Signal Amplifiers (Amps, Preamps, Distro Amps) - See Chart in Post #1

[holl_ands]

Antennas Direct, Antennacraft, Radio Shack, et. al. don't provide any overload specs,
so from a theoretical point of view we don't know how well they perform...

And we have yet to see a controlled A vs B vs C vs D comparison tests in a
VARIETY of MIXED (very high, high, moderate & weak) signal level environments....

[HWP]

I wonder why only the Winegard hdp269 is listed on the Antennas Chart, but none of the others get a mention. Perhaps just because they're new models since the chart was compiled?

Anyway, the Winegard 269 gets mentioned frequently around Digital Home for being a pre-amp that is good at handling a mix of strong and weak signals.

But Antennas Direct and Antennacraft also have comparable pre-amps that claim to have been designed with the same purpose in mind.

Granted there are not specs, but each company's write-up on each pre-amp reads very similarly.

[roger1818]

Originally Posted by HWP

Granted there are not specs, but each company's write-up on each pre-amp reads very similarly.

I don't trust marketing mambo-jumbo. Even specs can sometimes be misleading as they can vary the conditions to optimize the results. In the absence of specs though, you have to assume they perform poorly since they may be trying to hide something.

[HWP]

All of the pre-amps in question provide the usual detailed specs that we look for to ensure it's a decent pre-amp: noise figures and gain figures.

The additional claim that these pre-amps make is that these pre-amps provide medium-gain but they are also designed to have more tolerance for a mix of strong and weak signals while resisting overload.

But I don't see how any of these companies - all of which are trustworthy companies - demonstrate the claim with data. I don't know how they'd even measure it. But I'm sure an electrical person would know how to.

[alebowgm]

So The Source website still lists the old CM 7777 pre-amp. I ordered one earlier in the week, I had decided I wanted to use my CM4220HD with a VHF only antenna to try and get more reliable reception of CBET. Anyways, I received the new CM 7777 instead with one input instead of separate inputs. Haven't played around with it yet, but not happy. Going back in this thread (post 2940) I see this was noted back in mid-February but their website still lists the old model.

[majortom]

Originally Posted by HWP

I want to get one of these types of pre-amps but I'm not sure which one(s) might be good options.

You never said why you want to get one of those, as opposed to one of the ones shown in the chart?
The Winegard AP-8700 seems to work OK for me here.
I chose it based on it's Max input for multiple signals spec, but I was comfortable using it having already used one at the same location before.

[HWP]

I have a 7778 pre-amp. 4 miles from the CN Tower. The pre-amp works, but my sense is it works like a tank. It's working in spite of overload, I think.

The Winegard 269, which is on the Digital Home pre-amp list, has less gain, and has a reputation of being a pre-amp that is more suited than other pre-amps for areas where is is a combination of weak and strong signals. It is also said to have a high tolerance for strong signals - it is good at resisting overload. As far as I can see, it has that reputation because Winegard asserts that that is how the pre-amp is designed. I have not seen any specs regarding overload resistance, etc.

I have since become aware of the Antennas Direct PA19 and the Antennacraft 10g201 and 221 that have similar gain and noise figures and make the same claims about high tolerance for overload and for being suited to a mix of weak and strong signals.

So I wonder why the 269 is on the list and why the others aren't.

Also, I understand Stampeder's Antenna Chart as being a list of trustworthy antennas that get the Digital Home insiders' stamp-of-approval.

I wonder if the pre-amp chart is a less-formal list of quality pre-amps without any recommendations attached.

Anyway, my questions were posted in this thread because I thought someone here might be acquainted with those pre-amps or might be able to shed some light on why the other presumably quality pre-amps with published gain and noise specs aren't on the list.

In my case, I have started to wonder if my WBBZ reception would improve another measure if I had a lower gain pre-amp with higher overload resistance.

http://www.tvfool.com/?option=com_wr...de65fe91418b95

I know I'm better off with a pre-amp than without one. But I know my pre-amp is probably too strong for my location. So these other pre-amps seem like they might be up my alley.

If the Antennas Direct and Antennacraft pre-amps deserve to be on the list, they should be added.

[majortom]

the hdp 269, etc are on the chart because Winegard (and the other mfrs) provided the information necessary to determine the maximum input for two strong signals... Not because they have some magic stamp of approval.
Rather there is enough information provided in their specifications for the user to determine whether it should work or not at their location.

The others that you mention don't provide that information in their specifications so noone really knows how they'd peform. That's why they aren't on the modified chart. How I understand it at least.

You are probably right that the CM 7778 may be causing you some intermod, because it's one of the worst on the chart in that regard.
But, at least you knew that going in because the manufacturer specified it for you, allowing you to make an informed decision.

