OK, I turned the dial on the tester to 9V (meant for testing 9V battery). Reading is 7.78V at the PSU, and 7.78V after the 90' of coax, no difference.

Reiterating the situation;
Antenna > 8' RG6 > RC preamp > 90' RG^ > PSU > 2' RG6 > tuner (very poor reception)
Antenna > 100' RG6 > RC preamp > 1' RG6 > PSU > 2' RG6 > tuner (pretty good results)

Is there another test I should do with this meter?

EDIT: If it's helpful, this is my tvfool. Antenna is an M4 pointed directly at Buffalo (171 degrees magnetic).
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3de3b21ba53840df

My 2-cents:

60 Hz is so far away from TV frequencies that no great smoothing is needed to keep from modulating the TV signal or distressing amps downstream in properly designed gear. (Quite different in audio gear where a little bit of 60 or 120 Hz creeping in sounds terrible.)

But, the amp transistors and circuits are designed to work best at a given voltage. If the power supply allows the voltage to wobble around from that optimum value, the amp may not work as well. But overall, I don't think it really should be much of a concern given the parameters we are working within here.

Ben

Many thanks for that very careful explanation. Exactly the stuff I wonder about.

Now each source of impairment has a different fix (or no fix at all). Here's my amateur take:

1. sensitivity can be helped with a pre-amplification

2. multipath with antenna aiming

3. channel interference with antenna aiming and channel filters

4. overload from local stations with channel filters or broadband attenuators (as holl_ands mentions)

I have a 4-way splitter but it is within an 8dB-gain distribution amp. Of those, my pick for my situation would be pre-amplification. But since I am close to overload already, it should make overload worse... for no net gain in reception quality.

Hope that's not all the fixes possible because even the most likely option, #1, seems unlikely to be profitable.

Ben

That part of RC's reply really jumped out at me - the goal of a preamp is highest gain with lowest noise, so using an unregulated power supply is like shooting yourself in the foot. Always use a high quality regulated power supply with any type of TV signal gear.

The most common example of an unregulated power supply is a big dumb car battery charger, which inputs household 120VAC@60Hz (meaning the AC sine wave goes from one polarity to the other 60 times per second) and first transforms the voltage to 12VAC and then converts it to 12VDC at either 2A, 6A, or 12A. It does that conversion in a cheap and dirty fashion by simply cutting off the negative bottom of the AC sine wave, which results in DC pulses 60 times per second. It is those pulses that create all the noise trouble. Unfortunately some small transformers for electronic gear may be doing something similar, albeit at much lower power levels. This pulsing is one of the forms of the dreaded "60 cycle hum" in electronics.

A simple regulated power supply does the same as above but adds a capacitor in line so that the voltage dips that occur 60 times per second are much less drastic between pulses. A strong enough capacitor can result in a fairly flat DC output.
[This may be "Filtered", but is NOT a "Regulated" Power Supply - holl_ands.]
[A Full-Wave Rectifier "reverses the polarity" of the negative AC voltage swings.]

A better regulated power supply goes even further by reversing the negative bottom part of each wave's polarity 60 times per second to result in only positive pulses at the output, smoothed out by capacitance and filtering to make an almost perfect DC output. By making the output higher than required the manufacturer can then implement clipping that results in an undetectable pulse (an essentially flat DC ouput, which is the goal).

If you have a small transformer that came with a modern consumer electronics device it likely falls into the last category.
An UNREGULATED Power Supply typically consists of a transformer to reduce the voltage
to the desired level, followed by a (half-wave/full-wave) rectifier to eliminate the negative voltage
swings and a big capacitor to smooth out the humps, leaving a DC Voltage with some ripple:
http://en.wikipedia.org/wiki/Rectifier
http://webstaff.kmutt.ac.th/~suwat.pat/material/ene212%20ch%2015%20Power%20Supply.pdf

The time constant (T=RC) of the capacitor and load resistance needs to be much larger
than the time between the rectified AC input humps (60/120 Hz) to reduce this ripple.

If the Input AC voltage varies by +/- 5%, the Output DC level will vary by +/- 5%.
The Output DC level will also vary as the load changes.

