Help:receive HDTV bcst from 2 diff azimuth - AVS | Home Theater Discussions And Reviews
Local HDTV Info and Reception > Help:receive HDTV bcst from 2 diff azimuth
N6SPP's Avatar N6SPP 10:06 AM 04-13-2002

Need antenna info on properly receiving hdtv broadcasts.
=Receive location is N.SFO...
=Need to receive broadcasts from Sutro(sigs are solid), and from
the Fremont /Sunol hills (S.E. Bay area)...
=Sutro Tower is @ 180degs, and the Fremont hills are at abt 130degs to
the S.E.
==Tried one Radio Shack 17 ele UHF (15-2160) ant directed at Sutro--
again sigs were solid (90+ Sony hd-100 sig meter), and then pointed ant
towards Fremont area(+-) and sigs were moderate and "lockable".
==Gain on this ant is good, and beamwidth is rather narrow(good)...
==Connected 2nd 15-2160 ant using balun/RG6 to 1st ant. Am using one RG6 feedline to rf headend..
==Pointed one ant to Sutro, and the other ant towards Fremont--
with poor results.
==Did not try feeding the 2nd ant out-of-phase.
Antennas are on the same mast(top of 10th floor bldg)..
==i.e. Am unable to rcv bcsts from 2 areas at my one location..

Any ideas or refs would be helpful ! thankyou! Rick
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spwace's Avatar spwace 01:21 PM 04-13-2002
Combining antennas is a bad idea, it will usually cause severe multipath. Run the antennas separately to an A/B switch, or use a rotor and one antenna.
N6SPP's Avatar N6SPP 03:40 PM 04-13-2002
Thanks for reply- spwace

= System is for a client.. AMX/multi-screens/multi-zone audio etc...
a/b switch would have to be automated into control system..
rotor automation would also be over-the-top.. no manual stuff hi.

== We'll keep your ideas in mind..
I'll keep searching . Thank you . Rick
cpto's Avatar cpto 10:01 PM 04-13-2002
Q, spwace? I've seen antennas pointing in different directions on top of several buildings (usually apartments).

There must be somy was to combine the signals without multipath distortion. And, how significant is MP distortion with HD reception? I have no idea, and would appreciate your knowledge on this subject.

spwace's Avatar spwace 11:13 PM 04-13-2002
This is not really my area of expertise, but I do know that you can avoid multipath by installing filters in the individual antenna feeds, ahead of the combiner, so that each antenna only passes the channels it is intended to receive. I don't know what the cost of these filters is or where to buy them, but you should probably start with someone who installs apartment antenna systems.
spwace's Avatar spwace 11:34 PM 04-13-2002
Check out this website, they have the filters I was referring to.
Man E's Avatar Man E 05:08 AM 04-14-2002
I had a similar situation when I put together my OTA towers.
N6SPP's Avatar N6SPP 03:27 PM 04-14-2002
Thanks for nice info..

Our A/V company uses all home-runs to to keypad/control panel/
rf distro/DSS/OTA/ spkrs ,etc . locations in a clients home..

We do A/V switching with Extron devices etc. and also modulate and
combine sigs when required.....

The dual OTA is a little new here, and your info is of great help.

=chk'd out your pix and stories.

I'm an HF guy , but i do get into VHF/UHF ants -- work a little
Amateur satellite, and am heavy into High-Speed-Meteor Scatter

see you later, Rick
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