View Full Version : "Miracle" Antenna
I'm considering buying one of these antennas. A big plus (for me, not others necessarily ;)) is the SMALL diameter RG-174 feed which I plan to run through a closed window. It'll BARELY fit:
I purchased the MMDs31 today. I'll update my experience with this antenna after I receive it. Actually, I prefer to use RG-174 since I'm running the feed-line through a closed window and would like to avoid using thin RG-6 adapters. Both the MMDs31 and LF Engineering's H-900 use RG-174 for a feed-line. If both of these antennas fail to meet my expectations, I'll just bite the financial bullet and pay the $450 for a magnetic loop. Personally, I think the MMDs31 will probably function acceptably. We'll see.
that does miracle : Mini-Whip PA0RDT..... and much much more cheaper !
Easy to assemble.
Check this site : http://websdr.ewi.utwente.nl:8901/
Enter 216 kHz/ LW / AM (Monte Carlo). Listen to the level of reception : 1200 km with a 900 kW transmitter, beamed N/W. Amazing reception.
If you just want to listen to shortwave broadcasts without a lot of hassle dealing with radials or baluns, you might want to try this antenna. My main concern lies in the weight of the discriminator and concomitant strain placed on the line. Although very preliminary, initial tests during daylight hours show noticeable improvement over an equivalent length of UNSHIELDED wire. Also, the level of noise from the MMDS-31 is noticeably lower as well versus an UNSHIELDED long wire without radials. Naturally, this performance increase is expected. I haven't been able to test DRM broadcasts, yet, since the Disco Palace transmission has been absent for the past week. I should, however, be able to test the rebroadcast of REE from Cariari tonight, though, when ambient noise levels are lower. Although, I'm using this antenna in a fixed position outdoors, I also tested it very briefly indoors before installing it outdoors. Amazingly, in a building with metal siding, the MMDS-31 even picked up some shortwave broadcasts indoors which were listenable. This antenna would be nearly ideal for tenants living at least 50' off the ground in multiple story apartment complexes since one could just drape the antenna vertically from a balcony. So far, I'd recommend this antenna if a prospective owner has sufficient space whether installed outdoors or indoors in an attic. YMMV
Unaided, the 31' length of the MMDS-31 limits frequencies to above 6.6 MHz in the broadcast bands.
Here's a link to purchase Miracle's MMD antennas:
I wouldn't place this link here if I thought this antenna wasn't worth trying. In my limited experience, if a SWL doesn't want to mess with antennas or waste valuable time, just bite the financial bullet and buy this antenna if one has the space for it. The more I use it, the more impressed I become. To be honest, I wish I had purchased this antenna back in May of 2012 when I had originally planned. A vertical orientation is optimal if possible.
Miracle's MMDS-31 is great detector of disturbances in the ionosphere... Tonight and last Friday evening, such disturbances have been clearly audible as increased noise during reception. During these disturbances, I'm limited to receiving stations within ~ 2500 miles which is certainly better than receiving none before buying the MMDS-31. ;) Lately, polar auroras have been a nuisance ... , i.e. nearly every other day. When these ionospheric disturbances start, I just wait at least 6 hours before attempting to receive any shortwave broadcast beyond 2500 miles.
I agree with Telspace, the PA0RDT is MUCH cheaper. I have modified mine slightly and they work fine from around 40 kHz to about 25 MHz. And the pick-up element is 5 cm long (however, I use a 70 cm whip instead). I feed my three active antennas with 20 m RG-58 (the price per meter of RG-174 puts me off...).
Both yourself and Telspace aren't the first folks to mention the Mini-Whip. If I find some time in the distant future, I may have a closer look. Links of detailed information for constructing the Mini-Whip would help. Personally, I wish someone would build and sell them. If we're EVER going to be successful in promoting DRM, compact and efficient antennas must be for SALE as many people will NOT and do NOT have the time, skill, or desire to build antennas. All of the comments on the Mini-Whip have been appreciated by myself. I've been aware of it for sometime. In the interim, Miracle's mixed-mode dipoles work well although they're not compact. I've been enjoying my experience with the MMDs-31. Before installing the MMDS-31, I was receiving a SNR averaging ~ 2 dB with the DR111 from most of the usual DRM broadcasts to the USA since the middle of October. Now, I'm averaging ~ 9 dB which still isn't enough to decode audio. However, propagation lately has been pretty awful and the alignment of the MMDS-31 isn't optimal at all, i.e. the proper orientation since I can't hang it vertically or change my current horizontal alignment. I'm limited by circumstances beyond my control. Furthermore, the persistently freezing weather hasn't helped. Ice and humidity are adversely impacting the strength of any received signals. If we ever start warming to ~ 50 degrees F with a concomitant drop in humidity, results will improve radically with the MMDS-31.
At this moment, i.e. 0010Z, I'm receiving the Cariari rebroadcast on 9.630 MHz at an AVERAGE SNR of 12 dB with the DR111 and MMDS-31. The ambient air temperature is about 42 F which is as warm as it has been since receiving the MMDS-31. Weather conditions still aren't perfect with overcast skies, but the ionosphere is about normal at the moment. Over the course of the next couple of hours, I'll receive some intermittent audio. Weather conditions won't improve much around here until March. Atmospheric conditions below the ionosphere DO affect HF transmission despite the prevailing dogma that the "solar cycle" exclusively affects HF transmission through direct excitation of the ionosphere.
Universal Radio is dropping Miracle's line for some reason. I haven't inquired yet, but it may be due to non-availability. I was contemplating buying another one.
Thankfully, Universal has new stock of Miracle's antennas. See the aforementioned link to buy from Universal. Whew! ;)
vBulletin v3.5.3, Copyright ©2000-2013, Jelsoft Enterprises Ltd.