All accepted registrations through July 14 at 7:30a ET have been activated. Thank you! -M.W.

Please note: Terms of Use have been amended effective June 9, 2019. Make sure you are aware of the new rules! Please visit this thread for details: https://www.mibuzzboard.com/phpBB3/view ... 16&t=30571

All user accounts that have been inactive since January 1, 2017 have been expunged. If you are one of these users and wish to submit a new post, please re-register. Thank you.

WJR vs. WWJ Fields at Utica, MI

The technical side of broadcasting. Think IBOC is a sham? Talk about it here! How about HDTV? Post DX reports here as well.
Rich
Posts: 65
Joined: Sun Dec 26, 2010 3:28 pm
Location: Illinois
Contact:

WJR vs. WWJ Fields at Utica, MI

Post by Rich » Sun Jun 09, 2019 8:15 am

Below is a table showing the calculated, daytime fields from WJR and WWJ in Utica, MI.

Just wondering if anyone owning one of the ultralight receivers with a "field strength" display in units of dBµ (like the Tecsun PL-880) would check to see how closely it shows the 5.3 dB difference between WJR and WWJ at/near the Utica location shown in the table, and report back?

Image



k8jd
Posts: 349
Joined: Fri Jun 28, 2013 3:35 pm
Location: Commerce, MI

Re: WJR vs. WWJ Fields at Utica, MI

Post by k8jd » Mon Jun 10, 2019 2:48 pm

Sure WWJ has those 6 towers beaming the signal north, try hearing WWJ out past Jacksonm going West !



User avatar
MWmetalhead
Site Admin
Posts: 4642
Joined: Sun Oct 31, 2004 11:23 am

Re: WJR vs. WWJ Fields at Utica, MI

Post by MWmetalhead » Mon Jun 10, 2019 4:28 pm

Yup; disappears rapidly (even during daylight hours) from Jackson westward. Their signal is probably stronger in Mt. Pleasant than it is in Jackson.


MEMO TO 89-EX: FIX YOUR SHITTY SOUNDING AUDIO!! WE CAN HARDLY HEAR THE FRIGGIN' STATION! Thanks in advance.

innate-in-you
Posts: 238
Joined: Wed Oct 31, 2018 8:54 am

Re: WJR vs. WWJ Fields at Utica, MI

Post by innate-in-you » Mon Jun 10, 2019 11:21 pm

But listen to their signal in Grand Sudbury at night!



Rich
Posts: 65
Joined: Sun Dec 26, 2010 3:28 pm
Location: Illinois
Contact:

Re: WJR vs. WWJ Fields at Utica, MI

Post by Rich » Tue Jun 11, 2019 5:39 am

... and even though WWJ radiates greater groundwave fields than WJR does toward the North, the calculated daytime field intensity from WJR is >80% greater than that from WWJ at/near that north-suburban-Detroit location in Utica.

The reasons for this: the ~10-mile longer path length, and the higher carrier frequency of WWJ, compared to WJR.



CK-722
Posts: 493
Joined: Sun Dec 16, 2018 3:53 pm

Re: WJR vs. WWJ Fields at Utica, MI

Post by CK-722 » Wed Jun 12, 2019 11:35 am

I just got back to the area, and have made some discoveries. The Local Normal DX Switch seems to also function on AM BC as an RF Gain Control. When in the Local Position, WJR reads ~47 dB and WWJ ~36dB. When in the DX Position, WJR reads 44 dB and WWJ reads 51. If you add 40 dB to the reading in the Local Position, I'd say that it reflects reality. The Summer Day signal is probably in the vicinity of 6.3 mV/m and the WJR signal is in the vicinity of 22 mV/m. Beyond that, we'd have to construct a fudge factor curve with the FIM-41 next to the PL-880. The DX position seems to have the AGC Stiffness, and even with a fudge factor, results would be complicated to analyze.

To those of you who think that "fudge factor" sounds like fudging the data, it's really a well known and accepted technique of making sense of data, not altering the results. Calibration of a FI meter is like an internal fudge factor generator which compensates for the overall receiver gain at different frequencies. You also may notice that the d'Arsonval movement markings on an FI meter are NOT LINEAR either, and is part of the calibration process. In Physics, an ideal spring is linear, but a real spring is not completely linear. The force of the spring balances the magnetic force from the coils in the d'Arsonval meter.

