Amplified Antenna On 4100

jdwdmi

Active Member
I see the MAC 4100 has a coaxial FM antenna input, would it be ok to use an amplified antenna?

Sorry if this is a dumb question, better safe than sorry, I don't want to damage anything. Thanks!
 
Using an amplifier FM antenna should not cause any damage.

Are you asking about in inside amplified antenna?

An inside amplified antenna may or may not improve the reception of the desired signal(s). In general the better the FM RF section of receiver or tuner, the less improvement will be seen in the quality of the received signal.

If you use an amplified antenna, try to keep it away from anything that might generate unwanted electrical noise (RFI), the noise will be amplified right along with the desired signal. Move the antenna around and look for the position that gives the best reception of the desired signal(s). Sometimes a change in position of just a few inches may make a big difference.

Even the position of the power cord for the amplified antenna may make a difference it the quality of the received signal.

If you have a choice and the manufacturer lists it, choose an amplified antenna with the lowest noise figure. This is the amount of noise the the electronics of the amplified antenna add to the desired RF signal, the lower the better.

When it comes to FM signal reception, it is just like real estate, it is location, location, location. What works well for one person may or may not work as well for another person due the difference in location.

One of the best working inside antennas it the simple rabbit ear style antenna. The elements can be adjusted to the correct length for the FM band and the position of the elements can be adjusted for the best reception in terms of signal strength, the rejection of unwanted signals and noise and minimizing the affects of multi-path signals (reflected signals).
 
Thanks JBLGuy for the good info. I was digging through a box today and found several old rabbit ears of different makes and models so it would be an indoor only set up. I was going to play around with them and see what one worked the best. I was wondering if an amplified antenna may possibly introduce unwanted noise. For AM I will just try some old speaker wire I have laying around.
 
Jim,
I hope the 4100 works out for ya, the 2105 has an easy life right now as it resides on a shelf, thanks again. Maybe we can get together on some tube deals as well!! :music:
Chris
 
Hey Chris

Should have it by next week. Glad it went to a good cushy home. I have a few pairs of tubes that's for sure :D. You never know, when I'm ready to go back to separates you may be ready to offload it. :thmbsp:

Talk to talk later
Jim
 
The MAC4100 deserves the best antenna you can justify. 12 or 14 element yagi on a tower with a rotator, absolutely. At the very least get an omni as high up as you can. When it is properly allighned the tuner section, with a good antenna, will find stations you did not know were there.

We found the amplified antennas just added noise, they promise a easy solution but get out performed by a dipole in the attic.
 
. . . An inside amplified antenna may or may not improve the reception of the desired signal(s). In general the better the FM RF section of receiver or tuner, the less improvement will be seen in the quality of the received signal.

+1. An "amplified" antenna merely adds another, outboard, RF amplifier stage. Never having owned one, my guess would be that a McIntosh tuner has a pretty good RF stage to begin with. A cheap outboard RF amp may simply increase noise. Nothing beats a good outside sky hook.
 
Thanks for the insight guys. I have a dipole in the attic that would probably do a pretty good job, I will have to think about trying to tap into that, though my setup is in an addition on the house and no access to the attic from it. It would be tricky. I have several omni's I will try out and see what they pull in. I not sure I want to go to the extent of mounting an outside pole though I'm sure it would have the greatest results.
 
Yes indeed, there is no substitute for a good sky hook, as any amateur radio operator can attest to.

Jdwdmi, if you do decide to go with an outside antenna, do not neglect proper grounding per the NEC.

If you decide to try a dipole antenna in the attic, use a simple non-folded dipole antenna, its feed point impedance will be close to 75 Ohms and you can feed it with low loss coaxial cable. Install some ferrite RF chokes right at the antenna to deal with common mode RF issues and you will be good to go.

And you will not have the loss that is incurred with the use of a 300 Ohm to 75 Ohm balun, which may be on the order of dB or so, however I have measured new balun transformers with upward of 3 dB of loss at FM broadcast band frequencies.

A rabbit ear style antenna is a nice, good working way to go. If it has 300 Ohm feed line, replace it with 75 Ohm coaxial cable. This style of antenna can be hung from the rafters, and as I have mentioned before, the length, orientation of the elements and position of the antenna can be adjusted for the best signal for the stations of interest in terms of signal strength, noise reduction and reduction of multi-path reception if that is an issue.

