How to hook up Optimod 8100A

[secondchoice]

http://www.aareff.com/en/fm-transmitter-limiter-kit.htm

Could someone use:

http://www.aareff.com/en/250w-erp-fm-transmitter-system.htm

for a translator? I don't see FCC certified on their website. The price seems too good verses:

http://www.broadcastwarehouse.com/bw-broadcast/tx600-stereo-fm-transmitter/24/product

 

[Kmagrill]

You are comparing a 100W exciter to a 600W transmitter. There's no comparison. Aside from the obvious power difference, the 100W unit has no FCC certification, does not have an integrated digital audio processor nor web-enabled remote control, nor is anything adjustable via the front panel. The BW transmitters have a menu driven LCD control panel that lets you perform basic functions without opening the box. BW transmitters also have an integrated LPF so they are certified for use as stand-alone transmitters. For the few dollars more that you would pay for a BW 150W transmitter, you would not have to buy an audio processor or remote control making the BW a better choice on value and also a better choice on performance, IMHO.

 

[secondchoice]

I was looking at the TX 150/300 for $2925, but it doesn't matter, There is no comparison due to the lack of the FCC Cert. I am working with a group that is trying buying a dark Class D (with some coverage) and hooking up a 250 watt translator. We have "found" an RF "hole" with no A,C or translator with in 80 miles and no adjacent for 50 miles. We were going to do it "backwards" getting the translator first then moving the AM in to feed it. Just got to find a translator close enough to move were we want it. I am afraid that a "non com." will find this "hole". A lot of stars have to align to make this work but nothing ventured nothing gained.

 

[TomT]

Unless there is already a licensed and operating translator you can buy, you are out of luck, at least for a couple of years. A new "window" for new translators is not likely to be opened for many years. The FCC is still working on the back-log of translator applications from about ten years ago, if there is a pending application in your area this might be a possibility. Some of those may be available for sale once they are processed and a cp granted, but that is a long shot.

2nd issue: Class D (daytime) AM station? If it is dark, be careful. You will have to be prepared to put the station back on the air before it is silent for a year, or the license will be cancelled without any possibility to revive it. FCC will not license new daytime stations. You will need to be sure the station can be put on the air without expensive repairs to the transmitter plant. If so, then you would need to be able to move fast to keep the license alive. Usual method is to create an LMA to buy with the owner, then put something on the air (Computer hard drive with ID's and music cranking away at the transmitter site is good enough) & notify the Commission that the station is back on. D.C. counsel advice recommended before shirt is lost.

For an FM translator rebroadcasting an AM station, where you could feed the translator transmitter by STL or land line directly from the studio, using built in or an outboard audio processor would be wise. AM processors are designed to compensate for the limitations of AM broadcasting; and do not sound all that great feeding an FM transmitter.

Note the antenna with the Areff package--doesn't look that rugged. Better to use something like an SWR CP antenna. Even for car radio reception--look around, there are a lot of window antennas and angled (i.e., raked back) whips in newer cars. Vertical only doesn't work as well with these antennas.

 

[Kmagrill]

I was looking at the TX 150/300 for $2925, but it doesn't matter, There is no comparison due to the lack of the FCC Cert.

Agreed. Also, the BW 150 is around $2,300 MSRP. The 300W is the one with the $3k price. In any case, you can get a better deal than MSRP when you contact the dealer.

As for the translator and AM station combination, unless you have a translator candidate in mind to move in, I would not suggest moving forward with the AM because there is a substantial risk that you won't find an available licensed translator to move. As has already been mentioned, the FCC will be a couple of years before opening a new translator window and many applications from the 2003 window are still frozen nearly 10 years later. Unless you are prepared to operate the AM station as a standalone, don't get involved until you have the translator lined up. Finally, translators come in a variety of powers and coverages. You'll need a qualified broadcast consulting engineer to make sure your selection will effectively cover your town. You also cannot just change channels randomly, even if you have identified a potentially unused channel. The best advice I could give would be to have a consulting engineer help you before buying anything.

 

[secondchoice]

There are two possible translators, both on the "dark" list. The real problem is they need to be moved about 50 or 60 miles and the "distance" is too far for the FCC. The land for the AM is not a problem. (bank owned and in a flood plan but no issue with stream run off or EPA) Could use a Kintronic short tower or used tower which ever is cheapest for AM. There is an existing tower for the translator. We are going to use an engineer but if the pieces don't fit (moving the translator) no need for the expense.

 

[TomT]

Unless you are just walking in the transmitter building and hitting "on"...walk away very fast.

Any kind of new tower will cost you $5K or more before the first shovelful of dirt is moved for construction. The reason is the system of extortion set-up for new tower environmental approval:

$3K for a "CON-sultant;" $1k or more to pay off the various Indian tribes; $2K or more for an archaeological study--they will come on site, dig a few holes, then cover them up again. Plus a fight because it is in a flood plain).

 

[Kmagrill]

There are two possible translators, both on the "dark" list. The real problem is they need to be moved about 50 or 60 miles and the "distance" is too far for the FCC.

Your situation is complicated.

