Antenna Rotor Controller

[haklesup]

I finally joined the HDTV club. Since I refuse to pay the cable company even more for something that comes over the air for free, I decided to resurrect the TV antenna on my roof. Works pretty good, I get about 8 digital stations pointing SE in San Jose, CA.<p>Naturally, I want to turn my antenna since local listings indicate I should get more stations but the controller was not supplied to me by the previous owner so I bought one on eBay Rotor Controller. <p>Now the one I got has an analog meter movement on the front with NESWN legend and 5 terminals on the back marked 1-5 (direction switch and power switch too). But the rotor only has 3 terminals marked 1,2,3.<p>Anybody have any idea how to connect this up without reverse engineering it (which is my last resort). Should I have gotten a different controller, maybe this one is incompatable. A general description of how the rotor control system is supposed to work would be very useful. I'm guessing this is a late 70's setup but I could be off by +/-10 years<p>I'm guessing that the other two terminals might drive the movement with rheostat feedback from a rotor with a matching brand name.<p>Alliance controllers which were more common purportedly (from other eBay ads) have 4 terminals. Any clue anout this in case I buy one of those too.<p>ANother possibly stupid antenna question. What is considered the front of an antenna. This is a multi element roof aireal and comes to a point at one end which I always assumed was the front but now I am not sure because it is presently pointing 180 degrees from where I understand the (san francisco) transmitters are and seems to pull in a good signal. (probably just lucky it was left in a sweet spot by the last user)<p>(PS I'll be getting to the AFT problem on the Sony soon now)

[russlk]

The narrow end of the antenna is the front, but it will receive from the back also (just not so good). My Radio Shack controller has 3 terminals, see if you can find one of those.

[Bob Scott]

Yup The narrow end is the front but you'll still get reception from the rear too because the antenna isn't perfect.<p>Here's the theory of the antenna controller at the house I stay at in San Jose: The controller has 3 terminals. You twist a knob on top to point the antenna in any direction with the directions of N, S, E, W printed on the top of the controller, or anywhere in between. Here's the old-tech solution to automatic timing of the turn: The controller has a duplicate rotor motor built into it and it rotates a shaft until the controller's rotor lines up with the position of the knob on top. The rotor at the antenna turns for the same amount of time so they both turn approximately the same number of degrees.<p>You can get one of these at RAT-SHACK.<p>I don't know what kind of "rotator" you bought. It sounds like it was made for some kind of antenna system that has elements switched in and out, sort of like the old CB Super-Scanner.<p>In San Jose I get best reception with the antenna pointed due West, shich is weird because most stations are almost due North in San Fransisco. Even get NBC channel 3 in Sacramento. With the antenna frozen in position becuse the rotor motor's bearings are dry I still get 2, 3, 4, 5, 7, 9, 11, 20, 36, 44, 54, 60 and 65 clearly, plus a whole bunch of Spanish, Chinese, religious and shopping channels that I have the tuners programmed to skip over.<p>Bob <p>[ May 08, 2004: Message edited by: Bob Scott ]</p>

[Dean Huster]

There's usually a pretty strong front-to-back gain ratio on Yagi and LPA TV antennas, especially fringe and deep-fringe models. Although you may get some signals from the rear, signal strength will be far stronger on one of several side lobes that the antenna will exhibit.<p>Dean

[dyarker]

Bob Scott, Is there a fairly big mountain, or something due West? I'm thinking the bounce path is stronger than the straight the path.

[Edd]

Well…..looks like you just got yourself an old Trio controller box of …post Neanderthal…...pre Cro-magnon vintage.
That’s somewhat challenging my “50’s cache memory, but typically a 500Ω ~2in dia wirewound pot was used at the top end rotor unit and a resultant AC readout on the meter in the control box, providing the antenna rotor positioning info. Initial rotary mechanical antenna positioning was initiated to establish calibration/coincidence between the two units.
Favorite control voltage for most units 18VAC/60~…with a select few running with 24VAC. Typically there will be an internal AC capacitor in the controller box of ~150-250 µfd.
Probably the most popular 2 brands were Alliance and CDE, my favorite being the old Alliance with its rotary dial that you just rotated to the desired positioning and a rear clear Lucite disk internally carried a red hash mark to coincidence to your desired setting with a mechanical thump occurring until that time occurred.
Also they worked mechanically different in the utilization of a small AC motor at the controller unit stepping the clear dial. There was a normally closed series switch actuated from a spring steel leaf/cover that was accessible by a finger thru a hole in the bottom of the unit. This way the top rotor motor could be temp disconnected from its power while the control box motor advanced, thus letting you calibrate between either cw and/or ccw rotation and not having to crawl the tower for an antenna clamp adjustment.
Looking at what you have on hand you might make these evaluations without pulling the rotor motor. Ohm out the three leads and find the common between the three wires from your two rotor motor windings. Inspect the innards of your box and confirm the aforementioned ~18VAC power xformer and cap. If so that might just enough to let you initiate a test for an operational drive action at the top end….not gear stripped or locked down.
Initially there will be an interconnecting of one of the transformers secondary windings two wires to the rotor motor common windings as previously ascertained.
This will hold true for both test modes.
Typically two different motor modes were utilized, one where you take one leg
of the 18VAC to the previously ascertained motor common and the other 18 goes thru the cap and to your choice of one of the run windings. Reversing is initiated by
disconnect and reconnecting to the other winding.
The other possible motor config was where the rotor motor common received one raw transformer 18 VAC leg ( just as before) and then one (of the two )run motor windings received 1 capacitor terminal while the other capacitor terminal went to the common.of the windings. This left the hot 18VAC terminal going to the other (unconnected) motor winding. For reversing direction, the cap and hot 18VAC connections were swapped. Just try out the possibilities by hook up of adequate clip leads and a visual check of the antennas boom tip, as it will mechanically amplify any little nuance of rotor movement. Power up for just an rapid evaluation via ur power switch..or AC line cord.<p>For remembrance/association:………for anyone that it might help in the future.
Antenna directionality ?
Mechanical analogy: Which is the business end of a dagger? (A Blondes response...the pointy thingee)
Electronic analogy: Laid out on the boom, the shortest /higher freq elements are on the front, the longer/lower freq elements are progressively cascaded towards the rear of the antenna.
If oriented backwards to the signal, consider the shielding/attenuative effect of the reflector and the longer rear elements to each shorter one forward.
(A select few larger antenna ‘Y’ designs do not have their ant elements in line on one boom, but on 2 forked booms toward the rear, but the element size layout still remains in the same order.)<p>Addenda: This was on laptop much earlier, pre posting; therefore there may some confluence of thoughts by others since that time.<p>73's de Edd
[email protected] .........(Interstellar~~~~Warp~~~Speed)
[email protected].........(Firewalled-Spam*Cookies*Crumbs)
<p>[ May 15, 2004: Message edited by: Edd Whatley ]</p>