FM radio antenna

[trash]

Now I'm thinking what a 75 ohm resistor across the antenna port will do. That should confirm or eliminate an internal problem.

[bristow]

Actually the second picture above is the original antenna that came with the receiver. The first picture shows the connection of the cheap antenna I bought, which is a rabbit ears style TV and FM antenna. Both work but hum. The hum doesnt happen when I play DVDs so it does seem to be a just the radio.

I went and enquired at HN in Nowra about the cost of a new amplifier/FM receiver; they dont make them anymore it seems. All I want is something that will pick up FM and I can plug my speakers and DVD player into to get a good sound. It seems that modern technology has passed me by...

[Gitch]

Could it be some sort of earth loop? Disconnect the other sources - i.e. DVD, and whatever else is connected. Leave only the speakers and power. Next, make sure the Amp is not touching anything else, including yourself and whatever else it is sitting on (put a newspaper underneath to help separated them). Is the noise still there??

[Antennaman]

When FM is selected as tuner mode, and all antennas are disconnected, is the hum still present, & does it vary with the volume control?

Or is the hum only present when a FM station is being received?

[Uncle Fester]

I went and enquired at HN in Nowra about the cost of a new amplifier/FM receiver; they dont make them anymore it seems. All I want is something that will pick up FM and I can plug my speakers and DVD player into to get a good sound. It seems that modern technology has passed me by...

I understand what you mean.
You might have to look in the second hand market, OP shops, Ebay, etc.
Seeing the amp section is still working how about just getting a tuner and connect it to a free imput
For example here is a very nice one from Kenwood right now:

... but please before you consider getting something else, confirm at least with a portable radio that there is no interference problem at that location, like I mentioned above. It could be something a simple as a dodgy Chinese power adaptor plugged in nearby.

[bristow]

Thanks for the replies folks...

When FM is selected as tuner mode, and all antennas are disconnected, is the hum still present, & does it vary with the volume control?

Or is the hum only present when a FM station is being received?

The hum is only present when the antenna is connected. There is no hum when FM is selected but the antenna is not connected.

Gitch: The hum remains if I disconnect the DVD player etc and isolate the receiver.

Trash: I havent had a chance yet to try the 75 Ohm resistor, but I will.

Nomeat: Thanks for that suggestion; I see there are quite a few receivers on Ebay; do such receivers have built in amplifiers (my current Marantz does) or are they simply tuners?

Finally, my neighbor suggested I just get a docking station/speaker/mobile phone/Ipod system, and dispense with the old system. IS that a good suggestion?

[Uncle Fester]

Nomeat: Thanks for that suggestion; I see there are quite a few receivers on Ebay; do such receivers have built in amplifiers (my current Marantz does) or are they simply tuners?

Finally, my neighbor suggested I just get a docking station/speaker/mobile phone/Ipod system, and dispense with the old system. IS that a good suggestion?

The one I posted above for $45 +post was just a tuner(no amp) that you can plug into your Marantz used as an amplifier. That tuner is old but very good quality.

Here is an example for complete receiver(with amp) for $99+p which looks like a good value if you might want surround sound one day. It has digital inputs, which I see as a big advantage over your old Marantz.
I don't know how sensitive the actual radio section is on these newer models are but Pioneer (in the eighties) had very good FM sensitivity back then.


Radio over internet:
Today people use their smartphone for everything which could be the reason why you are having troubles finding proper audio/radio equipment at HN.
That depends on your personal likes.

I use both, hifi and wifi
...and would never want to restrict myself to only one.

Internet radio means 100,000 radio stations from all over the world. That is very exiting for me, when I have the time to focus and fiddle around with it.

Just for listening to music in the background or while I am working in the garage, I prefer to just press one button on an old radio and have the local radio station babbling on.
However I also have an old iPod(Ebay for $20) taped to an old 1960's portable radio(used as speaker amplifier) from a garage sale for 5 bucks. That is mostly also for the garage or garden.
The cons about using internet are that your favourite local station might not be broadcasting on the net and 3 hours radio a day will use about 4GB in a month(if that is an issue).

You could find an old Android phone/device(if you don't have one ask a mate) and see how you get on with listening to radio with it. Just connect it's headphone jack with a simple cable (3.5mm to RCA) to your Marantz.
Tunein is the most common app for radio, but IMO they have ruined it with the later versions.
However with Android you can install old versions by downloading the apk file directly like here:

Edit: Those docking stations with inbuilt speakers will sound like shit if you have been used to listening with decent sized speakers through your Marantz.
If you like the net radio idea then find a cradle to support you device with power supply and connectivity to your amp.

[bristow]

... but please before you consider getting something else, confirm at least with a portable radio that there is no interference problem at that location, like I mentioned above. It could be something a simple as a dodgy Chinese power adaptor plugged in nearby.

I tried with a portable FM radio and there was no interference at this particular location, so it seems specific to my radio receiver.

[mtv]

Possibly the hum could be being picked up from a device close to where the antenna wire is.... such as a power supply.

As an experiment, can you try the receiver in another room in the house?... to save moving speakers, use headphones if it has provision for them.

[gordon_s1942]

I had a hum one time but I think it was another Amp when I tried to connect the coax into the rear socket.
The coax was from this same antenna I have now with a 25db Kingray Amp.
I was using a standard PAL type connector so checked I hadnt caused a short but everything seemed ok so in desperation, I simply peeled the outer braid back so it didnt make contact with the plug case, connected the centre wire to the pin, plugged it in and NO HUM !!!

[Uncle Fester]

I had a hum one time but I think it was another Amp when I tried to connect the coax into the rear socket.
The coax was from this same antenna I have now with a 25db Kingray Amp.
I was using a standard PAL type connector so checked I hadnt caused a short but everything seemed ok so in desperation, I simply peeled the outer braid back so it didnt make contact with the plug case, connected the centre wire to the pin, plugged it in and NO HUM !!!

That would be the classic case of double earthing causing an earth loop but we have pretty much ruled that out now. He is already only connecting the centre wire without touching the plug case.

Yes by all means try the amp in a different location, possibly near a window. That won't solve your problem(unless you are willing to change your interior design) but if it still hums you have at least double checked that the receiver is the culprit.

[Antennaman]

If the amplifier only has a 2 wire power cord, earth the case of the amplifier, or the FM antenna connector outer, or the braid of the coaxial cable to see if this offers any help.

[Tom Mix]

FM receivers have rfamp next from antenna,might be Q, if has fault would be source of noise,hum. Think of it, amp powered up, suddenly input,ant ,not there!

[Alaves]

Maybe the antenna isn't in a working condition. Probably the new antenna was already dead when you received it.

Whatever it is, don't you think your radio has already done it's duty for his lifetime? It's been 25 years already. I don't think you should expect anything more from it.

[ol' boy]

Maybe the antenna isn't in a working condition. Probably the new antenna was already dead when you received it.

Whatever it is, don't you think your radio has already done it's duty for his lifetime? It's been 25 years already. I don't think you should expect anything more from it.

What a depressing outlook.

Doesn't say much for buying 1980 Class A Amplifiers for insane amounts of money

[mtv]

Maybe the antenna isn't in a working condition. Probably the new antenna was already dead when you received it.

Did you actually look at what the new antenna is?

It's just a short length of wire..... not much to go wrong there.


As for old gear..... love to keep mine running.

[bob_m_54]

Maybe the antenna isn't in a working condition. Probably the new antenna was already dead when you received it.

Whatever it is, don't you think your radio has already done it's duty for his lifetime? It's been 25 years already. I don't think you should expect anything more from it.

Why would you not want to keep a decent piece of equipment going, in favor of replacing it for a lot of the rubbish that's around these days.

What is your recommendation for this piece of equipment I purchased a few weeks ago, that needs to be refurbished yet?

[ol' boy]

The HiFi equivalent of a Muscle Car.

To add to this thread, i have tried many of the suggestions mentioned in this thread, when this happened to me
(Well worse, it was a clients Receiver.... So i really had to try a lot of things to get it back working as he was used too)

In my case, nothing worked.
Tried Earthing
Tried a new Passive Antenna
Tried Isolating the Receiver from any other equipment

[Onefella]

What is your recommendation for this piece of equipment I purchased a few weeks ago, that needs to be refurbished yet?

What a lovely old unit. Definitely worth refurbishing.

Here is an ad for it in 1962.

[ol' boy]

Speaking of strange Antenna behaviour
Yesterday i was doing my gutters, while i had the hose on the roof, i gave the 3 Terrestrial Andtennas and 4 Dishes a hose down.
Last night and today i have the entire Ch 7 group of channels dropping in and out due to low SNR.

Pays to just leave things alone sometimes