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

[balm]

will have to check current tomorrow ! (light sleepers around here )

who knows, maybe some of that dielectric grease got in there



I did quick check on my AP 3800, under "load", its 2% lower voltage (or 13.98 vice 14.27 V)


EDIT: bought that thing last October, used for a few days only !

[balm]

the current seemd to be 0 to .002 mA !, I assume no current



EDIT: Winegard is sending me a new one , not wasting any time !


Will report back, when I test it on the weak channels

[majortom]

Nice...Nuther victim of static discharge I wonder? HDP 269 right?

My AP-8700 is in it's second or third year I think.

[balm]

yes, HDP 269

I used a couple hours on 1-2 sunny days last fall. Then disconnected it for the winter (but left it in place) and it seemed to be helping out - weird. Then I took it down last week, and tested it and nothing! weird

[roger1818]

Hmm. Be it static discharge or some other issue, it sounds like there are reliability issues with the HDP 269. Until this is tracked down, I would suggest we discourage the use of it.

[balm]

will be difficult for me to "track down", since I dont know how else to test, or investigate the unit

any further instructions ?

Winegard doesnt want it either

[balm]

when I set my voltmeter to measure the DC current on the 10 A setting, it measures 0.045 A (or 45 mA) -

is this the correct DC current for the amplifier ? (the pwer supply specs 300 mA output) ?

also, when I measure DC current on the mA setting, or uA setting, it gives 0 A.
Im not sure why these 2 scales dont produce a reading.

[majortom]

it's possible the meter was damaged previously while connected to something incorrectly. It may have different shunts, different fusing for the diff current range.
Maybe take the meter apart and look for a blown fuse.

BTW, Did the replacement amp show up? Does it measure the same?
If the replacement measures normal on the mA range, then I guess that blows that theory...

[balm]

should receive any day now...


but want to make sure the old amp is a problem....maybe end up with 2 good amps, if its a question of faulty voltmeter !

only measured a kitztech amperage on the mA scale once last year, and if I remember it was working then...anyway I will try as you say, open it up


just looked, its sealed, & no replacement parts label !

[balm]

the 500 mA fuse is easily removed from the battery compartment, but I cant see anything wrong with it.

the 10A fuse is supposed to be removed by "qualified" technicien and is more difficult to get at

Im not sure if the 10A setting can work correctly, and the mA setting not work at all (due to fuse issues).....thats why im not sure if the 0.045 A makes sense.

[majortom]

set urself up to measure something else with relatively low current draw so ya can test the same mA current range. the current draw of a satellite dish LNBF while connected to a receiver (~100-200 mA)? a flashlight bulb or sumthin?

[re_nelson]

This is a report comparing the following preamps over a period of time spanning from 2012-03-05 to 2012-04-05, using this input system:

UHF: AntennasDirect 91XG
VHF: Winegard YA-1713 (for KXII sited in Madill, Oklahoma) and AntennaCraft Y10-7-13 (for Cedar Hill, Texas)

Here are the preamps tested over that timespan:

AntennasDirect CPA19
ChannelMaster CM-7777
KitzTech KT-200
Research Communications RC9263
Winegard AP8700
Winegard HDP269

NONE: Denotes NO PREAMP and is used as the baseline to measure the variance (shown as ``(Diff)'' in the tables below).

The measurement tool is a Silicon Dust HD Homerun which is run hourly at :30 past the hour via a cronjob to extract the raw values (SS, SNQ and SEQ) which are expressed in a 0-100 range by the device. Only SNQ is used for this report, the SS is ignored. Since all facilities are locked without any problem here at my location, the SEQ which always measures 100 is also discarded.

A Perl script then collates those values for each preamp, averages them and then calculates the difference from the baseline of NONE (NO PREAMP).

a). The antenna setup is in a attic of a dwelling with this TV Fool reading:

http://www.tvfool.com/?option=com_wr...0b86a607ba366a

The coax cable (RG-6/QS) runs 50 feet from the attic to a downstairs room where the readings were taken.

b). The attic has no radiant barrier and the setup was done using a Sencore SLM-1456 to optimize the gain and eliminate any traces of multipath. These spectrum scans (all high and flat) are typical at this site:

http://www.rabbitears.info/specan/re_nelson/

c). Since so many signals are very robust here, this report is limited to those channels that are a tad more of a challenge.

d). There are no FM facilities nearby nor are there any other forms of broadcast RF within a 20-mile radius.

e). This location is in exurban Dallas, Texas, USA. There are no farms, ranches or industrial sites in close proximity. It's a typical new suburban development with only younger trees hereabouts.

f). The preamps were rotated after about 18-24 hours of service and replaced with another model. The intent was to disperse each one over a period of time to mitigate weather and other environmental variations.

g). The SNQ readings from the HDHR device are nearly a perfect match with the "Signal Quality" numbers from a Zinwell ZAT-970A STB.

