Rural Fringe Help needed

john_bud

DTVUSA Jr. Member
#1
Hi!

Been diddling around with my TV for months and thought some expert help may be in order.

I have the RCA 800B1L converter boxes on 2 TVs. On the roof 30' above ground is an Antenna Craft HD1850 with a AP8800 pre-amp. The antenna is pointed to the weak channels and I have cleared out tree branches that might be in the way.


Is the reception map. I get 49, 15, 27,13, with strong signal as expected. 8 requires a rotation of the antenna - but the antenna is so large the rotator (and a new replacement was worse) can't reliably spin it. 11,22 come in most of the time with a few drop outs. 9 comes in about 75% of the time. The rest only come in sporadically. Channel 8 has ZERO signal as the antenna is currently pointed.

Here are my issues.
1) Signal strength flips around and goes to ZERO for a second or so when it's windy. It does this even on the strong channels. What is the deal with that? Is it a connection with the antenna? Amp? Cable? Splitter? or ?

2) The pre-amp only gives 19 db gain on the UHF. I see that the Model AP8283 gives 28 db on UHF. How much "real improvement" will I get from that switch? Or is there a better one to get?

3) I've read until my eyes are bleeding about converter boxes but they talk about "picture quality" and not ability to draw in weak signals. Which ones are REALLY better than the RCA boxs I foolishly got?

4) I would like to add an antenna to pick up Channel 8 and leave it. What gear is needed to get that done?

Thanks!

jb
 
#2
Zenith DTA901-b is great with weaker signals, but sadly if your's is flipping around the scale the Zenith will give up and go to 'red zone' of the meter and rebooting it is required. but it holds signals as low as 35%, but that depends on the channel you're trying to get, if it's not dishing out very much power to their DT transmitter you may need over 65% to get it.

But the good news is about 9-10 times you have a bad connection (even a tiny one) that causes the rapid 'perfect signal---no signal' problem. or you have wind. wind is sadly something about Mother Nature that i haven't yet found a way around. if your channels are 2Edge wind is going to cancel them out, even a tiny breeze. i think it's because wind is making any trees blow in it and the 2edge means the signal is bouncing off of trees, buildings, or even windmills. if that's happening the signal (imagine it's a laser beam) is bouncing all over the place and not getting to your box.
 

john_bud

DTVUSA Jr. Member
#3
35% ? 65%????


In my best dream state it never gets that high on any channel - never.

The RCA shows 40-55% on the strong channels.

The weak ones (that do come in) are in the 11-15% range. That produces a clear signal -except when it doesn't@! if you know what I mean.

How do I determine if there is a flaky connection with a cable?

jb
 
#4
flaky connections are the prime cause of great signal then no signal in seconds. you know that it's great signal since it peaks at that point, but it's going from that to nothing and that's because the cable is loose or wet or just bad. i don't get it, either. but wind is another cause, and that is not always your fault. it's the wind. unless your antenna is doing a little dance then there's sadly nothing you can do, you've fixed the problem at your end. i try not to use the cables that come with the box. they're normally those cheap 'push on, pull off' connectors that don't always grab well, and move in the wind, too. i buy high quality gold-plated HD cables, and make sure they're TIGHT. you have to really make them tight, any chance of them coming the tiniest bit loose then the wind is moving the cable and as the cable moves the center wire is moving around and there's your up/down signal swing. in wind that's not insane and not gale force (10-25mph) the signal should not move much if you're ok at your end.

If you have one of those RCA DTA800's those are the crappiest boxes for low signals. i'm guessing the audio does the 'bad compact disc skip' as well doesn't it? that's infuriating.
 
Last edited:

Jason Fritz

Administrator
Staff member
#5
35% ? 65%????


In my best dream state it never gets that high on any channel - never.

The RCA shows 40-55% on the strong channels.

The weak ones (that do come in) are in the 11-15% range. That produces a clear signal -except when it doesn't@! if you know what I mean.

How do I determine if there is a flaky connection with a cable?

jb
Specs on the Antenna Craft HD185 rate it as follows:

Mileage VHF Low: 100+ Miles
VHF High: 100+ Miles
UHF: 60+ Miles


Just an idea here, but have you actually tried removing the amplifier from your setup? They have a tendency to boost
signals and noise...too much noise = inter modulation = bad reception. Most forums including this one have mixed feelings on amps too, so I'm sure someone will probably call me crazy for suggesting removal of one...but you never know since each DTV reception problem is unique based on distance, topography, and all of the other RF broadcasted signals in the air.
 
#6
I live in wooded, hilly farmland terrain and i get a pretty steady 50-65% and every one of my channels (the ones that have gone digital + a few extras in sub-channel form) come in and i don't have to re-aim my antenna at all.

