Richard Topham Jr Posted April 17, 2013 Report Share Posted April 17, 2013 Click Below for a 90 Second Video Introduction to the Diversity Fin "When I got my Diversity Fin a little over a year ago I was skeptical- how good can a passive dual element antenna be on location? I first tested it out on a television show for the SyFy channel. On an extreme wide shot covering a walk and talk from a distance of about a city block I was amazed that I did not get a single dropout on my wireless mics. The unit has great range and coverage- and since it's compact in size, I also mount it on my bag and use it for ENG shoots. The ability to have one antenna position that does the job of two is a great addition to my equipment package. The Diversity Fin is now my primary antenna setup for wireless mics on location!" -Jason Friedman-Mendez Location Sound Mixer Click Here to Visit the Pro Sound Diversity Fin Page Call 212-586-1033 or E-mail Sales@pro-sound.com to setup a demo today! Quote Link to comment Share on other sites More sharing options...
Jack Norflus Posted April 17, 2013 Report Share Posted April 17, 2013 I have been thinking about getting one of these for a while. Anyone else using one? Quote Link to comment Share on other sites More sharing options...
Johnathan Sessoms Posted April 17, 2013 Report Share Posted April 17, 2013 Very cool! Thanks for posting! Quote Link to comment Share on other sites More sharing options...
ShubiSnax Posted April 17, 2013 Report Share Posted April 17, 2013 I used a couple of those a few months ago and they worked great. I was having a little trouble with standard fins/wings(tv towers across the street). I switched to these diversity antennas and it was night and day. Quote Link to comment Share on other sites More sharing options...
Jeff Wexler Posted April 17, 2013 Report Share Posted April 17, 2013 The test that I would be interested in is a comparison between 2 log-periodic (shark-fin type) antenna setup (most common) vs. this single/dual antenna from RF Venue. I have no problem whatsoever with my current use of a shark-fins on an antenna bar up in the air, but the idea of a single antenna doing the work of two could simplify things somewhat. Quote Link to comment Share on other sites More sharing options...
Jack Norflus Posted April 17, 2013 Report Share Posted April 17, 2013 The test that I would be interested in is a comparison between 2 log-periodic (shark-fin type) antenna setup (most common) vs. this single/dual antenna from RF Venue. +1 Quote Link to comment Share on other sites More sharing options...
nwstudios Posted April 17, 2013 Report Share Posted April 17, 2013 The test that I would be interested in is a comparison between 2 log-periodic (shark-fin type) antenna setup (most common) vs. this single/dual antenna from RF Venue. I have no problem whatsoever with my current use of a shark-fins on an antenna bar up in the air, but the idea of a single antenna doing the work of two could simplify things somewhat. The coil loaded rubber duck antennas for the horizontal polarity are going to have substantial less gain than would a second LP in horizontal. Try single LP at a 45 degree polarity... 90 degree polarity loss -20dB or greater 45 degree polarity loss -3dB Circular to linear polarity loss -3dB Quote Link to comment Share on other sites More sharing options...
Derek H Posted April 17, 2013 Report Share Posted April 17, 2013 The principal of this antenna seems to go against the idea of a diversity system that ideally looks at two identical antennas. For example, since the LPDA section of the antenna has some directional gain inherent to it's design and the other, more dipole-like, element probably doesn't wouldn't the diversity system of your receiver always defer to the LDPA half? Quote Link to comment Share on other sites More sharing options...
nwstudios Posted April 17, 2013 Report Share Posted April 17, 2013 This is a good read on diversity. http://en.wikipedia.org/wiki/Antenna_diversity Also a Derek H BTW... Quote Link to comment Share on other sites More sharing options...
