Quality translator

FM does it with frequency!
dbuckley
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Quality translator

Post by dbuckley »

We've got a couple of translator sites equipped with BW Broadcast TR300 translators, and they've both failed us, so da management are asking is there something we can buy that is in a different class of reliability, from a manufacturer that will be around for years to come, and with support for years to come, something we can expect an extended operational lifetime out of. Operational failure costs us real money to restore service, which as a community broadcaster, running costs is what hurts us, because, unlike capital expenditure, we can't get community funds for running costs. I did note a comment from a contributor that stated that You really have to consider all this stuff, BW, Ecreso, NIcom, etc disposable when it fails.

Power requirement is 300W, and if it can't be a translator, I'd settle for a transmitter, and we'll have a separate receiver. Or am I asking for the impossible, and at the 300W power level, all that is available is disposable machines? Should we keep buying BWs, which are great bits of kit when they're up and running, and swap them out as they fail, or perhaps build a high availability redundant arrangement around them?
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kkiddkkidd
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Re: Quality translator

Post by kkiddkkidd »

I would probably recommend something like one of the high end (650 or 655) Inovonics receiver's with composite output and a Nautel VS300. Having separate RX and TX with spares would give you some flexibility. Inovonics and Nautel both have long support cycles.

If you are directly feeding a translator, add the Orban Inside to the Nautel and sound like a full power station.

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Deep Thought
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Re: Quality translator

Post by Deep Thought »

Another vote for the VS300. Pretty much an all in one transmitter package (audio, remote control, email alarms, etc.) and they are tough little things. Not quite as tolerant of criminal neglect as the old Crowns, which have been documented still running as the building burned down around it or with an inch of dust clogging every possible air path, but close. Plus Nautel isn't going anywhere and still supports everything they've ever built.
Mark Mueller • Mueller Broadcast Design • La Grange, IL • http://www.muellerbroadcastdesign.com
level42
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Re: Quality translator

Post by level42 »

You can’t go wrong with the suggestions above. That being said, whether you stay with the BW, or purchase something else, more importantly: proper grounding, surge protection, ferrites on the coax, power, composite, network, etc., lightning dissipation on the tower, and keep the boxes clean, and cool.

You didn’t mention what failure the BWs had, I find their RF section very easy to work on if needed, and the power supplies are easy to replace off the shelf units. The controller is not really field serviceable. The Nautels on the other hand, are more difficult to work on. Additionally, the Nautel requires 240v, which might be more common in your country (most 300 watt units in the US run on 120v). The Nautel is also a larger form factor and you need to make sure you have a rack that is deep enough to accommodate it.
kcbooboo
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Re: Quality translator

Post by kcbooboo »

I'll also recommend Nautel VS300. But be aware that these units run on 240VAC and you'll need a step-up transformer, which they'll gladly sell you, if using them in a 120VAC environment. They can be bought with a good audio processor built-in. Add a small Inovonics receiver and you're off and running.

The VS300 does seem to be overly sensitive (in my opinion) to the slightest reflected power. One station had a 3-cavity bandpass filter on its output and that forced the VS300 to cut back power drastically.

If you'll be translating an HD station's multicast channel, make sure the receiver will stay on the selected channel if the signal should go away or the power gets cycled. Some revert to the analog signal and stay there, requiring a site visit to get them back on the correct digital signal.

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awsherrill
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Re: Quality translator

Post by awsherrill »

Nautel updated the VS300 power supply awhile back, and the newer units will run on 120 or 240. Two power cords are included.
TPT
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Re: Quality translator

Post by TPT »

Also submit my vote for the VS300. On 220 volts--as noted supplies have been upgraded to work on 110. However, I have one that's been on the air for several years using a 110 to 220 upconverting device I bought on Amazon.

Several other problems with the BW broadcast units:

1. They don't play well with other transmitters on active sites. I own a site that is used for my Class A (3500 watts tpo), plus another Class A running 800 watts--and four translators. Two Gates Air kilowatts, an Ecreso kilowatt and a little 300 watt BW. Both identifiable spurs are mixing between the Ecreso and the BW. Site is 17 acres, nothing gets off the hill, but still...

