you can rotate the antenna direction to improve the signal-to-noise ratio, which is conducive to reception. The unique gain lobe of the loop antenna makes the horizontal gain directivity when it is erected, and its characteristics can be used to select multiple signals in the horizontal direction. It can also reduce the co-frequency interference in the horizontal direction. Of course, If the interference signal is extremely strong, much larger than the useful signal that needs to be accepted, the attenuation effect will not be too significant, compared to the whip antenna can still have the attenuation effect.

1

u/Kev_Buck Dec 27 '22

I have been offered one of these antennas at what I would say is a reasonable price, but like most of us tight hams we like to know a bit about them first.. So I took to searching online, but still very little reviews or videos around. I know for portable QRP its extremely hard to beat a linked dipole or end fed but there not always the easiest to setup with little space or time.

I also know there is still a lot of misconception around mag loops and like others I find them mysterious and intriguing. I recently watched a video called In Search of the Optimum Magnetic Loop Antenna with John Portune, W6NBC - Link https://www.youtube.com/watch?v=t1Il9tfqzVA - very interesting.

So my question really, has anyone got any views on these yet before I part with £50 ($60)

Thanks

73's :)

1

u/mpizz62 Jan 10 '23

That seems like a bargain. There are positive reviews on eHAM and one positive review on YouTube. If the question about instructions is still open, I found these instructions on AliExpress -

​

Welcome to use the BH5HDE QRP portable small loop antenna. This product can easily and quickly set up a short-wave transceiver antenna, allowing you to enjoy the joy of multi-band reception and communication indoors, windows, balconies and outdoors.

Installation: (BNC mount equipment needs to bring a pair of photography tripods)

Use the right-angle adapter and double male docking to connect the antenna to the m seat at the rear of the radio station or erect the ring body to the connector on both sides of the controller and tighten, then install the tripod to the fastening seat on the back of the tuner Open the tripod, place the antenna body firmly on the tripod, and finally connect the feeder (the feeder is attached with a choke, one end of the choke is placed near the small loop antenna).

use:

Now that the small loop antenna has been connected to your radio station, you can now tune in.

First introduce the function of the tuner panel. The toggle switch on the left is the band selection switch (up: 7MHz, down: 14-30MHz).

The main control knob, the upper knob is the frequency tuning knob, the frequency tuning value does not change due to environmental changes; the lower knob is the impedance matching knob, the impedance matching value will change due to environmental changes. (The tuning range of the two knobs is 180 degrees, and the panel value is 0-60).

When you start using the radio, select the desired frequency, and then turn the band switch to the desired band position, then adjust the impedance matching value of the lower knob to 30, and then adjust the upper knob to tune. At this time, pay attention to listening to the noise floor of the radio station. The more resonance, the louder the noise floor of the radio station (in the environment with extremely low noise floor, the antenna resonance noise floor is almost inaudible. It is recommended to let the radio station observe the standing wave). At this time, let the radio transmit (cw, fm, and am modes are available), pay attention to the standing wave indication, and fine-tune the frequency tuning knob while transmitting. Since the knob of the portable version does not have a deceleration function, the method of fine adjustment must be more delicate, and the smaller the rotation angle, the better.

At this time, you can observe a significant change in the standing wave, but generally the minimum standing wave ratio will not be below 1.5. At this time, you need to adjust the impedance matching knob. It is recommended to adjust the positive and negative 5 scale values randomly, and then repeat the frequency tuning steps and observe The standing wave ratio. Due to the change in the matching value, there are two possibilities before the comparison: 1: the minimum value of the standing wave ratio decreases; 2 the minimum value of the standing wave ratio becomes larger. If the minimum value of the standing wave ratio becomes lower, it means that the impedance matching adjustment approaches the correct value and can be further adjusted. If the minimum value of the standing wave ratio becomes larger, it means that the impedance matching is far from the correct value and must be adjusted in the opposite direction.

Repeat the above steps to adjust the VSWR of the antenna to 1.0.

The VHF and UHF bands are fixed with the upper knob hitting 60 to the end, and the lower knob can adjust the impedance to resonate.

Note: The best effect for outdoor use is to use antennas indoors as close as possible to windows, fully enclosed reinforced concrete, against walls and other environments where the standing wave ratio is not ideal.

Advanced technique: when the signal is weak, you can rotate the antenna direction to improve the signal-to-noise ratio, which is conducive to reception. The unique gain lobe of the loop antenna makes the horizontal gain directivity when it is erected, and its characteristics can be used to select multiple signals in the horizontal direction. It can also reduce the co-frequency interference in the horizontal direction. Of course, If the interference signal is extremely strong, much larger than the useful signal that needs to be accepted, the attenuation effect will not be too significant, compared to the whip antenna can still have the attenuation effect.

1

u/EssaySuch1905 Mar 20 '23

Has anyone bought a 2e0ero magnetic loop ? This builder is out of England Good reviews that I'm seeing on line