stacked two CM-4228 vertically

[firemantom26]

I stacked two CM-4228 vertically from that I have two equal lengths of coax going into a uhf UHF combiner, than into my CM 7777 amp. I want to add another amp to this. Will it help or will it hurt reception and if it will help what is the best way to do this, also what should the spacing betwwen the two antennas?


Thank You

 

[Jim5506]

Look at http://www.hdtvprimer.com/ANTENNAS/16bay.html

 

[firemantom26]

Look at http://www.hdtvprimer.com/ANTENNAS/16bay.html

Yes, I have read this and just wonder what peoples results has been when adding a dual amp and how much space is better between each antenna.

 

[Lorenzo]

I think that unless you have a very long coax downlead (200 feet or more) and have a lots of tvs running or lots of loss before the receiver (multiple vcr's hooked up) the gain of the 7777 is plenty.

The real improvement can be had with careful selection of the matching transformers and the 2 set coupler. All need to be minimum loss items as signal quality lost before the preamplifier can never be recovered. Also check carefully how the matching transformers are hooked up to the 300 ohm terminals of the antennas- they need to be the same- you may have to change one the the transformers hookup to see which hookup gives the stronger signal.

I think for best overall reception the 2 reflecting screens of the 4228's should either be touching or be very close to touching.

 

[firemantom26]

I think that unless you have a very long coax downlead (200 feet or more) and have a lots of tvs running or lots of loss before the receiver (multiple vcr's hooked up) the gain of the 7777 is plenty.
The real improvement can be had with careful selection of the matching transformers and the 2 set coupler. All need to be minimum loss items as signal quality lost before the preamplifier can never be recovered. Also check carefully how the matching transformers are hooked up to the 300 ohm terminals of the antennas- they need to be the same- you may have to change one the the transformers hookup to see which hookup gives the stronger signal.
I think for best overall reception the 2 reflecting screens of the 4228's should either be touching or be very close to touching.

Thank You for your help

 

[NightHawk]

An alternate method is to electrically connect the two 300 Ohm inputs with two stiff parallel bare copper wires (strip some Romex) spaced about an inch apart. Do not cross them and do not let them touch each other or anything else. Solder your baluns 300 Ohm input to the two wires equidistant between the two antennas. Space the two antennas so that all 16 bowtie tips are spaced equaly. This requires some overlap of the back screens. Connect the 75 Ohm output of the balun to the pre-amp input. With this arrangement only one pre-amp is needed and no coupler.

 

[NightHawk]

The procedure I listed eliminates any need for a second amp or a coupler. It's much simpler and less prone to phasing issues than trying to combine the output of two pre-amps. I constructed this array for my neighbor and it works well.

 

[firemantom26]

4228 help

--------------------------------------------------------------------------------

The way I am going to try it is two equal lengths of coax coming off each baulms into two 7777 amps, run two coax cables "RG6' into the house, then into the power supplies, than combine them at that point, then from there into the TV. What were the best results you have had on spacing each antennas? I have them with each bow tie at equal lengths. I had to over lap the screens to do this. what do you think. How important is the spacing of each antennas?
Thank You