Forum Jump: 
 9Likes
Reply
 
Thread Tools
post #61 of 127 Old 03-01-2018, 10:46 AM
AVS Forum Special Member
 
rabbit73's Avatar
 
Join Date: Apr 2008
Location: S.E. VA
Posts: 3,048
Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 775 Post(s)
Liked: 318
Amazon has a review by an installer who received "warehouse specials" that had DOA power supplies.

I bought my RCA TVPRAMP1R from Walmart; it looked new and not a return. It's doing OK with my GE 34792 indoor antenna.

If you can not measure it, you can not improve it.
Lord Kelvin, 1883
www.megalithia.com/elect/aerialsite/dttpoorman.html

Last edited by rabbit73; 03-01-2018 at 10:51 AM.
rabbit73 is online now  
Sponsored Links
Advertisement
 
post #62 of 127 Old 03-01-2018, 02:32 PM
Senior Member
 
ncsercs's Avatar
 
Join Date: May 2001
Location: Westmont, IL
Posts: 365
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 143 Post(s)
Liked: 70
Should the power supplies feel warm to the touch because both of mine felt cool?

Nick

Every day I beat my own previous record for the number of consecutive
days I've stayed alive. - George Carlin - 1996
ncsercs is offline  
post #63 of 127 Old 03-01-2018, 05:36 PM
AVS Forum Special Member
 
rabbit73's Avatar
 
Join Date: Apr 2008
Location: S.E. VA
Posts: 3,048
Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 775 Post(s)
Liked: 318
EDIT 11-3-2018
I now think the no-load voltage that I measured below of 19.5 VDC indicates a defective power inserter which contains a voltage regulator. The no-load voltage should be about the same as the voltage when the preamp is connected. Please see my more recent post later in this thread:


TWO Defective RCA TVPRAMP1 Preamps


http://01966633.com/forum/25-hd...l#post57053714

You can see the voltage regulator in this photo by Calaveras:








It's an AX1117 Low Dropout Linear Regulator.
________________






Well, warm and cool are kind of subjective. The transformer should feel warm if the preamp is drawing current. If it feels cool, the preamp might not be drawing current. If it feels hot, suspect a short.

IIRC, there was a post about the power transformer having a different current rating. Obviously, a transformer with a current rating of 100 mA would run a lot warmer than one rated at 200 mA. Mine is the RCA AC/DC Adapter Model RR-28-1200080D, rated at 12VDC, 80 mA output; it runs very warm.





In order to measure the voltage to the preamp when it is connected (voltage under load), you need access to the center conductor. I use a T-Adapter:







An 80 mA transformer for a 70 mA current draw seems cutting it too close for long term reliability.
Attached Thumbnails
Click image for larger version

Name:	RCAPreampCurrent.jpg
Views:	488
Size:	191.2 KB
ID:	2368740   Click image for larger version

Name:	RCA_TVPRAMP1R_PwrInserterCU.jpg
Views:	52
Size:	182.4 KB
ID:	2477478  

If you can not measure it, you can not improve it.
Lord Kelvin, 1883
www.megalithia.com/elect/aerialsite/dttpoorman.html

Last edited by rabbit73; 11-03-2018 at 09:40 AM.
rabbit73 is online now  
Sponsored Links
Advertisement
 
post #64 of 127 Old 03-01-2018, 08:54 PM
AVS Forum Special Member
 
rabbit73's Avatar
 
Join Date: Apr 2008
Location: S.E. VA
Posts: 3,048
Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 775 Post(s)
Liked: 318
Testing Coax

When troubleshooting a preamp problem, it is often necessary to check the coax.

DO NOT MAKE RESISTANCE MEASUREMENTS ON THE COAX WITH AN OHMMETER WHEN THERE IS VOLTAGE ON THE COAX; you will probably damage your meter.









Attached Thumbnails
Click image for larger version

Name:	TestingCoax1.jpg
Views:	450
Size:	198.3 KB
ID:	2368838   Click image for larger version

Name:	TestingCoax2.jpg
Views:	427
Size:	196.2 KB
ID:	2368840   Click image for larger version

Name:	TestingCoax3.jpg
Views:	447
Size:	201.7 KB
ID:	2368842   Click image for larger version

Name:	TestingCoax4.jpg
Views:	443
Size:	193.0 KB
ID:	2368844   Click image for larger version

Name:	TestingCoax5.jpg
Views:	441
Size:	215.4 KB
ID:	2368846  


If you can not measure it, you can not improve it.
Lord Kelvin, 1883
www.megalithia.com/elect/aerialsite/dttpoorman.html

