I just wanted to mention that I noticed a 28DB mast type outdoor pre-amp at Princess Auto. 20 bucks. Not sure of its performance but it sure appears robust and has metal casing. I would be interested in what you thought about it.

Let's see - "28 dB" and $20. Sounds like something with no performance specifications.

Let's see - "28 dB" and $20. Sounds like something with no performance specifications. Indeed! :) The questions from JTJB and genx raise an excellent point: unless you buy one at a yard sale for a couple of bucks it is very important to stick with signal amplifiers and preamps that have their full specifications published on the packaging and/or online. Unfortunately with many of the cheap deals in stores the only specification that seems to get any mention is gain, which does not give us anywhere near the information we require to make a sensible decision.

If you can't tell what it actually does, don't buy it. ;)

It has 75 or 300 ohm input/output does this mean that I can get rid of my 75-300 balun/transformer for even more gain? Thanks for the input

Philips Mast Amplifier sws2083w/17
Bandwidth - 40- 860 MHZ
Gain - 28db vhf 22db uhf
Max output level 105 db Mivro V
Input Impedence 75/300 ohms
Output Impedence 75/300
Noise 4db/below at500 MHZ

See Philips Website:
http://www.p4c.philips.com/cgi-bin/dcbint/cpindex.pl?slg=en&scy=us&ctn=SWS2083W/17

Yup, you can see selectable 300-ohm twinlead and 75-ohm coax input/outputs.

Yup, it has "Noise Figure 4dB/below AT500 MHz".
Which begs the question: What is the Noise Figure above 500 MHz (Ch19 & UP)????
I'm disappointed...the German based Philips company is usually so meticulous,
even if they are reselling Asian made products....

genx, the 300 ohms input output on the power inserter means you can use 300 ohms twinlead wiring, to the TV and/or the antenna. Nobody would recommend that for a new install.

It has 75 or 300 ohm input/output does this mean that I can get rid of my 75-300 balun/transformer for even more gain? Thanks for the input

Philips Mast Amplifier sws2083w/17
Bandwidth - 40- 860 MHZ
Gain - 28db vhf 22db uhf
Max output level 105 db Mivro V
Input Impedence 75/300 ohms
Output Impedence 75/300
Noise 4db/below at500 MHZ


Hi:

I have this preamp connected to a vhf-hi/uhf (4-bay KROSS with vhf dipole) antenna in my attic for the last month or so. It's not my main antenna. The combo does ok. At my location what I noticed is that for weaker vhf signals like rf 11 if I didn't use an fm trap it would kill the signal(rf11) totally. With this attic combo I am able to get rf11 at about 50-55 on the lcd signal meter where 40 is needed for decode. It can also see rf10 CKVR at around 10-15. So if you have strong fm stations nearby an fm trap is needed for weaker vhf-hi signals.

For UHF it does ok. I really haven't done a real comparison between this and my main antenna, an attic installed SBGH Gen1 with CM 0064C preamp. I would have to change their positions and see if anything changes. Maybe I should. Anyways for 20 bucks I couldn't resist. My only real problem stations are 17, which I get for the most part with my SBGH but I just sometimes lose it moreso than the other buffalo stations such as 2/4/7 which I get reliably. 29 Is even worse but I don't care about that channel. Anyways my SBGH combo is able to get 17/29 way more reliably but that's not a fair comparison because their positions are different. For other channels like 2/4/7/23/49 both combos are good enough to be considered reliable. Also I should note that I lost rf 11 on my SBGH after the transition.

So if you have good signal at your location then a preamp such as this will be adequate. However if you have marginal signal then you may have problems.

P.S. I should mention how to hookup this preamp. On the antenna input portion it will only take a 300 ohm antenna input. My antenna only had a 75 ohm F connector. Therefore I ran a short piece of rg-59 coax from the antenna output into the fm trap. Then another short piece of rg-59 coax from the fm trap output into a balun with the legs of the 300 ohm portion connected to the input of the preamp. Between the power inserter and the preamp I used rg-6 coax. The switch position at 75 ohm's for the portion between the inserter and preamp. Why they included a 300 ohm connection possibility between the inserter and preamp I don't know. However they give you a choice so you can use 75 ohm coax. I hope that helps.

Back before the analog shutdown, I tried a couple pre-amps that could be considered overload resistant- CM 7778 and the W HDP-269. The 7778 was still too strong for my location, while the 269 was a winner, however it is very fragile, frying after a storm/lightning. Now that the powerful analogs are gone maybe the 7778 might deserve another chance? Also heard the AD PA-18 should be in the running too, but it doesn't have separate uhf/vhf inputs. Anyone using these pre-amps after the analog shutdown and notice anything different?

If anyone is interested, I can confirm that the CM-0068DSB is extremely tolerant of nearby lightning strikes - I had two strikes from the same storm near me within a short period of time. The one in the evening disrupted my 480p HDMI connection from my DVD player (it's only a 6ft cable) and the one during the night made the entire house shake violently, to the extent that I thought a tree had fallen within a few feet of the cottage.

Throughout the storm, the pre-amp remained plugged in and it still works fine. It seems unlike some pre-amps, this one can take a beating.

Also heard the AD PA-18 should be in the running too, but it doesn't have separate uhf/vhf inputs.
I have no on-hands experience with their products but if you are considering the PA-18, you should look into their CPA-19 also. From what I read, similar performance, higher overload tolerance and ESD survivability if what they say is true.

The PA18 should be considered for rural/fringe use only. It is not difficult to overload. Unless in wicked terrain that severely attenuates signal power, I don't suggest it within 30 miles of the transmitters.

