Author Topic: New feed: BLM/WRI/NEL/N12/3N6  (Read 215796 times)

Offline JohnN

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Re: New feed: BLM/WRI/NEL/N12/3N6
« Reply #100 on: December 06, 2013, 08:00:47 PM »
There's something strange going on on 21.5... Almost sounds like a ray gun or something. I think it stopped now. Oh, ps. 100th post in this topic.

Offline InterpreDemon

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Re: New feed: BLM/WRI/NEL/N12/3N6
« Reply #101 on: December 06, 2013, 11:29:58 PM »
John, for VHF there are a number of home-brew choices that would probably outperform what you have now to the point where one antenna would do the job despite additional signal splitting. That bow-tie styled vertical dipole you have has a distorted gain pattern unless your mast is non-metallic, has less than unity gain, the primary objective being to handle all the typical scanner bands from 30 to 1300 mHz somewhat OK, and suffers losses from the 300/75 balun transformer. A decent VHF ground plane tuned and matched properly for our band on the top of your mast would almost certainly outperform it by at least the 3dB you are looking for and give a more uniform omnidirectional pattern as well. One can be made for almost nothing, numerous instructions all over the web, purchased for not much more. If you are handy with plumbing and/or machine tools there are better options like the vertical sleeve dipole (below) which can be designed to give very broad coverage of the VHF air band in addition to above-unity gain. I also threw in a photo of a higher grade, broad band ground plane than can be made if you have access to a machine shop.

Offline JohnN

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Re: New feed: BLM/WRI/NEL/N12/3N6
« Reply #102 on: December 07, 2013, 12:22:15 AM »
I just remembered that I need to be able to pick up UHF, as well as VHF. Part of the feed is UHF mil-air communications from McGuire/Lakehurst. I guess my ideal solution would be to use the antenna that is up there for ZNY/KWRI/KNEL (with the amplifier and a 2 way splitter) and get a second antenna for the CTAFs. I think I need the amplifier to get the ground side, but the CTAFs should be fine without the amp.
On a side note, does anyone know how to check why a feed is down when it's running on a Raspberry Pi? My feed's been down for about 20 minutes, but I don't have a clue how to fix it. Hopefully it will just fix itself by tomorrow.

Offline RonR

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Re:
« Reply #103 on: December 07, 2013, 10:05:27 AM »
Hi John,

My feeds all run off of Pi's. They occasionally go down from time to time and all I do is power off the Pi, wait a few seconds and power it up again. That usually gets it back up. I have two Pi's bere at home and each Pi supports two feeds. I have seen it where one of the feeds  goes down while the other feed on the same Pi stays up. Not sure why that happens. Just power down and power up your Pi, that should fix it.

Sent from my Galaxy S4 using tapatalk

Offline JohnN

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Re: New feed: BLM/WRI/NEL/N12/3N6
« Reply #104 on: December 07, 2013, 11:16:13 AM »
Yeah, the power cycle did it. I think mine went offline from a power glitch last night. The lights flashed, and that must have been enough to knock the Pi offline.

Offline RonR

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Re:
« Reply #105 on: December 07, 2013, 11:38:51 AM »
Yeah, that power glitch definitely could do it. And then sometimes I think the Pi just wants to take a "coffee break" but forgets to come back from its "break"...you end up having to remind it to come back to work :). And in my case there are times when my Pi only half works. Go figure. Almost always though any of those problems is fixed by cycling the power.

Sent from my Galaxy S4 using tapatalk

Offline InterpreDemon

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Re: New feed: BLM/WRI/NEL/N12/3N6
« Reply #106 on: December 07, 2013, 07:46:38 PM »
John, a 1/4 wave VHF ground plane tuned to around 125 would be about a 5/8 wave antenna at 307mHz and probably pick up the UHF just as well as that ST-2, perhaps better. The most important thing at first is to plot the azimuth and distance to your targets as well as their relative received strength right now, then one can plan the attack.

Offline JohnN

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Re: New feed: BLM/WRI/NEL/N12/3N6
« Reply #107 on: December 07, 2013, 08:10:42 PM »
I'll make up a map of the frequencies I'm scanning and distance, to the best of my abilities. I'll post it here when I'm done.
Here's a Google map that should have all of the transmitter locations and antenna location. I'll work on measuring the distances now.
https://mapsengine.google.com/map/edit?mid=zzHylcNSSWM4.kmVSMlwu1coM
Ok, here's a map with all of the distances measured on it. I'll have to change the number colors. On my laptop, they have a dark gray background, so they are actually readable.

