: BC - Victoria, The Island, Sunshine Coast, BC Interior, BC North - OTA
2011-10-19, 08:48 PM
yes sweeping the whiskers forward means pulling them 2" towards front of antenna. Mine are slightly curved though not sure if that makes any difference.
The 91XG is a very good antenna just all that juicy gain wasted above UHF51, it is begging to be redesigned for UHF14-51.
My new work in progress mod is making the X shaped elements longer to try and shift the gain curve 20-25 channels to the left. I also purchased a bunch of 1" OD aluminum tubing to make a 91XG with rod elements, based on the modelling done by 300ohm, instead of the X shaped elements. I am going to compare both modified setups with the stock 91XG elements and versus my other anttenas.
ideally I would like to end up with 2 high gain UHF anttenas that peak at different parts of the UHF spectrum, one around RF25 and the 2nd somewhere around RF48
Of all the antenna configurations that I have played around with, my favorite is the M4, for its relatively small size it definitely packs a wallop.
2011-10-19, 09:13 PM
Yeah, I agree... That 91XG has its best gain wasted in upper UHF. But I read that AD will not redesign it since I guess they dont get that many customers (not their bread-and-butter antenna) to make it their while to redesign.
Though I've read that what you can do is put a larger mesh reflector and that should give you 1-2 dB gain on low UHF...
As for M4, if I dont buy that kit, is it easy to make? Seems similar to coat hanger antenna I made from YouTube a few years back... Only difference is the whisker length and phase spacing... could I build M4 using coat hangers instead of 10 guage wire?
PS, can you get Seattle channels now with your current 91XG setup?
2011-10-19, 10:17 PM
I can get 4 Seattle channels daily through all kinds of weather with the 91XG,M4 or HD-8800 though a couple of channels (31 and 39) sometimes pixalate and dropoff for a few hours each day. A 5th channel RF25 is just under the cliff during cloudy or rainy weather (oddly the strongest channel according to TV Fools). RF38 KOMO is almost always SNR29-30 100% even during pouring rain and heavy snow with the M4 and 91XG, slightly less (SNR28) with the HD-8800. RF48 KING is typically SNR22-25 all day and night with the 91XG or M4 (perhaps 1db more with the 91XG). The HD-8800 is weakest on RF48, a good 3db lower than than the 91XG.
Just to add, finding the best sweet spot on your property can make a huge diference for deep fringe reception, at this location the east side is 6-7db hotter than the westerly side.
At this address, it is all about putting the antenna with the most forward gain in the best location on the property and then minimizing losses downstream (short cable runs and good sensitive tuner). I do not use a UHF preamp as it makes things worse from the strong Mt Seymour channels causing overload, though since the analogs were shut down and the 3 story house was built behind, the level of overload has dropped significantly.
If you have severe multipath or adjacent / co-channel channel interference, then stacking a 2nd antenna or picking a narrow beam width antenna like the 91XG, could be as or more important.
2011-10-19, 10:24 PM
Wow, that's great SNR for Seattle channels 100+ miles away from you. Amazing.
Since they are in the high UHF range, the 91XG is appropriate for you, but not for me.
I gotta get the courage to make this M4. (heh).
How do you find the sweet spot? Walk around with a portal DTV using its signal meter?
I just used Tvfool and plotted around my yard and coincidentally it found my current/original spot to be the best signal... go figure?! (heh).
Oh, and I think the 4-bay or 8-bay antennas are best for wooded / treed areas, which I have, lots of tree in my path.
2011-10-19, 10:47 PM
Yep I took a small Tv outside with extension cord and hooked it up to the antenna on a 16' pole and then walked all over my property. Spent a few hours going back and forth but it was worth it. I used the DB4 (before it was turned into an M4) as it was very small and light and easy to drag around.
2011-10-19, 10:56 PM
Nice, I can imagine your neighbours giving you "strange" looks! (heh)...
16' pole? Wow... that's gotta be heavy with your DB4 ontop... I can barely hold up a 10' pool with antenna on top.
2011-10-19, 11:54 PM
OTA Victoria - Tillicm/Gorge Area
12-1 * * * * *KVOS-DT * * * * * *MeTV * * * * * * * * * *Old TV Shows
12-2 * * * *KVOS-DT * * * * * *THECOOLTV * *Music Channel
21-1 * * * * *CHNUDT1 * * * * * * Channel 7 - JoyTV 10
23-1 * * * CIVI * * * * * * * * * * * * CTV two
24-1 * * * *KBCB * * * * * * * * * * ShopNBC.com
24-2 * * KBCB-2 * * * * * * * Spanish channel
24-3 * * KBCB-SD. * * * * * ShopNBC.com
27-1. * * * CKVU-DT * * * * * * CItyTV
29-1. * * * CHNM-DT. * * * * *OMNI NEWS
Do you think I could get any others?
2011-10-20, 12:32 AM
MoreDB - do you know if bending the elements forward a bit on a CM 4228HD works as well? I started trying to read the mods thread a few months back and a) found it too technical and b) got overwhelmed with info.
Gillani - have you looked at plugging your address in at TVFOOL.COM? That will give you a pretty good idea. Also rotating your antenna (towards the entrance of Puget Sound) and rescanning might yield you some of the US channels.
Like me (Maplewood / Tattersall area) - most of our channels are deep fringe so an indoor antenna isn't likely to cut it. You'll likely need a higher end outdoor antenna (~100 bucks) to pick up additional Seatac and / or Mount Seymour channels.
