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Re: Radio for Radio
To: CRTech <crtech@crtech.org>
Subject: Re: Radio for Radio
From: Geoff Fairbairn <geoff_fairbairn@hotmail.com>
Date: Tue, 11 Sep 2018 16:18:07 +0000
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Thread-topic: Radio for Radio

... and I meant to say: 8 ohms is the load that you can put on the output, not the output impedance of the car radio - that'll be more like zero ohms. I would not expect any problems driving 600 ohms from a car radio output through a 1:1 transformer, or into a hi Z input provided you don't turn the wick up too high - you're transferring volts not watts. 


Geoff




From: Geoff Fairbairn <geoff_fairbairn@hotmail.com>
Sent: 11 September 2018 17:02
To: CRTech
Subject: [CRTech] Re: Radio for Radio
 

These are stereo transformers that are intended for car radios. There are many similar on Amazon and other sites, all very unpricey. To connect one side for balanced, chop off the female phonos and solder the wires onto pins 2 and 3 only. Chop off right up at the females as the tails are very short and don't leave much for soldering a second time after you forgot to put the boots on the first time - so I've heard. Alternatively there are versions with the transformers in a box with phono sockets instead of flyleads. The impedance mismatch will only affect the level and with a car radio you'll be setting that with the volume knob anyway.


https://www.amazon.com/InstallGear-Ground-Isolator-Noise-Filter/dp/B077Y5DLBB/ref=sr_1_2_sspa?ie=UTF8&qid=1536680534&sr=8-2-spons&keywords=ground+loop+isolator&psc=1


Geoff


www.amazon.com
Fulfillment by Amazon (FBA) is a service we offer sellers that lets them store their products in Amazon's fulfillment centers, and we directly pack, ship, and provide customer service for these products.





From: Mark Carol Bohnett <mbohnett43@bevcomm.net>
Sent: 10 September 2018 20:29
To: CRTech
Subject: [CRTech] Radio for Radio
 
Dear Sirs

We have a Full Power site in Minnesota that is fed primarily with a IP based signal.  The emergency back up has been an off-air broadcast receiver but the antenna is only 15ft off the ground, directly in behind a large self supporting tower (lots of grounded steel).  Depending on the day, the signal is fair but never clean.  In fact I have to point my antenna between the steal struts to get any signal. 

If I move the antenna and pole to the other side of the tower, the signal and sound quality is perfect.  The problem is the site is owned by American Tower who charges you for the very air you breath while on site!  We are attempting not to add more monthly costs to a moderately supported signal; therefore, we are searching for an alternative.

I was commissioned to use a "car radio" for a test (and to my surprise) and the audio quality was actually better that the professional receiver. 

Now I have to build a site with a car radio and interface it into the broadcast world.  I have used in the past the Bogen impedance matching transformers.  The spec is 10K input to 600 balanced out.  The speaker output of the radio is 8 ohmn therefore, I am looking for a 8 ohmn to 600 ohmn transformer.  I found the "Classic 119DA" transformer but they are pretty pricey.  Has anyone found (in this same or like situation) some "miracle" cure for matching a car radio into a line level device (preferably without a amplifier in between)?

If not, I'll probably go with the Bogens and hope for the best, but I wanted to see if any one had found a better alternative before I build the site.

Any thoughts would be appreciated.

E. Mark (MN)
References: Radio for Radio
(Mark Carol Bohnett <mbohnett43@bevcomm.net>, 10 Sep 2018 19:29:59 -0000)
Re: Radio for Radio
(Geoff Fairbairn <geoff_fairbairn@hotmail.com>, 11 Sep 2018 16:02:45 -0000)
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