[HWP]

...well...at least they gave me the opportunity to make an informed decision. I'm not sure how informed the decision actually was. I'm still not sure I understand how to interpret pre-amp data.

I thought maybe those other pre-amps are newer than the Pre-amp Chart.

...So, can you recommend a pre-amp for me? I need a pre-amp because WGRZ has a tendancy to flicker on me in the winter, WPXJ will flicker on me in the winter too unless I have more direct aim. With the pre-amp, I don't have to aim at either WPXJ or WGRZ to get them. That allows me to focus aim on WBBZ which I suspect also benefits from having a pre-amp - especially in cooler weather. And I don't think it will hurt having a good pre-amp once CHCH and CHCJ come online on UHF coming in straight from behind the CN tower for me.

With my 7778, I get rock-solid reception of everything from Buffalo and Batavia - except for WBBZ, which is 99% reliable three seasons per year, and probably about 90% reliable in the winter. I need to aim my antenna through the CH Tower to get CHCH on RF11 - and while it works, it is weak. I'm pretty sure my pre-amp is causing CHCH and everything from Toronto to be dialed-down when I point towards Toronto. Anyway, I know a different pre-amp would be better, and now I'm trying to choose the right one.

I'm probably going to switch antenna setups this summer to a DB4e for its wider beamwidth and an Antennacraft y10-7-13 for WBBZ. If I replace with the appropriate pre-amp, I feel like I will have made my best attempt possible to achieve my potential for my everyday channels.

I'll keep the rotator because it's very useful and fun to have, but I think with my new setup, I might not ever need to use it for anything other than summertime dxing.

[El Gran Chico]

Is there such thing as a maximum distance from pre-amp to power source. I'm thinking of doing an experimental antenna placement near the edge of my property (long story why). To do it, I'd have nearly 100 feet of RG6 between the pre-amp and the power source.

Didn't want to try it and then find out the power is too far. The pre-amp I was going to try it with is a HDP-269 if that matters. Thanks for any advice.

[majortom]

should be fine, considering they are designed to make up for such losses.
The ap8700's power injector has a voltage regulator inside it.
Does the hdp 269 have the same? Looks like a Splitter with a red LED, the voltage regulator is inside that device.

[Jase88]

El Gran Chico, that's a good question. I have probably 120' of coax, and my CM7777 seems fine. Though I'm wondering if solid copper conductor coax would help longer runs? I suppose copper-clad likely does just as good a job of getting current to the pre-amp.

Most coax is copper clad steel. The cost of solid copper RG6 is typically twice (or more) the cost.

[BOUVAL]

Didn't want to try it and then find out the power is too far

El Gran Chico,

You can add a length of RG6 to your actual set-up, you'll see.

Hasta luego
.

[nezdepain]

On my paper instructions for my AP8700 it says "A maximum preamp-to-power injector coax length of 150 feet RG-6 copper clad center conductor, or 300 feet of RG-6/U with solid copper center conductor, or 150 feet RG-59 is acceptable"

[ProjectSHO89]

From the standpoint of delivering operating power to the amplifier module and the effects of coaxial cable on that power, one must know several things.

1) What is the current and voltage requirement of the amplifier? How much tolerance to lower power does the amplifier have?

2) What is the DC resistance of the coaxial cable?

Most pre-amps I've run into require anywhere from 30 to 140 mA at 12-18 volts DC. One must also find out if the power regulation (if any) is provided from the power supply, the power inserter, or in the amplifier module. If the regulator is in the power supply or inserter, then the voltage supplied to the amplifier would be reduced from the DC loss of the cable in accordance with Ohm's Law and lower operating voltage may affect the capabilities of the amplifier. If the regulator is located in the amplifier, the loss of power would not be a problem as long as the voltage delivered meets or exceeds the minimum requirements of the amplifier circuitry.

At RF frequencies, CCS performs pretty much the same as solid copper due to the skin effect. However, DC resistance of solid copper will be lower than that of CCS. DC resistance of coaxial should be available in the data sheet of the cable from larger manufacturers.

Extraordinarily long cable runs are best done with solid copper core RG11 as it offers the best performance in terms of DC power delivery and efficiency in carrying the RF signals back from the amplifier. For most installations solid core RG6 should be fine out to several hundred feet while CCS RG6 would be less.

Several examples with DC Resistance per 1000':

Belden 1694A - RG6 Solid copper core (6.4) with tinned copper shield (2.8)
Belden 1829A - RG6 CCS (28.0) with 60% AL shield (9.0)
Belden 7731A - RG11 Solid copper core (2.5) with tinned copper shield (1.5)
Belden 1523A - RG11 CCS (11.0) with 60% AL shield ( 4.1)