This is really cool, William R. Hepburn, the same guy who brings us the Tropo DX forecasts, now has a new automated DTV logging system. He’s got a 70 foot tower in Grimsby, Ontario equipped with what looks like a Channel Master 3671 and a UHF Yagi that’s vertically polarized.

This is what he says about his setup;

Equipment...

Tuner... Hauppauge Aero-m
Control Software... TS Reader + Hepburn perl scripts + Windows Task Scheduler
Antenna... modified* CM-3671 @ 70' AGL 209' HAAT

I’ve been watching this site the past few days and noticed it log stations that just went digital … take a look it’s an amazing setup!

http://dxinfocentre.com/logs/dxtv.htm

http://www.dxinfocentre.com/etc/antenna-VU.jpg

He’s got a 70 foot tower in Grimsby, Ontario equipped with what looks like a Channel Master 3671 and a UHF Yagi that’s vertically polarized.


WOW! I had no idea he was from Grimsby.

70 foot tower? I'm so jealous!


The CM3671 is a great antenna- it's what I use.

If you keep that page open it'll update live as soon as it finds a new digital station...

Less then an hour ago... it logged this one...

2011-08-27 0234 7 7.1 CIII-HD ON MIDLAND

I have antenna envy. :)

I actually bought the CM-3679 25 years ago from Radio Shack in my pre-satellite days along with the rotator. Unfortunately the rotator won't rotate any more (probably a seized motor).
Fortunately it seized pointing north to Camp Fortune north of Ottawa where most of the transmitters are located.
Unfortunately, because I can't rotate it south, I can't pick up any of the US stations.
Maybe someday I'll replace the rotator.
It's a great antenna that gives a great picture.
Sure glad I left it up there (30-foot tower) when I went Bell ExpressVu in '99.
(I actually left it up there for the FM signals).

WOW.....What a rig!!!!

This automated DTV DX Log provides an excellent record regular locals stations and interesting record of recent tropo events.

Where is his tower located? It might be worth checking out on my next walk :)

Are you sure that it's a UHF Yagi that is vertical? Looks like a VHF. Can anyone enlighten me? I'm assuming that the VHF, or UHF yagi is for signals that are over 150 miles away. Don't signals change polarity once they are about 150 miles away? Need more info on this, because I'm thinking of trying to play "this game".

Yes Prince you're absolutely correct... it's not just UHF... it's a wide bandwidth Log-Periodic UHF/VHF 50~1300 MHz antenna. And yes it's vertical to catch signals that have gone past 150 miles.

This is it here,
http://www.grove-ent.com/ANT16.html
http://www.grove-ent.com/media/crant.jpg

Just wondering about that vertical antenna. Could any yagi be modified to do the same job? I was wondering if one of those hybrids that do VHF High/UHF would do a similar job, if mounted vertically. Going to have to sell my house and move out to Prince Edward County, so I can play this interesting DXing game. :cool:

Theoretically, a polarization "mismatch" can affect a received signal by upwards of 20 dB. In practice it's not that much but you will notice a difference if you're trying to receive a horizontally polarized signal with a vertically polarized antenna.

Theoretically, a polarization "mismatch" can affect a received signal by upwards of 20 dB. In practice it's not that much but you will notice a difference if you're trying to receive a horizontally polarized signal with a vertically polarized antenna.
Trying to nail down some of the long range Tropo. I often get some decent stuff, that is over 200 miles away and wondered if changing polarity might enhance it. Seems like the UHF works fine, for signals over 200 miles but nothing much on VHF high. Going vertical might make it feasable. I would run it with a dedicated line and it's own CM7777 and use an A - B switch to change it back and forth.

The Hepburn Automated DTV Log System address has been changed:
http://dxinfocentre.com/hepburn/logs/dxtv.htm

2012-07-24 1931 5 2.1 KCWX-HD TX FREDERICKSBURG
2012-07-24 1931 5 2.2 KCWX-SD TX FREDERICKSBURG

Close to 2200 Km. wow.:eek:

I'm no expert about this whole "pulling channels in from far away" thing, but I took a peek at this guy's page, and he's pulled in channels from Colombia, Venezuela and Panama. That is damn impressive.

These extreme distant catches are all tropo event catches only. It would be near impossible to reliably catch anything that is well beyond the curvature of the earth's surface. Those distant signals come to his antenna by chance of extreme signal bounce/ducting/propogation.

His setup continuously scans for signals 24/7/365. Chances are that you've recieved similar distant signals but just didn't notice unless you just happen to scan at that particular split-second moment.

In theory,.. the question is in which direction did that distant 2200 Km signal come from. The 2200km distance would be the short and direct route. If it came the long route around the earth's 40,008 km,.. it may have travelled 37,808km...:p

keep in mind, the longest paths are usually from ch 2 thru 6, because it's such a lower frequency, behaves more like HF (2-30 MHz) does under certain conditions, ie - HF skip in the ionosphere occurs daily. When there are Sporadic E events (not a daily occurrence), the MUF for skip rises significantly above HF, sometimes in to the low band VHF TV range. This occurs in the lower part of the ionosphere, referred to as the E - layer, thus the term Sporadic E. It's not the same as tropo.

I agree it would most likely be 'Sporadic E propagation' [aka: Es,.. E-skip]. KCWX 2.1 is VHF channel 5RF [76-82Mhz] from Austin Texas 24kw.

This example of 1,340-mile (2,160 km) tropospheric ducting reception shows Auckland, New Zealand 175.25 MHz ch4 TV received by Robert Copeman, Sydney, Australia.
New Zealand TV-4 channel 4 (175.25 MHz) video received on December 3rd, 1975 by Robert Copeman, Sydney, Australia. The propagation mode was summer time trans-Tasman tropospheric ducting. The distance is 1,340 miles from Auckland to Sydney.
http://en.wikipedia.org/wiki/File:TV-4-NZch4-Auckland-tropo-1975.jpg

Even though the reports indicated tropo ducting,.. being that it is below 250Mhz it is just as likely due to E-skip propogation.

I don't know why this is being listed in 'OTA Station & Network Operational Status'?:confused: