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The Official AVS Antenna and Related Hardware Topic! - Page 517

post #15481 of 16086
Looking at the specs. on the HDB91x from solid signal and the other models from the chinese mfg. such as the 4 bays/8bays they are designed for 470 to 860 mhz.. Designed for the European UHF tv spectrum maybe some other countries? It would be nice if they had a 470 to 700 mhz USA model, maybe pickup a couple DB and narrow the BW. All those directors probably run out of steam rather quickly as you approach the low end of the USA uhf tv band. I imagine the 60 degree horizontal BW claim is about right for the low end of the UHF band as those directors become more transparent since the antenna would now be more common to just a simple corner reflector. Just a thought wink.gif
post #15482 of 16086
Ok... I got a question. I have an 91-XG, and am getting an antennacraft FM-6 to hook to my new clock radio in the bedroom, so wondering if I mounted the FM-6 on the same mast, about 3 feet below the 91-XG, would it cause any intereference problems on the FM side? I know that the 91-XG is safe from intereference, as I have a channelmaster 7775 on it, and it won't pass any FM signal anyway, but just wondering if the 91-XG would give me any trouble with my FM reception if they are that close together?
post #15483 of 16086
Quote:
Originally Posted by alphanguy View Post

I know that the 91-XG is safe from interference . .
Not necessarily, but at 3 feet, you will likely notice any degradation to either band. Just take note of your UHF reception before & after installation to see if you notice any changes. The recommended separation is closer to 4 feet.

I have 4 FM antennas & 1 TV antenna in the attic all within 1-4 feet of each other with no noticeable degradation in reception.
post #15484 of 16086
I just uploaded 4nec2 analysis for Stacked A-D 91XG UHF Corner-Yagi and A-C FM-6 Yagi:
http://imageevent.com/holl_ands/stacked/stackuhffm

Analysis confirms recommended minimum Boom-Boom Center Separation of 4-feet for negligible 91XG degradation to (mostly) F/B & F/R Ratios. Note unusually high F/R degradation for Sep=3-ft. The actual Raw Gain was only minimally affected, except when Separation was only 1-foot, resulting in about 1.5 dB Gain reduction.

There was no noticeable degradation to the FM-6, so FM Band charts are not provided.




Edited by holl_ands - 8/14/13 at 4:35pm
post #15485 of 16086
For the first time in so many years, Winegard has introduced a new preamp, the LNA-200 Boost XT. It is supposedly more optimized for digital signals, as it claims an ultra low noise figure of 1.0, along with separate amplication of UHF and VHF signals using clear circuit technology. The gain is around 18db. It will be interesting to hear results of real world performance, and is a totally different design from their AP series Chromestar preamps.
post #15486 of 16086
Quote:
Originally Posted by tylerSC View Post

For the first time in so many years, Winegard has introduced a new preamp, the LNA-200 Boost XT. It is supposedly more optimized for digital signals, as it claims an ultra low noise figure of 1.0, along with separate amplication of UHF and VHF signals using clear circuit technology. The gain is around 18db. It will be interesting to hear results of real world performance, and is a totally different design from their AP series Chromestar preamps.
This is what I am showing on it:

Gain*: 20 dB L-VHF, 15 dB H-VHF, 18 dB UHF
Noise Figure*: 3 dB VHF, 1 dB UHF

http://www.winegard.com/offair/amplifiers.php

Just a typical Medium Gain Pre-amp, with the typical noise figure of all other Pre-amps in its class. Nothing special about it. The only thing special about it, is that it uses USB to power it, unlike conventional real Pre-amps.
post #15487 of 16086
Quote:
Originally Posted by gregzoll View Post

This is what I am showing on it:

Gain*: 20 dB L-VHF, 15 dB H-VHF, 18 dB UHF
Noise Figure*: 3 dB VHF, 1 dB UHF

http://www.winegard.com/offair/amplifiers.php

Just a typical Medium Gain Pre-amp, with the typical noise figure of all other Pre-amps in its class. Nothing special about it. The only thing special about it, is that it uses USB to power it, unlike conventional real Pre-amps.