Last edited by rabbit73; 11-03-2018 at 09:29 AM.
rabbit73 is online now  
post #65 of 127 Old 03-02-2018, 07:47 AM
Member
 
HunterZ0's Avatar
 
Join Date: Jan 2010
Posts: 67
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 10 Post(s)
Liked: 11
It's easy to tell if you have one that isn't being powered: I bought the Z version of this preamp from Amazon, and when I cut the power it basically doesn't pass any signal.
HunterZ0 is offline  
post #66 of 127 Old 08-02-2018, 08:33 AM
AVS Forum Special Member
 
jspENC's Avatar
 
Join Date: Nov 2004
Location: Jacksonville, NC
Posts: 4,648
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 168 Post(s)
Liked: 29
I picked up one of these, and it worked really well, until lightning struck power lines nearby, and I lost both VHF channels, so the VHF port fried. UHF was really weak at first, but came back to full strength. I took back the preamp. Now I'm not sure what I will do... I have had so many preamps fail, and most of them have been due to weather and power surges. I always unplug in severe weather, but had no warning on this event. This preamp works as well or even better than any I've had. I've had radio shack, Winegard, and channel masters over the years.
jspENC is offline  
post #67 of 127 Old 08-02-2018, 09:17 AM
AVS Forum Special Member
 
rabbit73's Avatar
 
Join Date: Apr 2008
Location: S.E. VA
Posts: 3,048
Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 775 Post(s)
Liked: 318
Quote:
Originally Posted by jspENC View Post
I picked up one of these, and it worked really well, until lightning struck power lines nearby, and I lost both VHF channels, so the VHF port fried. UHF was really weak at first, but came back to full strength. I took back the preamp. Now I'm not sure what I will do... I have had so many preamps fail, and most of them have been due to weather and power surges. I always unplug in severe weather, but had no warning on this event. This preamp works as well or even better than any I've had. I've had radio shack, Winegard, and channel masters over the years.
It is difficult to design a preamp that will survive a nearby strike, even if you have disconnected the power supply from the AC power.

Is the coax connected to a grounding block that is connected to the house electrical system ground? Is the mast also grounded?

I buy my RCATVPRAMP1R preamps from Walmart; they always look like new stock. Amazon has been known to send Warehouse Special returns that have a DOA power supply because they haven't been checked out.

The RCA preamp is so inexpensive, why not just replace it? It does have a history of a problem with the Combined/Separate antenna input switch. Sometimes it doesn't make good contact with the VHF input when in the Separate position.

Preamps with a very low Noise Figure, like the Kitztech, are more sensitive to static damage, but recent protection device improvements have made them more reliable. Other than that, I don't know of any preamp ratings for resistance to static damage. I wonder if the Antennas Direct Juice, or the Channel Master 3410 distribution amp used as a preamp would be any more reliable at your location. Since I haven't seen your TVFool report and don't know what antennas you are using, it is difficult to recommend a specific amp.

If you can not measure it, you can not improve it.
Lord Kelvin, 1883
www.megalithia.com/elect/aerialsite/dttpoorman.html
rabbit73 is online now  
post #68 of 127 Old 08-02-2018, 09:50 AM
AVS Forum Special Member
 
jspENC's Avatar
 
Join Date: Nov 2004
Location: Jacksonville, NC
Posts: 4,648
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 168 Post(s)
Liked: 29
Hello Rabbit.


I agree the preamp is not expensive. I have quite the complicated set-up. A tvfool report would not give you much for me, because it is just wrong. It shows just the opposite of what is reality for my location... Weak stations are shown as the strongest, and vice versa.


My antenna is grounded properly, if not, the strike would have fried the antennas and my TV's (which has happened before!)


My stations available are WWAY 46, WECT 44, WITN 32 WNCT 10 WCTI 12 WYDO 47 WUNM 19 WTMH 21 WSFX 30 WPXU 34 without an amp, but with an eagle aspen amplified splitter going to 3 TV's - Without this, I could not get WTMH at all, and WITN would be non watchable. All the others are fine.


With a preamp, I get WTMH perfect all the time, and add WUNK 23, WEPX 26 and WTMQ 35 (duplicates) with much higher signals on the first list of channels.