The CPA19 is MUCH more difficult to overload. It's appropriate for any location that calls for a preamp. It also has a nice notch filter between 250 and 400 MHZ so most public service 2-way traffic is attenuated. Almost as sensitive (within a few fractions of a dB) as the PA18, good overload tolerance, and better ESD survivability. What's not to like?

We've tossed around the idea of a design that has dual inputs, high-VHF only and UHF, and a low-pass filter at 700 MHz, but no serious effort is being made to advance it. I'd consider that the almost perfect solution for almost anywhere except those few areas with low-VHF.

Hello everyone,

Would a preamp help?

I live in an apartment and use a CM-4220HD antenna mounted on the inside my window. I receive most of the OTA signals in Ottawa except for those transmitted from a transmitter site (Herbert Corners) south of the city. Unfortunately for me, the stations transmitted from Herbert Corners are the ones I want to receive the most!!

Here's what I currently receive...

4.1 (LOS)
9.1 (LOS)
13.1 (LOS)
14.1 (1Edge)
24.1 (LOS)
30.1 (LOS)
40.1 (LOS)
43.1 (2Edge)

I have a Panasonic TV and according to it, the signal strength (quality?) of the "LOS" stations vary between 55% to 70%. The "1Edge"/"2Edge" stations vary between 50% and 60%. The "missing" stations (i.e. RF17, RF22, RF27 and RF42) vary between 25% to 45%.

Here's my TV fool report:

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d8387a876e9a6bd

Any thoughts or suggestions?

Thanks.

what would be good pre-amp for me? I want to be able to get Fox in stable. My Panasonic without any amp using a DB8 antenna is picking up Fox but not viewable (very pixelated to black screen)

Let me know whats good. I was thinking the Channel Master CM0068DSB or the Winegard AP-8275?

http://img191.imageshack.us/img191/1769/radardigital2.png

I just updated my "DTV Preamp Signal Overload Calculator - Rev L"
to simplify VHF calculations, in addition to earlier UHF version:
http://imageevent.com/holl_ands/files/ota
This will help to determine which Preamp is best to prevent overload
and maximize the SFDR (Spurious Free Dynamic Range).
[PS: Only manufacturers that provide meaningful Overload specs.]

With and without Preamp calculation of the System Noise Figure (NF)
(lower is better sensitivity) can be made here:
https://docs.google.com/spreadsheet/ccc?key=0Ap6QeEL-E_5VcGhzUk5aTkNwS3FnYnFLQ0g2aEZtTHc&hl=en#gid=0

Fol. Chart (Add Balun and Antenna-Preamp Loss if any) also determines
the System NF:
http://www.digitalhome.ca/forum/showthread.php?p=888368

what would be good pre-amp for me . . . . . I was thinking the Channel Master CM0068DSB or the Winegard AP-8275?


Neither one is a good choice IMO as they are designed for more fringe areas & overload easily. The Winegard 8700 OR AD CPA-19 may work, but to risk any chance of overload, I would personally use a Channel Master distribution amp. They simply rock in areas with a blend of strong & weak signals & are nearly impossible to overload.

The HDP-269 would be a good choice, but is sensitive to failure from static build-up or nearby lightning strikes. Proper grounding is a must for the 269.

@mau108

I would consider a low noise amp like the Kitz Tech KT-200. A perfect amp in suburban areas. It is great for pushing signals through losses in systems while sporting a low NF. The CM distro amps are around 3.0 NF

I built a stealth hawk and put it on my deck (10' high), hooked it to my TV with about 30' of coax cable. Got all the green and white stations but none of the pink stations shown on my TV Fool report. The stations I get are either about 60 deg or 310 deg and range from 11 mi to 22 miles away. The antenna is "pointed" directly between the two. I don't need to pull in any pink stations which are 50+ mi away. The location is in a residential area with no large buildings. But there are some tall trees between the antenna and the stations. Here is my TV Fool report:

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d14f3119ee5441c

Signal strength is very good with the antenna on the deck, but some stations fade in and out, especially ones in the higher range. 46.1 is almost unwatchable while 36.1 is steady. Both are on the same antenna mast, about 21 miles away and with similar signal MN and PWR (what ever that is). 46.1 will be 100% one minute, 0%, then 100%.

Question 1: Might this be due to the trees or a result of something else? Seems like 46.1 should perform like 36.1.

I will reinstall the antenna on the roof where it will be about 30' high but will "look" at the same trees only higher.

I will hook the antenna up to about 100' of coax which will connect with the former cable TV wiring. The signal will go to about four TV's that range from 20' to 75' from the cable input. One homerun wire from the cable input services them all with splitters as needed.

Question 2: Should I use an amp at the antenna or one where the cable comes in? Or both? Which amps(s) will work the best for me? With only one homerun to the cable input, do I need a distribution amp? Might the amps(s) help with the intermittant problem?

Any tweaks to what I propose or things to watch out for?

Thanks for any help you might provide! Great forum! I'm learning a lot about all of this. Can hardly wait to cut the cable!

gksull,

You should notice a big improvement when you go up to 30ft. You will also have more line loss due to the extra cable lengths. Some of your local stations seem to have a powerful signal in your tvfool report, which may be a deciding factor regarding amplification choices.

You will have 100ft cable run, so I'd recommend using a mast mounted preamp such as the CM7777 or Winegard 8780. When you buy the preamp, make sure they have a good return policy just in case it causes overload from those stronger channels. If overload becomes an issue, then you'll have to consider just using a indoor distribution amp/booster.

You have VERY POWERFUL nearby stations....high gain Preamps, like CM7777 will OVERLOAD...

One of the very low Gain Preamps....or a Distribution Amp MIGHT be okay...or MIGHT block
reception of weak stations....

Hi,

I also have CM 7777 should my preamp fm trap be set to "in" or "out"? I would like to optimize for ch 6.

thanks