There is something special about it. It can handle 20 dB more total input power than the older designs. That's a big deal for reducing preamp overload if strong signals are present. That doesn't prevent TV overload though.

Not sure what's up with the USB cable. Maybe it's just a cheap and common cable that they're using to get power to the preamp.
post #15488 of 16086
That Winegard spec sheet is a bad joke. It needs to be sent back to their "re-write" deparment, if they have one.
post #15489 of 16086
Quote:
Originally Posted by Calaveras View Post

There is something special about it. It can handle 20 dB more total input power than the older designs. That's a big deal for reducing preamp overload if strong signals are present. That doesn't prevent TV overload though.

Not sure what's up with the USB cable. Maybe it's just a cheap and common cable that they're using to get power to the preamp.
It is really no different than the Channel Master CM-7778, but the CM is a better design. As for the USB power supply, it is so that you do not need the wall wart, but to use the USB output on a TV (good for allowing you to fry the tv or other device the preamp is being power by, if the antenna is outside, and not properly grounded. Good design Winegard).
post #15490 of 16086
Quote:
Originally Posted by AntAltMike View Post

That Winegard spec sheet is a bad joke. It needs to be sent back to their "re-write" deparment, if they have one.
Majority of those spec sheets look like a kid from Junior High School wrote them, and attended the Chicago Public School system.
post #15491 of 16086
Quote:
This is what I am showing on it:

Gain*: 20 dB L-VHF, 15 dB H-VHF, 18 dB UHF
Noise Figure*: 3 dB VHF, 1 dB UHF

Yes, that's what Winegard says it is....

The sample I tested last week shows that either i got a bad amp or they need some new testing equipment for measuring noise figure on their pre-amps. The sample tested anywhere from 1 to 3 dB HIGHER than their claims, much like the 8700, 8800, and 269 that I've previously tested. All of them had high noise figures compared to their claimed specifications.

On the LNA200, I measured an average of 4.7 dB NF on low-V, 5.6 dB on high-V, and 2.8 dB on UHF as computed by the NF meter software. Major spikes from ingress were evident, some as much as 8 dB.

Ironically, the little indoor LNA100 DOES sample did meet the 1 dB NF on high-V and UHF (but not low-VHF).

Both did fairly well on OIP3 testing.


Quote:
It is really no different than the Channel Master CM-7778, but the CM is a better design.

Are you referring to the "Classic" or the new 2012 version? Just curious. I haven't tested a sample of the 2012 version of the 7778. I do own (personally) and have tested the new 7777 and, except for the case and the model number, it is nothing like its predecessor.

If you really like the old 7778, you might get a kick out of the $20 RCA pre-amp.
Edited by ADTech - 8/15/13 at 11:21am
post #15492 of 16086
I have the newer version ADTech. The two Channel Master Pre-Amps have been work horses for a very long time. They have had very few changes to them, other than maybe aesthetics. Using newer digital technologies to shrink the size of the circuit board, and fine tune the UHF & VHF circuits better.
post #15493 of 16086
Speaking of jokes, how can they claim that a 15-20 dB pre-amplifier that runs off of 5 volts DC can accept 2,074,700 micro volts at the input?



What's that, the self-destruct limit???? That's 17.4 dBm on the input??? Did some one who didn't know what they were doing take the Output IP3 number, subtract the gain, then covert that to micro volts or something?

Someone in Burlington must be into the corn squeezin's!

ADTech,
Quote:
Both did fairly well on OIP3 testing.