My antenna setup is a view TV 80 mile UHF pointing north, the VHF whisker just above, and a Winegard HD 8800 UHF pointing toward the southwest at the top 30 ft high. The two UHF's are joined with a splitter and go to a Radio shack gold combiner UHF/VHF
jspENC is offline  
post #69 of 127 Old 08-02-2018, 07:13 PM
AVS Forum Special Member
 
rabbit73's Avatar
 
Join Date: Apr 2008
Location: S.E. VA
Posts: 3,048
Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 775 Post(s)
Liked: 318
Quote:
Originally Posted by jspENC View Post
.....I have quite the complicated set-up. A tvfool report would not give you much for me, because it is just wrong. It shows just the opposite of what is reality for my location... Weak stations are shown as the strongest, and vice versa.
Yes, there are errors in the database used by TVFool to generate reports and they don't have sufficient staff to make corrections, especially with so many Repack changes.

This is a generic report centered on the intersection of Marine Blvd and Court St, near the Fort Sill National Bank, which might not be near your actual location:



This is a report from rabbitears.info with a list of channels that is more accurate:



Quote:
My antenna is grounded properly, if not, the strike would have fried the antennas and my TV's (which has happened before!)
Good. I lost a computer from a close strike. The computer was off, it was plugged into a surge suppressor strip that was off, but the strip was plugged in. The 20" Sony TV with a CRT in the living room survived, but the colors were weird. I turned it off and then on again, heard the normal "THUNK" sound of the degausser around the picture tube, and the colors were OK. The EMP from the close strike had magnetized the shadow mask.
Quote:
My stations available are WWAY 46, WECT 44, WITN 32 WNCT 10 WCTI 12 WYDO 47 WUNM 19 WTMH 21 WSFX 30 WPXU 34 without an amp, but with an eagle aspen amplified splitter going to 3 TV's - Without this, I could not get WTMH at all, and WITN would be non watchable. All the others are fine.

With a preamp, I get WTMH perfect all the time, and add WUNK 23, WEPX 26 and WTMQ 35 (duplicates) with much higher signals on the first list of channels.

My antenna setup is a pointing north, the VHF whisker just above, and a Winegard HD 8800 UHF pointing toward the southwest at the top 30 ft high. The two UHF's are joined with a splitter and go to a Radio shack gold combiner UHF/VHF
Combining two UHF antennas aimed in different directions with a splitter in reverse doesn't always work. You might think it is a signal problem, but it could be a combining problem. The same signals from two antennas will interfere with each other if they are not in phase when they arrive at the combining point. If you don't have all the signals when combined, that you had when the antennas were separate, that method of combining doesn't work for you.
Attached Thumbnails
Click image for larger version

Name:	jspENC AVSreport.JPG
Views:	270
Size:	292.3 KB
ID:	2436524   Click image for larger version

Name:	jspENC AVSreportRE.JPG
Views:	259
Size:	185.5 KB
ID:	2436526  

If you can not measure it, you can not improve it.
Lord Kelvin, 1883
www.megalithia.com/elect/aerialsite/dttpoorman.html

Last edited by rabbit73; 08-02-2018 at 09:14 PM.
rabbit73 is online now  
post #70 of 127 Old 08-03-2018, 06:58 AM
AVS Forum Special Member
 
jspENC's Avatar
 
Join Date: Nov 2004
Location: Jacksonville, NC
Posts: 4,648
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 168 Post(s)
Liked: 29
Quote:
Combining two UHF antennas aimed in different directions with a splitter in reverse doesn't always work. You might think it is a signal problem, but it could be a combining problem. The same signals from two antennas will interfere with each other if they are not in phase when they arrive at the combining point. If you don't have all the signals when combined, that you had when the antennas were separate, that method of combining doesn't work for you.

Thanks.



Yep, I tried just one antenna, and it worked fine if you had the antenna aimed just right on WITN, but then you don't get all the channels either, so you need a rotor, which was a pain when you have more than 1 TV, and more than 1 viewer.


Yesterday, WTMQ 35 must have been fixed, because now I get 75% on it. Also WITN is working just fine after the lightning and 14 inches of rain over the last month! Weird. I still get a little noise on WTMH 21 with the eagle aspen hooked up.


What do you think about a PCT amplified splitter? It has 8 db gain on each port. (4 ports)... The Eagle aspen has 2 I believe....
jspENC is offline  
post #71 of 127 Old 08-03-2018, 01:21 PM
AVS Forum Special Member
 
rabbit73's Avatar
 
Join Date: Apr 2008
Location: S.E. VA
Posts: 3,048
Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 775 Post(s)
Liked: 318
Quote:
Originally Posted by jspENC View Post
Yep, I tried just one antenna, and it worked fine if you had the antenna aimed just right on WITN, but then you don't get all the channels either, so you need a rotor, which was a pain when you have more than 1 TV, and more than 1 viewer.
Thank you for making the test. Unfortunately, that simple method of combining doesn't always work. Even if you only have 1 TV, there are problems with a rotor. You have to wait for it to aim the antenna in another direction and you have to rescan if your TV can't add a channel after scan for another direction.


