Remote Metering

[ka4koe]

Has anyone used a web cam to remote monitor a transmitter, similarly described for WROV at the link:

http://www.patrickwgarrett.com/WROV/Engineering/engineering.htm

In case the links are broken, here is the camera shot of the Plate I/E....

Now if I can only get K4SMN to let me take a photo.....

[WD8BIL]

Yes.

N3WWL had an RA250 he remote monitored with a cam IIRC.

[Opcom]

That is how you get the engineer to check the TX all night.

[flintstone mop]

Yes.

N3WWL had an RA250 he remote monitored with a cam IIRC.

Yes he did. I still have the cam. Some transmitters will allow remote metering. Maybe not the older TX's

Fred

[Mike/W8BAC]

Why would you want to tie your internet bandwidth up and recieve 1 frame in five when you live with the transmitter? If it's in the garage, go low tech, wire a real time camera and dedicated monitor. These days the cost is about the same and your internet isn't being wasted.

[Steve - K4HX]

The transmitter has overload protection. Why would you need to monitor the meters?

[ka4koe]

Maybe because its there.

[Opcom]

Remote viewing can be fun. Try it for red hot anodes. Remote viewing could be nice for a peak reading instrument so as to have a check on legal operation. Combined with a wireless remote control which may also be operated via the license, one could enjoy an early bird or boiled own net while using an easy chair in the house, leaving the cold or muggy lab to the gear.

[Steve - K4HX]

Just one more thing that will fail. KISS.

[W7TFO]

Your TX is already equipped to handle extension meters.

Pick a couple for Plt E&I, and RFA and you are golden.  Usually an 0-1mA movt.

73DG

[ka4koe]

Anudder query.....

Noticed on the skeemagic that the neutral is indicated as bonded to the chassis cabinet. Now, this is a no-no per the NEC for at least the past decade. Unless there is a need for 120V somewhere in the TX (haven't gotten into it that closely yet), I planned on bonding that connection to the ground safety conductor in the feeder from the main panel. You shouldn't have your safety ground used as a current return path, eg. cabinet "energized". If you may recall, all new 240V appliances (such as clothes dryers) that bonded N-G together at the unit now use 4 pin plugs.

[Opcom]

What can be done when an old piece of gear is wired/built that way? With some it could be a major rewiring. Whatever the hazard is, there should be a way to eliminate or reduce it.

[ka4koe]

Researching it and talking to others who have dealt with it at this point. HV wire should be in today so will get back on it after a break of a couple of days.

[KA3EKH]

Read the manual and the schematic! Unless modified the transmitter only requires 230 Volts and a ground connection. There is nowhere to attach a neutral in a BC1T all the transformers, contactors and everything else is 230 volt operation, recall that the fans were 120 volt but they are in series. I have installed several old Gates/Harris transmitters and know from experience that remote control is easy but you will need two sets of push buttons for Plate ON, Plate OFF (NC), Fill ON and Fill OFF also normally closed.  And BEWARE! The remote control circuts for that transmitter are all on TB1 and easy to get two but they all operate on the primary side of the AC line so they will bite! Regardless of the transmitter being on or off. The remote Ep and Ip show up on that strip too. Also KX4 or whatever they call the plate delay relay is always faulty and you may want to look to see if they had any resistor stacks for reduced night operation being that in Ham service they are just a waste of energy and generator of heat. If you do want to run at reduced power consider a 240 volt autotransformer prior to the plate transformer.

[ka4koe]

Read most of it, but as you know, its a lot to digest. Tnx for the heads up. Also going to use relays to avoid bringing 240V into the shack from down below.

[w4bfs]

I know this is a real complication but do you want real remote metering as in bipolar current loop instrumentation ?  this is of course not simple but doable 

[ka4koe]

I'm a big proponent of KISS with regards to metering.

Here is a screen capture of the input fusing/bonding. Text reads "solid grounded neutral". That could indicate a N-G bond (no-no) at the TX or a N-G bond at the main panel supplying the unit (OK). This skeemagic dates from around 1960 and there have been a lot of code revisions since then; on average, every 3 years when new codes are issued with latest revisions.

What we want to avoid is a situation where the chassis and conduit / raceway system (if metallic) is used as a current return path, which is a no-no per NFPA 70 for obvious reasons, eg. electrocution/energization of the metallic raceway/ground.

However, I am aware of no issues arising in the past with BC transmitters and this whole discussion may be moot/splitting hairs.

PAN

[KA3EKH]

There’s no reason to carry the neutral to the transmitter, it’s just a waste of a wire being you cannot attach it to anything. Unless something is wrong or someone has changed something no current in reference to the AC system is returned over the ground. If there was any AC current being returned over the ground circuit you have a problem like leakage or some change in the distribution. The ground is only a safety circuit, there is supposed to be a second RF ground that will be attached but that’s a whole different story. On some transmitters like the old RCA stuff a second 120 volt circuit was added for things like the cabinet lights or on the three phase transmitters you often had an additional 120 volt circuit that was used for control or other functions but that transmitter is a 240 volt thing and has no use for a neutral.
Over the years I have installed many broadcast transmitters and on the smaller one to three Kw 240 volt signal phase jobs always build conduit from the main disconnect to the transmitter with running just the two AC wires (red and black) and a safety ground (green). Sometimes have used MC where it had a white bundled in with the red, black and green and will just cut that one off being it won’t connect to anything. But the idea of extending a neutral to a transmitter where it isn’t needed and then bonding the neutral to the ground at the transmitter is pointless and a violation of the rule that the only place where neutral and ground is tied together is in the main panel.
If you need things to worry about in regards to the NEC think about what you’re doing in terms of providing a RF ground system that’s at a different potential to your utility ground? And if current will flow between the two ground systems over the safety ground to the transmitter and the RF ground. In commercial installations we always install a #6 or larger cable between the RF grounding system and the main AC distribution panel to prevent any difference of potential being carried thru any transmitter or RF device and at the end of the day our RF grounding systems are way better grounds the utility’s one ground rod.

[ka4koe]

...unless one wants/needs 120V somewhere in the cabinet for running aftermarket ventilation fans or other happy items. Taking either phase A or B against ground is bad....bad. Bonding N-G at the TX is just plain stupid and dangerous...no argument with you there. I think I mentioned this point earlier.

NFPA 70, Article 810 does not specifically address RF grounding per se.

I've been consulting in the EE field for the better part of 20 years and have seen lots of scary installations as well as designed ground ring counterpoise, Faraday cages, as well as NFPA 780 compliant systems for commercial 911 facilities. Typically we specify 5 ohms or less ground resistance for those installations. Lots o' fun and lots o' money!

The safety of my equipment, home, and family is in the forefront of my mind prior to throwing the big switch. I will need to relocate the main antenna to address RF field density concerns. The numbers for my existing antenna do not look safe.

Yes, my planned installation infrastructure is overkill; install a big red "EMERGENCY OFF" pushbutton or prominently labeled safety disconnect switch near the unit that will disconnect all current-carrying conductors - i don't want someone fumbling to unplug the infernal thing, install a fire extinguisher nearby (all fire types compliant), as well as a moisture/dust resistant spot smoke detector (this is a non-conditioned garage, btw).

My RF ground will consist of a length of HEAVY copper going straight thru the adjacent wall on the LH corner of the garage and then immediately bonded to a minimum 10' long, 3/4" copper clad steel ground rod. If I had an exothermic weld kit I'd use it to make up this connection. Total run for the grounding conductor (proper verbiage) will be 5' or less to the rod.

[KA2DZT]

You need to bond the new ground rod to the service entrance ground, hopefully that's not too long a run.