Of course still use the ferrite RF chokes to deal with the common mode RF issues.

Depending on the particular tuner or receiver and its quieting curve, an extra dB or so of signal may make a difference for a weaker station of interest.
 
The dipole antenna I have up in the attic is an older one for sure. I used the 300 to 75 ohm that looked like this

http://www.amazon.com/RCA-VH54R-Matching-Transformer-VH54R/dp/B00005T3EY

I have my antenna running 4 TV's for OTA reception. I'm not sure how much more splitting I could do before I lose enough DB's my OTA starts cutting out.

I never knew what those Ferrite Chokes were but may even have one laying around here somewhere. LOL! Will these help with my OTA signal as well?

Also would you use Ferrite Chokes on regular rabbit ears?

I think what I will start with is some simple rabbit ears I have from Radio Shack, I think I have 3 models of those that I can bypass the amplifier.

I also have one of these that I will try for the hell of it.

http://www.amazon.com/Omni-Directio...=1440697887&sr=1-1&keywords=terk+flat+antenna

If I'm not getting good results from any of those I will try and hook up the 4100 off the attic dipole. I will just do a temp set up near one of my TV's and see how much better the results are before attempting to fish a wire to where my gear is.

Thanks JBL Guy giving me alot to think about.
 
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"Also would you use Ferrite Chokes on regular rabbit ears?"

Note if they are being fed with 300 Ohm twin lead.

" I'm not sure how much more splitting I could do before I lose enough DB's my OTA starts cutting out."

That is hard to say, because it is all about how much signal is available for your antenna to intercept.

When using the generic RF splitter, there is about a 3 dB loss for every 2 splits, that is about a 50 percent attenuation for every 2 splits. And the thing with ATCS (digital OTA reception), you just fall off of a cliff when you reach that point.

If you can split your TV signal four times, you must be in a relatively strong RF signal area, although TV signal strength does not always correlate with FM broadcast band signal strength.

"Will these help with my OTA signal as well?"

That depends. If you antenna is a 300 Ohm feed point antenna and you want to use 75 Ohm coaxial cable, then you will have to use a balun transformer and there would be no need for the ferrite RF common mode chokes.

"I have my antenna running 4 TV's for OTA reception. I'm not sure how much more splitting I could do before I lose enough DB's my OTA starts cutting out."

BTW, I am not sure that I understand this, are you saying that this antenna is the same antenna that you want to use for your FM reception, the antenna that you refer to as a dipole antenna?

If you are using just a simple dipole antenna for OTA TV reception and have enough signal for 4 TVs, you must be in a high TV signal area, that is not to say that additional splitting of the signal would not drop you off of the digital OTA TV reception cliff.

I am taking what I believe you mean at face value, if the is not correct let me know.
 
Thanks for trying to interpret what I am asking. I ran us off course with my TV questions. :D

I have a large antenna in the attic that looks like this

http://www.bing.com/images/search?q...910&thid=JN.ucpR1IYN11WkzzsH/sbr+Q&ajaxhist=0

I use it instead of rabbit ears on my 4 TV's. I just assumed If I were to run another line to my Mac 4100 I could use it for an FM antenna. I have a Three-way splitter in the attic and a Two-way in the basement. Maybe its not a dipole and maybe it wouldn't work, I'm honestly not sure.

I am only 30 miles from most all TV and FM broadcast towers in my area. But when I ran the last TV off it one channel fades in and out, I think I lost some signal strength. My thought was if I ran one more split off of it for my 4100 I might risk losing some channels on my TV.

I live in the capitol of Iowa, most signals, radio and TV are broadcast within 30 miles of me. You get outside that area and the nearest town radio or TV are broadcasted it is roughly 90 miles. Omaha, NE is about 130 miles from me so unlikely to catch any of those FM channels. Lots of corn in between towns here.

I'm guessing with my proximity to the FM broadcast towers I might be ok with some ol rabbit ears?
 
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Nearly all of the tv/fm transmitters here are in one location on top of a mountain about 25 miles away. I put up a cheap Radio Shack vhf/uhf/fm antenna years ago and aimed it at the antenna array. Works great for hd tv, FM and hdfm. RG6 into the house with the signal split three ways for tv and a couple of FM tuners.

If possible, put up an outside antenna. You'll wonder why you didn't do it before.