You have a difficult location with channels in different directions that vary in signal strength. There are other ways to handle the problem besides a splitter in reverse, but they are more complicated. Like, you could settle for just one direction for all TVs, but have a separate tuner for just one TV for another direction, with its output connected to the AUX input of the TV.
Quote:
My stations available are WWAY 46, WECT 44, WITN 32 WNCT 10 WCTI 12 WYDO 47 WUNM 19 WTMH 21 WSFX 30 WPXU 34 without an amp, but with an eagle aspen amplified splitter going to 3 TV's - Without this, I could not get WTMH at all, and WITN would be non watchable. All the others are fine.
Quote:

With a preamp, I get WTMH perfect all the time, and add WUNK 23, WEPX 26 and WTMQ 35 (duplicates) with much higher signals on the first list of channels.

My antenna setup is a pointing north, the VHF whisker just above, and a Winegard HD 8800 UHF pointing toward the southwest at the top 30 ft high. The two UHF's are joined with a splitter and go to a Radio shack gold combiner UHF/VHF
WWAY ABC 46, -69.5 dBm, NM 21.4 dB, 225 degrees
WECT NBC 44, -70.8 dBm. NM 20.1 dB, 225 degrees
WITN NBC 32, -36.4 dBm, NM 54.5 dB, 2 degrees
WNCT CBS 10, -52.0 dBm, NM 38.9 dB, 2 degrees
WCTI ABC 12, -34.9 dBm, NM 56.0 dB, 12 degrees
WYDO Fox 47, -44.4 dBm, NM 46.5 dB, 12 degrees
WUNM PBS 19, -39.8 dBm, NM 51.1 dB, 12 degrees
WTMH IND 21, -45.2 dBm, NM 45.7 dB, 12 degrees
WSFX Fox 30, -75.4 dBm, NM 15.5 dB, 225 degrees
WPXU ION 34, -31.5 dBm, NM 59.4 dB, 183 degrees

WUNK PBS 23, -72.0 dBm, NM 18.9 dB, 350 degrees
WEPX ION 26, -82.0 dBm, NM 8.9 dB, 0 degrees
WTMQ 35 (WTMH)
Quote:
Yesterday, WTMQ 35 must have been fixed, because now I get 75% on it. Also WITN is working just fine after the lightning and 14 inches of rain over the last month! Weird. I still get a little noise on WTMH 21 with the eagle aspen hooked up.
If there are trees in the signal path, they will block the signals more when they are wet; the signals will improve when the trees are dry.

Quote:
What do you think about a PCT amplified splitter? It has 8 db gain on each port. (4 ports)... The Eagle aspen has 2 I believe....
With some signals that are very strong that don't need an amp and some signals that are weak and do need an amp, it is difficult to find a good compromise You might need to amplify only the weak channels and then combine. I don't know the specs for the Eagle Aspen, so I can't comment on it.

If you can not measure it, you can not improve it.
Lord Kelvin, 1883
www.megalithia.com/elect/aerialsite/dttpoorman.html
rabbit73 is online now  
post #72 of 127 Old 08-10-2018, 08:08 PM
Senior Member
 
ncsercs's Avatar
 
Join Date: May 2001
Location: Westmont, IL
Posts: 365
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 143 Post(s)
Liked: 70
I have one and have a question.....

There is a UHF antenna in the UHF input.

Want to put another UHF antenna in another part of the room to get a few other channels.

Can I plug this in the VHF input or do I need a combiner or a splitter?

Nick

Every day I beat my own previous record for the number of consecutive
days I've stayed alive. - George Carlin - 1996
ncsercs is offline  
post #73 of 127 Old 08-10-2018, 08:41 PM
AVS Forum Special Member
 
tylerSC's Avatar
 
Join Date: Jun 2010
Location: Mauldin SC, 29607
Posts: 6,199
Mentioned: 3 Post(s)
Tagged: 1 Thread(s)
Quoted: 1049 Post(s)
Liked: 212
Quote:
Originally Posted by ncsercs View Post
I have one and have a question.....

There is a UHF antenna in the UHF input.

Want to put another UHF antenna in another part of the room to get a few other channels.

Can I plug this in the VHF input or do I need a combiner or a splitter?
You will need a splitter/combiner for the UHF side of the preamp because the VHF side will attenuate or block the UHF channels.
ncsercs likes this.
tylerSC is offline  
post #74 of 127 Old 08-11-2018, 02:27 AM
Senior Member
 
ncsercs's Avatar
 
Join Date: May 2001
Location: Westmont, IL
Posts: 365
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 143 Post(s)
Liked: 70
Quote:
Originally Posted by rabbit73 View Post
Amazon has a review by an installer who received "warehouse specials" that had DOA power supplies.
I know this is old but.....