A REGULATED Power Supply means something quite specific: ADDITIONAL circuitry
is provided which will ensure that the output voltage does NOT vary with the load
or the input AC voltage. Typically, Voltage Regulator IC's use an internal or external
Zener Diode as a precision reference voltage, where sometimes the designer picks
the external Zener voltage corresponding to the desired output voltage...which will be
significantly lower (the "adjustment" range) due to drop across the control transistor:
http://www.national.com/an/AN/AN-1148.pdf

Since a REGULATED Power Supply outputs a constant DC voltage irrespective
of the input DC voltage, the AC ripple on it's input can be much higher, meaning
a much smaller smoothing capacitor can be used, resulting in an overall smaller and
probably less expensive "Wall-Wart" (which might even contain a voltage regulator IC).

From the RC engineer's description it appears he is saying that a Voltage Regulator is
built into the Preamp, which would provide a precise DC voltage to the internal circuitry
irrespective of how much loss there is in the (variable length) supply cable, as long as
the input met min and max input voltage (Vi) specs. In Post #1890, mlord reported the RC
(which model?) contained a "7805's style" (78XX series???) voltage regulator. You should
double check the part number inside YOUR Preamp, it might be a higher voltage (7808?):
http://www.datasheetcatalog.org/datasheets/228/390068_DS.pdf
Once you know which specific p/n you have, "Line Regulation" provides min/max Vi.
Of course, that is AFTER whatever voltage drop there is in the power supply feedline.

The Schematic for the CM-0265DSB shows a TLE4278GV10 Low Drop Voltage Regulator:
http://www.datasheetcatalog.org/datasheets/228/318412_DS.pdf
V10 suffix means 10-volts output. It uses an internal precision reference voltage.
There is an external V7330 Zener Diode across the input to limit the maximum input.
http://www.datasheetcatalog.org/datasheet/panasonic/SKE00006BED.pdf
I didn't find any information for the V7330 Zener Diode, but I would GUESS that it's
probably 30-volts, like the above Panasonic MAX7330 Zener Diode....

byebyecable,

OK, I turned the dial on the tester to 9V (meant for testing 9V battery). Reading is 7.78V at the PSU, and 7.78V after the 90' of coax, no difference.
Is there another test I should do with this meter?

Antenna > 100' RG6 > RC preamp > DC Passive Splitter here temporarily >1' RG6 > PSU > 2' RG6 > tuner (pretty good results)

^small jumper cable on unused Splitter Port 2> DC Volt meter

The dc voltage you measured on the other end is likely unloaded.
What I would do is temporarily place a DC Passive splitter inline with the TV side of the Amplifier at the far end (in ur attic I presume). That will allow you to measure the Loaded DC Voltage at the upstream end, aka Pre-Amp's TV side output...
Edit: Just noticed....Curious, why the Amp isn't at the antenna end?

If there's a significant difference Loaded vs Unloaded, then the PS isn't regulating very well.
In addition, make sure there is no AC ripple riding on ur DC power supply's output.
When measuring DC Volts (again, loaded) , record the reading. Then put the meter on AC Volts. The measured
AC component better be way less than say 1% of the DC Voltage. ideally zero or unmeasurable.
example: If I recorded 10 Volts DC, then switch to AC Volts and record 1 Volt AC, that's 10% AC Ripple.
That would be enough to make just about any electronic circuit misbehave.

holl_ands I was picturing the waveforms when I was posting and forgot about mentioning the zener diode - thanks. :)

The dc voltage you measured on the other end is likely unloaded. If there's a significant difference Loaded vs Unloaded, then the PS isn't regulating very well.

Thank you, the loaded voltage is 5.38 & RC has confirmed that's a problem. They offer;

1. Send back the PSU & they'll swap it for the 12V version. However, sounds like this is the subpar one they are talking about on their website.
2. Find a PSU 12V locally & they'll refund me for the PSU.

I'm not sure I like EITHER of these options - the idea was the have the finest pre-amp (a reasonably amount of) money could buy. Any opinions?

I plan on making an experiment using a 2nd preamp to feed a long splitted run which has difficulties. Let me know if you see any issues, especially with having 2 coax power inserters in the setup.

4228hd+vip302sr - cm7777(1st preamp) - 35ft rg6Quad - cm7777 coax power inserter - 9dB tap - 6dB attenuator (total 15dB attenuation) - KT-200 - KT-200 coax power inserter - around 100ft rg6Dual - 4:1 splitter - 4 tuners.

The "main" branch of the 9dB tap will go to my HTPC which close enough not to experience these issue with my fringe signals.

