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Can't Get WJBK Off-Air in SW Detroit

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ftballfan
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Re: Can't Get WJBK Off-Air in SW Detroit

Post by ftballfan » Sun Jan 20, 2019 11:26 pm

When I lived in Ypsilanti, I was able to get occasional pictures from WJBK with an indoor antenna. Then again, I had a third floor apartment facing Southfield. The other Detroits (WDIV, WXYZ, WMYD, WKBD, WTVS, WWJ) would usually come in no problem



CK-722
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Re: Can't Get WJBK Off-Air in SW Detroit

Post by CK-722 » Sun Jan 20, 2019 11:37 pm

I haven't heard WJBK since 1969. Whatever happened to Jerry Baxter?

Who would have believed 50 years ago that the FCC could convince VHF broadcasters that UHF was better? Yes, if you handicap VHF with low ERP and a typically inefficient VHF antenna. Who would ever believe that TV station engineers with amateur radio licenses would ever be telling people that small indoor antennas were actually efficient enough to get signals more than 20-25 miles away, unless they were on top of the highest elevation point in Livingston (Tyrone Township) or Oakland County T5N Townships?


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

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

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Re: Can't Get WJBK Off-Air in SW Detroit

Post by moldyoldie » Tue Jan 22, 2019 8:34 am

MWmetalhead wrote:
Sun Jan 20, 2019 8:37 am
This doesn't need to be complicated.

Any of the following antennas should offer reasonably good reception of all major OTA networks in Detroit:

https://www.bestbuy.com/site/insignia-i ... Id=8233003

https://www.bestbuy.com/site/insignia-f ... Id=8234002

https://www.amazon.com/dp/B000EIMKYC/re ... B000HKGK8Y

https://www.amazon.com/RCA-ANT121Z-Dura ... EBWR6ZWSM3

https://www.amazon.com/RCA-Amplified-In ... 75PYQM44S0


RCA & GE antennae tend to have short dipoles. That hasn't caused any problem for me, but then again, I live only about 5 miles from Fox 2's TX site. (Remember, at my old house, which is about 11 miles from the Fox 2 TX site, I actually needed to collapse the dipoles most of the way to maximize WJBK reception. That fact seemingly runs contrary to the laws of physics, but it is what it is.)

My suggestion would be to pick up the $7.49 Insignia from Best Buy if you can find a store that has one, or the $9.50 GE Antenna for Amazon. However, any of the five on the above list should work reasonably well.

I have the $9.50 antenna from link #3 in my home, and it actually works slightly better than an indoor amplified antenna I bought from Radio Shack about 12 years ago. I've compared signal strength readings on multiple channels to compare the two. (Performance of the Radio Shack antenna works best when I have the amplifier gain knob dialed in on the lowest setting possible.)
Thanks much, Mr. Metalhead. Will do some shopping and perhaps report back here with results.


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MWmetalhead
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Re: Can't Get WJBK Off-Air in SW Detroit

Post by MWmetalhead » Thu Jan 24, 2019 8:44 pm

I'm anxious to hear how things turn out. :)


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Re: Can't Get WJBK Off-Air in SW Detroit

Post by moldyoldie » Sat Feb 02, 2019 8:48 am

I'm happy to report that attaching this inexpensive antenna to my uncle's aforementioned set-up solved the WJBK problem - it and its sub-channels all came in loud and clear!

However, and perhaps this was an oversight on my part in regards to my original post, WADL and its sub-channels were received haltingly, and then not at all. They were picked up on the scan, but not identified as WADL. They were identified as PR(4 different numbers). My uncle said that he's always had that problem with those channels, but sometimes they came in at night. Since their tower was all the way on the east side I suggested that attaching a 25db amplifier might help if he really wanted them. Nor did he receive CBET just across the river in Windsor. He really didn't care much about them, however, and was very happy with the new antenna. :)

Thanks again for all the responses, and especially to Mr. Metalhead for the links, it was a re-education in the foibles of OTA television. :blink


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Re: Can't Get WJBK Off-Air in SW Detroit

Post by MWmetalhead » Thu Feb 07, 2019 8:27 pm

That's the same inexpensive antenna I use in my home whenever the cable goes out, moldy. :)

It works quite well for me on UHF and does a decent job on VHF 7 to 13. (Fox 2 transmits on VHF 7.)

