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Old 8-Aug-2013, 3:29 AM   #1
Pete Higgins
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RCA TVPRAMP1R Amplifier

I want to report my findings with my new RCA TVPRAMP1R Amplifier. This looks like one of the few remaining switchable dual VHF/UHF input, mast mounted, pre-amps. with a switchable FM trap. I got mine for $22.80 delivered from NothingButSoftware.com, but they are available through Walmart for $21.95, Office Depot for $22.99 and Solid Signal for $27.99 plus $4.95 shipping.

Manufacturer (for RCA) is VOXX International
RCA literature says :”Outperforms old preamps made for analog & preserves signal purity with Extremely Low Noise (ELN) circuitry” but doesn’t specify an actual NF. Other features listed include:
Separate or combined inputs for UHF/VHF (switchable)
Switchable FM trap reduces interference from FM frequencies

Before I ordered it I contacted Audiovox Electronics (the company who makes them for RCA) and requested its specifications. I received the following information in an email.

From Audiovox Electronics:
The TVPRAMP1R is spec at: 16dB gain with a 2dB noise figure and 22dB gain with a 3dB noise figure.

Thank you for using Audiovox Electronics

A follow up email indicated they did not have any more data available.

A technician @ Antennas Direct who goes by “ADTech” on the digital home web site had previously characterized this model around Christmas time and shared what he found on that forum. He has access to some pretty impressive HP test equipment for characterizing preamps. including an HP8569B Spectrum Analyzer & an HP 8970A Noise Figure Meter.

Here is what he found for the RCA TVPRAMP1R:
Low VHF - 3.9 dB NF/16 dB gain
High VHF - 3.1 dB NF/16.2 dB gain
UHF - 2.6 dB NF/23.7 dB gain

I wasn’t bothered that the RCA didn’t quite live up to its published specifications. On the contrary, it came much closer than others –some of which I own.

He also provided his sweep data of the FM Trap which I plotted. He used an HP 8970A that makes simultaneous noise figure and gain measurements. 5 data points were missing due to an 8970A annoyance in its data output where if the measured NF exceeds its self-calibrated max input (usually between 30 and 35 dB NF), it outputs a standard "garbage" value for both NF and gain that has to be ignored. Rather than substitute “filler” values, I chose to ignore the missing data. His data indicate a double notch filter offset to prevent channel six attenuation.



The supplied power brick is hard wired to the power inserter and is rated @ 12 VDC, 200 ma. Mine actually outputs 16.63 VDC. Output from the power inserter measured 9.50 VDC unloaded and 9.47 VDC with the amplifier connected. This is important to know because unlike my Winegard amps that have the voltage regulation in the mast head unit the RCA amp. has the regulation in the power inserter. For long cable runs or if you decide to use a different power supply/inserter you will need to insure 9-10 volts is delivered to the amp. I took mine apart to compare it to both of my Winegard preamps.





I probably wouldn’t have bought the RCA TVPRAMP1R Amplifier if ADTech hadn’t indicated they bench checked pretty good (compared to other preamps. he’s tested), well that and the fact that it only cost $22.80 delivered. I owe him a debt of gratitude for all the work he’s done and for sharing his data.

I connected my new RCA TVPRAMP1R Amplifier to my HDB8X & YA 1713 to give it a try. Voltage at the amplifier input measured 9.50 volts through 50’ of solid copper RG-6. I had it set for dual VHF/UHF inputs with the FM trap switched in. I wanted to first try it without the Antennas Direct FM band pass filter and the Channel Plus NF-471 channel 24-29 filter that I have to use to keep my Winegard AP-2870 from overloading to see how badly the new RCA overloaded. Boy was I surprised. It didn’t show any signs of overload!

