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  #46  
Old 05-15-2021, 10:09 PM
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ppppenguin ppppenguin is offline
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Originally Posted by Colly0410 View Post
I've often wondered why ITV didn't use low band/band 1? I'm thinking the London area could have used channel 5 & the north of England reused channel 1 as used by BBC in London as was far enough away from London to avoid co-channel interference. The gap between channels 1 & 2 was quite big because the original channel 1 from Alexandria Palace was double sideband so would have hopefully avoided adjacent channel interference. I suspect the real reason is the BBC took the hump & blocked ITV from using low band/band 1 for political purposes...
There is no way you could have achieved national coverage with BBC and ITV using just the 5 channels in Band I. It was only just about possible for BBC, and they had to place a few relays in Band III. It's a compromise between coverage, co-channel interference and (to a lesser extent) adjacent channel problems.

Remember that in the UK the aim was true national coverage, not just a good signal in major cities with poor signals in many other areas. I think the aim was to cover 98%+ of households.

It will take some work to find the relevant BBC reportsfrom the 1950s and 1960s, but they will be online here: https://www.bbc.co.uk/rd/search?Type=Publications
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  #47  
Old 05-26-2021, 02:36 PM
Colly0410 Colly0410 is offline
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I know ITV couldn't have used low band/band 1 in most of Britain as BBC had nicked all the channels, just in a few select areas. I'm thinking ITV could have covered most of northern England with one Low Band TX high up in the Pennines instead of two TX's on High Band. Later BBC TX's could have used High Band & viewers could have used a single High Band antenna to receive both BBC & ITV like they did in Lincolnshire. I suggested channel 5 for ITV London as I think it was unused in that area in 1955.

Read an article somewhere about the problems they had in New Zealand putting two national services in 3 Low Band & 5 High band channels, some areas had both services on Low Band & other areas were like Britain where Low & High Band was used...

When I rented an apt in Miami in 1989 there were three channels on Low Band = ch's 2, 4, & 6...
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  #48  
Old 04-02-2022, 12:07 PM
Colly0410 Colly0410 is offline
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Been thinking: In UK low band TV had lots of Sporadic-E co-channel interference, did low band viewers in US have the same problem? When I rented an apt in Miami in November 1989 I can't remember seeing co-channel interference on ch's 2, 4, & 6, did see ignition interference though. I know both Miami & Orlando used ch 2, but were they close enough to cause co-channel to each other?
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  #49  
Old 04-02-2022, 03:34 PM
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nasadowsk nasadowsk is offline
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I would suspect not. Even though Florida is famously flat (the highest point is 340 feet above sea level!), Miami and Orlando are still 200+ miles apart…
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  #50  
Old 04-07-2022, 06:29 AM
kf4rca kf4rca is offline
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I grew up in SC and there were two channel 4's roughly 200 miles apart. One in Charleston and the other was in Greenville. At one point I worked for the one in Charleston (WCIV) and I never heard of any co-channel interference problems.
Now, in the US, stations were assigned an offset of + or - 10kHz. which would reduce the possibility of interference.
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  #51  
Old 05-03-2022, 10:44 AM
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Penthode Penthode is offline
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Lo Band VHF for TV in the US and Canada did have its problems. During the summer months the Lo VHF (54-88 MHz) was plagued by co-channel interference between stations even thousands of miles distant. Even a relatively local channel could be wiped out by a strong co-channel station more than 1000km away.

In June 2009, during the "Nightlight" period of the US analog to digital transition, most of the TV stations across the US had already vacated the Lo VHF band with a few remaining nightlight stations only running transition promo loops. I did some DXing from where I then lived in Carbondale Illinois which is almost exactly in the middle of the Continental US. This is what I received in mid June 2009. I captured video clips of their IDs on my cell phone.