What did they measure, if you don't mind sharing?
Edited by ProjectSHO89 - 8/15/13 at 6:39pm
post #15494 of 16086
I get the same max input number....which is 20 dB better than AP8700....if we PRESUME they are comparing apples to apples (i.e. PEAK power in NTSC signals) and -46 dBc Crossmodulation levels.....for TWO equal strength input signals (NONE of which is found in their fine print).....
http://www.digitalhome.ca/forum/showthread.php?p=1708730
Discussion continues for another 10-20 posts....But I have NOT seen any independent verification for W-G claims.....
post #15495 of 16086
With the newer digital chips, you do not need a 12-30 volt power supply. It is obvious that Winegard has figured something out to make this work. Most likely they took the amp circuit out of the SensarPro, for the new LNA amps. Unless someone is able to find the Patent info showing the circuitry, or willing to purchase one of these, to dissect it, we just need to go by the claims that Wingard is putting out. All you really need is a series of Rectifiers to boost the voltage from 5 volts to the level that you need. With most rectifiers now being on a chip, it is easy to do with Micro circuitry rectifiers, that are very small.
post #15496 of 16086
Single ended LNA chips with medium gain, low noise, and high overload resistance are becoming more common. It's unlikely that Winegard had to do anything more difficult than selecting the semiconductor and designing the rest of the product around it. There's no need to boost the supply voltage.


It's pretty plain that someone screwed up the math in that advertising copy. You can't put two volts of signal into a pre-amp and expect it to operate.

They specify P1dB as +15/+18.4 dBm (V/U) with respective gains of 15-20 dB, that would indicate that the amplifier is already in compression at -5 to 0 dBm single tone input. 0 dBm =~ 273,000 uV -5 dBm =~154,000 uV. Clearly, the claimed input capability is ludicrous!
Edited by ProjectSHO89 - 8/16/13 at 5:17am
post #15497 of 16086
Quote:
Originally Posted by ProjectSHO89 View Post



It's pretty plain that someone screwed up the math in that advertising copy. You can't put two volts of signal into a pre-amp and expect it to operate.

Aw shucks. I was going to buy one and use its output to light up my Christmas tree off my USB port..
Edited by AntAltMike - 8/16/13 at 5:26am
post #15498 of 16086
I have a AP 8700 and might be going to the new winegard amp soon (one or two months).

Their marketing poop I thought was implying that the new amp could take Big Overload without crashing; but I really do not know.

Currently working on other projects that have to be cleared first before I get back to the "antenna project".

The main reason I am interested in the amp is to see I can get much better SNR, BER, and MER than I do with the 8700. In some situations the 8700 has been a little too dirty for me (poor SNR) even though the signal strength is higher.

If I get the new amp, I will post the results here. But the posts above indicate it is not much better than the 8700 or maybe not as good. So if the new amp cannot deliver the "goods" I would send it back.
post #15499 of 16086
Winegard has also just introduced a new Flatwave Air amplified antenna for outdoor or attic use, which also uses their new low noise amp technology. Probably a successor to the SS1000/2000 antenna, which are good for when a more discreet antenna is desired.
post #15500 of 16086
Quote:
What did they measure, if you don't mind sharing?

Sure. Click on images for larger version.

General frequency response.



Gain and noise figure, single sample. Note filters (FM, inter-band, cellular). Note ingress spikes that correspond with local (St Louis) broadcasts and other local signals. Note especially the huge ingress spike from the local Verizon LTE tower (736-746 MHz) that's a half mile away. That's what a plastic case gives you. Measurements taken in office environment, non-shielded.



Two-tone IMD test. Note that the screen shot does not include a 5.7 dB min loss pad on the input of the the spectrum analyzer, you must manually add that value back to indicated power levels. Note also that precision measurements, especially when set to 10 dB/div, are not possible on the HP8569B analyzer. I consider these as estimates only. This was one of the better sets of readings which were done at four different frequencies.



Note that this test corresponds to the EN50083-5 which superseded DIN45004B back in the late 90s. DIN45004B specs are still commonly given for Euro-Asian market masthead amplifier products

P1dB Results: +10 dBm @ 75 MHz, +12 dBm @ 200 MHz, +16 dBm @ 500 MHz, & +16 dBm @ 650 MHz. (Same spectrum analyzer, same cautions as to precision).

