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12-19-2009 Post does not mapped to Knowledge Tree
RonyWeissman
Lyon, France
Posts 138
Joined on 05-29-2004

Post #: 1
Post ID: 12509
Reply to: 12509
Antenna Cable Connection
fiogf49gjkf0d
Strange but I have found that my reception is significantly better if I don't use any connector between my antenna cable(radio shack RG whatever going up to rooftoop antenna) and my tuner but instead just strip off a bit of wire at the end of the cable and stick it directly into the antenna input on the tuner.  Actually how far I stick it in depends upon the station I am listening too, kind of kinky. What is wrong? Faulty cable?Happy but curious,R Weissman
12-19-2009 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,283
Joined on 05-28-2004

Post #: 2
Post ID: 12510
Reply to: 12509
The front-end entrance optimization.
fiogf49gjkf0d
 RonyWeissman wrote:
Strange but I have found that my reception is significantly better if I don't use any connector between my antenna cable(radio shack RG whatever going up to rooftoop antenna) and my tuner but instead just strip off a bit of wire at the end of the cable and stick it directly into the antenna input on the tuner. Actually how far I stick it in depends upon the station I am listening too, kind of kinky. What is wrong? Faulty cable?Happy but curious,R Weissman
It is not wrong. This is normal – you most likely have not optimally-tuned front end, at least it what I think. The entrance of antenna cable to front-end is very tricky thing and very fastidious thing. As you might see some tuners have choke and antenna cable come a specific tap of the choke. The choke moderates how the antenna transmission line is terminated, the loading capacitance and inductance. I think that what you do - sticking the antenna wires more or less deep -  is in fact changing the capacitance of the antenna and front-end coupling.

I feel it would be a good idea to let your technical to observe your tuner's front-end and optimize it for whatever they optimize it for. I would not feel comfortable with cable sliding here and there, it might be kind but you hardly can calibrate and moderate the improvement you get. I presume that RF technical shall be able to make sure that your front-end is optimized for your antenna.


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-20-2009 Post does not mapped to Knowledge Tree
RonyWeissman
Lyon, France
Posts 138
Joined on 05-29-2004

Post #: 3
Post ID: 12512
Reply to: 12510
French technician !?
fiogf49gjkf0d
 If anyone knows of a competent technicien please? I know lot's of small DIY shops but they would charge me several hundred euros to explain to me that they don't understand what I am saying.R Weissman
12-20-2009 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,283
Joined on 05-28-2004

Post #: 4
Post ID: 12513
Reply to: 12512
French technician. Oxymoron? :-)
fiogf49gjkf0d

 RonyWeissman wrote:
I know lot's of small DIY shops but they would charge me several hundred euros to explain to me that they don't understand what I am saying.

Yes, this is a good one. I am in the same boat with most of the shops – they love to flash bogus credentials but in reality they are extremely ignorant. Still, what you need to do is relatively simple procedure for RF technicians. What you need is not DIY audio shops – they are Morons but a regular RF shot. Look for a community of short wave and ham radio enthusiasts. Their technicians are actually RF-trained and they shall be able to help you. Well, any shop that does tuner alignment will have skills to tune for you’re the antenna interface.  BTW, be advised the in very many cases, in fact in most of the tuners, the front-end to antenna are not optimized or very poorly optimized. In all my tuners I left only Schwarz’s antenna interfaces untouched. With any other tuner I was able to get more gain and less noise by changing the way how antenna does into front end. For instance the technician who worked with my TU-1X (Ken Bernacky from Stereo Surgeons) trashed out whatever Sansui did it and run the antenna cable directly into front end. In the second TU-1X he did the same but he put a very small cap on the antenna’s jack. Whatever he did the TU-1X had insulting sensitively as a result. I do not know what he measured and what reasoning he used but I think that any knowledgeable RF person shall be able to do the same.

What you need to do, if your tuner is aligned, is to tune your tuner to a given station, attenuate the signal until it shows let say exact 75% of signal and note the multipath volume and the attenuation number. The key is that you have to do it after you slide your antenna bas back and force and found the absolutely best sound. Then give your tuner to a technician to tune up the antenna interface. Upon getting the tuner back with your new BNC-75 connector you need to make sure that you do not lost any sensitivity and the same station will hit the same 75% of antenna signal with the same amount (or more) of attenuation. I am a bit suspicions” if you tuner is aligned then your alignment guy had to deal with it. If he did not then to re-tune juts the antenna interfaces shall not cost several hundred euros. In fact I would not pay more than 100 euros, including the shipment… to Germany … :-)

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
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