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eHam Forums => Mobile Ham => Topic started by: KE5ATE on March 26, 2004, 05:28:48 AM



Title: Antenna Questions...help please
Post by: KE5ATE on March 26, 2004, 05:28:48 AM
Well I just got my license today and I've got a newbie question, ok, I've got a Wilson 1000 CB antenna mounted in the roof of my truck that is now going bye bye, the mount has a threaded connector like the back of a radio (so239), can I use the existing mount with a SG 7500 antenna, or do I have to replace the mount. If I have to replace it, what type should I go with, nmo or uhf, and what brand would you recommend?

Thanks in advance,
Allen


Title: Antenna Questions...help please
Post by: N1OU on March 26, 2004, 08:56:05 AM
Yes, you should be able to use the mount if it is in good shape.  Many ham mobile antennas are the "UHF" mount, meaning they will mate to an SO239 connector.  Check the coax, though.  It should be RG58 or similar 50-52 ohm and be in good shape, too (no cracks or flattened areas).  Sometimes the coax on CB antennas is surplus stuff of unknown value.  The mount itself should be sound, water-tight, and mechanically solid enough to support the antenna.

If you can, borrow an SWR meter and check the antenna once you have it all set up.  The mount doesn't have that much impact on SWR unless it is mechanically unsound, but this process is always a good idea for any antenna--things can "look" just fine and still not check out.  I'm not familiar with the antenna you mention, but make sure it is resonant for the band you want to use and adjust it (if it has adjustments) using the SWR meter with your transceiver tuned to the middle of the band or range you desire.

73

Gordon, N1OU


Title: Antenna Questions...help please
Post by: N1OU on March 26, 2004, 09:00:45 AM
I just looked in the Product Review section and found a Diamond SG500 dual band UHF/VHF.  You might want to read about it, too.  Reviews are moderate, but there aren't many of them.   For your mount, make sure you get the antenna with the UHF (PL259) base.


Title: Antenna Questions...help please
Post by: K0BG on March 26, 2004, 11:20:36 AM
Personally, I wouldn't use the SO239 mount. I don't know how yours is mounted, but most of them use a 3/8" hole and are not very sturdy. An NMO mount uses a 3/4" hole and is very stout.

Alan, KØBG


Title: Antenna Questions...help please
Post by: K5LXP on March 26, 2004, 12:53:48 PM
If you've got an antenna already that can use the same mount I would go ahead and use it to get on the air right away, but like K0BG said the NMO is really a better mount.  Once you've "settled in" on what you want your mobile station to have for antennas, I would plan a setup that used NMO mounts.  This gives you the best flexibility for exchanging antennas in the future.

Mark K5LXP
Albuquerque, NM