If you took Chemistry, Physical Chemistry, Analytical Chemistry, or even Medical Technology classes, you probably encountered a B & L Spec 20, which also illustrates a lot of the same principles. A Spec 20 is essentially an analog Spectrum Analyzer for Visible Light, Near IR, and Near UV frequencies/wavelengths. You always have a "Control" reading, which was also necessary in old FI meters, and apparently has been simplified with new FI meters. The Control has to be repeated at each wavelength to compensate for the source amplitude and light detector sensitivity at each wavelength. Spec 20s are still widely used. They have probably also been improved over the years, though like FI meters, the old equipment is still widely used.

https://en.wikipedia.org/wiki/Spectronic_20
Last edited by CK-722 on Wed Jun 12, 2019 2:11 pm, edited 1 time in total.


Is THAT where they got the idea for the 486-SX?

Same (x, y, z), different (t)

Your bullet missed my trial balloon.

RTN Price. Not guaranteed. As of 12:30, 157.71 Down 0.22.

Artificial Intelligence is a Child that needs a Parent to guide it through.

Rich
Posts: 65
Joined: Sun Dec 26, 2010 3:28 pm
Location: Illinois
Contact:

Re: WJR vs. WWJ Fields at Utica, MI

Post by Rich » Wed Jun 12, 2019 1:24 pm

V-Soft shows WJR with 18.4 mV/m, and WWJ (daytime) with 10.4 mV/m in ZIP 48315 — partly occupied by part of Utica, MI.

That would be a difference of 5 dB on the Tecsun display, if it was showing the relative difference between those two fields accurately.



CK-722
Posts: 493
Joined: Sun Dec 16, 2018 3:53 pm

Re: WJR vs. WWJ Fields at Utica, MI

Post by CK-722 » Wed Jun 12, 2019 1:36 pm

Any way you cut it, WWJ is substantially weaker than WJR except when you are quite close to WWJ.

Can you find enough data to reconstruct the WWJ site near 8 Mile and Meyers with a 186 degree antenna at the Hall and Van Dyke RL? The DA used a 400 foot second tower 31 degrees away. The nulls were toward WPEN and KPRC and were the equivalent of 1 kW into a half wave tower as I recall. I forget the other details. They are on the DOS based computer with the old VAX Database and AMR software which I would have to reassemble and hope it works.
Last edited by CK-722 on Wed Jun 12, 2019 2:08 pm, edited 1 time in total.


Is THAT where they got the idea for the 486-SX?

Same (x, y, z), different (t)

Your bullet missed my trial balloon.

RTN Price. Not guaranteed. As of 12:30, 157.71 Down 0.22.

Artificial Intelligence is a Child that needs a Parent to guide it through.

Rich
Posts: 65
Joined: Sun Dec 26, 2010 3:28 pm
Location: Illinois
Contact:

Re: WJR vs. WWJ Fields at Utica, MI

Post by Rich » Wed Jun 12, 2019 2:06 pm

CK-722 wrote:
Wed Jun 12, 2019 1:36 pm
...Can you find enough data to reconstruct the WWJ site near 8 Mile and Meyers with a 186 degree antenna at the Hall and Van Dyke RL? ...
A quick look at that for the 5 kW, non-D case shows about 20 mV/m at Van Dyke and Hall Rds, Utica (14 mile path at N30°E).



innate-in-you
Posts: 238
Joined: Wed Oct 31, 2018 8:54 am

Re: WJR vs. WWJ Fields at Utica, MI

Post by innate-in-you » Wed Jun 12, 2019 11:38 pm

(Duplicated by accident)
Last edited by innate-in-you on Wed Jun 12, 2019 11:50 pm, edited 1 time in total.



innate-in-you
Posts: 238
Joined: Wed Oct 31, 2018 8:54 am

Re: WJR vs. WWJ Fields at Utica, MI

Post by innate-in-you » Wed Jun 12, 2019 11:39 pm

Sadly, I think only two years ago the FCC site still had the full engineering for the Royal Oak Township TL.

the basic design can still be seen at fccinfo.com. The two tower array had a one taller Blaw-Knox tower and a shorter Blaw-Knox tower nearly south of it actually in the direction 170° azi.
The nulls have just slightly less than 20% of the maximum field strength, thus about 4% of the peak ERP.

