Why can I get FM and not DTV?

[Danny]

Originally Posted by indysteve

Most antennas are channel/frequency-specific and some are designed not to pass other frequencies, like some pre-amps. I haven't owned an FM-only antenna for a long time, so I don't have one to test your issue.

Steve is correct. And yes, I have a ten-foot long FM antenna, a twelve-foot long channel 2 yagi, and a thirteen-foot long low-band (channels 2-6) yagi. I can assure you that they are all *poor* performers on the frequencies for which they were *not* designed. At the same time, they all perform well on the frequencies for which they were designed.

I also have an old-style CM 8-bay, which some people claim is good on high-band TV. Compared to my two VHF-only antennas (both low- and high-band; one is 15-feet long, the other is 16-feet long), the 8-bay stinks on the high-band.

(Unfortunately, I don't have enough space to have all of those antennas up at once.)

[Michael-NJ]

Again echoing what people have already said above, with some of my own input...

The FM-6 is cut for a specific bandwidth, with the highest gain usually near the center of the (FM) band. Will it work on other frequencies (TV) sure, but results are far from optimized with your pattern ending up being all over the place (even off the back). The reason why you can hear FM, but not see DTV is, as people above said they’re two totally different animals. Analog FM can be heard in a weak form hundreds of miles away with the right equipment, meaning a very weak signal can still give you something listenable. DTV on the other hand requires a certain amount of signal before it can even decode, meaning the threshold is much higher.

As a comparison between the two, think of it almost like a CD (DTV)… that’s digital, it can read through scratches (weak signal), but once it reaches a certain point, too much of the data is lost and you start hearing skips (breakups), or the thing won’t play at all (no decode). Now compare that to an analog record (Analog TV), you can have a totally scratched up record (fuzzy picture), it might squeal like crazy (banding/CCI), but you’ll still be able to hear what’s left of whatever was on it (weaker DX).
I have a similar situation here with New York City. The ESB is 90 miles away, using a yagi antenna I can hear FM fine… even using something as small as rabbit ears. DTV on the other hand, same location, yet it’s trop only. And rare trop at that.

As for improving your antenna situation, it depends on what you want to receive. If you want to catch E-Skip there really isn’t a clear answer because of the varying signal levels that come in. In strong E-Skip (as Saul did) it’s possible to use even simple rabbit ears to log something. While weaker E-Skip will require a larger, more elaborate antenna. As for trop… personally I have received trop DTV on rabbit ears from Norfolk, VA and northeast NC from 200-250 miles away. Your mileage will vary there though, because trop does tend to get very intense along the coast here, something that as far as I know does not out west. That said, to get in on any UHF trop you don’t necessarily need anything “huge” (in terms of a giant VHF antenna), especially being UHF. I know some who have had luck with various bowtie antennas, 8, and even 16 bay. If you’re technical enough and want to save money, you can even build yourself. There are instructions all over the internet on how to build one. As for other modes like meteor scatter, or even AU (which I don't think has even been done on DTV yet?), you need a high gain antenna- even on FM.

[SlcDX]

Thanks for the suggestions guys. I guess it points to the fact that I still need a separate antenna for TV if I am going to get DTV DX in the summer. I'm thinking I will see how things are financially in about April and then I will probably invest in a better antenna for TV. I also might be in a different location by that point so the possibilities might be different.