Thanks for the update; happy to hear everything worked out!


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moldyoldie
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Re: Can't Get WJBK Off-Air in SW Detroit

Post by moldyoldie » Sat Feb 09, 2019 10:09 am

Forgive my ignorance, but is there a reason he can't pick up CBET-9 just across the river? He does like Hockey Night in Canada.


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innate-in-you
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Re: Can't Get WJBK Off-Air in SW Detroit

Post by innate-in-you » Sat Feb 09, 2019 7:08 pm

moldyoldie wrote:
Sat Feb 09, 2019 10:09 am
Forgive my ignorance, but is there a reason he can't pick up CBET-9 just across the river? He does like Hockey Night in Canada.
CBET is no longer "just across the river", it is on the same tower as CICO32 (TVO) and formerly used by CBEFT (54) before its demise, near McGregor.

However, it should be strong enough to be seen on rabbit ears with CBET's power and antenna height in SW Detroit.

My guess is that your antenna is not in the right place when your TV or converter passes channel 9. It will only capture the channel if the signal is both strong enough and not too heavily affected by multipath.

if you're lucky, your TV or converter box will have a "manual tunung", "add channel" or RF mode. If so, go to channel 9, and move the antenna around until a steady signal is seen and heard. If this happens, your TV/box may automatically save the channel in its memory, or it may ask you to confirm that you want to add the channel.

If it does not, try just entering channel 9, then try the antenna in different positions, until channel 9 comes in.

If it won't, send me a PM with the name and model number of the converter box, and I'll try to help.



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Re: Can't Get WJBK Off-Air in SW Detroit

Post by Rich » Sun Feb 10, 2019 7:13 am

RE: ...Who would have believed 50 years ago that the FCC could convince VHF broadcasters that UHF was better? Yes, if you handicap VHF with low ERP and a typically inefficient VHF antenna. ...

Just to note that the FCC authorized higher ERPs for analog TV stations using Ch 7-13 (316 kW) and Ch 14 and above (5,000 kW) than for Ch 2-6 (100 kW).

This tended to offset the increase in propagation loss with increasing frequency, and ~equalize their field intensities* for those channel ranges that arrived at receive sites (other things equal).

* regardless of the receive antenna in use



CK-722
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Re: Can't Get WJBK Off-Air in SW Detroit

Post by CK-722 » Sun Feb 10, 2019 1:09 pm

Rich wrote:
Sun Feb 10, 2019 7:13 am
RE: ...Who would have believed 50 years ago that the FCC could convince VHF broadcasters that UHF was better? Yes, if you handicap VHF with low ERP and a typically inefficient VHF antenna. ...

Just to note that the FCC authorized higher ERPs for analog TV stations using Ch 7-13 (316 kW) and Ch 14 and above (5,000 kW) than for Ch 2-6 (100 kW).

This tended to offset the increase in propagation loss with increasing frequency, and ~equalize their field intensities* for those channel ranges that arrived at receive sites (other things equal).

* regardless of the receive antenna in use
I was referring to the digital ERP's, not the analog. Where most models break down is in not considering terrain that varies more than the Bullington Model was allowed to address in the terrain roughness correction. As more and more factors are addressed, it becomes more apparent where the previous terrain loss models failed.

As the late great Dr. Salvati noted, even the tuned dipoles at VHF-Low, VHF-High, and UHF have considerably different apertures, which also causes lower gain. dBd is one factor, but dBd at each channel has large differences from the differences in aperture, and circuit noise and terrain variations are two others. UHF driven elements have much smaller apertures than VHF driven elements, and thus even if tuned, the gain of a UHF dipole at VHF channels is way into the minus. Another important difference between transmitting and receiving antennas. As we know, a small dipole or monopole can be tuned and matched to be quite an efficient transmitting antenna, though not as efficient as a larger one.
Last edited by CK-722 on Sun Feb 10, 2019 11:45 pm, edited 2 times 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, 2 deg source. As of 12:30, 157.71 Down 0.22.