Is there any way to open up the power injector and fix or improve the power supply?

Nick

Every day I beat my own previous record for the number of consecutive
days I've stayed alive. - George Carlin - 1996
ncsercs is offline  
post #75 of 127 Old 08-11-2018, 12:20 PM
AVS Forum Special Member
 
rabbit73's Avatar
 
Join Date: Apr 2008
Location: S.E. VA
Posts: 3,048
Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 775 Post(s)
Liked: 318
Quote:
Originally Posted by ncsercs View Post
I know this is old but.....

Is there any way to open up the power injector and fix or improve the power supply?
It is possible to pop open the power injector, but it might be difficult to close it again. It really wasn't designed to be opened and repaired; it's sealed. I would like to open mine to see what is inside, but I'm not willing to risk damaging it and have to buy another one at this point.

Someone else might have opened their power inserter and can show us a photo.

I have opened some UVSJs and was curious enough to see what was inside that I was willing to damage them.

The power injector most likely just contains a capacitor and a choke. The part that is most likely to malfunction is the power transformer that is connected to the power inserter.

Pete Higgins did a review of the TVPRAMP1R and stated that the power inserter contained a voltage regulator. He showed photos of the preamp circuit board, but he didn't show a photo of the inside of the power inserter:
http://forum.tvfool.com/showthread.php?t=13530

If you have the technical skills, it is possible to assemble a bench power supply or AC to DC adapter, a PCT power inserter, and a series resistor to simulate what the RCA power inserter and power transformer do, but it would be a lot more expensive than buying another TVPRAMP1R from Walmart. Why bother, unless you are curious enough to look inside?

Earlier in this thread I showed how to test the RCA TVPRAMP1R preamp.
ncsercs likes this.

If you can not measure it, you can not improve it.
Lord Kelvin, 1883
www.megalithia.com/elect/aerialsite/dttpoorman.html

Last edited by rabbit73; 08-11-2018 at 04:11 PM.
rabbit73 is online now  
post #76 of 127 Old 08-11-2018, 06:43 PM - Thread Starter
AVS Forum Special Member
 
Calaveras's Avatar
 
Join Date: Jan 2007
Location: Mountain Ranch
Posts: 5,793
Mentioned: 20 Post(s)
Tagged: 0 Thread(s)
Quoted: 1636 Post(s)
Liked: 348
I took mine apart. It's very easy to pop off the plastic top but the components are covered by a shield soldered to the board. There are some non-shielded components on the back.

The regulator looks to be the 1.25V version as that's the voltage I measured between the output pin and the GND/ADJ pin. Voltages can only be measured with the preamp connected. The no load output voltage is around 18V. The loaded output voltage is about 10V. I think this is because of the power supply which measures 18V under no load and 12V under load. I've seen other switching supplies behave like this.

I don't know why they're using a regulator like this in such a configuration. Seems unnecessarily complicated to me.

Edit: Added schematic. The regulator is a AX1117A Adjustable. I didn't measure the resistors to calculate the output voltage.
Attached Thumbnails
Click image for larger version

Name:	RCA Power Inserter.jpg
Views:	40
Size:	384.2 KB
ID:	2440666   Click image for larger version

Name:	RCA Power Inserter Schematic.jpg
Views:	22
Size:	52.4 KB
ID:	2440902  
ncsercs and rabbit73 like this.

Last edited by Calaveras; 08-12-2018 at 02:41 PM.
Calaveras is offline  
post #77 of 127 Old 08-11-2018, 07:41 PM
Senior Member
 
ncsercs's Avatar
 
Join Date: May 2001
Location: Westmont, IL
Posts: 365
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 143 Post(s)
Liked: 70
Quote:
Originally Posted by rabbit73 View Post
The power injector most likely just contains a capacitor and a choke. The part that is most likely to malfunction is the power transformer that is connected to the power inserter.
Based on this and what Calaveras just posted, it seems as if the wall wart is the weak point.

