What's going on here in East San Diego

day7a1 · 12-Dec-2013, 6:24 PM

http://www.tvfool.com/?option=com_wr...46ae8df81b3a04

I have an Antennacraft Y-5-7-13 in my garage (attic), with a cheap radioshack 10dB preamp.

I get all channels in the green and yellow, including the UHF 2Edge off-axis 14.7 miles away channels...except CBS channel 8. Mind you I get ABC 10 just fine, which is from the same mountain but a weaker signal.

I seem to get 8 sometimes during the day, and I did have it for awhile, but it's hard to blame the poor reception on the weather when 10 comes in perfectly all the time.

Any thoughts? Of course Hulu doesn't provide CBS shows, otherwise I wouldn't care!

ADTech · 12-Dec-2013, 6:28 PM

Try adding an FM filter BEFORE the amplifier.

GroundUrMast · 12-Dec-2013, 6:30 PM

Test reception with the antenna alone, outside clear of obstructions, higher is better. The RS amp may be doing more harm than good... the attic may be another impairment that is easily avoided.

http://forum.tvfool.com/showthread.php?t=13646

What does a TV Fool report based on 25' AGL look like, compared to your fist post?

I have seen the Y10713 serve as a UHF antenna when a preamp is located close to it's terminals. My theory is that the amp isolates the high SWR of the Y10713 (at UHF) from the line and so it sort of works.

I would not depend on the Y10713 alone in the San Diego market. I'd opt for a UHF antenna such as the Antennas Direct DB4e + Y10713 + UHF/VHF combiner. If a distribution amp is needed, the CM-3410 would be my choice for it's added gain and lower noise+distortion.

(ditto ADTech's suggestion re. the FM trap)

day7a1 · 12-Dec-2013, 7:01 PM

http://www.tvfool.com/?option=com_wr...46aeeb820b7081

I realized after my post that the ERP for 10 is a little higher than for 8, but the NM is a little lower.

I rent, so I really don't see putting up a 10 foot pole on the roof. There is a satellite dish mount I may be able to repurpose though.

Will a FM trap do anything for VHF-Hi? I thought it was mostly for 2-6, but interference would explain the drastic changes in reception.

I already tested the signal with and without an amp...it's significantly better with, but I don't think a stronger one will help...you can't amplify darkness. I'm pretty sure the one I have is overcoming the cable run, which is it's purpose, right?

day7a1 · 12-Dec-2013, 7:03 PM

Oh, also, the UHF is all just fine...I could use a paperclip in the back of the TV for those though, I can LITERALLY see them from my back yard.

Comenius · 12-Dec-2013, 7:52 PM

An FM Trap was the only way I was able to receive a VHF-Hi station in my location. Definitely give it a shot. Only $5 from Radio Shack and you can always return it if it doesn't help.

ADTech · 12-Dec-2013, 7:56 PM

My recommendation of the FM trap is targeted to your VHF reception issues of ch 8. You have at least one FM station that is 25-30 dB stronger than 8 into which its 2nd harmonic falls. Potential is high that it may be the issue and the FM trap is cheap and easy to try.

Also, make certain the front of the Y-5-7-13 is physically aimed towards La Jolla.

day7a1 · 12-Dec-2013, 9:33 PM

Actually ADTech...I feel I must correct you....

I have a TON of FM channels at the frequency that would cause second harmonic interference!

93.3 is 3.7 miles from me pushing out 50k watts...I'm guessing that will do some damage? Oh, and it's between me and the station I'm trying to get.

I didn't even realize that was a thing, so it looks like I'm off to get a trap and return a Redbox.

FYI, I tore down the old satellite dish and used the mount to more "professionally" mount the antenna in the garage. It's more clear of any obstructions around the directors and reflector and probably a few inches higher. It looks better too.

It's pretty strong right now, but we'll see later tonight I guess.

ADTech · 12-Dec-2013, 10:13 PM

You're right. I don't remember the exact coordinates used initially, but I just re-did the exercise and confirmed your info.

You might need more than one FM filter....

The primary sources of 2nd harmonics will be FM frequencies 90-93 FM. After that, intermodulation products in that amplifier will be the dominant factor.

Are you really sure you need that amp?

day7a1 · 12-Dec-2013, 10:56 PM

8 won't come in without the amp, but that was before I had an FM trap. I think it helps a lot with real channel 23 also, if I recall correctly. That's the only UHF that isn't on my doorstep.

