I built an M4. It receives all the channels I want. However in testing the location where to place the antenna I have a funny situation. If I place the antenna at location A, I get all the channels except one (FOX). FOX comes in at 25%. If I move the antenna 3 feet to the left (location B), I get FOX at 50% but CBS goes down to 50% (from 100%). Then if I move the antenna another 3 feet to the left (location C), I get FOX at 100% and CBS at 25%.
I am facing several walls of trees which appear to scatter the signals. I built a second M4, stacked it horizonatally with the first one and experimented by moving the stack through all 3 locations. Cannot get an optimum signal for either CBS or FOX with the two antenna stack. Whichever side I move the stack towards (either location A or location C) I lose considerable strength on either FOX or CBS.
I've decided to quit fiddling around with two antennas and three locations. Each of three locations does give me an optimum signal for 90% of gthe channles. I'll build a third M4 and put one in location A, the second one in location B and the third one in location C. Three antennas in three locations.
Question: how would I join the three M4s in a horizontal stack using wires? I don't want to use baluns and a splitter-combiner. How would I join in a horizontal stack the three M4s with wires and then use a balun to go to the preamp? Thanks.
Craig I will most certainly not answer your immediate question but will attempt to guess your predicament based on my own experience.
I've played with ganging (same as stacking except horizontal) two CM4228 WITHOUT balums. Basically I would hook up a flat cable from each antenna and terminate them on a mast combiner. My purpose was to receive a station in New Hampshire (NHPTV RF48) from Montreal which I ended up doing quite well but only if both antennas are electrically synchronized to the same polarity.
You see your antennas create a bonified DC electrical circuit which is subject to transmitter antenna polarity so basically, reconsider your stack and simply reverse one wire on one antenna to see if changing (or correcting) polarity will fix things for you.
You see in my predicament, all (33) stations out of 35 would be receivable with antennas connected in one way while 2 channels were further enhanced with wires crossed.
CraigRoyce - Why not build an antenna for only FOX or CBS? If one of them is VHF-hi then you can build a Yagi for it alone. Then you would need a special joiner (I forget which).
There might be an easy solution, or it might mean that you must put your antenna in a place where the trees don't interfere with the signals. Trees do interfere with TV signals, especially UHF.
All the stations are coming from one direction - 205 degrees. I aim there from all three locations A, B and C.
Both CBS and FOX are UHF. I'm thinking according to MClapp's specs of having an M4 with whisker length and spacing specific for CBS (11.7" ) and another M4 with whisker length and spacing for FOX (10.75"). The third M4 would be 9.5".
The trees are a solid wall 50 feet across with no opening. behind the wall of trees is a slope (hill) rising 20 feet up with another wall of trees 50 feet across. Then on top of that hill is another wall of trees. The fact that these M4s can get signals in the 80% range is a miracle! The trees are old trees about 50 to 60 feet tall - a mixture of firs, pines and maple trees. That's why I don't mind ganging multiple M4s since two M4's give me 80 to 90% on a majority of the channels. The VHF channels (NBC and PBS) come in at 90% rock solid. CBS and FOX are the outliers depending on where I place the antenna. But if I place the antenna at a certain location CBS and FOX do come in strongly.
What if I did this: Put the M4 customized for CBS at location A. Place the M4 customized for FOX at location C. Place the standard 9.5" M4 in the middle at location B.
Connect antenna A with antenna B. Connect antenna B with antenna C.
Connect A's left feed line with B's left feed line. A's right feed line with B's right feed line.
C's left feed line with B's left feed line. C's right feed line with B's right feed line.
Balun connected to B's feed lines.
Would that work? CBS and FOX at the edges (A and C). All other channels in the middle at B. Balun at B going to preamp and out to TV.
BTW the reason I key on both FOX and CBS is football - the NFL (AFC on CBS and NFC on FOX).
Yep, Post #15 in the OTA FAQ is an introduction to stacking/ganging antennas, and also here's a thread containing just about everything you will ever need to know on that topic:
Stampeder, I reviewed the stacking\ganging link you provided but did not see any post having to do with ganging three antennas. Most posts in that thread deal with stacking\ganging two antennas. My question still remains as to what is the wiring required for a three-way join. Is it as I surmised above (A to B and B to C left and right feed lines with balun on B)?
Another related question. Is joining the three antennas through the midpoints of their phase lines the only method of combining them (without multiple baluns)? Can the three antennas be joined using just wires at other points - not necessarily at the midpoint of a phase line?
I've seen antennas hacked together with the balun below the middle and even at the bottom of the antenna. I think for best results you need to join them at the middle to keep it balanced. Most use tight phase/joiners, some use longer (downward V).
I don't think anyone has joined three similar antennas. It might work, it might not. Stranger things have worked. The only thing you can do is... try.
I'm going to try it first in my backyard or attic to see if I can get a 3-way join working somehow. I don't want to climb up on the roof to experiment. Once I've got it working there, I'll redo it on the roof. I've got the 2-way gang working...so it's just a question of finding the right way for a 3-way join.
I'll volunteer to do some 4nec2 Modeling & Optimization to find "Best" Dimensions for a Holl_and Horizontal Harness (HHH) with THREE M4 Antennas....but this will be for ALL in SAME direction and IDENTICAL Antennas....and it's going to take awhile....
Is it possible to gang three M4s with each one having slightly different whisker dimensions? If I have an M4 with 11.7" (optimized for CBS) whiskers and another M4 with 10.75" whiskers (optimized for FOX), does that fall within the rule that ganging or stacking has to be done with identical (or is it similar) antennas?
Once I finish the 3x MATCHING M4 case, I'll change the dimensions on one Antenna and see if the combination is still working as "expected"....
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