Nick

Every day I beat my own previous record for the number of consecutive
days I've stayed alive. - George Carlin - 1996
ncsercs is offline  
post #78 of 127 Old 08-12-2018, 09:06 AM
AVS Forum Special Member
 
rabbit73's Avatar
 
Join Date: Apr 2008
Location: S.E. VA
Posts: 3,048
Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 775 Post(s)
Liked: 318
Quote:
Originally Posted by Calaveras View Post
I took mine apart. It's very easy to pop off the plastic top but the components are covered by a shield soldered to the board. There are some non-shielded components on the back.
Thanks for the photo so that we can see what's inside. The IC is an AX1117 adjustable low-dropout linear regulator.
Quote:
I don't know why they're using a regulator like this in such a configuration. Seems unnecessarily complicated to me.
I didn't expect that many components inside. If the regulator is connected to limit output current, it would protect against a short in the coax to the amp.

If you can not measure it, you can not improve it.
Lord Kelvin, 1883
www.megalithia.com/elect/aerialsite/dttpoorman.html

Last edited by rabbit73; 08-12-2018 at 09:48 AM.
rabbit73 is online now  
post #79 of 127 Old 08-12-2018, 01:07 PM
AVS Forum Special Member
 
jspENC's Avatar
 
Join Date: Nov 2004
Location: Jacksonville, NC
Posts: 4,648
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 168 Post(s)
Liked: 29
I'm probably going to get another one of these, unless someone knows for certain if the channel master 7778 is better protected from lightning. The old models had protection as I recall. I had one of them for many years, and through many T-storms.
jspENC is offline  
post #80 of 127 Old 08-28-2018, 02:20 PM
AVS Forum Special Member
 
jspENC's Avatar
 
Join Date: Nov 2004
Location: Jacksonville, NC
Posts: 4,648
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 168 Post(s)
Liked: 29
So I ordered and installed the Winegard boost LNA - 200 since I last posted. This pre-amp is a beast, and is much better than the RCA in terms of it's drawing in a stations signal. I've picked up channels I have never received before, and also sooner and more often once the sun sets. Stations from the low country of SC, and well into Virginia come in like they are a local each evening. I picked up a low power in Durham, WTNC LD, and that is just unbelievable, even though I saw it myself with no break ups.



There is no contest, the Winegard is the winner for me. Now the question remains, how long will it last?

Last edited by jspENC; 08-28-2018 at 02:26 PM.
jspENC is offline  
post #81 of 127 Old 08-28-2018, 03:16 PM
AVS Forum Special Member
 
tylerSC's Avatar
 
Join Date: Jun 2010
Location: Mauldin SC, 29607
Posts: 6,199
Mentioned: 3 Post(s)
Tagged: 1 Thread(s)
Quoted: 1049 Post(s)
Liked: 212
Quote:
Originally Posted by jspENC View Post
So I ordered and installed the Winegard boost LNA - 200 since I last posted. This pre-amp is a beast, and is much better than the RCA in terms of it's drawing in a stations signal. I've picked up channels I have never received before, and also sooner and more often once the sun sets. Stations from the low country of SC, and well into Virginia come in like they are a local each evening. I picked up a low power in Durham, WTNC LD, and that is just unbelievable, even though I saw it myself with no break ups.



There is no contest, the Winegard is the winner for me. Now the question remains, how long will it last?
The Winegard LNA-200 has had mixed reviews here so it is good to hear it is working very well for you. It is sold locally at Home Depot but sounds like you ordered from an online vendor.

I have good luck with the Channel Master Amplify, the 7777HD version with the adjustable gain. Have not tried the new dual input version, the Amplify Plus which they call the 7778HD. It would be good if you have separate UHF and VHF antennas, but they need to have a price drop. The regular Amplify has been selling for $69, a reduction from $89. The Amplify Plus is a bit pricey at $99.

Also with the RCA preamp you can substitute a better power supply if you choose to.
tylerSC is offline  
post #82 of 127 Old 08-28-2018, 08:06 PM
AVS Forum Special Member
 
ProjectSHO89's Avatar
 
Join Date: Feb 2009
Posts: 3,277
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 335 Post(s)
Liked: 155
Quote:
Originally Posted by jspENC View Post
So I ordered and installed the Winegard boost LNA - 200 since I last posted. This pre-amp is a beast, and is much better than the RCA in terms of it's drawing in a stations signal. I've picked up channels I have never received before, and also sooner and more often once the sun sets. Stations from the low country of SC, and well into Virginia come in like they are a local each evening. I picked up a low power in Durham, WTNC LD, and that is just unbelievable, even though I saw it myself with no break ups.
There is no contest, the Winegard is the winner for me. Now the question remains, how long will it last?

Most likely, you experiencing a temporary period of enhanced atmospheric propagation, not a magical preamplifier.