Normally, the rules permit translators to move provided that they meet interference criteria and provided that some part of the existing licensed 1mV contour at least touches some part of the proposed 1mV contour.

Recently the FCC began allowing waivers for translators to move further, if the proposed location is mutually exclusive with the existing location and the move is proposed in conjunction with bringing new FM service to an AM station. Mutual exclusivity would be defined as a showing that it would be impossible to build a new, full power, translator at the proposed location and on the same channel as the existing translator. The exhibit would have to show that the new site would work EXCEPT for the existing translator.

The big problem is that 50 or 60 miles is unlikely to be mutually exclusive, though it might be possible under some conditions. You would need an engineering study to determine if it works or not.

Additionally, the service contour of the translator must fit within the 2mV contour of the AM station and cannot extend more than 40kM from the AM station even if the 2mV contour does.

Well, this thread certainly has drifted far off of topic.

 

[secondchoice]

Unless you are just walking in the transmitter building and hitting "on"...walk away very fast.

Any kind of new tower will cost you $5K or more before the first shovelful of dirt is moved for construction. The reason is the system of extortion set-up for new tower environmental approval:

$3K for a "CON-sultant;" $1k or more to pay off the various Indian tribes; $2K or more for an archaeological study--they will come on site, dig a few holes, then cover them up again. Plus a fight because it is in a flood plain).

The land is now leased to a farmer (who has the option to buy from the bank and for a small percentage will buy an sign a long term lease). He is growing corn and soybeans on the land now so we might get around EPA and the archaeological studies. If we need a archaeological study, being part Cherokee, I have friends in the business.

 

[TomT]

Don't work that way. System is fixed to maximize the flow of money to Washington and to the tribes. Just gone through this, so I know...and I am an attorney.

1. You put a notice on the TCNS system at the FCC (Tower Construction Notification System). Several Indian tribes will pop up--most demanding money for consultation. Most get the check and then are happy. One in particular will demand an archaeological study--which must be done by a registered archaeologist with contacts with the state historical preservation office.

2. You must run a local public notice (e.g. legal ad in the newspaper)

3. You need to do an FAA form 7460 (probably the easiest part of the process unless the tower need be over 200 feet)

4. In addition you need to set a date for the FCC to put the tower on its website for 30 day notice.

This all takes time and money--at best 45 days, at best somewhere north of $5K.

But this is a dark AM--you still need a CP to move the site AND build the tower and ground system AND get on before the one year period runs out. Can't be done--this station is doomed.

 

[secondchoice]

The only reason to fool around with the AM is have something to feed the translator. No translator, no deal. The nearest dark translators (for sale) are over 57 and 64 miles away so unless there is a rule change it ain't going to happen. (At least with my money!)

 

[rickradio]

Well, this thread certainly has drifted far off of topic.

Which is fine with me...that conversation about the dark AM is interesting; as far as I'm concerned, carry on.

But about my 8100A, I'm thinking it's time to go transmitter shopping: I've had people both here and offline say pretty much the same thing about the TXs I'm currently using (Ramsey and EDM) because of the RCA inputs. The thing is though, I've looked at the TX1 10-milliwatt rig on the BW website, and it has left and right inputs too, not a composite input, albeit with XLRs instead of RCAs. Unfortunately, I'm really not much of a tinkerer, preferring instead to plug gear in and use it as it was built, as opposed to popping the cover and modifying it, which, unless I misread, is what some here have suggested. Moreover, it also has an onboard compressor/limiter (which can be disabled if you have external processing, which I do in the form of the Optimod, rendering the C/L in the BW redundant). Also, I'm currently using for processing a Behringer AutoPro MDX 1400, which also has a compressor/limiter. So, I'm not really sure what to do at this point. Should I just go with the BW rig, or is there Part 15 gear more suited for use with an 8100A? Any suggestions welcome...with my thanks.

 

[gtomas]

But about my 8100A, I'm thinking it's time to go transmitter shopping: I've had people both here and offline say pretty much the same thing about the TXs I'm currently using (Ramsey and EDM) because of the RCA inputs. The thing is though, I've looked at the TX1 10-milliwatt rig on the BW website, and it has left and right inputs too, not a composite input, albeit with XLRs instead of RCAs. Unfortunately, I'm really not much of a tinkerer, preferring instead to plug gear in and use it as it was built, as opposed to popping the cover and modifying it, which, unless I misread, is what some here have suggested. Moreover, it also has an onboard compressor/limiter (which can be disabled if you have external processing, which I do in the form of the Optimod, rendering the C/L in the BW redundant). Also, I'm currently using for processing a Behringer AutoPro MDX 1400, which also has a compressor/limiter. So, I'm not really sure what to do at this point. Should I just go with the BW rig, or is there Part 15 gear more suited for use with an 8100A? Any suggestions welcome...with my thanks.

I don't know where you've looked, but all BW transmitters have MPX input (it's that BNC connector just next to the XLRs ). And, as others have said, it will perform much, much better than Ramsey. I dare to say that BW has one of the best, if not the best PLL/exciter in the low-power market, allowing processing to shine fully without overshoots or other unwanted things going on.

