EAS Antenna Issue

FM does it with frequency!
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Qs23
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EAS Antenna Issue

Post by Qs23 » Tue Aug 01, 2017 10:18 am

Hey! It's your neighborhood IT guy with another RF problem.

So we've got an EAS issue going on right now that I'm trying to find a solution to. The attached photo shows what's going on. We're the blue star. The right map point in the EAS station we're supposed to be listening to. 104.9 @ 6 KW. It's about 36 miles away from us. Normally ok-ish reception. The issue now though is the left map point. That's a FM translator on 105.1 @ 250 W just over two miles away from us. And if you want to get specific, it's a 40 degree angle between the two stations.

So, our current setup for our EAS monitoring is an single omni antenna on the roof, with a six way splitter. (I didn't set it up that way, I just have to work with it) And the translator is blowing the monitoring station out of the water.

So, anybody got any good suggestions for a directional antenna that's got pretty decent side nulls?
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EAS Issue.JPG

grich
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Re: EAS Antenna Issue

Post by grich » Tue Aug 01, 2017 11:35 am

Wow. I don't know if you'll find one. With Samco's five-element yagi, at 45 degrees the gain is only 1.5 dB below the level at the peak of the main lobe.

Might need a tight filter.

vacuum tube
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Re: EAS Antenna Issue

Post by vacuum tube » Tue Aug 01, 2017 12:27 pm

Instead of pointing the yagi at the intended signal(104.9), you might try pointing it so the deepest side null is to the offending signal(105.1). That might work otherwise a notch filter may be in order. If the splitter has any amplification get rid of that.

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Re: EAS Antenna Issue

Post by w9wi » Tue Aug 01, 2017 12:55 pm

Good advice from "vacuum tube", about reorienting your antenna.

If you can get your hands on a HD radio, they frequently have *amazing* selectivity.

Are you sure you have to monitor 104.9? It is possible the Michigan EAS plan allows for an alternate monitoring assignment that's not subject to interference.
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ncradioeng
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Re: EAS Antenna Issue

Post by ncradioeng » Tue Aug 01, 2017 2:00 pm

Translators and EAS monitoring are quickly becoming mutually exclusive.

vacuum tube
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Re: EAS Antenna Issue

Post by vacuum tube » Tue Aug 01, 2017 2:14 pm

Good point w9wi, the Sony HD radios and tuner are amazing analog receivers. I am sitting right under the antenna for a 250w translator on 98.9 and can receive 98.7 60 miles away with no problem. The Sony XDR-F1HD tuners can bit found on ebay but they sell for more than what they cost new.

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Deep Thought
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Re: EAS Antenna Issue

Post by Deep Thought » Tue Aug 01, 2017 3:16 pm

Call the originating station and/or translator licensee and file a complaint that the translator is blocking reception of the "regularly received signal" of the class-A station. No I am not kidding. This is their problem, not yours.
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TPT
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Re: EAS Antenna Issue

Post by TPT » Tue Aug 01, 2017 4:27 pm

The Michigan EAS plan is under lock and key (password required--complete idiocy). I would call them or e-mail them and ask them to get you in touch with their state committee. Then ask for another monitoring assignment.

First...yes you can complain about the translator, but why start a fight?
Second, a monitoring assignment of a class A 36 miles away is ridiculous. Yes, you may be able to hear it "most of the time" but a good trop opening will wipe it out.

So find who runs the Michigan EAS system and get an alternative relay assignment.

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KPJL FM
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Re: EAS Antenna Issue

Post by KPJL FM » Wed Aug 02, 2017 7:22 am

Trim to fit, paint to match, tune for minimum smoke.

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Deep Thought
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Re: EAS Antenna Issue

Post by Deep Thought » Wed Aug 02, 2017 8:23 am

TPT wrote:
Tue Aug 01, 2017 4:27 pm
First...yes you can complain about the translator, but why start a fight?
You "start a fight" because the translator licensee is responsible for clearing this up. That means they are on the hook for the expenses necessary to return the affected station to its pre-translator scenario.

Having said that, this translator has been on since January 2013 so in this case it would be difficult to make any sort of argument about interference. Did the monitoring issues just start?
Mark Mueller • Mueller Broadcast Design • La Grange, IL • http://www.muellerbroadcastdesign.com

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Qs23
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Re: EAS Antenna Issue

Post by Qs23 » Thu Aug 03, 2017 9:56 am

We're the LP-2 for the area. 104.9 is the LP-3, but it's in the same building as the LP-1. So, the idea is that if something happens to the LP-1, the LP-3 can act as the LP-1 and get the info to us and then we work our way down the chain like normal.

Once a year they try this out for one of the RMTs.

So that's what's up

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Re: EAS Antenna Issue

Post by TPT » Thu Aug 03, 2017 5:37 pm

Still, reality must intrude. My primary monitoring assignment is a Class IV 25 miles away....because the state plan has never been changed to reflect the real world. I just monitor the FM relay, a Class B. Another non-com station isn't even in the state plan (it's 900 watts, been on the air since 2000).

I wouldn't waste a lot of time, or money. As I suggest above, just inform the state EAS folks that it is no longer possible to receive this Class A, and let them figure out a substitute.

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Slab Bulkhead
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Re: EAS Antenna Issue

Post by Slab Bulkhead » Sat Aug 05, 2017 11:02 am

TPT wrote:
Thu Aug 03, 2017 5:37 pm
Still, reality must intrude. My primary monitoring assignment is a Class IV 25 miles away....because the state plan has never been changed to reflect the real world. I just monitor the FM relay, a Class B. Another non-com station isn't even in the state plan (it's 900 watts, been on the air since 2000).

I wouldn't waste a lot of time, or money. As I suggest above, just inform the state EAS folks that it is no longer possible to receive this Class A, and let them figure out a substitute.
You have a monitoring assignment of a Class IV AM 25 miles away? That's insane...and probably every year you get asked why tests in the middle of the night don't get received.

The LPFM I take care of is not in the state plan, which has not been updated in 15 years. I just set it to monitor the same LP1/2 as everyone else around here does.

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kkiddkkidd
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Re: EAS Antenna Issue

Post by kkiddkkidd » Sat Aug 05, 2017 1:43 pm

TPT wrote:
Thu Aug 03, 2017 5:37 pm
I wouldn't waste a lot of time, or money. As I suggest above, just inform the state EAS folks that it is no longer possible to receive this Class A, and let them figure out a substitute.
I agree. I don't know about your state but TN and AL are very accommodating in valid changes to monitoring. I don't think it any longer takes FCC approval but haven't had to ask for quite some time.

Not wanting to monitor a particular station because they are "the competition" doesn't fly. Not being able to hear an assigned station (due to interference or location) is a fact of life and reality.

One of my old TN clients couldn't hear their assigned monitor source due to their own xlator. Their assignment was easily changed to a secondary source.

Many states use the state sat radio network as an official source and at least in the recent past, in TN you can use a state radio backbone 2-way system that spans the entire state. I have a number of stations using TRN but no one local using the TEMA radio system. I am assuming that it is still an accepted source.

The point of all this being, don't wear yourself out trying to bend the laws of physics. There may very well be other alternatives available.
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