You'll probably have to curb your enthusiasm once the atmosphere returns to normal.
ProjectSHO89 is online now  
post #83 of 127 Old 08-29-2018, 05:27 AM
AVS Forum Special Member
 
jspENC's Avatar
 
Join Date: Nov 2004
Location: Jacksonville, NC
Posts: 4,648
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 168 Post(s)
Liked: 29
Quote:
Originally Posted by ProjectSHO89 View Post
Most likely, you experiencing a temporary period of enhanced atmospheric propagation, not a magical preamplifier.


You'll probably have to curb your enthusiasm once the atmosphere returns to normal.

You could be right, but I don't think so, because I have had OTA TV for many years, not long after digital TV got started, and I've never had this kind of reception, but if something changes, I'll update my review. As for now, I have to say that the Boost blows away the RCA. Typically for me, the winter gives better results, because I live in an area with huge trees all over the place.



I have two UHF antennas joined together by a splitter for stations in my area that are in opposite directions, and then a Radio shack gold combiner joining a VHF element, which then runs into the preamp. The antennas are over 25 ft high. One is the Winegard HD8800 and the other is a ViewTV 80 mile.
jspENC is offline  
post #84 of 127 Old 08-29-2018, 07:49 AM - Thread Starter
AVS Forum Special Member
 
Calaveras's Avatar
 
Join Date: Jan 2007
Location: Mountain Ranch
Posts: 5,793
Mentioned: 20 Post(s)
Tagged: 0 Thread(s)
Quoted: 1636 Post(s)
Liked: 348
Quote:
Originally Posted by ProjectSHO89 View Post
Most likely, you experiencing a temporary period of enhanced atmospheric propagation, not a magical preamplifier.


You'll probably have to curb your enthusiasm once the atmosphere returns to normal.

You beat me to it! He should get back to us after a month. It's not possible to draw conclusions after only a day or two. Unusual conditions have fooled me too many times after making a change. I know better these days. There's nothing I measured in the bench tests of the RCA and LNA-200 preamps that would lead me to believe that you'd see much difference between the two.
rabbit73 likes this.
Calaveras is offline  
post #85 of 127 Old 08-29-2018, 08:04 AM
AVS Forum Special Member
 
rabbit73's Avatar
 
Join Date: Apr 2008
Location: S.E. VA
Posts: 3,048
Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 775 Post(s)
Liked: 318
Quote:
Originally Posted by jspENC View Post
Typically for me, the winter gives better results, because I live in an area with huge trees all over the place.
The loss of the leaves probably compensates for the loss of Tropospheric Propagation. But, we really can't be certain because we can't see the signal lines in relation to the trees in a satellite view of your antenna location.

Trees block TV signals.
http://www.hdtvprimer.com/ANTENNAS/siting.html
scroll down to Trees and UHF



Quote:
Originally Posted by jspENC View Post
My antenna setup is a view TV 80 mile UHF pointing north, the VHF whisker just above, and a Winegard HD 8800 UHF pointing toward the southwest at the top 30 ft high. The two UHF's are joined with a splitter and go to a Radio shack gold combiner UHF/VHF

Quote:
Originally Posted by jspENC View Post
Yep, I tried just one antenna, and it worked fine if you had the antenna aimed just right on WITN, but then you don't get all the channels either, so you need a rotor, which was a pain when you have more than 1 TV, and more than 1 viewer.
Yes, having more than one direction and more than one TV makes a solution more complex. But, you are obviously not satisfied with your present compromise solution.

If combining two UHF antenas with a splitter in reverse doesn't work as well as separate UHF antennas, then your antenna system is not optimum for your location.

So, now you have two factors working against good reception: the trees and non-optimum combining.

If you can not measure it, you can not improve it.
Lord Kelvin, 1883
www.megalithia.com/elect/aerialsite/dttpoorman.html

Last edited by rabbit73; 08-29-2018 at 08:46 AM.
rabbit73 is online now  
post #86 of 127 Old 08-29-2018, 11:43 AM
AVS Forum Special Member
 
jspENC's Avatar
 
Join Date: Nov 2004
Location: Jacksonville, NC
Posts: 4,648
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 168 Post(s)
Liked: 29
The combining two UHF antennas was much better than just the one antenna. I was able to get the low power station WTMH this way, and also WITN, which was terrible with the antenna aimed towards the southwest. I have to point this way to get the most channels. MeTV on WITN is all I care about on that channel. I do not watch NBC on there. I did not want to use a rotor since there are other viewers which sometimes want to watch the channels in the opposite directions. I also have VHF high stations that need the whisker, so 3 antennas combined, two with a backwards splitter, and those are joined to a VHF/UHF combiner designed for just that purpose, and that gives a boost of it's own to the UHF channels. This morning I had CBS and ABC from Richmond. I have never watched these for an hour, let alone picked them up before to where I could watch them. Also WSKY 9 was on, and I have never seen it since the transition from analog. The boost preamp brought it in... I never saw it with the Stellar labs VHF I used to have up, which was a good VHF antenna.



