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Bill Roche
Intermediate Member
Username: Oxy8384
Post Number: 75
Registered: 12-2003
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 03, 2009 - 02:08 pm: | 
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I put a CM4228 in my attic (2-story house with clear view to the south) on a hilltop in Fallbrook a few years ago with a preamp and have always gotten good signal for all the UHF DTV locals (except Fox when Fox was on Ch6). Now I have lost 8 and 10, of course. I am willing to put a VHF antenna in my attic (I prefer not to put anything on the roof if I can avoid it), if it will give me back my VHF DTV channels.
I have heard VHF travels farther and is even less affected by walls, etc. than UHF, so I am hopeful it will work in my attic, too. Does that sound right?
Also, I think my pre-amp has both VHF and UHF inputs (I'll need to go up and check), which means I already have the needed combiner in the preamp.
I'd rather keep the antenna as small as possible, but large enough for good strong reception. I also only need a VHF antenna, not a VHF/FM/UHF combo. I figure I am far enough away that I could get both channels well with even a narrow-spread directional.
Any advice or recommendations would be greatly appreciated.
Thanks in advance,
Bill |
Chuck Grim
Intermediate Member
Username: Chuckg
Post Number: 60
Registered: 10-2003
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 03, 2009 - 07:44 pm: |
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I suggest that you buy a VHF antenna from one of the places that have a 30 day no questions asked return policy like Fry's or Radio Shack. Then you can take it back if it does not work OK.
Chuck |
James Feinberg
Junior Member
Username: Sandiegoguy
Post Number: 8
Registered: 04-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 03, 2009 - 09:24 pm: |
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Bill,
If your preamp is blocking the VHF frequencies from your 4228, that could be all that is keeping you from getting 8 and 10 right now. Before you get a new antenna, try connecting the antenna to the VHF input on the preamp instead of the UHF input, and see if you can get those two channels. If so, then you can either replace your preamp or put a splitter between your antenna and the preamp (cheaper, but introduces some line loss).
In my case, I found that the 4228 did not work well for channel 8, but others seem to have had better luck in different areas.
I'm much closer to the transmitters than you are, but I was able to get 8 and 10 with just rabbit ears on my roof (to supplement my 4228 for everything else). |
Gary Stigall, XETV
Moderator
Username: Garys
Post Number: 489
Registered: 12-2002
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, May 04, 2009 - 10:53 am: |
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I agree with James. If you find with his experiments that you still don't have adequate upper-VHF reception, you can try a separate 5-element VHF antenna:
http://www.solidsignal.com/prod_display.asp?prod=Y5-7-13&mybuyscid=2765736891
Regarding XETV, you might try putting a layer of aluminum foil, or an oven pan over the back side of your attic 4228. Your problem is not one of inadequate signal, but of reception of co-channel interference from the north and northwest. Let us know if this helps. If it doesn't, you may want to try an antenna with better rear side rejection:
http://www.solidsignal.com/prod_display.asp?prod=TD-43XG
(Message edited by garys on May 04, 2009)
Gary Stigall
Dir. of Engineering
Bay City TV - XETV
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Bill Roche
Intermediate Member
Username: Oxy8384
Post Number: 76
Registered: 12-2003
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, May 04, 2009 - 02:01 pm: |
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Thanks for all the smarter-than-me advice. I won't be able to experiment until next weekend, but i will definitely post back with my results. |
JoeM
Intermediate Member
Username: Joem
Post Number: 63
Registered: 09-2005
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, May 04, 2009 - 04:40 pm: |
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Bill Roche wrote:
... I have heard VHF travels farther and is even less affected by walls, etc. than UHF, so I am hopeful it will work in my attic, too. Does that sound right?
Yes, that's generally true. But note that VHF doesn't benefit as much from using a preamplifier, so try to see if you can get by without amplifying the VHF signals. Also see my tips on using rabbitears in the "Channel Master 4228HD" thread. |
Bill Roche
Intermediate Member
Username: Oxy8384
Post Number: 77
Registered: 12-2003
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, May 09, 2009 - 06:23 pm: |
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Well, I did my experiments, today, and got the following results. I did not get 'control' data before I began, but here is what I found. The following numbers represent signal strength out of 100 for each channel I received. A value of XX means my Dish DVR didn't pick up the channel at all during the scan; a value of NL means the receiver could Not Lock the signal. The first value is without the preamp (which is a UHF-only preamp), 2nd is with the foil & no preamp, and the 3rd is w/foil and preamp.
