Newbie reception question

Chris05 · 3-Jan-2012, 12:39 AM

Hi All,

Trying to diagnose a reception problem. I recently located to northern Mn
got a place in the country, picked up a used tower, rotor, antenna and amp
all in good shape and got it setup.

Here is tv signal analysis:
http://www.tvfool.com/?option=com_wr...4033445446e310

equipment:
tower: 20 ft main, with a 20 ft crankup section and 10ft mast on top.
antenna, I believe to be Antennacraft CCS1233 vhf/uhf model.
cable: less than 100 ft from ant to amp.
amp:CM spartan 3, with 2 way split downstream of amp.
Tv: Panasonic lcd with digital tuner and CM Ota DVR.

Antenna is set to 38 deg and approx 30ft in height, nearest treeline is
approx 100 ft away.

Reception: 31.1-31.4 digital, signal is perfect. Analog 29 is grainy.
Problem chan is 13.1, it will not lock at all.

I tried leaving tv set to 13.1 and rotating antenna from 0 deg N to 90 deg E,
but no success.

Today, I even tried setting antenna to 111 deg, and tried for other chans,
no success..... but 31.1-31.4 chans came in perfectly even at this angle.

I am scratch'n my head as to why 13.1 won't show up at all.

Any recommendations?

Thanks,
Chris

GroundUrMast · 3-Jan-2012, 3:41 AM

One thing that stands out, the preamp would be more effective if it where located just below the antenna. Signal quality lost in the coax run between the antenna and amplifier is lost forever.

Can you verify that the FM trap is switched 'in' per step 5 of the manufactures installation instructions?

Chris05 · 3-Jan-2012, 4:20 AM

Hi,

Yes, the preamp is located at antenna, the pwr supply box is near the tv.

I can't verify the Fm trap switch, as antenna does retract enough for me to reach from
roof. It requires laying over the tower, that requires extra manpower.

So.... if I have to pull this tower down I need to convince myself the antenna is good.

Ideally, I would aim at 111 deg, as there seems to be more available, just not sure
the antenna / preamp is up to the task. If a new ant/preamp would make a big improvement, I would consider doing it when I pull the tower.

Chris

Electron · 3-Jan-2012, 6:18 AM

All outside coax cables are suspect of being bad , the matching transformer that connects the antenna to the coax that connects to the the preamp is suspect of being bad. All other out side connections are suspect of being bad. My self and question askers have said , " I know that matching transformer is Ok " . "I know that section of coax is Ok". " I know that preamp unit is Ok at the antenna , I know that power supply in the house for the preamp is Ok". One way to prove out the reception is to connect a known to be good matching transformer to the antenna and a known to be good long length of coax from the matching transformer DIRECT to the Tv through a open window or open door.

Chris05 · 3-Jan-2012, 7:03 PM

Hi,

Update on situation. I went up on roof to take a pic of antenna for posting here and
saw that the twin lead wire looked loose. I stripped back to fresh wire and reconnected to antenna, during this step I noticed that twin wire is quite brittle, so I plan to replace it soon.

I re-aimed antenna to 111 deg and did a re-scan, and was surprised ! Am now receiving cbs,nbc,abc, fox and pbs, 19 digital channels in total, some are repeats.
The only chan with problems is cbs/3.1, signal is around 35-45 %, and will not lock. All other chans/signals show 55-80% and are stable, considering it is a windy day and
antenna is moving abit, this is good progress.

Any ideas on improving 3.1 reception?

Chris

Tower Guy · 3-Jan-2012, 11:59 PM

Quote:

Originally Posted by Chris05

Any ideas on improving 3.1 reception?

1. An antenna with more gain.
2. Try other locations and heights for your existing antenna.
3. A combination of better antenna and optimized location.

http://www.hdtvprimer.com/ANTENNAS/siting.html

GroundUrMast · 4-Jan-2012, 1:06 AM

Quote:

Originally Posted by Tower Guy

1. An antenna with more gain.
2. Try other locations and heights for your existing antenna.
3. A combination of better antenna and optimized location.

http://www.hdtvprimer.com/ANTENNAS/siting.html

Agreed on all points.

If the existing antenna is a CSS1233, there are quite a few antennas available with substantially more UHF gain. The XG91, HD9032 and HD9095 come to mind. With 8 to 10 dB more gain, KDLH becomes a realistic goal.

The existing antenna could continue as the VHF portion of the system, simply combine the two antennas with a UVSJ.