Originally Posted by whitis
What, exactly, is the basis for these comparisons?
I wouldn't expect a single bowtie to outperform a silver sensor.
Even a commercial double bowtie with indoor stand and with undersized reflector (chinese, Channel master CM-4149, Radio Shack 15-623) , while it had higher raw gain, had lower net gain than the silver sensor below channel 32 (often much lower). The DB2 2-bay does outperform the silver sensor by as much as 3dB net gain from 14-51. The silver sensor has a pretty flat 6-7dB net gain over 14-51 and maybe not much less even in low/high VHF (plot is low resolution in that area). Over the same range, a single 7-1/2" 70 degree bowtie with solid triangular plate elements and with no reflector has only about 2-3dBd or 4-5dBi (Antenna Engineering Handbook). The silver sensor outperforms the sharpshooter (SS-3000) on net gain for all channels from 14-51.
The silver sensor is one of the best commercial indoor antennas with the DB-2 2bay outdoor being a good candidate for indoor use if you improvise a stand.
The terk HDTVi is a similar design (clone) to the silver sensor except that instead of swept back wings it they curve forward and it adds rabbit ears for VHF. The HDTVa is the same but with an amplifier built in. Probably not a very good one as they don't cite noise figures. No one seems to have modeled these and no gain/frequency or gain/direction plots seem to be available.
Now some like the radioshack 15-234 simple bowtie. one person
gave the impression it might have performed about as well or better as a 4-bay CM-4221. If that is the case, though, his signal might not be coming from the direction he thinks or his signal is too strong. It shouldn't be anywhere close.
Silver sensor is apparently reported to do better than the terk.http://www.htpcnews.com/forums/index...howtopic=19610
but the author might have been confused about which antennas were compared.http://www.hdtvexpert.com/pages/antin.htm
(silver sensor does very well on carrier to noise especially with a good amp)
and a test report on the radio shack simple bowtie (not much good for comparison):http://www.hdtvexpert.com/pages/8vsb.htm
I would put the silver sensor right under the DB-2 and the terk below it.
The silver sensor does have one critical flaw. When it is knocked over, the plastic piece that holds the F-connector can separate from the boom and the internal coax connection can break. Thus, I suggest that it be modified with three plastic wireties. hold one flat under the boom and wrap another around the boom forward of the rearmost element pair and tighten. Connect the second wire tie (the one that went inside the loop of the first around the stand. Then use the third to secure the coax cable to the stand.http://www.hdtvprimer.com/ANTENNAS/comparing.html
Stumbed across spectrum analyzer comparison of outdoor antennas Scala 1469, CM-4228, CM-4248, CM-5646, CM3671, Winegard HD7210 and SS1000, and antennas direct 91XG on a 20' mast in houston area.http://www.avsforum.com/avs-vb/showt...72#post6245872
Worth looking at the spectrum to compare analog and digital stations. Analog stations were a lot higher but digital stations broader, as you would expect. Be interesting to see what the integrals under those curves (on a linear scale) would be. Digital signals were stronger than the color subcarrier. It was amazing how close adjacent digital/analog or digital/digital stations were.