2. Don't like working with high power on the same stick. 500 watt BW on same tower as 17 kw B-1, Have had all kinds of fun keeping it on power--starts cutting back with 5 watts turn-around from the B-1. Had VS 300 in line for a time, perfectly happy This is with 14 mhz frequency separation. We're buying this translator, probably will do some re-arranging. The VS300 was used for off-air pickup (fed from Inovonics composite receiver) when we couldn't use internet for brief period, the BW is equipped with an internal audio processor. May break down and buy the Orban card & sell of the BW, off-air reception not great.
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Deep Thought
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Re: Quality translator

Post by Deep Thought »

kcbooboo wrote: Wed Sep 16, 2020 5:57 am The VS300 does seem to be overly sensitive (in my opinion) to the slightest reflected power. One station had a 3-cavity bandpass filter on its output and that forced the VS300 to cut back power drastically.
That is the fault of the bandpass filter. I installed a four translator combined site in February using a Kintronic Labs four station combiner (essentially four three cavity filters) and the Nautel VS1's didn't even blink. Spurs and mix products were at least 85 dBc down and the site has been running without any issues since it was commissioned. By the way, if you are looking for FM combining equipment in this power range Tom King has some terrific stuff at 1/3 the price of "brand S".
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dbuckley
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Re: Quality translator

Post by dbuckley »

Seems like the Nautel VS300 for the win.
level42 wrote: Wed Sep 16, 2020 5:54 am You didn’t mention what failure the BWs had
One of them has had an exciter board fail, the other is as yet unknown.
level42 wrote: Wed Sep 16, 2020 5:54 am Additionally, the Nautel requires 240v, which might be more common in your country
We're in New Zealand, so 240V-land, so needing 240V is not a problem :)
level42 wrote: Wed Sep 16, 2020 5:54 am The Nautel is also a larger form factor and you need to make sure you have a rack that is deep enough to accommodate it.
Thanks for the heads up!
level42 wrote: Wed Sep 16, 2020 5:54 am The Nautels on the other hand, are more difficult to work on.
What does this mean? We don't repair in-house, we rely on third parties to do our repairs for us, so the transmitter or translator gets swapped for something to get us back on the air, and the failed unit gets repaired by the third party. In the case of the last BW repair, that meant a return to the UK, as it apparently couldn't be repaired in New Zealand. I've never heard of the New Zealand agent for Nautel, Intelcom services, so I guess they deal with the "big boys" and have a workshop and facilities appropriate for the big FMs and TV stations. Certainly, I'd be asking how repairs are handled before recommending splashing the cash.

E2A - do Nautel do spares kits for these machines?
kcbooboo wrote: Wed Sep 16, 2020 5:57 am The VS300 does seem to be overly sensitive (in my opinion) to the slightest reflected power. One station had a 3-cavity bandpass filter on its output and that forced the VS300 to cut back power drastically.
A-ha! Wouldn't you know it, we have Delta Meccanica 3 cavity bandpass filters on the output of our translators, ordered from the factory tuned for the correct frequency. How big an issue is this "slight sensitivity"? Anyone else aware of this?
kcbooboo wrote: Wed Sep 16, 2020 5:57 am If you'll be translating an HD station's multicast channel...
Nope. Straight FM only.
TPT wrote: Wed Sep 16, 2020 10:21 am Several other problems with the BW broadcast units: 1. They don't play well with other transmitters on active sites.
Interesting. So far, we've been the only broadcast station at any of our sites, but at one translator site another station has acquired a license to transmit, and their licensee is for 1500W, we're just 300W, their transmitter is allegedly installed, but they've not switched on yet, they're 2.4MHz away from our transmit frequency.
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Re: Quality translator

Post by ChuckG »

TPT wrote: Wed Sep 16, 2020 10:21 am Several other problems with the BW broadcast units:

1. They don't play well with other transmitters on active sites. I own a site that is used for my Class A (3500 watts tpo), plus another Class A running 800 watts--and four translators. Two Gates Air kilowatts, an Ecreso kilowatt and a little 300 watt BW. Both identifiable spurs are mixing between the Ecreso and the BW. Site is 17 acres, nothing gets off the hill, but still...