Jeff Wexler Posted April 17, 2013 Report Share Posted April 17, 2013 The performance of this antenna may be quite different depending on the diversity system your wireless system uses. For antenna diversity (which Lectro uses) the use of two different types of antennas may or may not be a problem (Larry?). For all the other wireless sets that use receiver diversity (Zaxcom, Audio, Ltd., etc.) I am just as clueless whether this sort of combined antenna would work properly. That is why I would like to do a real world test, with an antenna diversity system AND a receiver diversity system. Quote Link to comment Share on other sites More sharing options...
bigmaho Posted April 17, 2013 Report Share Posted April 17, 2013 Diversity systems compare the rf inputs from 2 antennas. It doesn't matter if they are identical or not. Usually you would want the 2 antennas to be a half wavelength apart to minimize the possibility of both hitting nulls simultaneously. I'm thinking this antenna would be more of a convenience than anything else, though in some circumstances having an omni dipole as the 2nd antenna could grab a signal (perhaps bounced off a wall) that the high gain directional lpa could miss. I'm curious why this antenna needs a jacket. In high wind or wet weather it could add a lot of weight. I've been using Zaxcom and Lectro antennas lpa's with cutouts to lessen wind resistance. Quote Link to comment Share on other sites More sharing options...
greg sextro Posted April 17, 2013 Report Share Posted April 17, 2013 gotta say I've seen many reviews and talk about this product on this site. in the pursuit of being helpful, here's a link: http://www.trewaudio.com/audioflow/dipole-vs-sharkfin-vs-polarized-diversity-diversity-fin/ Quote Link to comment Share on other sites More sharing options...
Michael Miramontes Posted April 17, 2013 Report Share Posted April 17, 2013 I'm also curious to see how this antenna compares to the dual blue fins I'm using. Anyone thinking of doing a test? Quote Link to comment Share on other sites More sharing options...
cjh Posted April 17, 2013 Report Share Posted April 17, 2013 thinking of getting one of these for bag rigs, still pretty big but very portable. also, any user experience out there with the "RF Venue Spotlight" antenna, again a reasonably large unit (19" round) but it looks like it could be a great way to get around interference onset or in studio applications etc, could be hidden on set or on wall out of shot. C. Quote Link to comment Share on other sites More sharing options...
LarryF Posted April 17, 2013 Report Share Posted April 17, 2013 The performance of this antenna may be quite different depending on the diversity system your wireless system uses. For antenna diversity (which Lectro uses) the use of two different types of antennas may or may not be a problem (Larry?). For all the other wireless sets that use receiver diversity (Zaxcom, Audio, Ltd., etc.) I am just as clueless whether this sort of combined antenna would work properly. That is why I would like to do a real world test, with an antenna diversity system AND a receiver diversity system. Hi Jeff, We tried this antenna both ways, i.e., antenna and receiver diversity and didn't notice any performance improvements over two good discrete antennas. (The SR and Venue receivers can be run in either antenna or receiver diversity so it makes comparisons easy.) I would say the benefit of this antenna is in being similar in boom and space requirements to a single antenna. Outdoors, I'd prefer the dipole section to be vertical because there are fewer reflections to rotate the signal from vertical to horizontal but that is minor and they wouldn't have a null of the LPDA to place the dipole in anyway. IMHO you'd buy this antenna for its compactness. Best Regards, Larry Fisher Lectrosonics Quote Link to comment Share on other sites More sharing options...
Jeff Wexler Posted April 17, 2013 Report Share Posted April 17, 2013 Thank you, Larry. I knew you would be able to move me from totally clueless to a somewhat more informed position. If this antenna performs adequately compared to the use of two discrete antennas, I agree that the reason to have it would be the simplicity and size of a one piece antenna. Quote Link to comment Share on other sites More sharing options...
Jack Norflus Posted April 17, 2013 Report Share Posted April 17, 2013 We tried this antenna both ways, i.e., antenna and receiver diversity and didn't notice any performance improvements over two good discrete antennas. So no performance improvements - but was there any decrease in performance? Quote Link to comment Share on other sites More sharing options...