The NF-471 is designed to remove RF channels 24-29 but rolls off slow enough that at my location it also removes channel 30 (KPBS, 15.1 @ -96.3 dBm from San Diego) and channel 31 (KTLA, 5.1 @ -103.5 dBm from LA) plus channel 32 (KDOC, 56.1 @ -110.9 dBm from LA). So by just swapping out the AP-2870 with its required filtering I added channel 24 (KBEH, 63.1 @ -98.6 dBm from LA), channel 26 (KVCR, @ -15.60 dBm from Box Springs Mtn.), channel 30 (KPBS, 15.1 @ -96.3 dBm from San Diego) and channel 31 (KTLA, 5.1 @ -103.5 dBm from LA) plus channel 32 (KDOC, 56.1 @ -110.9 dBm from LA). Not sure why I couldn’t get channel 29 (KFTR, 46.1 @ -107.4) but it wasn’t there with my 91XG/PCT MA2-M combination either.

I should probably be shot for what I tried next, but I pointed my CM-4228 towards LA and combined its output with the HDB8X and applied that to the UHF input. This should give me a further boost in signal strength probably >1dB & <3 db. While I can’t quantify how much of a boost in signal strength this gave me, it wasn’t enough to put the RCA into overload. Based on a sample size of one, and some less than scientific testing I conclude that the RCA TVPRAMP1R Amplifier is way more overload resistant than my Winegard AP-2870 and possibly even my single input Winegard HDP-269. The HDP-269 is specified for high signal environments but last year when I had mine connected to my 91XG/Y10 7-13 through a UVSJ it was overloading, which is why I switched that array over to PCT MA2-M drop amps.

Finally, I disconnected the dual UHF antenna configuration and connected just my CM-4228 to the RCA’s UHF input. Subjectively, I couldn’t tell any difference between the two UHF antennas when used with the RCA preamplifier.


I did feel like, on a channel-by-channel basis, my SNR’s were higher than with the AP-2870. Again, that’s very subjective and could be nothing more than propagation. Dealing with predominately 1-Edge & 2-Edge signals I experience a lot of day-to-day and even hour by hour variation in signal quality.


The signals that I suspect overload both of my Winegard amps. are an FM station KOLA on 99.9 MHz @ -13.4 dBm and KVCR on RF channel 26 @ -15.6 dBm. Both stations are on Box Springs Mtn. ~ 3.5 miles from my back door. To make matters worse, I have to point my antennas right at them to get the LA stations.

Based on one day of testing, I think this is a quality product that has shown good tolerance to overload. Here is a link to my TV Fool report so you can see the type of signal environment I’m faced with.
http://www.tvfool.com/?option=com_wr...1dda169109ca5c
Attached Images
File Type: jpg RCA FM Band.JPG (46.5 KB, 5051 views)
File Type: jpg RCA TVPRAMP1R Amplifier 1 TV Fool.jpg (440.4 KB, 5309 views)
File Type: jpg RCA TVPRAMP1R Amplifier 3.jpg (396.8 KB, 5330 views)
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Old 10-Aug-2013, 4:27 PM   #2
tripelo
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Compare Original CM-777x to TVPRAMP1R

Quote:
Originally Posted by Pete Higgins View Post
... report my findings with my new RCA TVPRAMP1R Amplifier. This looks like one of the few remaining switchable dual VHF/UHF input, mast mounted, pre-amps. with a switchable FM trap.
Hi Pete.

Thank you for your efforts.

Your efforts to characterize and describe components are undoubtedly helpful to many others.

Thank you for your images.

They looked familiar.

Attached are a couple of images comparing images of the original CM-777x to your image of the RCA preamp.



The image below is the coil/switch side of the PCBs.

Notice that the coaxial connectors are on opposite sides of the PCBs.



.
Attached Images
File Type: jpg Trace side CM777x _RCA.jpg (152.7 KB, 4842 views)
File Type: jpg Coil Side-CM777x_RCA Comp.jpg (144.7 KB, 4868 views)
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Old 10-Aug-2013, 5:58 PM   #3
Pete Higgins
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RE: Compare Original CM-777x to TVPRAMP1R

tripelo,

Thanks for posting the photos.

