[TowerTalk] Fwd: TIC-Ring Question

Mon Nov 14 19:34:03 EST 2022

Post all the pictures you want on towertalk at groups.io

73, Jim W7RY


On 11/14/2022 10:25 AM, Grant Saviers wrote:
> Resent w/o pictures per K7LXC request, contact me off list if wanted.
>
>
> -------- Forwarded Message --------
> Subject: Re: [TowerTalk] TIC-Ring Question
> Date: Fri, 11 Nov 2022 11:10:15 -0800
> From: Grant Saviers <grants2 at pacbell.net>
> To: towertalk at contesting.com
>
> Hi Dave,
>
> Re limit switches, I had to fabricate limit switches for the K0XG 
> rings on my Rohn 65 tower.  7 rings.  The mount has the switches on 
> the tower leg, and the ring uses a 3x3x1/8 6061 angle plate and a 
> delrin block to actuate the IP65 Honeywell microswitches.  I don't 
> recall why I used IP65 vs IP67.
>
> I was willing to sacrifice about 30 degrees of due south pointing to 
> not have to have overtravel in the switch assembly, since each switch 
> has some deadband.  That simplified things a bit, with hardly any DX 
> (except HC8!) in due south from WWA.
>
> It took a bit of cut and try to get the distance from switch roller to 
> actuator plate trip point correct by modifying the thickness of the 
> plastic block or the offset from the tower leg (I think what is shown 
> in the pictures).  One constraint is the actuating block has to rotate 
> without interference.
>
> The switches are Honeywell IP65 from the picture.  They are on the 
> underside of the mounting plate.  I think I replaced one (of 14) in 
> the past 6 years, but it measured ok.  The switches go to a j-box with 
> diodes so the ring can be reversed off limit.  One diode failure also. 
> My plan is limit switches are last resort if the RT21 programmed 
> limits are off.
>
> I did have to change the ring centering cam rollers from factory to 
> get the ring and pinion gears to fully engage and haven't observed any 
> jumps, but that is not proof it hasn't happened a small amount.  The 
> top ring @140ft is 3L 48ft boom 40m full size.
>
> What I learned:
>
> Use much larger diodes - the K0XG motors are 180v DC PWM driven and it 
> is difficult to find 1kv 10a diodes that are not stud mounted so I did 
> the best I could.  Also, use TVS protection since it might be full 
> motor voltage/current being interrupted.
>
> Put a high value resistor across the switch contacts so bad switch, 
> wiring, or bad diode can be analyzed from the shack, if one can't 
> reverse out of a limit.
>
> Clearly mark the inside of the j-box with wiring and part orientation 
> and photograph it.  Most tower climbers aren't EE's.
>
> Waterproof plastic j-boxes aren't, so always have a smaller than bug 
> size drain hole at the low point.  Maybe 50" of rain here per year. ;( 
> Use 6x6 rather than 4x4 j-boxes.
>
> I like the idea of a back-up magnetic azimuth sensor, looked a bit at 
> them but wondered how they would work among all the steel and RF.
>
> 73,
>
> Grant KZ1W
>
>
>
> On 11/11/2022 10:11, Leeson wrote:
>> I've been using a TIC ring rotator here on a big 7el 10m Yagi for the 
>> past 20 years with good success, but it has a couple of well-known 
>> unresolved problems: In the high winds we have on our hilltop (147 
>> mi/h 3s gust measured), it can jump a tooth on the motor or pot gear, 
>> which eventually makes the direction indicator pot totally out of 
>> sync, or even damages it. Since the ring rotor doesn't have physical 
>> limit switches, that has permitted over-rotation that parts the coax.
>>
>> Re direction indication, has anyone had any success with alternatives 
>> such as magnetic or microswitch gear tooth counters? Or a simple 
>> compass module with output that a Green Heron RT-21 can read (0-5 
>> volts)? See G6EJD, KJ4JJH, K3NG. I'd like to have direction 
>> indication that mounts directly at the ring or antenna boom itself, 
>> rather than through a coupled gear. and it should work at zero speed.
>>
>> Second, has anyone had success with adding waterproof (IP67) limit 
>> switches? Honeywell, Omron, IP67 microswitches or cheaper imports? If 
>> a magnetic gear tooth sensor is used, what kind of spacing precision 
>> is required? With 360 teeth, the 1° precision should be plenty for HF.
>>
>> I am aware of modifications and updates (e.g., N1CX) that may help 
>> prevent gear tooth skipping, but I want something bullet-proof that 
>> really gives me full confidence. Even a partial failure in a contest 
>> can compromise an otherwise winning effort; in our big HC8 station, 
>> we gave up on rotators and went with multiple antennas per band. But 
>> for my less complex setup here at home, I intend to try to resolve 
>> both of these problems when the weather permits, and am interested in 
>> hearing the experiences of list folks.
>>
>> BTW, I resolved the climb-over issue with a small 3-rung steel ladder 
>> mounted below it on the tower face. And if the limit switches work 
>> out, I'll add them to my prop pitches, as well.
>>
>> Thanks, Dave W6NL/HC8L
>> _______________________________________________
>>
>>
>>
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-- 
Thanks and 73, Jim W7RY