We're comparing apples and oranges here. You've talked about 1 5/8", 3 1/8" & 4 1/8" Heliax usually employs EIA Flange connectors although 1 5/8" is widely used with "D" connector terminations in relatively low power modes.
We don't usually do that here in amateur communications. I've worked as a broadcast engineer. I've done multiple transmitter configurations / installations from AM (including directional arrays) to FM and to TV. The commercial companies have literally unlimited monetary resources when putting up a system. You do it once, you do it right, and you don't spare the money. The smart broadcast companies don't fool around. They know better. You short change on anything, and you pay the price down the road. I've seen that happen, and I've had to clean up the previous engineer's mess. Not a pretty sight. You can't compare that to an amateur setting with limited money. Connecting Heliax to an antenna directly in amateur use is just plan senseless. A jumper works pretty much every time, especially if it's done correctly. Look at the previous posts on this forum. I think you'll find that most of the people responding will suggest that a jumper is used. Don, KD9PT ----- Original Message ----- From: Don Kerouac To: [email protected] Sent: Sunday, September 13, 2009 8:01 PM Subject: [Repeater-Builder] Re: coax cable In the past 35+ years that I have worked in broadcasting, we have connected Heliax directly to antennas wherever possible. This includes 3/8", ½", 7/8", 1 ¼", 1 5/8' (3/8" Heliax is generally used as sampling lines for AM directional arrays). Foam or pressurized air line versions. 1 5/8", 3 1/8" & 4 1/8" Heliax usually employs EIA Flange connectors although 1 5/8" is widely used with "D" connector terminations in relatively low power modes. I have never encountered or heard of Heliax cracking. When properly installed and supported with attention to minimum bend radius a direct connection should last a loong time.something we are picky about in the broadcast industry. The only Heliax failures I have experienced were with clients that had bullet holes.usually air line for high powered FM stations. Reasons to go with Heliax every time (regardless of length): 100% shielding.no equivocating here Almost unlimited life expectancy Stability.undamaged 30 year old Heliax will test as good as new Economy.in the long run it will be cheaper Lowest possible loss.TX & RX My two cents. I don't own any Andrew stock! Don Kerouac K9NR Midwest Broadcast Services, Inc. E-mail message checked by Spyware Doctor (6.1.0.447) Database version: 6.13250 http://www.pctools.com/spyware-doctor-antivirus/