The trees are to my west and east. The south and north are fairly clear due to the street directions. The direction to the main towers is downhill to the south, which helps out.
jspENC is offline  
post #87 of 127 Old 08-29-2018, 06:34 PM
AVS Forum Special Member
 
JHBrandt's Avatar
 
Join Date: Apr 2008
Location: S. Garland, TX
Posts: 6,422
Mentioned: 60 Post(s)
Tagged: 0 Thread(s)
Quoted: 2541 Post(s)
Liked: 1232
Quote:
Originally Posted by Calaveras View Post
You beat me to it! He should get back to us after a month. It's not possible to draw conclusions after only a day or two. Unusual conditions have fooled me too many times after making a change. I know better these days. There's nothing I measured in the bench tests of the RCA and LNA-200 preamps that would lead me to believe that you'd see much difference between the two.
Very true. However, also consider the possibility of manufacturing variation between preamps of the same model. He may have been lucky and gotten an LNA-200 with an exceptionally good NF, or you may have been unlucky and gotten one with an exceptionally poor NF (or both).
JHBrandt is offline  
post #88 of 127 Old 08-29-2018, 07:51 PM - Thread Starter
AVS Forum Special Member
 
Calaveras's Avatar
 
Join Date: Jan 2007
Location: Mountain Ranch
Posts: 5,793
Mentioned: 20 Post(s)
Tagged: 0 Thread(s)
Quoted: 1636 Post(s)
Liked: 348
Quote:
Originally Posted by JHBrandt View Post
Very true. However, also consider the possibility of manufacturing variation between preamps of the same model. He may have been lucky and gotten an LNA-200 with an exceptionally good NF, or you may have been unlucky and gotten one with an exceptionally poor NF (or both).
The LNA-200 average NF on UHF was 3.0 dB and the RCA average on UHF was 3.3 dB for the ones I measured. I suppose his RCA could be defective and has a really bad NF. Short of that, it's impossible for the LNA-200 NF to be better than 2 dB and almost no one can distinguish a 1.3 dB difference unless you carefully do a real time A/B comparison. The kind of improvement he reported sounded more like 10 dB.

No matter how you look at it, I don't think it's a valid test.
rabbit73 likes this.
Calaveras is offline  
post #89 of 127 Old 08-30-2018, 07:07 AM
AVS Forum Special Member
 
jspENC's Avatar
 
Join Date: Nov 2004
Location: Jacksonville, NC
Posts: 4,648
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 168 Post(s)
Liked: 29
Sometimes less is more. It could be the RCA was too powerful for my location and picked up strong cell towers. I have a better result at the tuner with the boost is all I know, and that's all that matters in my application. It feeds 3 TV's. I was less than impressed with the RCA longevity, that's for sure. I certainly can't recommend it for people that have their antennas installed way up over the roof or on a tower, because the failure rate would have them climbing more than I would want to. I may order a channel master in a few weeks just to see what it will do in comparison. My pre-amp connects on the ground (I've learned from the past on having to climb too much) and I could switch it fast. Once I am satisfied that it is going to last, I may put it close up on the antenna, but I can't imagine it would be better, and may be worse from too much interference. I have LP FM radio just a couple of miles away.
jspENC is offline  
post #90 of 127 Old 08-31-2018, 10:31 AM
Senior Member
 
Lend27's Avatar
 
Join Date: Jan 2002
Location: Georgia
Posts: 365
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 208 Post(s)
Liked: 53
Quote:
Originally Posted by tylerSC View Post
The Winegard LNA-200 has had mixed reviews here so it is good to hear it is working very well for you. It is sold locally at Home Depot but sounds like you ordered from an online vendor.



I have good luck with the Channel Master Amplify, the 7777HD version with the adjustable gain. Have not tried the new dual input version, the Amplify Plus which they call the 7778HD. It would be good if you have separate UHF and VHF antennas, but they need to have a price drop. The regular Amplify has been selling for $69, a reduction from $89. The Amplify Plus is a bit pricey at $99.



Also with the RCA preamp you can substitute a better power supply if you choose to.


Can I use a Power Supply from an old Channel Master CM7775 preamp with the RCA preamp?


Sent from my iPad using Tapatalk
Lend27 is offline  
Sponsored Links
Advertisement
 
Reply HDTV Technical



Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off