When FM transmitter is plugged in amps go crazy and play music even when turned down & buzz

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McDonalds
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Re: When FM transmitter is plugged in amps go crazy and play music even when turned down & buzz

Post by McDonalds » Tue Feb 14, 2017 2:18 pm

can give that a try it will not hurt to put some underneath see if anything happens as long as its far enough from the element which in my case the aerial is on a box.
at least if the swr is bad the thingy will switch off so cannot damage it.

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Re: When FM transmitter is plugged in amps go crazy and play music even when turned down & buzz

Post by Maximus » Tue Feb 14, 2017 8:32 pm

If you're using any form of distribution amplifiers, they normally get swamped with the massive amount of signal, due to the wideband amplification that is inherent. Perhaps run a direct reed to the freeview receiver/s.


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Re: When FM transmitter is plugged in amps go crazy and play music even when turned down & buzz

Post by Maximus » Tue Feb 14, 2017 8:37 pm

I used to make the CFL lights glow in the house from only 30W. Put the aerial outside, but above the roof and any tv aerials and you should be ok. Plus the signal will travel much further.

I used to run 100w from the loft back in the old days and I found out that 15w travelled much further just by putting the same aerial 6ft above the ridge!


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Re: When FM transmitter is plugged in amps go crazy and play music even when turned down & buzz

Post by NTR » Tue Feb 14, 2017 9:31 pm

If the Antenna is outside - surely you're drawing more attention to yourself? Even if its only a hobby station? I've messed with some discrete antenna designs in the past to try and disguise the fact it's an antenna, but I've never managed to make anything that fully blends in. Currently, I have a J-pole ladder line home made antenna in the roof and it seems to work well on low power - Even though it looks nothing like an antenna, I would still be too scared to shove it on the roof.

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Re: When FM transmitter is plugged in amps go crazy and play music even when turned down & buzz

Post by Maximus » Tue Feb 14, 2017 11:15 pm

Things work in the loft but the roof tiles have a tendency to reflect a lot of the signal back downwards. Also the mains wires like to absorb the rf and send it round the house.


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Re: When FM transmitter is plugged in amps go crazy and play music even when turned down & buzz

Post by Banus_radio » Thu Feb 16, 2017 12:26 am

The last time i run a transmitter from a loft was about 10 years ago from a flat on a hill. We switched on running around 150watts and my chest felt tight along with the rest of the dj's. We had a very bad swr. Our techniks wouldnt hold speed and mixer buzzed like mad. I had to fit chokes in the mixer even when the antenna was on the roof. Im come a long way since then thank god

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Re: When FM transmitter is plugged in amps go crazy and play music even when turned down & buzz

Post by halfwave » Thu Feb 16, 2017 1:34 pm

I have the first GP Antenna that you asked about, http://www.ebay.co.uk/itm/321860242503? ... EBIDX%3AIT
currently installed in my loft. I'm only pushing 7 Watts, and don't seem to be having any RF problems.

There are a selection of top elements supplied to choose from, which cover certain
frequency ranges, so you just choose the one that covers your broadcast frequency
when assembling the aerial.

The element is made up from the main base element (A), and you then screw on
the top part (either: B1, B2, B3, B4 or B5), whichever is right for your frequency.

frequency Ranges:

85.5-90.5.5MHz(A+B1)
90.5-95.5Mhz (A+B2)
95.5-100.5Mhz(A+B3)
100.5-105.5Mhz(A+B4)
105.5-110.5(A+B5

The nice thing about the GP antenna is that it takes up less vertical space than
a Dipole. As the bottom reflectors are installed at an angle, which reduces
the overall height of the antenna.

Also make sure you let them know, if you order one, which connection type
you require for the coax connection to your transmitter, i.e BCN, TNC, NJ.

FYI.
When I bought one from China, I did not have to pay TAX, but I guess I may have been lucky?

Hope this helps a bit.

McDonalds wrote: Tue Jan 24, 2017 2:31 pm I have seen this one
http://www.ebay.co.uk/itm/321860242503? ... EBIDX%3AIT

if I got would it be taxed though as got a phone and had to pay £32 back for it because it came from china.

or this one is in the UK

http://www.ebay.co.uk/itm/131829420694? ... EBIDX%3AIT

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Re: When FM transmitter is plugged in amps go crazy and play music even when turned down & buzz

Post by McDonalds » Thu Feb 16, 2017 4:11 pm

nice to know its easy to use.
and does up to 100 watts so will be more than enough for my use.

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Re: When FM transmitter is plugged in amps go crazy and play music even when turned down & buzz

Post by NTR » Thu Feb 16, 2017 8:13 pm

This is what I use - I made it myself and was very easy to make, I just calculated and changed the lengths to the broadcast band. It works very well and cost nothing to make really, plus it does not look like a traditional antenna. I only test with a few watts, but there is never a issue with RF. I live in a small village and this antenna covers the whole place and to the next village - so pretty efficient, it would obviously go further if it was on the roof, but I don't fancy drawing too much attention. I've used the same design on a TX site on high ground at 25watts and it covered pretty much the whole city I was broadcasting to.

http://www.essexham.co.uk/slim-jim

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