Derek H Posted April 17, 2013 Report Share Posted April 17, 2013 This is worth reading. http://www.rfvenue.com/rfvenue_blog/rfvenue_blog.html I'm guessing that the author, Mike Benonis, is the designer of the antenna. Describes the theory behind the antenna. Claims to take a "polarization diversity" approach, with the idea that it is highly unlikely to have a null in both polarization modes at the same time. Seems to make sense for indoor spaces. I suspect two LDPAs with higher gain would still be the better choice for outdoor use. If you wanted to flip the polarization of the dipole element on this antenna couldn't you just bend each whip 90 degrees so that they are vertical with one up and one down? They look to be the jointed type of BNC whip. I agree this looks like a good solution for compact set-ups. Quote Link to comment Share on other sites More sharing options...
studiomprd Posted April 17, 2013 Report Share Posted April 17, 2013 We had several of these in play on the stage at center field at the recent ProBowl for pre-game and halftime; they were mounted to the back of the stage (behind the performers) and seemed to work well feeding the RX's which were located hidden behind the stage with amplifiers and other gear Quote Link to comment Share on other sites More sharing options...
Glen Trew Posted April 17, 2013 Report Share Posted April 17, 2013 Here is comparison I made soon after the polarized dipole entered the market: http://www.trewaudio.com/audioflow/dipole-vs-sharkfin-vs-polarized-diversity-diversity-fin/ Glen Trew, CAS Quote Link to comment Share on other sites More sharing options...
LarryF Posted April 17, 2013 Report Share Posted April 17, 2013 [snip] Claims to take a "polarization diversity" approach, with the idea that it is highly unlikely to have a null in both polarization modes at the same time. Seems to make sense for indoor spaces. I suspect two LDPAs with higher gain would still be the better choice for outdoor use. If you wanted to flip the polarization of the dipole element on this antenna couldn't you just bend each whip 90 degrees so that they are vertical with one up and one down? They look to be the jointed type of BNC whip. [snip] It is also unlikely that you will get two vertical nulls at the same instant but it happens. And at about the same rate as two polarization nulls as far as I could tell in informal walks at Lectro. The reason for having the dipole perpendicular to the LPDA is that the LPDA has a perfect null along that perpindicular line for horizontal signals. The dipole has a null along that line for vertical signals. That is to say, the LPDA is in the dipole's null and the dipole is in the LPDA's null. Bending the arms of the true dipole puts that dipole in the LPDA's field and vice versa. Or think of the LPDA as a series of vertical dipoles. You can't make the other dipole even somewhat vertical without interaction between the two sets of "vertical" dipoles. Best, Larry F Lectro Quote Link to comment Share on other sites More sharing options...
Soundwil Posted April 17, 2013 Report Share Posted April 17, 2013 Having read your posts Larry I am asking myself the question: When using 2 LPDAs - one for each of the diversity system - is there an advantage to orientating one by 90° so that there are no null points? Quote Link to comment Share on other sites More sharing options...
LarryF Posted April 18, 2013 Report Share Posted April 18, 2013 If the transmitter antenna is vertical, the two LPDA's should be vertical for best overall results. Best Regards, Larry F Lectro Quote Link to comment Share on other sites More sharing options...
cjh Posted April 18, 2013 Report Share Posted April 18, 2013 While we're on the topic, is there any way to make a miniature LPDA type antenna by scaling everything down..? I know this would reduce it's effectiveness and is probably an uneducated crazy idea but just putting it out there. There is definitely an antenna market for bag rigs that require more than whips and aren't as fragile as the Lectro Dipoles (which are great antennas but I'd prefer something with more directionality). C. Quote Link to comment Share on other sites More sharing options...
LarryF Posted April 18, 2013 Report Share Posted April 18, 2013 While we're on the topic, is there any way to make a miniature LPDA type antenna by scaling everything down..? I know this would reduce it's effectiveness and is probably an uneducated crazy idea but just putting it out there. There is definitely an antenna market for bag rigs that require more than whips and aren't as fragile as the Lectro Dipoles (which are great antennas but I'd prefer something with more directionality). C. #1 With antennas it is Gain, Size, Bandwidth. Mother Nature will let you optimize any two if you compromise the third. Since an LPDA is somewhat similar to a series of half wavelength dipoles, making it smaller means smaller wavelengths and therefore a higher frequency of operation, i.e., not the frequencies where you want it to operate. #2 Fragile? Not something I've heard before. What to we need to make stronger? Best Regards, Larry Fisher Lectrosonics Quote Link to comment Share on other sites More sharing options...
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