There's no amp, it's a old set of Sears rabbit-ears with UHF halos and VHF dipoles from the 1960s, so old it has twin lead cable and the base is made of metal. and i get all my channels even if a little wind is there. i have it sitting on the ground outside and it works wonders. i don't have to be nervous about getting up and moving around now since it doesn't mess up reception the way an indoor antenna does. i just experimented with this and it works better than high-dollar roof and HDTV antennas. keep in mind though that all my channels are in the green/yellow according to TVFool, and i live 30 miles away from the transmitters.
 

john_bud

DTVUSA Jr. Member
#7
Specs on the Antenna Craft HD185 rate it as follows:

Mileage VHF Low: 100+ Miles
VHF High: 100+ Miles
UHF: 60+ Miles


Just an idea here, but have you actually tried removing the amplifier from your setup? They have a tendency to boost
signals and noise...too much noise = inter modulation = bad reception. Most forums including this one have mixed feelings on amps too, so I'm sure someone will probably call me crazy for suggesting removal of one...but you never know since each DTV reception problem is unique based on distance, topography, and all of the other RF broadcasted signals in the air.

As a matter of fact, yes. The first set up was the antenna with no amp. It got 3 channels fairly strongly and one channel did the break dance. No other channels were there at all. So with out an amp, it would be better off reading a book!

The sad thing is the low number channels 2,4,5, 9, 11 are why I got the antenna with strong VHF gain only to find that they are actually on higher frequencies.:(

jb
 
#8
The only way to get the 2 edge is to have an antenna that will tilt Like the antennas direct 91-xg as most of your stations are 2 edge I would suggest placing the 91-xg over the antenna craft. the pre amp you have is way too noisy replace with a channel master titian 2 7777. the antenna craft has no gain on UHF so that is why I suggest placing the 91-xg over top of it 4 ft and tilting it 15 degrees up. what rotator are you using? suggest the channel master 9521A it will handle large antennas
 

john_bud

DTVUSA Jr. Member
#9
Ok.

Couple questions. The specs on the 8800 are
Average Gain:

* VHF - 29 dB
* UHF - 19 dB

Average Noise:

* VHF - 2.7 dB
* UHF - 2.8 dB

The specs on the 7777 are

Specifications:

* Number of Inputs: 1/2 (VHF & UHF)
* Input and Output Impedance: 75 Ohms
* Input and Output Connectors: F Type Connectors
* VHF Gain: 23 dB
* VHF Noise Figure: 2.8 dB
* VHF Output Capability: 57 dBmV
* Switchable FM Trap
* UHF Gain: 26 dB
* UHF Noise Figure: 2.0 dB
* UHF Output Capability: 51 dBmV


To my eye, it looks like the "paper specs" are pretty close. Is it your real world experience that the 8800 is not living up to its paper? I do tend to be skeptical of many paper specs!

The paper specs on the Antenna Craft HD1850 show it having a 10 db UHF gain.

1 Gain (dB)
VHF Low Band 6.2
VHF High Band 10.7
UHF Band 10.0

2 Half-Power Beamwidth (deg.)
VHF Low Band 65.0
VHF High Band 34.0
UHF Band 37.5

3 Front-To-Back Ratio (dB)
VHF Low Band 20.2
VHF High Band 17.3
UHF Band 13.7

The 91-xg is shown at 16 db. If I couple that 6 db gain with the 9 db gain going to the 7777 pre-amp -- Will that significantly improve the situation? (I'm assuming you think it will or else it wouldn't be your recommendation!) What amount of gain would be a reasonable expectation? I am guessing that from the chart for my location I would shift the signals listed up by the 15 db ? Is that how to read it?

If I do go with the 91-xg and aim it at the weak UHF stations, I should be able to point the current antenna closer to channel 8 and have it pick up all the current strong signals and not need a rotator. I would then remove it from the equation and have a bit more stable stand as a result. On the 91-xg, I would need to play with the up / down angle too? Good too know.

Last Q. The signal drop from 50% to 0. You agree that is probably the co-ax?

THanks!

jb
 
Last edited:
#10
The 91-xg is shown at 16 db. If I couple that 6 db gain with the 9 db gain going to the 7777 pre-amp -- Will that significantly improve the situation? (I'm assuming you think it will or else it wouldn't be your recommendation!) What amount of gain would be a reasonable expectation? I am guessing that from the chart for my location I would shift the signals listed up by the 15 db ? Is that how to read it?

If I do go with the 91-xg and aim it at the weak UHF stations, I should be able to point the current antenna closer to channel 8 and have it pick up all the current strong signals and not need a rotator. I would then remove it from the equation and have a bit more stable stand as a result. On the 91-xg, I would need to play with the up / down angle too? Good too know.

Last Q. The signal drop from 50% to 0. You agree that is probably the co-ax?

THanks!

jb
Can't say for sure on whether the 7777 will definitely improve your reception, but it's worth a shot. The important thing to do with the 91XG is make sure that you do aim in the right direction with a good rotator because it's a very directional antenna.
 
#12
Pre amps do not improve the gain of an antenna they only keep weak signals from dropping off once they leave the antenna. this is a common misconception. if you have 9 db from antenna it only maintains the 9db to the tv. the 7777 has only 2.0 noise on UHf where the 8800 is 2.8 this is were they differ UHF is more susceptible to noise than VHF because it is a weaker signal.
 
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