You don't have to use the built-in compressor/limiter and stereo generator, you can plug in your external processor (such as 8100) directly. You know, adding processing and stereo generator is more complicated to do, then just having an external processing. So that's an option there for you, that you don't have to use. Or to just have as a backup.

I'd probably lose the Behringer and use the 8100 alone...


Regards,
Goran Tomas

 

[RadioMan203]

So, I'm not really sure what to do at this point. Should I just go with the BW rig, or is there Part 15 gear more suited for use with an 8100A? Any suggestions welcome...with my thanks.

If you're looking for Part 15 gear, the BW transmitters will greatly exceed the allowable field strength under Part 15.239 if you plan on connecting it to an antenna. I've used the 5 watt BW transmitter to power an on-campus FM radio station which consists of radiating (i.e., leaky) coax which is suspended in the ceiling. I also walked the building perimeter using a Potomac FIM-71 field intensity meter to insure the signal stays within the building.

As far as Part 15 transmitters having a composite or baseband input, I believe Decade in Canada may offer their MS-100 in a version with a composite input option. I also assisted one of my forum members in adding a composite input to his original model C. Crane FM transmitter to accommodate an old Optimod 8000. Keep in mind, any modification may void a given transmitter's Part 15 certification, mentioned in case that is important to you.

 

[rickradio]

I don't know where you've looked, but all BW transmitters have MPX input (it's that BNC connector just next to the XLRs ).

Actually, Goran, it was on the BW website; there's a downloadable tech manual for the TX1/TX1 10 mw version. And I see you're right: it DOES have a composite input, after all! What threw me was that it says "BASEBAND/MPX" above the jacks, and as wet behind the ears as I am, I didn't know that "BASEBAND/MPX" and "composite" were just two different names for the same thing. All you have to do is move the MPX loopthrough jumper to "off" to accept audio from the 8100 through the BNC input jack.

And, as others have said, it will perform much, much better than the Ramsey. I dare to say that BW has one of the best, if not the best, PLL/exciter in the low-power market, allowing processing to shine fully without overshoots or other unwanted things going on.

Yes, I can hardly wait to see how well it performs...but with its $745 price tag, it's gonna be a while before I can get one.

You don't have to use the built-in compressor/limiter and stereo generator, you can plug in your external processor (such as your 8100) directly.

I'd probably lose the Behringer and use the 8100 alone...

Couldn't agree more...both of your suggestions are what I plan to do. The reason I had the Behringer in the first place was that I didn't have the OPTIMOD-FM. But now, I plan to reassign the Behringer (probably as a voice processor over in my production setup) as soon as I can raise the necessary buckage to get the BW. Thanks, Goran; you were a big help.

If you're looking for Part 15 gear, the BW transmitters will greatly exceed the allowable field strength under Part 15.239 if you plan on connecting it to an antenna.

I was planning on getting the 10-milliwatt version of the TX1, Bill.

Keep in mind, any modification may void a given transmitter's Part 15 certification, mentioned in case that is important to you.

Wasn't planning on modifying it in any way.

 

[RadioMan203]

@rickradio: Even 10 milliwatts can get you in trouble with the proper antenna. It's been documented pretty extensively all around the 'net that as little as 11 nanowatts into a half-wave dipole antenna will produce the maximum legal field strength allowed in 15.239. Unless you plan on attenuating the transmitter's output you'll likely exceed that limit.

 

[Kmagrill]

@rickradio: Even 10 milliwatts can get you in trouble with the proper antenna. It's been documented pretty extensively all around the 'net that as little as 11 nanowatts into a half-wave dipole antenna will produce the maximum legal field strength allowed in 15.239. Unless you plan on attenuating the transmitter's output you'll likely exceed that limit.

When I was a kid of about 12, the part 15 rules were different. I think it was 50uV/m at 9 meters which worked out to be about 5mW into a 6" wire antenna. Radio Shack made an FM wireless mic that was just an unbuffered single transistor oscillator feeding a 6" wire. Normally, it had a range of about 150'. We hooked up the wireless mic to a 30' long aluminum mast that we shoved out the top of a mango tree with the transmitter attached right at the bottom. Three wires ran into the house, power (9V battery), ground and audio. We covered about a 4 block radius with our "radio station". Never got a visit from the FCC. Today, they might arrive at the door with FEMA, Homeland security, the FAA and US Marshal's service.

My rule of thumb for keeping out of trouble with the FCC is to keep the usable signal on your property. I have a 1W transmitter at home for parties and for listening to while I mow the yard, etc. I keep it inside and near the floor so that the field is high in the house, but degrades to near zero at the property line. If nobody's able to receive the signal but you, no complaints will be filed.

 

[dannyscott101]

I just caught this thread, but when I had Bill & Kim Sacks refurb my 8100A, I had them add a set of padded outputs with de-emphasis to provide a 'flat' unbalanced output.

The test jacks and the composite output are still intact, so broadcast use is unaffected. (It is currently at the transmitter site of the 'real' radio station as a backup unit.) I hooked these unbalanced outputs to my Ramsey kit with good results! (Okay, 'good' considering that it's a 'toy' transmitter)