I know that by attenuating/reamplifying I will lose some SNR, but I'd like to know if the problem was not having enough Signal to start with...

OK, I send the PSU for my RC pre-amp back to RC today via airmail as they requested. They will return a smoothed fully regulated (working) 12 volt PSU.

$17 to send that PSU back to the UK - should I have asking them for that $$ back?

$17 to send that PSU back to the UK - should I have asking them for that $$ back?

I'm not impress with RC products at all. I tested two different RC9260 and they were very ordinary. Very overrated product in my IMHO.

If one were to obtain a 12volt power supply localy , which one would work properly for the RC amp?

I've been reading reading and reading and am on overload now. I want to get a stronger signal as i have added a splitter to go to 2 tv's

Here is my setup

Outdoor antenna its an eaglestar > to CM7777 preamp > preamp power supply > 2 way 1GHZ splitter > to tv's

Now my signal is pretty bad and i've adjusted my antenna as per my tv fool map. But the signal is still low. I have read about using a Distribution Amplifier in the mix as well but don't want to overload my tv sets (using built in tuners)

So this is what i have read, is this correct?

Outdoor antenna its an eaglestar > to CM7777 preamp > preamp power supply > Distribution Amplifier > to tv's

Thanks for help

No, you are not in an area that requires that kind of boosting. Lots O trouble is what U will get. I would try a better antenna.

Whositwhatnow, I think ur existing setup should be more than sufficient for most scenarios.
But not knowing where u live...what's ur tvfool look like?

Edit: ^^^^^ Agree antenna could be the answer, but still maybe post ur tvfool.

@byebye_cable
I have the same situation with my RC preamp.
I took a look @your TVFool and you are way to close to towers. You are getting overload.
I just got my RC preamp back from it's second failure. Customer service is great BTW...
Anyways I mount the preamp in my master bedroom some 20 feet from the antenna, then a small 6 foot piece to the PSU then to 3 way splitter. This has been the best setup for me. Up to this point I have had a KitzTech in the same situation and it had been wonderful.
You might want to get a three way splitter or attenuators and terminate the unused ends if you are only feeding one set.
It is sorta of an expensive distro amp, but most distro amp's have higher noise factors.

Actually, I have tried using the preamp loss chart,
My question is: What affect does moving a preamp 20 feet form the antenna have? Aside the obvious amplifying noise, does my .04NF now become 3NF?

What affect does moving a preamp 20 feet form the antenna have?

I'm not looking at the numbers at the moment, but assuming no other active chains downstream, it degrades the overall system noise figure by roughly the amount of insertion loss of that 20 ft. Or you could think of it as using a lower antenna gain. In some cases it may not necessarily be a bad thing, like in the presence of multiple strong signals...

It took me a long time to tweak my setup. I was bent on placing any preamp near the antenna, but being so close to transmitters I have found my happy place to be 20 feet away.
People that are close to transmitter should try this. Took me two years to figure out.

Using a longer lead from the antenna to the pre-amp also has the same effect as raising the noise figure of the pre-amp or putting an attenuator on the input to the pre-amp.

20' of RG6 will exhibit a bit over a dB of insertion loss at 700 MHz with a lower amount for the lower frequencies.

Regardless of the loss of let`s say 2dB for 20 feet, does my noise factor go from .04 to 1.5NF or is it just an attenuation thing where I my 23 Db preamp is effectively 20 dB now

passive components, such as a coax cable do have a Noise Figure associated with them.

-1 dB loss = + 1 dB Noise Figure
-2 dB loss = + 2 dB Noise Figure
-3 dB loss = + 3 dB Noise Figure

the key to understanding any cascaded receiver system including the spreadsheets in Post #1 is understanding friss's formula. Take a look.

http://en.wikipedia.org/wiki/Noise_figure

You can read about how the Noise Figure of an Amplifier stage may be measured in a laboratory setting here:
http://cp.literature.agilent.com/litweb/pdf/5952-8255E.pdf

There is an article about Understanding Noise Figure on qsl.net here

http://www.qsl.net/va3iul/Noise/Understanding%20Noise%20Figure.pdf

There are some examples that step ya right thru friss's formula here

http://www.ieee.li/pdf/viewgraphs_mohr_noise.pdf

Or ya can just use the spreadsheets in Post #1 and plug in ur own numbers to manuallly
verify your own setup, which you are most intimately familiar with.