SNQ scans from 2012-03-05 21:30 to 2012-04-05 22:30

CH       NONE   AP8700 (Diff)    CPA19 (Diff)  CM-7777 (Diff)   HDP269 (Diff)   KT-200 (Diff)   RC9263 (Diff)
--       ----   -------------  --------------    ------------   -------------   -------------   -------------
 9       79.5     96.2 (16.7)     98.1 (18.6)     96.3 (16.8)     94.9 (15.4)     95.2 (15.7)     96.8 (17.3)
12       83.7     88.0 ( 4.3)     87.5 ( 3.8)     88.4 ( 4.7)     88.7 ( 5.0)     85.2 ( 1.5)     86.5 ( 2.8)
18       60.0     76.5 (16.5)     79.0 (19.0)     76.5 (16.5)     71.0 (11.0)     75.2 (15.2)     80.9 (20.9)
20       65.5     80.2 (14.7)     77.7 (12.2)     78.6 (13.1)     76.4 (10.9)     79.8 (14.3)     77.5 (12.0)
21       73.8     92.1 (18.3)     94.5 (20.7)     92.5 (18.7)     86.4 (12.6)     91.0 (17.2)     94.3 (20.5)
25       64.0     93.0 (29.0)     90.5 (26.5)     89.8 (25.8)     84.6 (20.6)     89.1 (25.1)     88.8 (24.8)
27       56.3     83.8 (27.5)     83.5 (27.2)     84.6 (28.3)     77.4 (21.1)     85.7 (29.4)     82.1 (25.8)
28       63.5     84.0 (20.5)     83.9 (20.4)     84.4 (20.9)     80.5 (17.0)     83.9 (20.4)     83.4 (19.9)
31       60.0     77.6 (17.6)     79.0 (19.0)     79.5 (19.5)     76.4 (16.4)     72.7 (12.7)     79.1 (19.1)
34       70.7     85.7 (15.0)     86.8 (16.1)     86.6 (15.9)     84.3 (13.6)     86.2 (15.5)     87.8 (17.1)
50       62.7     91.2 (28.5)     91.5 (28.8)     88.6 (25.9)     79.8 (17.1)     89.0 (26.3)     92.9 (30.2)
51       66.2     97.4 (31.2)     96.7 (30.5)     97.8 (31.6)     83.5 (17.3)     93.5 (27.3)     98.6 (32.4)
Average  67.2     87.1 (20.0)     87.4 (20.2)     87.0 (19.8)     82.0 (14.8)     85.5 (18.4)     87.4 (20.2)
         ----   -------------  --------------    ------------   -------------   -------------   -------------
NumScans   79      103             101             101              99             102             102

My conclusion is that they're all very close in terms of performance. At my near ideal location, the average user wouldn't be able to tell the difference between them unless he or she were checking the signal diagnostic readings.

[be236]

Wow.. I bought a KT-200 coax last year and seeing your results above I'm a bit disappointed that it can't do better than CM7777 or CPA19.. which I should have bought and it would have been cheaper.

I bought the KT-200 because of its rated low NF of 0.4dB. Alas...

[re_nelson]

The KitzTech KT-200 has been a letdown for me. I've tried it on various antenna configurations and it's always been middling at best. ADTech actually had my KT-200 on hand for a few weeks. He confirmed that the NF are very good.

With a Sencore SLM-1456, looking at raw power, that KT-200 coax unit shows very high gain on VHF and then a gradual downward slope as the frequencies increase.

The pricey RC9263 did live up to its billing at my site. The CPA19 was the real surprise of the bunch and the AP-8700 was a very good performer.

[roger1818]

Originally Posted by re_nelson

My conclusion is that they're all very close in terms of performance. At my near ideal location, the average user wouldn't be able to tell the difference between them unless he or she were checking the signal diagnostic readings.

Interesting evaluation. I think the keywords are "At my near ideal location." if all you are doing is boosting otherwise strong signals to overcome cable and splitter loss, then pretty much any amp will do. A low noise amp shines when you have weak signals.