Ok, here is the map with readable numbers. Everything is color-coded. All numbers are in miles.
« Last Edit: December 07, 2013, 10:28:52 PM by JohnN »

Offline JohnN

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Re: New feed: BLM/WRI/NEL/N12/3N6
« Reply #108 on: December 07, 2013, 11:48:34 PM »
Just another update. I found another 2006 on ebay, so I'm going to see how that auction goes. I'm not really expecting to win it. Does anyone have any experience with a Realistic Pro 2020? There's one currently on ebay for $19.95, and $10 shipping Buy it Now. If I can't get a 2006, would the 2020 be a good one?

Offline InterpreDemon

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Re: New feed: BLM/WRI/NEL/N12/3N6
« Reply #109 on: December 07, 2013, 11:52:19 PM »
I am going to guess, based upon the sky in the photo of your antenna, that you have the antenna "pointed" toward BLM. If that is so, the first thing I would do is rotate the mast 180 Deg and point it at NEL. The reason is that at VHF I think the pattern is probably slightly cardiod, with a couple dB in favor of the side of the mast the antenna is adjacent to. If true, you should pick up WRI and 133.5 a bit better after the rotation, since overall you need more gain to the southwest than you do for the east and northeast. But I caution that the exact pattern of that antenna may contain some notches and lobes, so a variety of changes could occur. For example, if there is a sharp notch (null) in the pattern that can be identified, it could be aimed at that NOAA station. On the other hand, a strong lobe could be aimed at Barnegat, etc. If I had exact dimensions of the antenna I could model it on the computer, including the effect of the mast as installed, but the mfr data is very limited, in fact they do not even provide any gain figures, so it would probably be a waste of time where simple experimentation would give better data, for example, rotating 90 degrees each week and observing the results... basically in three weeks you know the best you could do with that antenna alone, then decide whether what you were not getting was worth another or better antenna.

If it were me, I would probably cut all the angled radiators off that thing, leaving the two long vertical ones, then cut them down to about 24" each, attach the coax directly at the feed point without the balun and mount the thing at least 30" from the mast... that would give you a 1/2 wave vertical dipole with fairly uniform gain around the compass card. But there again all my life I have had no qualms about instantly voiding the warranty and "improving" stuff I had just paid good money for (to paraphrase the old Zenith commercials, "the quality goes in before the name comes off") whereas you might not be so inclined. So best to first find the ideal positioning of that antenna as the Chinese engineers designed it, then go from there.
« Last Edit: December 07, 2013, 11:54:55 PM by InterpreDemon »

Offline JohnN

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Re: New feed: BLM/WRI/NEL/N12/3N6
« Reply #110 on: December 08, 2013, 12:10:37 AM »
If I remember correctly, I think it is aimed toward WRI. I have no problem rotating it and experimenting. It just may have to wait a few days, because it's supposed to start snowing and icing tomorrow, and on Monday I start my internship (I have to be in by 6AM, which means I have to leave by 5:30. That should be fun.) Oh, and just a correction about the engineers that designed the antenna. Their website says it was designed and Manufactured in the USA. That was one of the selling points for me. I wish I came here before buying an antenna.

Offline InterpreDemon

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Re: New feed: BLM/WRI/NEL/N12/3N6
« Reply #111 on: December 08, 2013, 12:47:15 AM »
Methodically spinning it around over the course of the next couple weeks should prove enlightening. Sometimes these things take a bit of time to make the pattern clear, seasons, with and without leaves, etc., so the time to be thinking about making significant changes would be next Spring. By then you will know what is worth trying to pick up and what not, and what it will take to do it. Just keep in mind that to bring a marginal signal to the point where it is reliable takes about three to four times the signal strength.

Offline JohnN

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Re: New feed: BLM/WRI/NEL/N12/3N6
« Reply #112 on: December 08, 2013, 05:46:57 PM »
I just had an idea. I'm thinking maybe I should make an antenna dedicated to KWRI/KNEL/ZNY, and leave the Antennacraft up there for the CTAFs. I spent almost $50 on that antenna, so I'd like to use it for something. I don't have a problem making a custom antenna, I just have to figure out how to know what size to make it. I'll also have to look and see if there is enough room for 3 antennas on the roof. If there is, maybe I could have an antenna dedicated to each scanner.

Offline InterpreDemon

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Re: New feed: BLM/WRI/NEL/N12/3N6
« Reply #113 on: December 08, 2013, 07:28:27 PM »
The thing to do is get that ST-2 rotated to the point where it gets everything but ZNY, NEL and WRI as good as possible, then a two or three element beam aimed at NEL should take care of the rest. On the other hand, it could well be that at the right rotation you might get the Southern three with the ST-2, in which case a ground plane at the top of the mast would easily take care of the rest. But I doubt the ST-2 will ever be able to pick up Barnegat solid, whereas a beam would and it's just a matter of how much beam you need. If you need over 5-6 dB to get it in solid you'll have to go three element. Once we know how much gain and frequency range is needed, I can give you the construction details for the antenna.