2. Don't like working with high power on the same stick. 500 watt BW on same tower as 17 kw B-1, Have had all kinds of fun keeping it on power--starts cutting back with 5 watts turn-around from the B-1. Had VS 300 in line for a time, perfectly happy This is with 14 mhz frequency separation. We're buying this translator, probably will do some re-arranging. The VS300 was used for off-air pickup (fed from Inovonics composite receiver) when we couldn't use internet for brief period, the BW is equipped with an internal audio processor. May break down and buy the Orban card & sell of the BW, off-air reception not great.
3. They make no effort with parts support. I had two 300W units in the shop, both with failed power supplies. BW had none in stock, no plans to get any and no retrofit available to make a different supply work. I found the exact same PSU's myself from Meanwell. BW didn't even look. A simple PC board alteration would have allowed several other supplies to fit.
BW's response was "buy a new transmitter" and just expected me to throw these two units out. They were less than 4 years old.
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dbuckley
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Re: Quality translator

Post by dbuckley »

level42 wrote: Wed Sep 16, 2020 5:54 am ferrites on the coax
I missed this first time round, and Deep Thought's photo reminded me of it. What's with the ferrites on coax? I get ferrites on signal cables, they get rid of RF where there shouldn't be RF, but I'm having some difficulty understanding why ferrites on a coax?
DaveSt
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Re: Quality translator

Post by DaveSt »

dbuckley wrote: Wed Sep 16, 2020 8:53 pm
Interesting. So far, we've been the only broadcast station at any of our sites, but at one translator site another station has acquired a license to transmit, and their licensee is for 1500W, we're just 300W, their transmitter is allegedly installed, but they've not switched on yet, they're 2.4MHz away from our transmit frequency.
The spec for isolation on the Delta combiners is >30dB. With the 2.4MHz spacing which is quite close, the isolation may not be much better than 30dB. That means you can get 1500W-30dB=1.5W back into the other transmitters. That should not be enough to put a decent 300W transmitter into foldback. As the difference in transmitter powers becomes larger, the isolation issue is more significant. You also need to watch the intermods if any of them fall above 108MHz.

For the Delta combiners it is wise to always choose one with a rating of twice the transmitter power. They do not have temperature compensation, so they can detune when hot. The Kintronic combiner photos posted by Deep Thought earlier is really a Delta combiner. They get badge engineered a lot because they are so cheap.

As for the transmitter, I would go with Eddystone, GatesAir or Nautel depending on what is best supported where you are.
dbuckley
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Re: Quality translator

Post by dbuckley »

It's not a combiner situation, the other station will be on a separate antenna. We're on a single folded dipole, and I suspect they'll be on the same, or a stacked pair.
kcbooboo
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Re: Quality translator

Post by kcbooboo »

I believe the BPF was a brand "S". 3 cavities in a triangular configuration. I never swept them, so it's possible they weren't tuned to the correct frequency. The BPF was a requirement at the site due to other translators already present. I think the BPF was quickly bypassed and we still saw no intermod. I don't remember if modulation caused the increase in SWR but without the filter the reflected power was zero; with it, several watts, and when you're running 75w TPO, I wouldn't expect the TX to complain about 5% reflected, which is high but not THAT high.

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Re: Quality translator

Post by TPT »

At my one site the BW is on 107.9, while the full power is on 93.9--at 17 kw erp off a 4 bay. The BW won't make power reliably--folds back. The VS300 comfortably made the required power--but didn't have a processor available to use the internet feed so had to go off-air with a weak signal. We're buying this translator, so once we close will have to evaluate possible solutions.

At my site with 4 translators have a Gates Air at the site running 250 watts just 20 feet below a Class A running 750 watts with a VS-1. The translator is on 103.5, the Class A on 103.9. No fuss, no foldback, no obvious spurs or other interaction.

I heard about that problem with failed power supplies, too, on the BW transmitters.
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