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roger1818,

I somewhat agree with BOUVAL, the most vulnerable portions of the RCA’s circuits are already pretty well shielded. Not only is there a full length metal plate that all three ‘F’ connectors contact, there are two “through-hole” spring clips in the center of the circuit board to provide additional grounding for the exposed (green) backplane. It’s hard to see in the photographs, but the ‘F’ connectors have square bodies that serve as standoffs to separate the coil side (brown) of the circuit board and the metal plate. The RCA uses discrete chip inductors & capacitors with a fairly tight packing density that should yield much less “antenna effect” for signal pickup than the Winegard design. Because of this, I don’t think mounting it in a metal enclosure would significantly (or even moderately) affect performance as long as you allowed ~1” or more of clearance between the green side of the circuit board and the enclosure.

On the other hand, my AP-2870 circuit board is completely surrounded by plastic and as near as I can tell the plastic doesn’t afford any shielding. It uses numerous micro strip-line inductors etched on completely unshielded portions of the circuit board. These form resonant circuits that I believe makes their design cheaper to mass produce but much more vulnerable to signal ingress (pickup). I have considered mounting my Winegard’s in metal boxes and shared BOUVAL’s concerns of the shielding upsetting the distributed stages.

I didn’t think to measure the board, and believe additional shielding would only be marginally effective in the harshest of environments. If you still think you’ll need additional shielding, I’ll be happy to pull it down and measure it for you.
 

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True enough. After I posted the question, I was thinking more about it and you are right and the metal plate along with the ground plane and clips should form a Faraday cage. As long as the holes in the cage are smaller than the shortest wavelength you are worried about, it will provide effective shielding.
 

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Using DiSEqC Rotor 18VDC with RCA Amp.

majortom,

You may be able to use your rotors 18 VDC without running new cable. It looks like the power comes in to the RCA amplifier and splits in two directions. You might get away with cutting the traces on both sides of the power input ‘F’ connector and bridging the cuts with 2200 picofarad (pf) chip capacitors. Then mount an L7810 (or equivalent) to the green side of the circuit board. Scrape away some of the ground plane resist and solder the center terminal of the L7810 to the ground plane. Run a jumper from the power input ‘F’ connector center conductor to the L7810 input pin. Tack solder a 10 millihenry (mh) choke to each of the original power paths and connect the other ends to the L7810, 10 V output leg. I would also bypass the output leg with a .1 uF capacitor to the ground plane.



Basic Idea:
Cutting the traces keeps your rotors voltage out of the amplifier. The 2200 picofarad (pf) chip capacitors couple the RF signal to the output. The regulator lowers the input voltage to 10V. The 10 millihenry (mh) chokes apply 10 V back to the amplifier's voltage paths.
 

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The metal plate in the RCA provides is a far from complete Faraday shield at RFI ingress shielding. The noise figure meter readings show the painful results. Still, it's better than the all-plastic boxes.

FM ingress shows up as spikes to more than 10 dB (filter off), Verizon's 4G wireless more than 7 dB. Other sources including idle lab gear are anywhere from .5 to 3+, depending of frequency and incoming signal power.

Still, not bad for an amp that retails for not much more than a single Jackson.
 

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ADTech,

I’ve got a second RCA due to arrive on Wednesday. I’ll swap out the first one with the new one to test it and then make up new cables and install it on my tower.

I doubt that my local FM or TV station signal strengths vary unless they were to change power or antenna radiation patterns. I am, however, a little apprehensive reporting amplifier results because my 1-Edge & 2-Edge signals show a lot of variance. At least with antennas, I can swap between them using a coaxial switch and take my readings a few seconds apart. I did swap out the AP-2870 (with your FM filter and the NF-471) from where it was constantly overloaded with the RCA and no filters and so far it hasn’t shown any signs of overload. Can’t be sure if the additional shielding is preventing sufficient ingress or the design is inherently more overload resistant.

On the plus side, since Time Warner dropped CBS -and CBS is blocking Time Warner internet access; my wife & I were able to watch Unforgettable on CBS last night out of San Diego using the RCA. We also watched the CBS news out of LA @ 11:00 PM, although the LA station wasn’t strong enough to watch @ 9 PM.
 