CK-722
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Re: Can't Get WJBK Off-Air in SW Detroit

Post by CK-722 » Sun Feb 10, 2019 1:45 pm

Here's a gem of a link about FM antennas by Michael Salvati in Audio from 1978, though I couldn't find his MATV CATV book links.

https://www.americanradiohistory.com/Ar ... 978-01.pdf


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, 2 deg source. As of 12:30, 157.71 Down 0.22.

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MWmetalhead
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Re: Can't Get WJBK Off-Air in SW Detroit

Post by MWmetalhead » Sun Feb 10, 2019 3:11 pm

CBET-DT does not transmit 26 kW in the direction of Detroit...nor anywhere near that amount of power.

Based on its directional pattern specs, CBET only sends somewhere between 4 kW and 9 kW toward various sections of Detroit. The SW Detroit area is closer to the 4 kW side of the scale.

When one also accounts for the refineries & steel mills that sit between SW Detroit and McGregor, ON, it's little surprise that indoor reception is difficult.

Rabbit ears with copper material are probably required to have a decent shot of receiving CBET from a ground floor receive location in SW Detroit.

https://www.fccdata.org/?lang=en&cantv=CBET-DT


WLAV in Grand Rapids puts all Metro Detroit classic rock stations to shame.

innate-in-you
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Re: Can't Get WJBK Off-Air in SW Detroit

Post by innate-in-you » Sun Feb 10, 2019 6:56 pm

Zug Island and USS Ecorse Works are off-axis to a path from McGregor to W Grand Blvd (which is walking distance from Downtown).

Apartment towers on Windsor's west shoreline could be a problem instead.

I'll have to work out the details later.

It was interesting to note that 26kW is their peak ERP. I had read elsewhere that IC quoted ERP in average power



CK-722
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Re: Can't Get WJBK Off-Air in SW Detroit

Post by CK-722 » Sun Feb 10, 2019 9:14 pm

It's always been confusing, because the Canadian Regulators ALWAYS have specified the AVERAGE ERP for DAs, not the PEAK ERP. I could never understand until fairly recently why they said 325 kW ERP for the Sign On and Sign Off of Analog Channel 9, and WRTH showed 178 kW ERP. The FCC has always specified the PEAK ERP in any direction for FM and TV. It was also misleading when they said it was the Windsor Detroit Area's most powerful TV station, when they should have said VHF TV station. That most powerful statement really hasn't been true since WKBD-TV went up to 525 kW, as I recall, in the mid 1960s. Even then, the 325 kW Peak ERP barely beat the 316 kW ERP for Channel 7 WXYZ-TV.


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, 2 deg source. As of 12:30, 157.71 Down 0.22.

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

Re: Can't Get WJBK Off-Air in SW Detroit

Post by innate-in-you » Sun Feb 17, 2019 1:59 am

Okay, so I did a TV Fool check on the intersection of W Vernor / W Grand Blvd, assuming an antenna height of 4' above ground.

Surprised to see TV fool estimating that CBET is only 4dB weaker than WJBK there, and the signal is reasonably strong. CBET is in almost exactly the opposite direction as WJBK.

At about 200m, CBET's HAAT presents a handicap in distance (relative to the stations in the Southfield / Royal Oak Twp. tower farm), but still clearly visual line-of-sight to W Grand Blvd./W Vernor.

The antenna / power information on the Rec site are confusing and may have errors. The radiation plot is shown to peak at 13kW ERP, even though the data shows 26kW ERPMax and 13kW average. This causes me to suspect that the ERPs given for each of the azimuths are twice what is shown on the radiation plot. The 26kW figure also causes the ERP to match that shown by TVFool.

Contrary to what I said before, there are no apartment towers on the Windsor side blocking the path from CBET to that intersection.

There is a large church on the even side of W Grand Blvd about .5km SSE of the intersection. It would not represent an optical block of that path, but could be a factor due to the Fresnel Zone.

Really, with DTV, the problem is usually in the last 30 meters. If the residence in question has a two-story brick house next door down, it would likely be difficult to get a signal clear of multipath for the signal to decode reliably, and especially so if there is also a brick house to his NNW as well,.

Finally, DTV is often lost in the last meter. Reflections from a metal appliance, or a person (especially in motion) could cause trouble. Then there is autointerference - the TV set or converter box circuitry emits RFI that interferes with the signal to the converter box itself!



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