FM reception, and how to optimize it!

[onwardjames]

I would just LOVE for someone to help me understand the best way to get FM reception.

75 ohms?? 300 ohms??? What is the best way to get FM reception?? One of those "amplified" fm antennaes?? Seems to add noise...

Big outdoor antennae??

Any suggestions??

Oh, and to save server space, a real non-sequituer.....

Can a 8mf cap be replaced in a crossover by an 8.2?? What are the consequences?? Having a hard time finding 8mf for cheap..

[Windwalker]

Good simple\entertaining reads on this here (http://kalx.berkeley.edu/recept/rooftop.htm) and here (http://kalx.berkeley.edu/recept/antsurvy.htm)
from the kids at Berzerkeley

[Negotiableterms]

I'm going to move this thread into the Tuners forum, where there are a bunch of folks who think about this topic for days at a time. Good luck with your quest!

[ticntoc]

Good simple\entertaining reads on this here (http://kalx.berkeley.edu/recept/rooftop.htm) and here (http://kalx.berkeley.edu/recept/antsurvy.htm)
from the kids at Berzerkeley

Lots of good reading there. Or just trot down to Radio Shack, Sears or your local home supply megga store and pop for a good outdoor antenna. If you live out in the boonies. You may also need a rotor to pick up stations in opposite directions. Most of these antennas are 300 ohm twin lead. Me, I live within spitting distance of LA and use about 2 feet of 20ga wire hung on the mini-blinds and peg the signal strenght meter.

To save space...yes, 8.2 mfd and 8.0 mfd are close enough. Tolerance of most caps are 10%, some 20%. so you are well within the ball park.

Glenn

[thisOne]

I tried all kinds of antenna solutions, ones with rotors, those amplified pieces of junk from Rat Shack, all gave me agita...

Then I scrolled down to the bottom of this page and clicked on the FM Antenna banner below. I got one of their 1/2 wave dipoles and my reception has never been so great and so trouble free. It's amazing that all one needs is two simple rods, not conected to each other, on the roof.

[ticntoc]

Then I scrolled down to the bottom of this page and clicked on the FM Antenna banner below. I got one of their 1/2 wave dipoles and my reception has never been so great and so trouble free. It's amazing that all one needs is two simple rods, not conected to each other, on the roof.

Like I said, 2 pieces of 20ga wire. Works for me. Just trying to cover a few more options. I only use a beam antenna for Ham Radio.

[mhardy6647]

The best solution? A good-quality, purpose-built outdoor directional FM antenna (Yagi) and a rotator; installed as high as you can get it.

[Oerets]

onwardjames ,
Do you have a 75 ohm fitting on your unit , or only 300 ohm ? Most 75 Ohnm inputs are a direct connection to the radio's recieving circuts . Coax(75 Ohm) will have more loss per foot then 300 ohm . Better noise filtering with 75 Ohm .Getting you antenna up as high as possible would be the best , Aiming it at the stations tower .
Indoors a set of Rabbit ears should work unless you can put a Yaggi in the attic . Otherwise anything outside will go onto a mast of sometype .
You might (will) get different signal strengths on the radio stations , unlikly they will all be strong in the same antenna's location .
My experance with antenna amps is not a good one .


The cap should work just fine on the crossover , just do both of the speakers the same .


Good luck ,




Barney

[onwardjames]

Thanks to all, again, for helping out.

So, to synopsize, 75 is cleaner, but less efficient, and 300 grabs those harder to reach radio stations??

I swear, I worked in radio as a dj for twelve years, and could NEVER figure it all out.

And for cap tolerances, I noticed in Parts Express, some of the "boutique" caps were 10% tolerances, and the bargain Daytons were 1%! I would think that lower would mean a better soundstage and imaging??

But I've been wrong before.

I have a buddy wanting to again recap some speakers, and he was thinking of using the higher dollar caps. Trying fruitlessly to save him money. Don't ask me why..

[Paul C]

8.2 uf is fine for use in place of the 8.0.

This thread may interest you.

http://audiokarma.org/forums/showthread.php?t=73451

Details of my FM antenna. Radio Shack no longer has these, but if you will simply Google "Antennacraft FM6" you will find the same antenna sold by a number of places for under $30.

