Collins R390

[rfry]

WJR vs WTOR Groundwave Signals

...And of course the new WTOR "Toronto" on 770. That overlaps WJR in Canada and over the water.

No doubt about the groundwave interference in Ontario caused by the sidebands of WTOR (770 kHz) to WJR (760 kHz), and vice-versa.

Comparing the groundwave fields of the two in London, ON (about 116 miles from each transmitter site) and assuming 15 mS/m paths for both stations, WJR has about 3 mV/m and WTOR has about 1.5 mV/m.

London, ON is on the 263 degree radial from the WTOR transmitter, and at that bearing their IDF at 1 km is about 1420 mV/m.

WJR has an IDF at 1 km of about 2845 mV/m toward all azimuth bearings.

The fields in London, ON were generated using the FCC groundwave propagation charts for those IDFs, frequencies, and ground conductivity.

The fields from the two in London, and the difference in the IDFs on those bearings both show that WJR radiates about four times as much power toward London as WTOR.

Comparing the groundwave fields of WJR and WTOR in Erie, PA shows 0.64 mV/m for WJR for a 162 mile path, and 0.27 mV/m for WTOR for a 95 mile path. Conductivity assumed to be 8 mS/m in both cases.

Of interest, WJR has about twice the groundwave field in Erie, PA as KDKA, even though KDKA uses a Franklin type antenna, and the KDKA-Erie path length is around 109 miles (about 33% shorter than WJR-Erie).

RF

 

[Schroedingers Cat]

WABC vs WBBM, I could almost always detect a carrier with BFO , day or night.
On winter daytimes with good skywave dx, I could "copy", on an average day.
On a good day I could just listen.

Iboc makes this level of sensitivity moot.

What about WEW 770? Could you get that? It would seem that it would be stronger than WABC. R-L shows the 150 uV/m reaching Peoria. When you used the BFO, were you nulling out WEW? What was the beat frequency between WEW and WABC?

 

[Schroedingers Cat]

This discussion reminds me of a sad event. A local ham had passed away whose family was friends of my wife's family. His wife had a basement still jammed full of ham equipment. I took what I could, and arranged for a couple of hams with a trailer to take out the heavy stuff. Well, the deal fell through, and the late ham's wife was apparently angry at me because of it. I felt really bad about it, but I had no way to transport it, and no place to store it. I am reminded of the Steely Dan "Reelin' In The Years" line, "You wouldn't know a diamond if you held it in your hand". There was a bunch of really heavy stuff, and I wonder if there could have been a Collins R390 or clone that eventually got trashed. The guy had been in the military, so it is possible.

 

[radioman148]

WABC vs WBBM, I could almost always detect a carrier with BFO , day or night.
On winter daytimes with good skywave dx, I could "copy", on an average day.
On a good day I could just listen.

Iboc makes this level of sensitivity moot.

What about WEW 770? Could you get that? It would seem that it would be stronger than WABC. R-L shows the 150 uV/m reaching Peoria. When you used the BFO, were you nulling out WEW? What was the beat frequency between WEW and WABC?

I only heard WABC a couple of times on mid winter days. Now if you're talking about after 2PM CST, I heard it a lot. In the 60s I used to hear Dan Ingram's show as early as 2:30PM quite often in Dec & Jan, but around noon only 2 or 3 times and all those times were in December around Christmas. In each case I was hearing other stations from the east such as WCBS, WNBC, WBZ, WHAM, & WCAU.

 

[BobOnTheJob]

WABC vs WBBM, I could almost always detect a carrier with BFO , day or night.
On winter daytimes with good skywave dx, I could "copy", on an average day.
On a good day I could just listen.

Iboc makes this level of sensitivity moot.

What about WEW 770? Could you get that? It would seem that it would be stronger than WABC. R-L shows the 150 uV/m reaching Peoria. When you used the BFO, were you nulling out WEW? What was the beat frequency between WEW and WABC?

WEW must have had pre-sunrise in the 60's....I was often tuned to WABC at 7AM Eastern in winter and hearing WEW's national anthem clobber WABC in the greater Cincinnati area on some mornings. Dan Ingram's show....playing Petula Clark - Downtown when it was a current hit as my dad was driving us into downtown Cincinnati...great memories...and the song that's now stuck in my head for today.

 

[radioman148]

WABC vs WBBM, I could almost always detect a carrier with BFO , day or night.
On winter daytimes with good skywave dx, I could "copy", on an average day.
On a good day I could just listen.

Iboc makes this level of sensitivity moot.

What about WEW 770? Could you get that? It would seem that it would be stronger than WABC. R-L shows the 150 uV/m reaching Peoria. When you used the BFO, were you nulling out WEW? What was the beat frequency between WEW and WABC?

WEW must have had pre-sunrise in the 60's....I was often tuned to WABC at 7AM Eastern in winter and hearing WEW's national anthem clobber WABC in the greater Cincinnati area on some mornings. Dan Ingram's show....playing Petula Clark - Downtown when it was a current hit as my dad was driving us into downtown Cincinnati...great memories...and the song that's now stuck in my head for today.

I used to listen to WABC in the pre-sunrise hours in the Chicago area in the 60s & heard either Herb Oscar Anderson or later on Harry Harrison.
A few times I heard WEW sign on & a few other times I heard now defunct WCAL in Northfield, Mn sign on.

 

[Tom Wells]

Didn't get the R390-A until maybe 1992 or 3. Never heard WEW even back when I lived in NW Indiana in the 60s.

I wasn't typically using the BFO for zero-beat AM detection. I would use it to detect a signal, but the
Collins Radio magneto-restrictive filters are so beautiful you wouldn't want to throttle the audio
with the smasho effect that comes with the BFO on.

I used a 1.6 kc (whoops) khz Collins filter in my 5 tube homebrew regen IF superhet for a while, but could not
tolerate the effective loss, and returned to a regular 455 khz IF transformer. The response and sharp cutoff even on the
1.6 was as knife adge as can be imagined. No slope at all the skirt response. Uncanny.

If I ever get free of of my particular stationary orbit over a black hole, I'd like to bring the R390-A back to life.

 

[cyberdad]

And of course the new WTOR "Toronto" on 770. That overlaps WJR in Canada and over the water. I bet it's also a thorn in WABC's side to no longer be the only 770 station in the state of New York.

I think it may be the other way around. WTOR, as I think everyone here knows, is a highly directionalized attempt to provide ethnic/brokered programming to the Toronto-Hamilton Metro. Their signal isn't bad in the intended target area, but IME, WABC is clearly audible underneath regularly around sunrise/sunset.