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Looks like the power insertor that comes with it has a 3 terminal regulator inside it, an AX1117. Essentially the same function as an LM317 adjustable regulator. Looking at the values of R1 and R2 (200 and 1.3 Kohm) it is designed to output ~ 9.4 VDC, and indeed what I measured coming out of it.
I took the liberty of disassembling it, replacing the wall wart with an F Connector, so I can more easily test it by powering the device with my Rotor. Doesn't look like it'd be too hard to place that circuit inside the Amp itself, but this should suffice for now. Of course I'll have to find some other type of weather proof box or sumthin to seal it up in if it works out OK and I decide to keep this in place. We'll see what happens here in a few days.






 

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majortom,

Nice work. Very useful information -thanks for sharing.

How did you get the plastic covers off? How were you able to unsolder the back plate?

The one I ordered last Thursday night, arrived today. I wasn’t expecting it until Wednesday. I measured the output voltage from its power supply and it measured 9.41 VDC unloaded & 8.91 VDC with the amp. inline. Current draw built up slowly as the unit heated up to a maximum of 78.8 ma so (if I looked at the right rotor) your rotor supply should handle the amp. just fine. With less than 80 ma draw, a 1200 ma regulator seems like overkill! Not sure how you wired the new port, but I assume you wired it to bypass the pigtail, so the RF goes out the new port and through the rotor?

I had just left for a Urologist appointment when it arrived and got home too late do any more than bench check it. Doctors seem to think because I’m over 70, I should have something wrong. They can’t find anything, but just like a gambling addiction, they want to keep testing until they get lucky. I still remember the vice principle telling me I wouldn’t live to see 18.

I plan to drop my tower tomorrow and try the new amp. If I get it all done I’ll post back. Good luck with yours.
 

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Nice, glad ur hangin in there Pete...
The plastic case snaps together, so pretty easy to get it apart.
I have a Weller 8200 Soldering Gun that I use when working on antique radios (the other part time hobby). They only tack solder it in 4 corners, so pretty easy to unsolder even if ya used a soldering iron. I used a 2.2uH choke (what I had handy) from the TV connection to where the pigtail + lead was. So really don't need the extra F connector. Fills in the empty hole though, LOL. We'll see how it goes.
 

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RCA TVPRAMP1R Amplifier

I received my second RCA preamplifier on Monday. Unfortunately, I got home too late to do any more than bench check it. Ordered Thursday night –delivered on Monday.

Yesterday, I dropped my tower and removed the PCT MA2-M from my 91XG.



I also removed the PCT MA2-M from my Antennacraft Y10 7-13.

I made up new antenna cables w/boots and installed the RCA TVPRAMP1R Amplifier on the mast between the two antennas. I configured it for separate inputs with the FM trap selected.

(It works better vertical!)

I decided to use the supplied power supply/inserter. The run from the garage to the amplifier is ~125’ through copper coated steel RG-6 so I was expecting I might encounter too much voltage drop. Turns out, it works just fine. The RCA draws <80 ma and my 3 PCT MA2-M’s were drawing almost ten times as much.

While I was at it, I decided to remove my mast mounted regulated power supply and supply my FM antenna through its dedicated coax. I also removed the 125’ of RG-6 I used to send power to the PCT amps. Ready for another antenna? I must have hooked something up wrong because when I got done, TV worked great but I lost my FM feed. I’ll be trouble shooting that tomorrow.

My Winegard AP-2870 overloaded with my 8-Bays on my push-up mast, but it overloaded a lot worse on the tower with the 91XG, so I was half way expecting on the tower the RCA might overload as well. No such luck. Last night and all day today it’s been rock stable with no signs of overload what so ever. When I was first setting up my system, because of the big price difference, I never would have considered buying the much cheaper RCA amplifiers. Just shows to go ya!

Subjectively, I think the RCA is out performing the PCT drop amps. especially on VHF. Rescanning I’m picking up 1 low VHF channel, 1 high VHF channel and several UHF channels that I haven’t received in the past. Of course I’ll have to learn new languages to understand some of them. The RCA is specified to have 1 dB more gain on VHF & 7-8 dB more on UHF so that could be the reason with my long cable runs. The PCT’s are specified to have a Noise Figure of 2.7 dB (avg.) & 4.0 dB (max) with no distinction between VHF & UHF so it could be that I’m seeing a NF advantage. My main concern was with overload from my two strong local stations and that doesn’t seem to be an issue with either of the RCA’s that I have inline. I would sure like to know where the 1 dB compression point is reached with this design.

If we can tear majortom away from his “boat anchors” long enough it will be interesting to see how his performs.
 