There are two connections for 300 ohm lead on the antenna. I connects the two leads from a 300 ohm to 75 ohm balun, or transformer, to the antenna, and screwed on RG6 cable. I sealed where the cable screwed on with Seal All to keep out moisture.

You can also just use 300 ohm twinlead.

So, that is a basic roof mounted yagi setup. You can also use most any VHF TV antenna, if you already have one, since the FM band is actually a small bit between TV channels 6 and 7.

And there are better FM antennas you can buy.

For something simple, for my shop and bedroom systems, I was not getting very good results from the little T-shaped "dipole" antennas, and actually got better results from a 5' wire. That is a 1/2 wave, fyi.

I had about 40' of wire stretched outside for use with my Grundig portable as a shortwave "longwire". I tried it with my FM receiver and tuner and it worked GREAT. Not quite as good as the rooftop antenna, but much better than anything indoors.

So I went out in my shop and scrounged a roll of 22 ga stranded insulated hookup wire. I snaked it through the window near my bedroom receiver, and hung it along the edge of the roof with little plastic Christsmas tree light hooks. I went down the edge of the roof, around the corner, and about 15 feet at right angles to the first run. Altogether, about 35' or so. I didn't measure. I am getting EXCELLENT reception. Again, not quite as good as the rooftop antenna, but very good.

I made a similar antenna for the workshop.

And for AM, I highly recommend this little untuned aka broadband loop.

http://audiokarma.org/forums/showthread.php?t=64918&page=3&pp=15 (my post #33)

and

http://audiokarma.org/forums/showthread.php?t=125817

[onwardjames]

Thanks for the thread and the help Paul!

[Yankee Dog]

I agree a good antenna properly installed will be your biggest bang, but, you can also easily add a 75 ohm coax "F" connector to the back of your stereo (if it does not have one) and remove the balun like in this thread:

http://www.audiokarma.org/forums/showthread.php?t=62700&highlight=install+connector

Makes connecting your coax a breeze.

Then there is filter mods and filter boards... YD

[ticntoc]

Thanks to all, again, for helping out.

And for cap tolerances, I noticed in Parts Express, some of the "boutique" caps were 10% tolerances, and the bargain Daytons were 1%! I would think that lower would mean a better soundstage and imaging??

But I've been wrong before.

I would guess that you may be wrong again. 1% tolerance would mean that the cap would be 8 mfd plus or minus 0.08 mfd. It may or may not sound better. In fact there is a faction on this forum that will suggest that you may loose that "vintage" sound. I have no experance at it. But my guess is that 1% tolerance is a waste in a cross over network.

Glenn

[hpsenicka]

The tighter tolerance will help to ensure that both crossovers in a pair of speakers have similar characteristics.

[Jeffhs]

Lots of good reading there. Or just trot down to Radio Shack, Sears or your local home supply megga store and pop for a good outdoor antenna. If you live out in the boonies. You may also need a rotor to pick up stations in opposite directions. Most of these antennas are 300 ohm twin lead. Me, I live within spitting distance of LA and use about 2 feet of 20ga wire hung on the mini-blinds and peg the signal strenght meter.Glenn

I live between two cities (Cleveland and a lakefront town called Ashtabula) and can receive every local station from both areas, simply by using a 6-foot length of zip cord on my Zenith MJ1035, the built-in antenna on my Zenith C845 and by using the built-in whip antennas on my other radios. Most people today don't bother with big outdoor FM or TV antennas anyway, unless they are interested in distance reception or want to get stations from other nearby areas, because of the increased power output of today's FM stations as opposed to the same stations, say 35-40 years ago. If you are within any reasonable distance of your city's local FMs, you should hear them just fine; in fact, if you are within "spitting distance" of Los Angeles, you probably have more signal from all your local stations than you need. The local stations' towers are probably all atop very high mountains, so they likely have coverage areas extending at least 100 miles or more.

[onwardjames]

The tighter tolerance will help to ensure that both crossovers in a pair of speakers have similar characteristics.


Sorry again to carry off-thread, but I'm going with the Daytons. 3 bucks a pop. And symmetry with both crossovers shouldn't be a bad thing, eh? Like the idea of 1% tolerance.

Hoping I don't lose that vintage sound...