2011-10-20, 12:37 AM
Thanks..guess I will dive more into OTA. I though I caught more channels prior to the digital move. It would be nice if I could pick up CBC and Global.
2011-10-20, 12:42 AM
Mount Doug might be blocking your LOS to Mount Seymour (thus preventing you from picking up the Mount Seymour channels.
Look in the Forum's FAQ - there's a link for Stampeder's recommendations for antennas. I went with the CM 4228HD, CM 7777 pre-amp, and rotator. I get a pretty good selection of channels (although I'm at relatively high elevation).
2011-10-20, 12:46 AM
This site says that *new* CM 4228HD is "disaster."
2011-10-20, 12:56 AM
All I can tell you is I have an unmodified CM 4228HD with a CM 7777 preamp and I get more channels consistently than most of the people on this forum who have identified themselves within a 10km radius from me (albeit they are all at lower / slightly lower elevations).
I get Mount Seymour, Bellingham, and Seatac with a CM 4228HD. Although it wasn't originally on Stampeder's list of recommended antennas - it's there now. It can't be that bad. Sure there are likely better performing ones - but apparently I won't benefit from the improvements.
2011-10-20, 12:57 AM
Like with buying a computer - you can always research more til the cows come home and find another system that has something slightly better. The key question is, "Does it suite your needs?" A CM 4228HD seems to work just fine for me.
2011-10-20, 01:07 AM
Yeah, I've got some tall trees in front of me and I heard bay-type (vertical) antennas are better than horizontal (Yagi) types...
So, I'm leaning towards HD-8800, then U-8000, then DB8, and CM 4228.
Holls_ands says that HD-8800 is the best of the bunch:
W-G HD-8800: Ch14=13.7 dBi, Max=15.5 dBi, per Ken Nist's HDTVPrimer.
Super-G-1483: Ch14=12.5 dBi, Max=16.0 dBi, per 300ohm 4nec2.
Old CM4221: Ch14=12.3 dBi, Max=14.5 dBi, per holl_ands 4nec2.
A-D 91XG: Ch14=11.5 dBi, Max=17.0 dBi, per holl_ands mod to Ken Nist's EZNEC.
CM4221HD: Ch14=11.2 dBi, Max=15.0 dBi, per holl_ands 4nec2.
CM4228HD: Ch14=10.5 dBi, Max=14.9 dBi, per holl_ands 4nec2.
2011-10-20, 04:48 AM
be236 I believe the gain figures that holls_and posted were the RAW gain numbers. The HD-8800 net gain is not the greatest above about RF35 (it starts to rapidly fall off), Going from memory of what I read on HDTV Primer website, it is because of mis-matched impedence and a poorly designed co-phase line. Others on this forum would know more about such things. The CM4228-HD is a good antenna, the Antenna Hack website tested it versus the old CM4228 and found it to be actually better on many channels, plus there is a whole thread devoted to hacking it for beter performance.
Pro Gunner the swep the whiskers forward trick should work on the CM4228-HD, you also need to put a curve on the reflector screen though to match the curve of the whiskers. I am not sure how that would wotk on horizontally stacked 4 bays or commercially built 8 bay antennas. I suppose you could curve both reflector screens equally.
2011-10-20, 10:59 AM
Ah, ok, RAW gain... that sounds reasonable. If correct, then drop off in gain after channel 35 would mean that I'd lose RF 43 CBUT. Hmm... Do I wanna lose that channel? I gotta think about it.
Well, maybe I should just buy that M4 kit or make my own. How much money in parts do you think it'd take to make. Is there a website that gives explicit instructions on how to make this? (other than the website that shows you the dimensions).
2011-10-20, 09:46 PM
How about this (http://m4antenna.eastmasonvilleweather.com/instructions/4%20Bay%20Kit%20Assembly%20Instructions.html) page for the kit or this (http://m4antenna.eastmasonvilleweather.com/Drawings/PDF%20Drawings.html) page for rolling your own?
2011-10-20, 10:52 PM
Here's my tvfool report:
I built my second gh10n3 Gray-Hoverman antenna following this plan:
I live in a condo on the top floor of a 4-storey building and have no way of installing an antenna on the roof. So, my GH antenna is made of 1.5 x 1.5 inch kiln dried pine, 1/4" T6 aluminum rod for reflectors and 1/4" copper rod for the active element. I am also using a Kitz Technologies KT-100VG pre-amplifier at the 8' mark of a 20' piece of RG-6U cable.
My location is a bit of a challenge since my condo faces SW; to get the Vancouver/Bellingham stations, I have to orient my antenna to the NE, which means the signal is blocked by my condo and a condo on the other side of the hallway. Nevertheless, my reception results today with the antenna pointed to the NE are nothing to complain about:
If I point my antenna to the west (through the window), I can get 2-1 CBU-DT but I lose 10-1 and 42-1 which is no loss, really, as I get them on other channels.
I must say that today seems to be an exceptional day for reception.
I hope this encourages others to build a Gray-Hoverman for use indoors.
2011-10-21, 11:26 AM
Have you tried picking up the Seattle stations with that GH?
How complicated is building this GH vs building M4, since M4 looks less complicated...
Also, how precise do you have to be, meaning if you're off by a few millimetres, will that adversely affect gain? (I assume yes).
2011-10-21, 03:51 PM
When you turned your antenna to the west, can you still get 27-1 and 29-1? They are transmitting the same signal(i.e.re-transmitter) as 10-1 and 42-1 in Victoria area.
On the other hand, 17-1 is the re-transmitter of 23-1 in Vancouver area.
Sorry, I missed that you've mention you can get them on the other channel. My Fault :P