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Just to clarify, are you amplifying the UHF & VHF antennas separately with 2 RCA pre-amps?
From the following quote (and picture showing both inputs being used) I would say he is amplifying VHF & UHF with 1 RCA pre-amp. Certainly makes for a much cleaner install.

I configured it for separate inputs with the FM trap selected.
 

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RCA TVPRAMP1R Amplifier Update

hoopitup2000, roger1818 is correct. I have two OTA antenna setups that I play with. The original is on a push-up mast with a Channel Master CM-4228 and Winegard YA 1713. I am using one (two week old) RCA amp. with that setup. The second is a tower I erected last summer with an Antennas Direct 91XG and an Antennacraft Y10-7-13. I just installed the second RCA amp., that I received on Monday with this setup. Both amps are configured for separate VHF/UHF antenna inputs and both amps have the FM filter in use.

I have one local FM station on 99.9 MHz that FM Fool lists @ -13.4 dBm and one local UHF TV station that TV Fool lists @ -15.6 dBm. I have to point right at them to get the 1 & 2 Edge Los Angles TV channels, hence my overriding concern with signal overload. So far, neither RCA amp. has exhibited the signs of overload that both of my Winegard’s (AP-2870 dual input & HDP-269 single input) displayed.

As Roger pointed out, it does make for a much cleaner installation. To support the PCT drop amps, I ran a separate 125’ RG-6 to carry 20 VDC power and built a power distribution box with 4 ‘F’ connectors (1 input & 3 outputs) and a 15 VDC regulator ckt.


Each of the regulated outputs powered a +15 dB PCT MA2-M drop amp. (1-FM, 1-VHF High & 1 for UHF). Until the RCA’s these were the only amps. I could find that didn’t overload. Using the RCA, I was able to replace all of that with just two short antenna jumpers.

I had the tower down this morning, troubleshooting my lost FM signals. It’s looking like I did something to blow the FM drop amp. I was out in 100 degree heat for several hours reconfiguring the TV portion and by the time I got to the FM install I was pretty light headed so I could have done something dumb. Since I should only have ~3.1 to 3.5 dB of loss across the FM band I pulled the amp. and re-raised the tower. FM reception is restored.



Before anybody comments, I have noticed that the array works slightly better with the tower vertical!
 

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The cable company once installed a signal booster of some kind in my house, its an
Antronix MVRA501B/AC Voip Integrated Residential Amplifier Outputs 4+1P FWD gain =0dB RTN. Gain 0dB
FWD 52-1002 Mhz
RTN. 5 - 42 Mhz
It has a total of 7 connector jacks on it. 4 are for outputs and 1 is for Voip (whatever that is).
Is this a good amplifier, can I use it for FTA TV signals from an antenna, now that I am off cable?
Thanks!
Schoolbus
 

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^^^

I did a quick search, but I couldn't find specific specs to your amp. I doubt it has 0dB gain on the forward (52-1002 Mhz); likely at least 5-7dB gain. 0dB gain on the return is likely--due to the low frequency of the return path, amplification--beyond that needed for insertion loss--would only cause problems.

This amp likely has a 6kV surge protector. This is obviously beneficial when used with an antenna. It offers greater protection of your TV's against surge caused by lightning.

VOIP is Voice Over IP. Basically the port is optimized to work with a cable voip modem.

3dB noise level is somewhat high for an antenna preamp.

In summary, the amp will work as a distribution amp for over-the-air, in a situation where you intend to distribute the signal throughout your home.
 

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"0 dB gain" amps are not uncommon in the cable world. Basically, they're just an amp with gain equal to the splitter insertion loss. For example, a 4-output device would have a 7-8 dB amp in front of a splitter, an 8-output one would have an 11 dB amp, and so forth.
 

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To my knowledge, we never used such amps at Rogers Cable in Ontario. Interesting to see that they've been deployed elsewhere.

In terms of OTA use, it would be best to avoid such an amp. Unless of course your cable runs are short, and your signals are strong...and you just want to cancel out insertion loss of a splitter.
 

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Winegard LNA-200

FYI,

If you’re considering a Winegard LNA-200 pre-amplifier Solid Signal has them on sale right now for $32.99 + $5.95 shipping with promo code AMP25. That's less than half of the $69.99 MSRP. For this price, I ordered one to try.

It will be interesting to see how it compares to the RCA TVPRAMP1R's that so far have worked out really well for me.
 
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