Antenna help

[Tristan]

Hello everyone, I'm looking for antenna advice:

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3dcc49d13d87e4e3

Goal is to receive real channels 9,11,13,33,38,39,48.

I'm running a dedicated RG6 cable (separate from cable internet) to a rooftop antenna, just above roofline (flat root) perhaps total of 20-25 feet above ground. 50-75 feet of cable run, no splits (just one TV). Receiver is a Magnavox DVR with digital tuner H2160MW9 if it matters (Have a really old CRT television). It displays a signal strength on a 0-100 scale (gain factor? it doesn't specify), anything above 20 seems to be reliable.

Here is my work so far:

Got a free antenna from my father in law that he wasn't using. Not sure the model, but looks similar to common UHF/VHF directionals such as Channel Master 4242. Mounted it on the roof about 75 feet cable run, and it worked really well, just seemed pretty directional. Could easily get 9,11 also 33 (despite being 60 degrees apart, but seem to have really good LOS to 33). 38,39,48 were spotty, despite being close and same direction (I'm on the backside of a local hill between me and those towers). I could never seem to get them all together, and they were often spotty. I could only get 13 by turning the antenna away from everything else, and thus really could only get it by itself.

Next I tried a Winegard MS-2002 in the same location. Did not work at all for me: almost nothing even with the built in pre-amp (either it is a poor antenna, or I'm overloading due to proximity of some towers, only about 5 miles away, or some other reason). I returned it.

Next I tried Antennas Direct C2-V-CJM in the same location. Worked pretty well, but overall signals were lower. Able to get almost everything except 13 (still too far to west). 9,11,33 would all be fairly reliable, but less so than with the "4242," although now I could get 38,39,48 (but not all at same time and not all 3 quite reliable enough to watch). I tried adjusting direction a little, and even re-located the antenna to a shorter cable run position (although it is about 5 feet lower) and if anything the signals are about the same, maybe a little worse.

So my questions:
1) Is there any single antenna that can pull everything in, or are the stations spread to far?
2) How much can I expect height above ground level to matter?
3) Will the flat roof affect reception? (will the antenna receive better from the side of the house nearest the towers)
4) I chose the C2-V-CJM for the wide reception angle. It's newer, but seemed to be accumulating good reviews on-line. Is there something better? Overall gain seems a little weak.
5) Would it work to use the "4242" or something similar pointed towards 13 (I think it could also pull 9 & 11), combine it with a UHF antenna receiving 33,38,39,48 via VHF/UHF combiner?
6) Would a pre-amp help? I can't seem to find many models that separate VHF/UHF anymore.

Thanks everyone. I admit this has progressed from a casual "hey, let me try that antenna you're otherwise going to throw away" to full-blown obsession. My goals seem achievable, and I don't mind spending money on the right equipment if it will make a difference.

Thanks,
--Tristan

[Tristan]

A few more questions I forgot:
1) will angle of antenna make much difference? (angling up 10-15-20 degrees above ground?)
2) does re-scanning with the receiver make much difference? I did some adjustment by moving the direction of the antenna and having someone watch the broadcast and report the "gain" numbers of reception. I did not do any actual re-scan with the receiver.
3) if pre-amp is necessary and used with two antenna vhf/uhf joiner configuration, where best to put the pre-amp? Just after the joiner?

Thanks

[GroundUrMast]

You have an all to typical 'Seattle' TVFR... At least one hill in the way. :(

This is a tough situation, similar in many respects to what I was facing at the house I just moved from in NW Seattle.

The following is one approach... certainly there are others.

The Capitol Hill, Queen Anne Hill call for a large UHF mounted as high as you can practically and safely achieve. Antennas such as the Antennas Direct 91XG or Winegard HD9095P are appropriate for going after the Queen Anne Hill group (KOMO, KING, KONG, KIRO) (KUNS is still on Tiger Mnt. despite what's shown in the TV Fool database). I would connect an FM trap followed close by an Antennas Direct CPA-19... the signal out of the power insertion block connected to the UHF port on a UVSJ. It's reasonable to hope that a usable compromise aim could be found that would give you the KZJO signal with this antennas also.

Antennas such as the Antennacraft Y10713 or Winegard YA1713 would be the type I'd choose for receiving the real CH-13 signal from Gold Mnt. On this antenna, I'd install an FM trap, followed by an Antennas Direct CPA-19 preamp. From the signal out of the power insertion block I'd feed into the VHF port of the same UVSJ mentioned above.

Your shot at Tiger Mnt. is enviable and should not require a big antenna. You may get lucky and see a reliable signal from an antenna aimed at Capitol or Queen Anne Hill. If that doesn't happen, you have to decide if another antenna is going to be used, the CS2 would do quite well but you'll need to decide how to combine or otherwise switch all these antennas. Consider this idea... http://forum.tvfool.com/showthread.php?t=2882 or even this idea, http://forum.tvfool.com/showthread.php?t=820

If you don't see the signals form real CH-9 and CH-11 reliably on the Y..713 mentioned above, you'll need to consider a second Y..713 antenna. I expect that it will need to be combined with the Tiger Mnt. UHF antenna.