The receiver I used was an unmodified RCA Victor TV model 8T243 made in 1948-49. I used a 50ft mast VHF-UHF antenna with rotator. The direction of the antenna position varied as the ducted signal sometimes curved along its travel:

CKCK Channel 2 Regina Sask. 2000km
CBAT channel 4 Fredericton NB 2000km
WGBH channel 2 Boston MA 1500km
WPBT channel 2 Miami FL 1200km
XEFB channel 2 Nuevo Leon 1400km
KRMA channel 6 Denver CO 1500km
KASA channel 2 Santa Fe NM 1600km
KPHO channel 5 Phoenix AZ 2000km
Attached Images
File Type: jpg 2009 Reception Map.jpg (48.0 KB, 13 views)

Last edited by Penthode; 05-03-2022 at 10:50 AM.
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  #52  
Old 05-09-2022, 09:41 PM
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Jeffhs Jeffhs is offline
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Quote:
Originally Posted by Penthode View Post
Lo Band VHF for TV in the US and Canada did have its problems. During the summer months the Lo VHF (54-88 MHz) was plagued by co-channel interference between stations even thousands of miles distant. Even a relatively local channel could be wiped out by a strong co-channel station more than 1000km away.

In June 2009, during the "Nightlight" period of the US analog to digital transition, most of the TV stations across the US had already vacated the Lo VHF band with a few remaining nightlight stations only running transition promo loops. I did some DXing from where I then lived in Carbondale Illinois which is almost exactly in the middle of the Continental US. This is what I received in mid June 2009. I captured video clips of their IDs on my cell phone.

The receiver I used was an unmodified RCA Victor TV model 8T243 made in 1948-49. I used a 50ft mast VHF-UHF antenna with rotator. The direction of the antenna position varied as the ducted signal sometimes curved along its travel:

CKCK Channel 2 Regina Sask. 2000km
CBAT channel 4 Fredericton NB 2000km
WGBH channel 2 Boston MA 1500km
WPBT channel 2 Miami FL 1200km
XEFB channel 2 Nuevo Leon 1400km
KRMA channel 6 Denver CO 1500km
KASA channel 2 Santa Fe NM 1600km
KPHO channel 5 Phoenix AZ 2000km
When I lived in suburban Cleveland, I received some almost unbelievable TV DX. It was in the summer sometime in the '80s, and the station I received on the color TV in my living room at the time was KWGN-TV, channel 2, somewhere out west, 2000 miles from where I lived at the time (I cannot for the life of me remember where the station was located, but it will probably come to me shortly after I post this). In addition, again in the eighties, I received some great TV DX using just the monopole VHF antenna on my 12-inch Sharp all-channel b&w portable TV. The station, again, was an NBC affiliate some 2000 miles away. I was at my grandmother's farm in Richfield, Ohio (between Cleveland and Akron) at the time, and the reception was almost unbelievably good while it lasted.

Unfortunately, however, since I moved to my current residence 21 years ago, I haven't seen any TV DX, since my TV is connected to Spectrum "streaming" TV service, without a cable box (I have been informed by Spectrum that, since I now have this service, I no longer have traditional cable, and so do not need a box). From this, I am thinking the cable operator may not be using traditional cable boxes any longer; however, this is just a guess, although with streaming cable, I am honestly not sure what is going on. I do know, however, that my charge for this service is just under $30 a month; it would be a lot higher, I'm sure, if I had a cable box. Being a senior citizen on a fixed income, this is welcome news, as I honestly do not want or need an additional charge (for a cable box or anything else associated with my television service) on my bill. The additional charges (two) on my cable bill are for Internet and home telephone service.
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Last edited by Jeffhs; 05-09-2022 at 10:06 PM.
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  #53  
Old 05-11-2022, 03:14 PM
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jr_tech jr_tech is offline
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“ KWGN-TV, channel 2, somewhere out west, 2000 miles from where I lived at the time (I cannot for the life of me remember where the station was located”

Denver Colorado, about 1250 miles from Cleveland....good dx catch.

jr
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  #54  
Old 10-12-2022, 07:38 AM
Colly0410 Colly0410 is offline
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Originally Posted by Colly0410 View Post
England has a history of older TV's not being able to receive new stations, you had the BBC only sets not able to receive ITV in the late 50''s/early 60's, (no high band tuner) then 405 lines VHF only sets not being able to receive BBC2 on 625 lines UHF in the late 60's/early 70's. Then more recently the digital changeover, but you could & still can buy cheap digital converters, I've got 4 of them, 2 with RF outputs for my really old TV's (1971 Elizabethan & 1985 NEI) that don't have SCART or HDMI inputs...
Up till the early 1950's you'd have TV's that were fixed tuned to a certain low band channel. If you bought it in London area it'd only get channel 1 & if bought in the Midlands it'd only get channel 4. If you moved area I presume you'd have to sell your old TV & buy a new one, I don't know if they could be converted to another low band channel...
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