---------------------------------------------------------- Avionics-List Digest Archive --- Total Messages Posted Sat 04/26/14: 1 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:01 AM - Re: Garmin SL-30 poor VOR reception (D L Josephson) ________________________________ Message 1 _____________________________________ Time: 06:01:57 AM PST US From: D L Josephson Subject: Re: Avionics-List: Garmin SL-30 poor VOR reception Matt wrote: > > Are you using "RG-58A" or "RG-58C/U"? "RG-58A" is really lossy. ""RG-58C/U" is > better, but still not that great. I would strongly recommend RG-142 or RV-400 > for that application. I have RG-142 installed in my RV-8 connected to an SL-30 > and to a CI-158C antenna mounted in the top of my vertical stab and I get > outstanding I wonder what the source of that information is. Commercial RG-58A, mil spec RG-58 (MIL-DTL-17 M17/28-RG058) such as Belden 9203, RG-142 and RG400/LMR400 are all rated between 3.3 and 4.9 dB per 100 ft at 100 MHz -- around 1 dB for a practical airplane installation. > > Pull the RG-58 out, get some RG-142 and some high-quality BNC connectors (the crimp-on > kind NOT the screw-on kind) and then see how things work. You may still > have a problem with the NAV receiver on the SL-30, but upgrading your cable > will go a long way in improving your reception in any case. Original RG-58 cable was just fine for decades with receivers far worse than the Garmin. In my experience, connectors are the problem nine times out of ten. Commercial grade crimp connectors from a manufacturer that also supplies military grade connectors (Amp, Amphenol, Kings) crimped with the manufacturer-specified tool checked for the correct crimp dimensions by someone experienced with this process is the key. Original military soldered connectors are also OK but only if the installer is experienced enough to get the dimensions right without melting the dielectric. Quick test, after you've confirmed that the cable has continuity end to end and isn't shorted: grab the cable in one hand and the body of the connector in the other. Using moderate force, can you rotate the connector body with respect to the cable? If so, cut it off and try again, it is not terminated correctly. This isn't the cause of all problems but is usually diagnostic of whether it was crimped right in the first place. ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message avionics-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Avionics-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/avionics-list Browse Digests http://www.matronics.com/digest/avionics-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.