I'm sure someone on here who has actually designed a DA could replicate the FCC's engineering using the figures on fccinfo.com.

I strongly doubt that the nulls were anywhere near 1000 watts ERP.
I grew up near I-94 and Cadieux on Detroit's East Side.
On my crystal set, WWJ was plenty strong by day, and absolutely dead when they went to night pattern. A good radio with tubes or transistors could still pick them up, but I could hear other voices on the channel.

For those saying "They were not Blaw-Knox - they were not like WLW". Blaw-Knox also made square form towers.



CK-722
Posts: 493
Joined: Sun Dec 16, 2018 3:53 pm

Re: WJR vs. WWJ Fields at Utica, MI

Post by CK-722 » Thu Jun 13, 2019 1:06 am

Thanks for the information. I wish they would have the scale, though with rudimentary software, you can figure it out. It's 5% greater for the Standard Pattern. I seem to remember the maximum at 350 degrees being in the range of 840 mV/m at 1 mile, 1351 mV/m at 1 kilometer, in the Standard Pattern.

Here's the direct link to the design parameters.

http://www.fccinfo.com/CMDProFacLookup. ... ign+Search

WWJ 5 kW Night Parameters

http://www.fccinfo.com/CMDProEngine.php ... 6&sHours=N

I'll have to see how far back they have the legacy DA parameters and patterns.

The legacy DA WFDF (1941) parameters are on the 50 kW Day APP. Also this link.

http://www.fccinfo.com/CMDProEngine.php ... 4&sHours=N

So are the WXYT legacy (1959) DA parameters, but here's what's on the site.

http://www.fccinfo.com/CMDProEngine.php ... 6&sHours=N

Also the WOOD (1941) DA parameters.

http://www.fccinfo.com/CMDProEngine.php ... 9&sHours=N

Notice the 1941 modifications of the spacings, WWJ 920-950 30-31, WFDF 880-910 90-93, WXYZ(T) 1240-1270 135-138, and WOOD 1270-1300 110-113. These were the oldest DA designs. WXYZ(T) moved from Joy Rd. in 1959 to Broadcast House on 10 Mile Rd.


Is THAT where they got the idea for the 486-SX?

Same (x, y, z), different (t)

Your bullet missed my trial balloon.

RTN Price. Not guaranteed. As of 12:30, 157.71 Down 0.22.

Artificial Intelligence is a Child that needs a Parent to guide it through.

User avatar
Big Signal
Posts: 95
Joined: Fri Oct 20, 2006 2:46 pm
Location: Southeast Michigan

Re: WJR vs. WWJ Fields at Utica, MI

Post by Big Signal » Thu Jun 13, 2019 8:24 am

As a side note WWJ's 6 tower array is approx. 12 miles south of WJR's stick.


It's all about the money!

Rich
Posts: 65
Joined: Sun Dec 26, 2010 3:28 pm
Location: Illinois
Contact:

Re: WJR vs. WWJ Fields at Utica, MI

Post by Rich » Thu Jun 13, 2019 11:54 am

(Corrected for 5 kW at common point)

Below is a NEC4.2 study showing the nighttime groundwave fields at a radius of 14 miles from WWJ using their tx site on 8 Mile Road (if I did it right). The array parameters were taken from the links provided earlier in this thread by CK-722.

I didn't bother rotating the pattern 10° CCW (to match reality), but this will still give an idea of what the nighttime field was in Utica back then: about 25 mV/m.

Image



innate-in-you
Posts: 238
Joined: Wed Oct 31, 2018 8:54 am

Re: WJR vs. WWJ Fields at Utica, MI

Post by innate-in-you » Thu Jun 13, 2019 11:58 pm

I'm wondering if that pattern chart assumed identical towers.

The actual pattern was weaker to the south, and with a distinct "chin" at 170°.



Post Reply Previous topicNext topic