On a general note, You need to see a usable, reliable signal at the antennas terminals before bothering with a preamp. A preamp is only able to 'repeat' what is 'hears'. If the preamp is fed an unreliable signal, the best it can do is output a stronger unreliable signal.

Finally, an alternative approach might be found using tuned channel combiner product from www.tinlee.com.

[Tristan]

Thank you, very helpful.

Just a clarification: I've seen on other threads that KCPQ (Fox, real channel 13) is now also broadcasting in the Seattle area on real channel 22. Just so I understand this, that means the same programming but on different channels? So if I can get channel 22, then I can effectively ignore channel 13? How would a digital tuner handle that (I don't see the "virtual" channel for 22 listed, would it show up as 13.1 or 22?

That would simplify things if I can focus my UHF on the Queen Anne/Capital Hill group, and bring in 9 and 11 on VHF (same general physical location). That leaves only real channel 33 to worry about, but as you mention that one is easier.

[GroundUrMast]

The data stream broadcast on real CH-22 is identical to that broadcast on real CH-13. So some tuners will be confused seeing the same virtual channel and PID.

Yes, If you can get a reliable signal from real CH-22, you'd be best skipping reception of real CH-13.

[Tristan]

Some experimentation and feedback:
I added ten feet to the mast (Channel Master 5-foot mast, item # 1805, I used two). I was surprised what a difference this made:

-with the old style, salvaged antenna, pointed to about true north 210, every channel was a little stronger, and I now get real CH-25 and CH-39, so I was only missing CH-13 and CH-38 from my goal channels
-with the antennas direct CV-2, also pointed to about 210, the results were rather impressive: nearly everything I care about was watchable, but CH-38 was still completely absent.
-with this latter arrangement, CH-13 was now arriving, but the signal was weak and unwatchable. The tuner seemed to go to CH-13 twice when browsing (perhaps it was receiving both CH-13 and real CH-22 and getting confused)? Also, CH-13 was arriving via virt 22.2, completely watchable. Perhaps this is where my tuner decided to park real CH-22 (the Seattle based signal for FOX)?

I'm pleased with these results, and it suggests I can get everything I want with one antenna (the CV-2). I can just delete channel 13 from the tuner and get that broadcast via 22.2, or perhaps a selective filter would be better?

What still puzzles me is this:
-why virtual CH-4 (real CH-38) is now absent: previously I was readily able to get it. Virtual CH-4, CH-5, CH-7 are nearly identical transmitter locations.
-would a selective bandpass filter removing real CH-13 be better to avoid interference instead of simply deleting channel 13 from the tuner memory? Tinlee makes such products.

If anyone in the Seattle area has insight into this I would greatly appreciate it.

[GroundUrMast]

Are you blocked by trees? (My wife & I recently looked at a couple of houses for sale in your area, so I think I know the answer.)

Reading the manual for the H2160MW9 (http://www.magnavox.com/support/download_list.php?model=H2160MW9), it looks as if the tuner is not one that allows manual addition of digital channels, just manual deletion (what a great feature :rolleyes:).

I suggest that you hold off trying to block real channel 13 reception. You need to focus on receiving a reliable real CH-38 and in so doing, you may find that the signal on real CH-22 is made reliable also. (If you are happy with the quality of virtual channel 22.2 (broadcast on real CH-25), that takes care of KCPQ reception... but the signal on VC 22.2 is about half the bit rate of VC 13.1 on real CH-13 & 22. (Yes, virtual channels and real channels can be confusing :().

I still think you need more antenna than a CS2 to make the KOMO (real CH-38) reliable. As I mentioned earlier, "Antennas such as the Antennas Direct 91XG or Winegard HD9095P are appropriate for going after the Queen Anne Hill group (KOMO, KING, KONG, KIRO)...". As you have seen, altitude is also your friend.

[Tristan]

Update:
I tried the Antennas Direct D4Be, plus or minus the CPA-19 (amplifier). I didn't try hard to optimize aiming, just aimed in the general best direction to compare performance or various combinations:

-The amplifier made only a slight difference (a few channels were stronger)
-The D4Be drops 9 & 11 (not surprising, it is not supposed to receive VHF)
-The D4Be brings in 27 and 31 (KONG and KBTC), but unusable
-The C2V performs a little better for 33, 42, 46, 50

I have the old antenna I salvaged: it gets very strong VHF signals (even at lower heights). I'll probably try mounting that lower, then add the DB4e with a joiner.

Although the CPA19 seemed to make little difference, will it be helpful if I start combining antennas (thus weakening the signal)?

Or, a hair-brained idea: can I remove the small VHF element from the C2V and combine it with the DB4e? What is inside the connector of the C2V? Is that an internal UHV/VHF joiner?

--Tristan