The preamp will take of the losses after the antenna terminals (and help with weak TV tuner gain). For one thats about the best against overloading, get the Winegard HDP-269. Its also one of the lowest priced ones too.
Designing custom antenna for my very specific local needs?
This is a question to all the OTA gurus on this forum.
I would like to design custom antenna for my location,
based on the numbers given by tvfool.
The weakest channel I'd like to get is 23 (ION) and for this I'd probably need a preamp.
By looking at the tvfool chart I've come up with a list of frequencies, azimuths and target gains.
My question are:
Are the target gains enough (with /without preamp)?
Are some if target gains to much if I am to use a preamp?
Could I go with less gain on any channel?
Thanks in advance,
nikiml
I would like to design custom antenna for my location,
based on the numbers given by tvfool.
The weakest channel I'd like to get is 23 (ION) and for this I'd probably need a preamp.
By looking at the tvfool chart I've come up with a list of frequencies, azimuths and target gains.
My question are:
Are the target gains enough (with /without preamp)?
Are some if target gains to much if I am to use a preamp?
Could I go with less gain on any channel?
Code:
Chan Network Dist Path NM azim target gain
(mi) (dB) (deg) (dbi)
-------------------------------------------------------
20 CBC 19.8 LOS 49.6 50 0
18 Ind 26.2 LOS 46.7 -50 0
40 19.8 LOS 44.4 50 0
44 OMN 20.2 LOS 43.1 50 0
64 OMN 20.2 LOS 41.6 50 0
35 Ind 26.2 LOS 38.6 -50 0
24 SRC 19.8 LOS 37.4 50 0
32 CW 57.6 LOS 37.2 0 0
65 GTN 19.8 LOS 34.9 50 0
66 Sun 19.8 LOS 34.8 50 0
53 Ind 19.8 LOS 33.5 50 0
43 PBS 57.6 LOS 29.5 0 1
14 Fox 57.5 LOS 24.2 0 1
39 CBS 86.2 LOS 21.7 -5 1
33 NBC 85.4 1Edge 17.5 0 5
38 ABC 87.5 1Edge 12.9 -5 8
26 Ind 87.1 1Edge 11.5 -30 9
49 MyN 86.3 1Edge 7.7 0 10
7 Ind 88.0 2Edge -7.2 -10 8
23 ION 100.2 2Edge -13.5 10 16nikiml
1 - 4 of 24 Posts
If you had clear LOS to it, and -14 NM was just a matter of distance, roughly about 24dbi antenna gain for consistant viewing, as far as Ive gathered. Holl_ands would give you a better estimate.And what would be the gain needed for channel 23 (NM -14db)?
So for his channel 23, that would mean an antenna with 21.7 + dbi.Resultant signal output power from antenna: -90dBm + 14dB = -76dBm
Assuming there aren't significant losses in your system, then this should fall within the sensitivity range of your ATSC tuner (-83dBm).
Well, if your tuners internal amp is poor, the preamp gain will help boost it. If your tuners gain is already great, the AGC circuit is going to limit additional gain benefits. (I havent seen an AGC adjustment control on a TV in a very long time. It used to be common.)How tipical is the sensitivity you mentioned (-83dBm)?
Will preamp help here or a preamp will also have similar sensitivity?
Big difference between being able to detect a station versus getting a consistant strong lock on it. Thats why I added 10 to the figure (instead of 0).what do you make out of the explanation in the tvfool signal analysis faq, just below the table:
So basically from what I understand :
If you take the initial NM value for a given channel, add your antenna gain, subtract all the other system losses, and still end up with a value above 10, then you should be able to lock onto that channel.
1 - 4 of 24 Posts
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