It does look like it could be a re-layout of the Channel Master legacy design, only with a higher parts count. Usually the goal is to make things cheaper by reducing the parts count. I wonder if Audiovox made them for both Channel Master and RCA?

If it is a re-layout, I’m surprised the RCA showed the immunity to overload I experienced. From what I’ve read the Channel Masters had good gain and noise figure specifications but were prone to overload in strong or mixed strong/fringe environments. With my -13.4 dBm FM & -15.6 dBm TV stations I would have expected the Channel Masters to overload even worse than the Winegard’s.

Do you know if the CM-7777 or CM-7778 had onboard voltage regulation? I don’t see anything that looks like it could be a voltage regulator but that was one convenience of the Winegards. Also, did the Channel Master amps have any shielding? It looks like reversing the mounting orientation allowed better shielding for the coils.

In any case, I’m glad I found the RCA’s. I thought with both Channel Master & Winegard discontinuing their dual input pre-amps. it was going to create a real hardship for those of us that use separate VHF and UHF antennas. It doesn’t hurt that the RCA is available through local outlets like Walmart & Office Depot for less than half the price of the Channel Masters & Winegards.

I’m anxious to see how the one I just ordered performs on my tower.

Last edited by Pete Higgins; 10-Aug-2013 at 6:30 PM.
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Old 10-Aug-2013, 6:48 PM   #4
tripelo
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Quote:
Originally Posted by Pete Higgins View Post
...It does look like it could be a re-layout of the Channel Master legacy design, only with a higher parts count. Usually the goal is to make things cheaper by reducing the parts count...
It is not a complete re-layout, looks like a minimum re-layout.

Probably etch was changed only where necessary, i.e. to replace components that may not be available or may be to costly.

An example:

The modular FM Trap was replaced with discrete parts. That did increase parts count.

Quote:
I wonder if Audiovox made them for both Channel Master and RCA?
Could be.

Quote:
... I’m surprised the RCA showed the immunity to overload I experienced.
Yes, interesting.

Quote:
Do you know if the CM-7777 or CM-7778 had onboard voltage regulation?
No the older CM-777x didn't have on-board regulators, or off-board either (CM-0747).

The CM-777x series used a bank of resistors to lower the supply Voltage.

At the left of both images (CM & RCA) you can see those paralled resistors. The RCA has fewer ( count 3 and 2), than the CM (count 5 and 4), probably because the Voltage is regulated down before it gets to the RCA preamp.

The CM-0265 (related to CM-0264) had an on-board regulator.

Quote:
...I don’t see anything that looks like it could be a voltage regulator but that was one convenience of the Winegards...
Some of the Winegards have a regulator in the inserter as well as in on the PCB.

Note: The above regulator comments apply only to the CM and WG preamplifiers that I have scrutinized.

Quote:
...did the Channel Master amps have any shielding?...
Yes. The CM-777x has a metal housing, it is fairly tight with respect to RF.

Quote:
...It doesn’t hurt that the RCA is available through local outlets like Walmart & Office Depot for less than half the price of the Channel Masters & Winegards.
Yes, good for OTA'ers.

.

Last edited by tripelo; 11-Aug-2013 at 5:30 PM. Reason: Add Note & CM shield comment
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Old 13-Aug-2013, 4:58 AM   #5
GroundUrMast
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Pete, thank you for the time and money you've put into this review!

I have to admit that I have always had a hard time recommending RCA product due to their lack of meaningful documentation. RCA owes you more than a passing 'thank you' for doing what they should have already done themselves.

This and the ANT-751 have made the list of credible products, no thanks to RCA's efforts, but rather to the kindness of folks like you who have spent their own time and money to test the products and then share the knowledge.

Again, Thank You
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If the well is dry and you don't see rain on the horizon, you'll need to dig the hole deeper. (If the antenna can't get the job done, an amp won't fix it.)

Last edited by GroundUrMast; 13-Aug-2013 at 5:01 AM. Reason: sp.
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