Channel......no preamp....w/foil....foil+preamp
6-1 XETV........NL..........NL.........NL
8-1 KFMB........74..........84.........NL
10-1 KGTV.......100.........100........NL
10-15 KZSD......100.........100........NL
15-1 KPBS.......72..........74.........80
15-2............XX(?!)......75.........80
28-1 XHJK.......XX..........XX.........NL
39-1 KNSD.......XX(?!)......70.........76
39-2............70..........70.........76
39-3............70..........70.........76
51-1 KUSI.......77..........85.........92
57-1 XHUA.......NL..........NL.........75
69-1 KSWB.......85..........85.........92
So I'm pretty happy - no need for expensive new equipment and the foil seems to have improved things across the board (except KGTV which is coming in at 100%).
So what's the best plan to get the VHF with the UHF? A splitter and combiner to bypass the preamp for the VHF? (Sounds like there may be noise issues...?) Or a new VHF/UHF preamp? (Doesn't sound like the VHF will benefit much from the preamp and might have the same issues as the combiner/splitter combo. I'd rather not have to bother with another antenna up there.
Any combiner/splitter mfr/model recommendations appreciated. There seem to be the $2 ones, but I'm not sure they're any good...?
Gary,
No joy on XETV. Is it possible this is a directional issue? Any other suggestions? I get no signal at all for XETV.
Thanks, all! |
Mike Mantle
Advanced Member
Username: Mm1
Post Number: 368
Registered: 09-2003
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, May 09, 2009 - 08:21 pm: |
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Bill, you didn't mention which direction your antenna is pointed. The fact that you have much better levels on KGTV and KFMB than any of the Miguel stations (KNSD, KUSI, KSWB, KPBS) makes me think it is pointed toward Soledad. Perhaps if you nudged it a bit more south toward TJ, you would pick up XETV.
(Message edited by mm1 on May 09, 2009) |
Bill Roche
Intermediate Member
Username: Oxy8384
Post Number: 78
Registered: 12-2003
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, May 22, 2009 - 06:26 pm: |
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I put in two basic splitters (one as splitter; one as combiner), not the UHF-VHF specific type and it all seems to be working just fine. I did turn the antenna a little more south, but have lost signal strength on a couple of the Miguel stations, so I'm not inclined to turn it any more for fear of messing up the channels I really care about. I can get XETV from Dish for the few times I watch it.
Thanks all, for your help. This was a lot easier than I imagined! |
holl_ands
Advanced Member
Username: Holl_ands
Post Number: 2107
Registered: 06-2004
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, May 23, 2009 - 06:42 am: |
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You're getting closer....but there's lots of room for improvement.
Exactly how did you use both a Splitter and a Combiner????
I'm presuming you took the output of the CM-4228 and split it into
two cables, one of the cables connects to UHF (only) Preamp.
The output of the UHF Preamp is then combined with the other
Splitter output.
A basic splitter is losing 3.5-4.5+ dB on both UHF and VHF.
Combining unamplified VHF with the Preamped UHF signal loses
another 3.5-4.5+ dB on the VHF signal, but much less on UHF
due to being after the Preamp.
Unless you are using a Combiner with DC Pass Thru, the Preamp's
Power Insertion Module would need to be connected between the
Preamp and the Combiner.
================================================
The following UHF/VHF Band Separator/Combiner only loses 0.5 dB:
http://yhst-18278607509093.stores.yahoo.net/pico-0389.html
The Pico Macom specs says that it has DC Pass Thru on the
VHF PORT (ONLY) in order to power a Preamp.
This is opposite from what most people would want (power to UHF Preamp).
[Hmmm, I wonder if the specs got it reversed????]
Hence UHF Antenna+Preamp is connected to it's Power Insertion Module
and THEN combined with the VHF Antenna in the UVSJ Combiner.
Which means plugging Power Insertion Module into an AC outlet in the attic.....
Presumably the same configuration as above, except two UVSJ's
in place of the Splitter and Combiner....
Of course, a separate VHF antenna could be readily added later.
================================================
It would help if you could enter your location into www.tvfool.com
and when it spits out a results page, copy the URL into a post on
this forum. Then we can see how much terrain blockage you have....
(Message edited by holl_ands on May 23, 2009) |
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