All accepted registrations through August 22 at 9:00p 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: viewtopic.php?f=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.

Search found 27 matches

by Rich
Thu Aug 08, 2019 5:43 am
Forum: Engineering & DX'ing
Topic: Shortwave - WBCQ new 500kW transmitter on 9330kHz
Replies: 8
Views: 566

Re: Shortwave - WBCQ new 500kW transmitter on 9330kHz

Ed Joseph wrote:
Wed Aug 07, 2019 3:04 pm
I guess since the people bankrolling the operation are flat-earthers, ... how do they explain global skywave???
Maybe they believe that a flat Earth gives them line-of-sight propagation paths to all "global" locations ?
by Rich
Tue Jul 30, 2019 6:54 am
Forum: Engineering & DX'ing
Topic: Reduced ERP from "Overheight" FM Stations
Replies: 18
Views: 655

Re: Reduced ERP from "Overheight" FM Stations

Additional: The mounting environment of an FM transmit antenna has a very significant effect on its radiation patterns, as the tower structure and other re-radiators near the antenna aperture become part of the antenna system. The image below shows these effects for one case by comparing the radiati...
by Rich
Mon Jul 29, 2019 9:20 am
Forum: Engineering & DX'ing
Topic: Reduced ERP from "Overheight" FM Stations
Replies: 18
Views: 655

Re: Reduced ERP from "Overheight" FM Stations

The radiation pattern on the left side of the image below shows an extreme example of the pattern distortion than can result from mounting a stock, "omnidirectional" FM antenna on the side of a large-faced tower.

Image
by Rich
Mon Jul 29, 2019 8:18 am
Forum: Engineering & DX'ing
Topic: Reduced ERP from "Overheight" FM Stations
Replies: 18
Views: 655

Re: Reduced ERP from "Overheight" FM Stations

Remember that there are only one or two azimuths of a DA that have the full measured maximum field ratio. All other directions are less than maximum, regardless of the licensed pattern envelope field ratios. That is true. Directional FMs are licensed for the maximum ERP they may radiate in the hori...
by Rich
Wed Jul 24, 2019 6:19 am
Forum: Engineering & DX'ing
Topic: Reduced ERP from "Overheight" FM Stations
Replies: 18
Views: 655

Reduced ERP from "Overheight" FM Stations

FM stations with antenna heights greater than the HAAT permitted for their Class of station must reduce their ERP to provide a radius to their 1 mV/m field contours equal to that of a station exactly meeting the maximum ERP and HAAT authorized for that Class. As an illustration of this, below is a c...
by Rich
Mon Jul 22, 2019 8:57 am
Forum: Engineering & DX'ing
Topic: Another Good Resource On Indoor vs. Outdoor Antennas
Replies: 4
Views: 184

Re: Another Good Resource On Indoor vs. Outdoor Antennas

Proper orientation of a directional TV receiving antenna will ensure optimal reliability... True, and sometimes the most useful orientation is not in the direction one expects. For example, when I lived at the north end of Lincoln Park along the Lake Michigan shoreline in Chicago (late 1960s) and a...
by Rich
Mon Jul 22, 2019 4:56 am
Forum: Engineering & DX'ing
Topic: Another Good Resource On Indoor vs. Outdoor Antennas
Replies: 4
Views: 184

Re: Another Good Resource On Indoor vs. Outdoor Antennas

... Preamps are noisy, and don't give you gain like noise free gain from antenna placement and gain Another benefit can result from using a directional outdoor antenna. It can reduce interfering signals arriving from co- and adjacent-channel stations with compass bearings well away from the directi...
by Rich
Sat Jun 15, 2019 10:06 am
Forum: Engineering & DX'ing
Topic: WJR vs. WWJ Fields at Utica, MI
Replies: 22
Views: 1168

Re: WJR vs. WWJ Fields at Utica, MI

Here is a study using NEC4.2 set for an Earth conductivity of 8 mS/m: The WWJ 186° radiator at 8 Mile Rd used alone, and driven with 5 kW would generate about a 20.6 mV/m field in Grosse Pointe, MI (a 14 mile path at N107°E). The 186° radiator used alone and driven with 1 kW would generate a field o...
by Rich
Fri Jun 14, 2019 6:22 pm
Forum: Engineering & DX'ing
Topic: WJR vs. WWJ Fields at Utica, MI
Replies: 22
Views: 1168

Re: WJR vs. WWJ Fields at Utica, MI

CK-722 wrote:
Fri Jun 14, 2019 3:58 pm
As far as I can see, the pattern can be reconstructed from the data on fccinfo, ...
Below is an easy way out by taking the pattern from the fccinfo page and adding some text labels to it.

Image
by Rich
Fri Jun 14, 2019 6:45 am
Forum: Engineering & DX'ing
Topic: WJR vs. WWJ Fields at Utica, MI
Replies: 22
Views: 1168

Re: WJR vs. WWJ Fields at Utica, MI

... I think it shows what the FI would be along points of a circle equidistant from the old WWJ tower, about 14 miles away. Correct. I don't know why the first circle is 0 and not the center of the graph. I set the lower limit of the scale to less than zero field to give more resolution to the lowe...
by Rich
Thu Jun 13, 2019 11:54 am
Forum: Engineering & DX'ing
Topic: WJR vs. WWJ Fields at Utica, MI
Replies: 22
Views: 1168

Re: WJR vs. WWJ Fields at Utica, MI

(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 rot...
by Rich
Wed Jun 12, 2019 2:06 pm
Forum: Engineering & DX'ing
Topic: WJR vs. WWJ Fields at Utica, MI
Replies: 22
Views: 1168

Re: WJR vs. WWJ Fields at Utica, MI

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).
by Rich
Wed Jun 12, 2019 1:24 pm
Forum: Engineering & DX'ing
Topic: WJR vs. WWJ Fields at Utica, MI
Replies: 22
Views: 1168

Re: WJR vs. WWJ Fields at Utica, MI

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.
by Rich
Tue Jun 11, 2019 5:39 am
Forum: Engineering & DX'ing
Topic: WJR vs. WWJ Fields at Utica, MI
Replies: 22
Views: 1168

Re: WJR vs. WWJ Fields at Utica, MI

... 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 c...
by Rich
Sun Jun 09, 2019 8:15 am
Forum: Engineering & DX'ing
Topic: WJR vs. WWJ Fields at Utica, MI
Replies: 22
Views: 1168

WJR vs. WWJ Fields at Utica, MI

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 an...