I can certainly test it again, though.

Can you recommend a FM trap, or is the RS one about the best one can get?

ADTech · 12-Dec-2013, 11:30 PM

The RS trap is fine for your circumstances.

day7a1 · 14-Dec-2013, 3:07 AM

So I put the trap in, but didn't get a chance to see if it worked. 8 came in with and without the trap during the day, but after we got back later last night hardly any channels were coming in at all. I removed the trap and they were all back. Must be a bad trap...

I was thinking about getting an ASKA AM-125, it's only $12 on solid signal and is probably a better amp and trap than radioshack, but there seem to be no reviews. Anyone know about aska products?

ADTech · 14-Dec-2013, 1:44 PM

The last thing you need is a high gain amplifier. Your proximity to the main transmitters on San Miguel will overload most amps.

Start over from a basic system. Completely passive with the FM filter (or two in series)to see if an amp is even needed.

day7a1 · 29-Dec-2013, 9:40 PM

So I ended up putting the antenna on a 10.5 foot pole above the roof. Tried all combinations of amplifier, trap, and direct connection. I'm getting no better signal on real 10 and 8 no matter what I do. Sometimes it's worse than when it was in the garage. Sometimes they come in fine, sometimes both are so poor they might as well not be there. Sometimes during the day is best, sometimes not. Sometimes warm weather is best, sometimes not. What could possibly help if I can't even isolate a single problem? It's like no matter what I do, the next day it may not have any effect. The wife is pushing for cable and I'm at my wits end. I just can't figure out why it only doesn't work when there is something we really want to watch!

day7a1 · 2-Jan-2014, 4:04 AM

No takers, huh?

2-Jan-2014, 4:46 AM

Put the Y5-7-13 antenna outside in the clear of of building and roof obstructions.

Aim the Y5-7-13 antenna at about 291 degree magnetic compass direction.

Here is how to aim antennas , http://www.kyes.com/antenna/pointing/pointing.html.

Use a Real and Actual magnetic compass to aim antenna.

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Install a NEW matching transformer (balun). That connects the Y5-7-13 antenna to the coax.

Install a NEW Continues length of coax to the NEW matching transformer.

Run the NEW Continues length of coax from the NEW matching transformer through a open window or door , direct to 1 Tv.

No amplifier.

Yes Test reception with and without the FM traps.

If you have more then 1 Tv , Test reception with other Tv's connected 1 at a time to the NEW continues length of coax.

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Digital Broadcast Tv Tuners can develop - Digital Glitches - that are not cleared out with simple channel scans.

To clear tuner do Double Rescan.

http://www.wchstv.com/DoubleReScanAlert.pdf.

ADTech · 2-Jan-2014, 11:22 AM

Go to TWO FM filters in series. Sometimes, it just takes more FM attenuation than a single filter offers, especially when the FM is LOS and the VHF signal path is terrain-blocked.

If that doesn't work, you're likely looking at some sort of electrical interference which, without test gear, can be very, very difficult to isolate and correct.

3-Jan-2014, 1:23 AM

+=>
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-->If<-- is some type or kind of electronic or electric interference , is possible the Y5-7-13 antenna can be used to locate the interference.

With a NEW Long Continues Length connected to the Y5-7-13 antenna.

Aim and move the antenna around to different locations to find a place with less or no interference.

Connecting the antenna to a battery operated Tv will allow more mobility to find the interference.

day7a1 · 8-Jan-2014, 1:24 AM

Adding a second FM trap helped a lot...not completely, but a lot. I'm going to add a 3rd trap when I get a chance, but I sure wish that instead of 3 6dB FM traps I could have 1 18 dB trap. Where might I get one of those?

Also...and I only add this because I have no doubt it's a quick answer...airplanes seem to cause some pretty frequent and intense interference, is that normal?

GroundUrMast · 8-Jan-2014, 4:56 AM

Check with tinlee.com for high performance filters.

Airplanes made wood, cloth and plastic are no problem (if their engine is also non metallic)... but aluminum, steel and titanium make really good signal reflectors. Yes, aircraft passing nearby will cause reception problems. Signal arriving from two or more directions is called multipath, a common source of trouble for tuners. An antenna with high gain may be a little less susceptible. Custom stacking of antennas may be able to reduce the antennas 'view' of angles above the horizon.

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