Murray
 
Sounds like a good set up Murray. I wonder sometimes why I live by cornfields and not mountains :scratch2:

I have a feeling the wife is not going to allow any towers in the backyard just for radio. I'm sure it would yield the best results though. It would be great to just set it and forget it.

Going to just hook up the 4100 off the RG6 in the bedroom that runs to the attic antenna to see what difference it makes in signal strength. If its improved I will try and run one to my gear in the sunroom.
 
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You say your TV antenna "looks" like the antenna in the picture, but it is hard to tell if the rear portion of the antenna is just for VHF high band or if it covers VHF low band channels. It your antenna is a combination UHF and VHF high band antenna, it may not be the best at receiving FM broadcast signals, and even if it includes VHF low band channels it will not work as well as a purpose designed FM broadcast antenna.

Or possibly even as well as a set of rabbit ears, depending on the particular TV antenna.

Again it is location, location, location and the available RF signal strength. You have nothing to loose by trying your TV antenna for FM reception and about the only place an RF pre-amplifier may improve a signal (since your are having issues with one of your TV signal splits) is when one us used in a relatively strong RF signal environment to overcome the losses incurred with multiple splits of the signal.

You probably would not need a lot of gain, not more than 10 dB and if the RF pre-amplifier had a low noise figure, it should help and if the FM broadcast band signal supplied by the TV antenna is relatively strong, the pre-amplifier may improve the FM reception if you try to use the TV antenna for FM reception.

Skippy_ps's situation is a good example of location, location, location and to reiterate what I have said before, there is no substitute for a good sky hook if you are able and willing to invest in one.
 
I'm not sure what the exact type of antenna it is. I had no idea there were so many variables, it was left by the previous owner and had the thin twin leads when I first saw it. I bought the 300 to 75 transformer I ran it to one TV and bingo, it worked perfect.

I have a set of Radio Shack rabbit ears that says VHF UHF and FM on it. Hoping it will do the trick.

http://support.radioshack.com/support_video/doc62/62052.pdf
 
I tend to be pedantic and I suffer from super OCD, so I tend to include a lot of details in my posts, I am not trying to make it more difficult for you to decide what to do or more complicated.

And others are reading this thread and some may have a situation where saving a dB or 2 or keeping noise out of the signal by dealing with common mode noise ingress issues, may make the difference between a signal that is listenable (maybe not full quieting, no hiss or noise) but is listenable versus not being listenable (to much hiss and noise).

Good luck with your rabbit ear antenna, they work quite will in many situations. I took a quick look at FM Fool for generic Des Moines and it showed a lot of receivable station, but they are located all around the compass and rabbit ear antennas can exhibit some rather sharp nulls in signal reception, so one location, adjustment or orientation may not work equally well for all stations.

Just out of curiosity, what has prompted your desire to improve your antenna situation.

Are the stations, in town or out of town, just weak in signal strength or are they stronger but still with more noise than you would like? Is there distortion that might be the result of multi-path (signal reflection) issues?

Inquiring OCD minds would like to know.:D:D:D To be clear I mean no disrespect with my little poke of fun about my OCD. I am mostly just like Monk on the old TV series.:yes::yes:
 
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For a time I had used the non-amplified version of the Radio Shack FM/VHF/UHF antenna you have shown and it worked fairly well given my challenging reception area.

Its main shortcoming was that it needed to be re-oriented for different stations which was not always convenient with the 3' masts fully extended making placement difficult at times, moving it here and there to keep from bumping into the damn thing knocking to the floor. Of course this was an unpowered unit; if it needed AC power, inconvenience would have been multiplied!

Finally had enough and had an outdoor Magnum Dynalab ST-2 mounted outdoors, at the roof peak and it provides FM signal to both my systems. Signal reception is far better than it ever had been with indoor antennas while killing two birds with one stone. Best damn thing I ever did.
 
This is a great thread witnessed from my perspective. I've been using rabbit ears inside 1st level garage for my Mac1900. I bought an antenna today that is Yagi style that I will put up in the attic space above the garage. My preference is to increase signal strength for stations on left end of the dial in the greater DC area 88.5, 89.3, 90.9 I am about 20-25 miles out from the broadcast antenna with some terrain in between. My antenna will be at approx. 350 ft above sea level. I may also split the signal for to TVs currently managed by fios stbs.
 
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