Hello everyone,
I'm planning to install a diplexer ahead of my 70cm mast-mount preamp soon, and was interested to know any tips or tricks before I buy a diplexer and climb the tower.
I was planning to go the cheap route, and buy the $35 MFJ-916b sold by my local ham store, but read in the manual:
"The MFJ-916B is designed for indoor use. If you use the MFJ-916B outdoors, it should only be used for short periods of time under good weather conditions. Do not use the duplexer outdoors when there is any kind of precipitation."
After reading that, I'm considering spending a little extra and buying the Comet 416c that others have had good luck with.
I had planned to mount the unit inside of a section of PVC pipe with a pipe cap glued on the top, and open at the bottom. A single U-bolt should attach the unit to the tower.
Please reply with any suggestions, or perhaps you know of an unpublished sale going on somewhere? Thanks!
Happy New Year to everyone on the list, and I hope we'll see P3e launched in 2008!
73,
Kyle Yoksh K0KN Olathe, Kansas
Kyle,
I would recommend putting the preamp as close to the antenna as possible. The diplexer should go between the radio and pre amp. If you are planning to feed dc to the preamp on the coax, you need to make sure the diplexer will pass the dc to the preamp.
73 de Ken W5KQ ----- Original Message ----- From: "K & R Yoksh" yokshs@sbcglobal.net To: "Amsat BB" amsat-bb@amsat.org Sent: Thursday, December 27, 2007 9:51 PM Subject: [amsat-bb] mode J filter / Comet CF416c
Hello everyone,
I'm planning to install a diplexer ahead of my 70cm mast-mount preamp soon, and was interested to know any tips or tricks before I buy a diplexer and climb the tower.
I was planning to go the cheap route, and buy the $35 MFJ-916b sold by my local ham store, but read in the manual:
"The MFJ-916B is designed for indoor use. If you use the MFJ-916B outdoors, it should only be used for short periods of time under good weather conditions. Do not use the duplexer outdoors when there is any kind of precipitation."
After reading that, I'm considering spending a little extra and buying the Comet 416c that others have had good luck with.
I had planned to mount the unit inside of a section of PVC pipe with a pipe cap glued on the top, and open at the bottom. A single U-bolt should attach the unit to the tower.
Please reply with any suggestions, or perhaps you know of an unpublished sale going on somewhere? Thanks!
Happy New Year to everyone on the list, and I hope we'll see P3e launched in 2008!
73,
Kyle Yoksh K0KN Olathe, Kansas
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
At 10:51 PM 12/27/2007, K & R Yoksh wrote:
Hello everyone,
I'm planning to install a diplexer ahead of my 70cm mast-mount preamp soon, and was interested to know any tips or tricks before I buy a diplexer and climb the tower. ...
I had planned to mount the unit inside of a section of PVC pipe with a pipe cap glued on the top, and open at the bottom. A single U-bolt should attach the unit to the tower.
Hi Kyle,
I have had a CF-416c installed outdoors at around 40' for several years with no problems. This unit is not waterproof though so before installing it, I took the bottom cover off and ran a bead of Marine GOOP around the bottom flange. Then I screwed the cover back on it. I mounted the CF-416 on top of my preamp (SP-7000) using black wire ties with the bottom cover of the CF-416 facing down. The body of the CF-416 is a cast aluminum box so this keeps water out except for the bottom plate. Mounted on the preamp, the water just runs off. I did not do any thing special to the cables or connectors.
I have also used an unmodified (i.e. un-GOOP'd) CF-416c for several years for portable operation (with occasional rain) and for extended outdoor antenna testing (with lots of rain) with the unit just hanging by its coax cables and no protection at all and it seems to have survived those ordeals with no ill effects. I just now unscrewed the bottom cover to look at the insides and it seems fine. The biggest potential issue is the aluminum tape over the tuning holes in the bottom cover. This hasen't caused any problems for me but if you happen to puncture the tape, you would have a hole in the bottom cover where water could get in.
Best of luck with your projects, Tony AA2TX
participants (3)
-
Anthony Monteiro -
K & R Yoksh -
Ken Shutt