The good news is that I talked the boss into a new spectrum analyzer and a new signal generator and they should be here late next week! wink.gif
Edited by ADTech - 8/26/13 at 9:17am
post #15501 of 16086
Just ordered LNA100 from Amazon for $42.97 no shipping charge. Will try to improve attic installation. Will report results.
post #15502 of 16086
If you have an electrical outlet in your attic and your reception is due to insufficient signal power at the TV, then the LNA100 would likely help.

However, adding an amplifier might not do the intended job if the problem is due to poor signal quality that is a result of the antenna selection and placement. In some cases, the amplifier will do more harm than good, so it is necessary to properly identify the root cause of the reception concern in order to see if an amplifier would be useful.

Or, you can just throw an amp at the problem and see if it solves the un-diagnosed problem, it sometimes does.
post #15503 of 16086
A cheaper alternative, the RCA low noise inline amp is sold at Walmart for $15. Their preamp is good, so the inline amp may use similar design circuitry. But I have found preamps usually work better with attic antennas than those inline amps. I guess because of the separate amp and power injector.
post #15504 of 16086
Quote:
Their preamp is good, so the inline amp may use similar design circuitry.

They are nothing like each other..
post #15505 of 16086
Quote:
Originally Posted by ADTech View Post

They are nothing like each other..
Well, I guess they may be different then. But the RCA inline amp is still a cheap alternative for $15 at Walmart. Perhaps better than the Radioshack inline amp, I don't know. But worth a try when an inline amp is all you may need. But in my case, I have found a preamp works best with an attic antenna.
post #15506 of 16086
Guessing and knowing are two completely different things.

Sometimes pre-amps and distribution amps are interchangeable, sometimes one topology has the advantage over the other. Sometimes, it doesn't matter as either may work.
post #15507 of 16086
Mauldin, SC is in the Greenville market and has line of sight transmission paths to the center of the zip code 29662. The only signal that might be borderline for you without a preamp would be your channel 13. You might benefit most from using separate VHF and UHF antennas if you are not already.

Which channels so you have trouble with, with and without amplification?
post #15508 of 16086
Quote:
Originally Posted by AntAltMike View Post

Mauldin, SC is in the Greenville market and has line of sight transmission paths to the center of the zip code 29662. The only signal that might be borderline for you without a preamp would be your channel 13. You might benefit most from using separate VHF and UHF antennas if you are not already.

Which channels so you have trouble with, with and without amplification?
I am in zip code 29607. My signal is split to 3 TVs. Using an original Channel Master 4248 UHF Diamond antenna, Radioshack rabbit ears for VHF, Holland UVSJ, and Kitztech 200 preamp. Can receive most local channels without preamp, except WLOS-13. Amp is needed to receive 13 and Charlotte, NC signals from 75 miles. I get reliable reception from WBTV-3, WCNC-36, WJZY-46, and WMYT-55. And WSOC 9.1 and 9.5 mainly at night. I used to barely receive 9.5 more regularly during the day, which is a low power translator on RF30 from 60 miles. But some interference is now drowning out this low power signal, perhaps when RF16 very close by recently increased power. I would like to filter out RF16 and RF43 which are strong signals that may be overpowering RF30 in the amp. I had filtered out RF7 and RF9(29) which are very strong, but did not help with RF30. But all other channels I receive reliably, and I can even get WBTV RF23 without the amp from 75 miles. But RF30 is not a reasonable expectation at my distance due to low power, and my antenna is in the attic. But I did get it for over 2 years until recently. But I get all locals and most Charlotte reliably with my current set up. So long story short, preamp is needed for Charlotte.
post #15509 of 16086
post #15510 of 16086
Apparently Winegard is phasing out many of its AP Series Chromestar preamplifiers. So if you are interested, you may need to order now before certain models are no longer available. Looks like only the medium and low gain 8700 and 269 models may remain. The higher gain 28db models may have been discontinued, including the 8780, 8275, and UHF 4800. As they now appear to be featuring the new LNA-200 Boost XT low noise amp. But it is more moderate gain around 18db, so I wonder if they will eventually produce a higher gain version of this new model.
Edited by tylerSC - 9/5/13 at 11:44am
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