Improving radio reception

[Leef]

Hello all,

I'm trying to improve FM reception on a radio in our kitchen to pull in our church services better. The radio/cd/cass cost only$150 new recently so I don't expect it to be a great tuner. The FM antenna is only a single wire and the AM antenna is two wires in a "loop": both come out of the rear of the radio and are attached internally.

I have a TERK antenna which I'd like use to boost reception but I don't know how to attach it? The TERK antenna has two wires which are now attached to a coax connector by screws. The other two wires are just stripped back at the ends and look like thin lamp cord.

Can anyone help me determine which set of wires on the TERK are AM and which are FM since I don't have a manual or diagram? Then, how would I attache the wires to improve FM reception since the radio only has one wire and it originates from inside the housing?

Finally, do these type of TERK antennas with an adjustment dial and power by electricity work at all?

Thanks ,


Leff

[Pat]

Never heard of a TERK ant. There is a lot of snake oil sold to the unknowing in the area of radio and TV reception. Do you have a wiring diagram for your radio?

As far as wiring your TERK to your FM...it is extremely unlikely that you will hurt anything if you experiment with various permutations and combinations of connections. IF some combination works, use it.

Frequently, the antenna connections on entertainment electronics have the A.M. and F.M side by side and will share a common connection. A non directional antenna such as a "turnstyle" is often a good solution for FM listening. A turnstyle looks like its name. It is actually two folded dipoles mounted at right angles to each other. Radio Shack used to sell a good one pretty cheap. I think it came with a BALUN (Ballanced to unballanced transformer.) You can put it in the attic or on a pole above the roof.

You might just run a length of wire up into the attic and connect it to your radio. Sometimes this works well. If you only want to get the one station or stations lying along a line you can make your own antenna pretty cheap. (Maybe 20 cents for some wire to get what sells for $10)

You need a few feet of 300 Ohm twinlead (old fashioned TV antenna lead-in wire, flat two conductor) The antenna is in two parts the actual antenna which is cut to the length depending on the frequency of interest and the lead in or feed which can be as long as required.

You assemble the two pieces of wire as per the drawing. Twist the wires together at the ends of the horizontal portion (soldering is even better.) cut asmall section ouf one of the horizontal conductors out and inseert the vertial piece, again twisting and soldering. The end at the botom with the two bare wires commects to the radio. Try one wire to the terminal labeled FM and try various other places for the second conductor, choosing whatever works best.

This antenna is a bit directional with best reception broadside to the horizontal wire and poorest reception off the ends of the horizontal wire. I'll save you most of the chitchat about velocity factor, The speed of light in free space, and such and just suggest a horizontal length that is about right for say 100 Mhz. IF your station is around 108 make the horizonal part 8% shorter. IF your station is around 88 then make it longer by 10-12%. This antenna is not hyper-sensitive to exact lengths.

Now then C = about 3*10**8 meters per second (or if you really care... then about 299 792 458 m / s), velocity factor is about .98 (Gary or someone with access to ARRL Ant handbook correct me if I get too far off working from memory.)

This antenna is called a folded 1/2 wave dipole. Its horizontal member is sized according to the length of 1/2 the wavelength at the freq of interest or how far does a radio wave go during 1/2 of a cycle at 100 Mhz (cycles per second)

Do the math... I get about 57.9 inches. Tack it to the wall or hang it up with the horizontal part mostly horizontal, more or less broadside to the direction toward the station.

A quick GOOGLE shows where you can buy this for $10 but you can make one in 2-3 minutes for a few cents worth of scrap antenna lead-in wire.

So make the horizontal part about 57.9 inches long.

I GOOGLED on TERK. I suppose some of their stuff works but it seems too long on hype and too short on engineering to appeal to me.

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

[Leef]

Pat,

Wow, thanks for the advice. That's exactly what I was looking for. I haven't done the math, but the station I'm trying to tune in happens to be 99.9 mhz so I assume you're example is perfect. However, all of the antennas are connected internally. Unless I try to open the casing, all I have to work with is one single solitary wire labeled "FM".

So can I twist/solder this wire to one of the wires at the bottom of the vertical portion and leave the other unattached and get good results?

I'm also curious: do you have any experience with brands like the C Crane radio, or Henry Kloss' Cambridge Soundworks or his Tivoli radios. They claim to have good receivers/tuners built in, but I'm no expert - I've just read the descriptions in some catalogs like Crutchfield. I wouldn't mind learning more about this and owning a good tuner to combine with a proper antenna.

Leef

[Pat]

Leef, Experimenting with this is safe and cheap. I'd recommend connecting one of the conductors at the end of the feed line to the FM wire and "try" a few connection locations for the other feed wire. Candidates would include: 1. the AM wires, one at a time but not both together and 2. a chassis ground connection if available (this assumes the set is UL approved.

Don't let "specsmanship" cost you a lot of $. If you can't hear the difference then what difference does it make. Most any of the folks who posted here admitting to being ham radio types could ofer advice.

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

[twstanley]

Pat: FYI on Terk antennas, I have used them for a few different things, they seem to be decent quality.

http://www.terk.com/

[Pat]

Thanks for the URL. I had already visited it after finding it via Google and did a quick survey of some of their product literature. They are selling a lot of hype along with the technology. It is the norm, now. Even Radio Shack (picked up a catalog yesterday) has gushing pseudo tecnobabel where factual commentary would serve the customer far better.

Their level of technical communications would appeal to someone who would think 50 amp fuses at the same price as 15 amp fuses would be a bargain since you get more amps for your dollar.

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

[GaryM]

</font><blockquote><font class="small">In reply to:</font><hr />
...someone who would think 50 amp fuses at the same price as 15 amp fuses would be a bargain since you get more amps for your dollar.

[/ QUOTE ]

You mean it's not like miles per gallon?