• HD Blade HDBLADE100 Antenna Comparison Tests



    SolidSignal sent me both the signal finder SL 1000 from King Controls
    King Controls SureLock SL1000 Digital TV Signal Finder (SL-1000) from Solid Signal
    and the HDBLADE100 antenna
    Solid Signal HD-BLADE Indoor Digital Flat Indoor TV Antenna (HDBLADE) from Solid Signal
    to test and see how they worked and to see if I could use them for any future attempts at testing various antennas, either purchased or built.

    In this blog I'll look at the HD Blade antenna. For those who don't know anything about this antenna, it is a flat, floppy antenna embedded in a floppy two-color mat that is made for mounting to a wall or simply laying flat on a table or other flat surface. You can read about it and see some photos by searching for "blade" on the SolidSignal site.

    When I first looked at this antenna and read some of the comments about it, I thought that it might be some kind of design that exhibited some minor gain over a standard wide-element bowtie dipole antenna (BT, BTA) that has long been in use for UHF TV. If we look at the design, which can be seen in the photos taken of the light-colored side of the antenna mat, we see: (1) A standard wide-element BT and (2) a pair of loop antennas that are vertically stacked (which one might assume should lead to some kind of gain) and (3) there are four "tails," for lack of any better description, which come off of the loop sections, two per loop.

    I asked for, and received, the gain plots for this antenna. The plots and gain figures seem to be consistent with those of a single element dipole antenna whose center design frequency is around 651 MHz, UHF Channel #44 (UHFC#44). The maximum gain was ~ 2.2 dBi (a dipole has a free space theoretical gain of 2.15 dBi) and then the gain decreased. All other frequencies showed lower gain than the gain at 651 MHz.

    The gain figures fluctuated with different frequencies, also as expected. How this would actually compare to a single element BT, I don't know, but I wouldn't be surprised to find that they are pretty much the same, with differences only in which frequencies exhibit the various peaks and valleys on the gain figures. The plots also showed the gain of the antenna in the VHF TV section and these were, across the board, very poor indeed, Again, this is expected of any UHF antenna being used in the VHF range, so no surprises there.

    From the online description comes this simple statement: "Latest technology allows silver elements to be printed onto a thin plastic sheet, giving you the strength of a bow-tie antenna squished in a flat, easy-to-mount package" So, by their own advertising, you are buying a fancy looking BT and paying about two to three times what one would pay for the single element BT, if they were still available. As far as being "squashed flat," the mat it actually thicker than a standard BT made out of 16 gauge wire would be, so I'm not sure what they're trying to say. Yes, the silver elements are much flatter than the wire used in a standard UHF BT antenna, but that is neither an advantage nor a disadvantage because the wide elements in the BT design are used to increase the bandwidth of the antenna far more than the diameter of the wire, or the flat, but wider-printed, element.

    Yes, it is cute, and it looks much nicer than the wire BT elements, but if we're talking about hiding the antenna behind a TV or picture, then I'll simply say that (1) the BT antenna will fit behind anything the Blade will fit behind, but conversely the Blade will not fit behind everything the BT might fit behind. (2) Neither antenna should be placed behind any electronic piece of equipment such as a TV, since TVs are RF emitters and digital TVs are probably worse and will probably interfere with the antenna's ability to receive the TV stations of interest, especially in the direction of the TV screen. Here you're asking the TV signal to go through the TV - which has wires and circuits in it - to get to the antenna - not a good idea.

    So, on the surface and by their own advertising, the Blade is simply a BT antenna. Is it any better given that it is a BT with a little something extra added?

    I did some quick and simple tests of the HD-BLADE TV Antenna (HDBLADE006) and my homebrew BT. I ran three very basic tests: 1. Each antenna was connected to the SL 1000 Signal Finder 2. Each antenna was connected to my Alinco Wide Band Receiver (WBR) to check a few stations. 3. Both antennas were connected to a portable DTV and a few channels were checked. The results of this comparison of the two antennas using the three signal receivers was:

    1. The SL 1000 Signal Finder results were identical. No channel information is available from the SL1000.

    2. The results from the Alinco WBR on all stations checked were as close to the same, for both antennas, as I was able to tell.

    3. The TV test between the two antennas was pretty much the same. I think the BLADE was a bit more difficult to test than the BT since it was more difficult to attach to the mast and put up, but I suspect that if I had been able to do that, then the results would have been identical as well.

    I did conclude that the Blade was too floppy to use for comparison testing of other antennas which would be mounted onto a mast. Also, since it was similar to the BT - and all tests I ran confirmed this - I figured that the bowtie would work better as the "standard" antenna against which to test and compare all other antennas.

    The bottom line is this: My homebrew BTA will be used as the reference antenna for all further tests. Since it costs almost nothing but a little time to make, it's also lighter on the wallet. If you want to make one of your own, you can use my diagram/photo to make one out of a couple of old clothes hangers, a few screws, a small plastic or wood rectangle to hold the two bowtie elements in a dipole configuration, and some twinlead or coax as the feed line attached to each half of the antenna. I also mounted mine on an old broom handle so it is much easier to use in testing situations when the antenna needs to be rotated. It gives good, broad directional results.

    As for the Blade antenna, I have to admit that I was looking for a bit of gain over a standard UHF bowtie and I did not find that either in my brief experiments or in the literature. Still, if you live in an area where a bowtie antenna would work the Blade will do just as well and it sure looks nicer.

    Until next time, happy viewing!
    Phil K

    All my blog articles are listed at: Karras' Corner
    or
    Karras' Corner Article Links on my KE3FL web site.


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    Comments 22 Comments
    1. VOS's Avatar
      VOS -
      Since this is a receiving antenna, doesn't the 300Ω balun actually cause each of the four elements of the bowtie to be 75Ω?
      Without the balun it would seem that they would be 18.75Ω, if the TV [load] is 75Ω

      If this is the case, it might explain why large antennas tend to be 300Ω, as they are combining several elements.
    1. VOS's Avatar
      VOS -
      I've been thinking this over and I guess the question is if the signals are in phase, do these two circuits have the same impedance?

      Attachment 690

      Four loads in parallel clearly drops the impedance, but with one load and four inputs in phase, are any of the inputs affected by the others?