For example, here's a 4-element beam that gives 8 to 9+ dB gain with a good impedance match from 118 to 134, optimized for 129.5. You aim that baby between NEL and Barnegat and you'll get everything including the finger prints on the microphone. But if you note how the pattern changes with frequency, there may be ways of getting what you need off the back lobe(s) for the local airports depending upon the frequency.

Offline JohnN

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Re: New feed: BLM/WRI/NEL/N12/3N6
« Reply #114 on: December 11, 2013, 02:34:06 PM »
Just added KMJX (Robert J Miller Airpark) to the CTAF feed, as was requested. I think it should be within range for me.

Offline JohnN

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Re: New feed: BLM/WRI/NEL/N12/3N6
« Reply #115 on: December 13, 2013, 02:07:48 PM »
I was just planning on going up and rotating the antenna, but of course the roof has to be covered in ice. Don't know when I'll be able to get up there next, since there's supposed to be more snow this weekend. Maybe next weekend I'll get to try. We have an old rotating thing from when we used to have a TV antenna up there. Maybe I'll get to install that and I won't have to go on the roof to rotate the antenna.

Offline InterpreDemon

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Re: New feed: BLM/WRI/NEL/N12/3N6
« Reply #116 on: December 13, 2013, 02:38:46 PM »
That would be cool... you could really figure out the pattern with that, getting best signal coordinates for each ground station... dialing as they are talking.

Offline JohnN

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Re: New feed: BLM/WRI/NEL/N12/3N6
« Reply #117 on: December 13, 2013, 06:16:35 PM »
Does anyone know where I might be able to find the frequencies for the Warren Grove Bombing Range? Sounds like they're doing some bombing practice there or at McGuire, and I'd like to listen in. I'm looking on RadioReference, but not finding much. I have to look at a map, anyway, and see if it should be in range. Looks like it's about 30 miles from me, so that should be plenty close enough to pick up the aircraft.
« Last Edit: December 13, 2013, 06:19:48 PM by JohnN »

Offline AeroBill

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Re: New feed: BLM/WRI/NEL/N12/3N6
« Reply #118 on: December 14, 2013, 10:26:17 AM »
Re: Warren Grove

Go to Phillyscanner.com. They list the frequencies. You have to scroll down quite a ways to get to the list.


Offline JohnN

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Re: New feed: BLM/WRI/NEL/N12/3N6
« Reply #119 on: December 14, 2013, 10:57:30 AM »
Thanks for that link. Looks like they have every frequency I could ever want to find.

Offline AeroBill

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Re: New feed: BLM/WRI/NEL/N12/3N6
« Reply #120 on: December 14, 2013, 11:07:19 AM »
RE: PhillyScanner

Yes. Very comprehensive.
Should have mentioned that on the home page you need to select View Guide, then Miscellaneous and then
Aviation to get to what you want.

Enjoy.

Offline JohnN

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Re: New feed: BLM/WRI/NEL/N12/3N6
« Reply #121 on: December 14, 2013, 11:31:51 AM »
Thanks for the tip. Turns out the bombing practice is at Lakehurst, so the these frequencies weren't needed. I've been listening to the Lakehurst feed, and haven't heard anything that sounds like military practice. Oh well.

Offline JohnN

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Re: New feed: BLM/WRI/NEL/N12/3N6
« Reply #122 on: December 15, 2013, 01:08:11 PM »
Just got down from the roof. I rotated the antenna about 90 degrees, it's aimed more towards McGuire/Lakehurst/Barnegat now. I should be able to get the rotator up around Friday.

Offline JohnN

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Re: New feed: BLM/WRI/NEL/N12/3N6
« Reply #123 on: December 31, 2013, 08:09:28 PM »
Well, I've been listening to my feed for the past few hours, and, if anything, I think ground side reception has degraded for 33.5. Has anyone else been listening to the feed, and do you agree that after the rotation the reception has gone down?

Offline JohnN

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Re: New feed: BLM/WRI/NEL/N12/3N6
« Reply #124 on: January 14, 2014, 12:20:59 AM »
33.5 is now locked out. In reality, it was never supposed to be on the feed, and was just there as a test. If I can get a 3rd scanner and make an antenna specifically for 33.5 I see no reason it couldn't have its own dedicated feed.