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HD Radio needs to have better antennas included

J

jras20

I think instead of dipole antennas they need to include a better antenna. Something like a omni antenna

listed: http://www.starkelectronic.com/acantena.htm#FMSS

Dipoles just wont cut it unless your in the City. I had to much trouble with mine trying to get it with a dipole. I can recieve FM Stereo great with my analog radio with a dipole antenna from Houston Radio 84 miles out. Even 60 miles to San antonio I can recieve FM stereo great with a dipole antenna and a analog radio. I think if HD is going to make it, they need to include better antennas. Thats my thoughts anyways.
 
The "turnstile" antenna shown here is simply two horizontal dipoles mounted 90 degrees apart and fed in quadrature to make the azimuth pattern omnidirectional. The gain is not much different from a dipole, so any improvement in reception is actually the result of mounting the antenna outside the building, or at a higher elevation above the ground, or both. On a residential rooftop, it's not unusual to measure a 10 to 20 dB increase in received signal compared with a typical indoor antenna, which would indeed make the difference between horrible and good HD FM reception.

But needless to say, not everyone has the opportunity to mount outdoor antennas at home or at other locations where they wish to use "the portable medium". A more practical approach would be to implement a full-digital Single Frequency Network system which allows on-channel boosters to fill in areas of poor coverage. Trying to make the SFN concept work with HD (Hybrid Digital) is troublesome, as discussed in this paper:

http://www.nprlabs.org/publications/reports/20060401_SingleFrequencyNetworks_AM-JCK.pdf
 
Well if they are they have changed drastically from when I used to go there, in fact I was told that they had sold all their existing stock to some TV shop in the area (those still exist?) so it may exist as an online store or maybe they are just selling antennas, phones etc, like Rat Shack. They used to carry a full line of all electronics, caps tubes, resistors etc. no more.
 
KB1OKL said:
Well if they are they have changed drastically from when I used to go there, in fact I was told that they had sold all their existing stock to some TV shop in the area (those still exist?) so it may exist as an online store or maybe they are just selling antennas, phones etc, like Rat Shack. They used to carry a full line of all electronics, caps tubes, resistors etc. no more.
Click to expand...

There are two types of Radio Shacks. One type doesn't carry components, another does. Any Radio Shack store should be able to tell you the nearest part stocking store. They have pretty much the full selection they had a few years ago. Not great, but enough for emergencies. For the rest of your needs, get an account at Digikey, Mouser, and Newark and you should be in pretty good shape.

I don't know about antennas - Radio Shack is obviously out of the antenna (and speaker) business, but the rise of the web should provide enough online resources to get what you need.
 
Why not throw in TWO of those dipoles? ;D

Without going to my books, I'm thinking that you'd just need to cut the leads from one of them to a half wavelength shorter than the other, then splice them. Mount them to the ceiling in an "X", just like the "real" omni antenna, and you're done.

Of course, nothing beats an outdoor antenna......
http://home.iprimus.com.au/toddemslie/Sweden-FM-DX-antenna-small.jpg
 
kenglish said:
Without going to my books, I'm thinking that you'd just need to cut the leads from one of them to a half wavelength shorter than the other, then splice them. Mount them to the ceiling in an "X", just like the "real" omni antenna, and you're done.
Click to expand...

That would only work if you are in an area where stations are coming from multiple directions, and are all within 20 miles or so.

If people hate to use a single dipole correctly, they sure won't use two. It would be an eyesore on their ceiling.

The only thing I have seen that has a chance of working is the Godar, which is actually a small log periodic in a plastic case. It has gain, and at 30 miles out, it brings in about half a dozen more HD signals than a dipole at the same height.

Properly installed, a dipole can get HD at 50 miles. Crumpled up on the floor, not even 30 miles.
 
rbrucecarter5 said:
kenglish said:
Without going to my books, I'm thinking that you'd just need to cut the leads from one of them to a half wavelength shorter than the other, then splice them. Mount them to the ceiling in an "X", just like the "real" omni antenna, and you're done.
Click to expand...

That would only work if you are in an area where stations are coming from multiple directions, and are all within 20 miles or so.

If people hate to use a single dipole correctly, they sure won't use two. It would be an eyesore on their ceiling.

The only thing I have seen that has a chance of working is the Godar, which is actually a small log periodic in a plastic case. It has gain, and at 30 miles out, it brings in about half a dozen more HD signals than a dipole at the same height.

Properly installed, a dipole can get HD at 50 miles. Crumpled up on the floor, not even 30 miles.
Click to expand...

I know the subject here is FM, but I've read of your loop antennas and lack of sucess decoding AM HD.

I'm wondering if your loops are capacitively coupled, inductively coupled, and if inductive, how tightly coupled?

I thinks you may need really loose coupling for the pickup loop, and maybe reduced Q for the outer tuned loop, so's not to discriminate too
much against the sidebands.
 
Tom Wells said:
I know the subject here is FM, but I've read of your loop antennas and lack of sucess decoding AM HD.

I'm wondering if your loops are capacitively coupled, inductively coupled, and if inductive, how tightly coupled?

I thinks you may need really loose coupling for the pickup loop, and maybe reduced Q for the outer tuned loop, so's not to discriminate too
much against the sidebands.
Click to expand...

I assume it is the residential environment I live in. I've purged all interference producing sources long ago - far more effort than most AM listeners would. But that doesn't mean my neighbors have.

A broader band loop is something I've already tried with some success - but I notice that when the neighbor next door (and he is a good 60 feet from my AM antenna) is out of town, I have better luck at HD lock. I think the problem is his computer 60 feet away, he leaves it on 24/7 when he is in town and only shuts down when he leaves town. I can see the screen through the window of his house so I know when it is on. When he is out of town, AM HD locks on stations up to 30 miles away. In town with his computer going, I have trouble on ones 10 miles away.

The funny thing is - analog AM is not affected at all. I can put a huge loop on the radio and not get a single trace of his computer interference. Of course I have to shut down my own wireless network, computer, TV, and cable box - ALL of them interfere with HD lock on AM.

None of that bodes well for HD AM. Because shutting down all that stuff is not an option for most people, and my neighborhood is spaced out quite a bit more than most. A lot of the newer houses are crammed 3 feet apart.
 
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