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Posted: Sun Nov 11, 2001 3:15 pm
by GJ
Hi, i have an MT2100 VHF, i wonder what type of antenna to use.
What type antenna has the most gain, the one that has a colorcode for each band (162-174MHz =blue) or the larger widebandantenna (138-174MHz =red)?
I have frequency's programmed from 145-172MHz.
Thanks!!
GJ.
Posted: Sun Nov 11, 2001 7:33 pm
by Tom in D.C.
GJ: Helical antennas on HT's, especially on VHF, do not have any gain. The only way you can increase the bandwidth of an antenna is to make it a "gain" antenna, which would be about three feet long, but even then you'll have a hard time getting more than 6 mHz bandwidth with the SWR remaining under 2:1. For receiving it doesn't matter that much, but for transmitting you could conceivably eventually damage the final amplifier if the SWR is too high for too long. HT antennas are best used for narrower bandwidth coverage, and 148-174 mHz is a real stretch.
Tom, W2NJS
...in D.C.
Posted: Sun Nov 11, 2001 7:48 pm
by N4UMJ
I have a related Saber VHF antenna question as well that someone here could maybe answer. I have two Motorola VHF Rubber Duck Antennas. One is 5-7/8" long and the other is 6-5/8" long. Both have black dots on the bottom of the threaded portion.
Anyone have the exact dimensions for the different bands. I am assuming the longer of the two would be for the VHF low split of the band that I want to work(2 Meters Ham.)
For what its worth I have a brochure form Motorola that lists three different Heliflex antennas for the High Band. They are:
8505816K22 136-150.8 MHz
8505816K21 146-162.0 MHz
and
8505816K23 157-174.0 MHz
no dimensions though....
Thanks for any info,
Eddie N4UMJ
Matthews NC
Posted: Tue Nov 13, 2001 2:16 pm
by Will
For the MT2000/Jedi radios with the small center pin in the radio's antenna "jack", use the NAD 6563A 8505518V01 red color code inside the connector covers 136 to 174, 8.1" long and "it works".
For other radios with the 1/4x32 thread,
I use the Antenex broadband, part # DEXW136MX
for 136 to 162 and DEXW148MX for 148 to 174 range with very good results.
http://www.antenex.com
Posted: Tue Nov 13, 2001 7:54 pm
by /\/\y 2 cents
Get the "VHF Wideband antenna" for the JEDI or ASTRO Series. They look like an 800 Dipole you would see on an STX (6" thick then goes to Thin, commonly called a side stabber) Your Local Motorola shop will probably not know what you are talking about, so if you need help I can get you in touch with someone who has them in stock. They work great, I tested it on simplex and it let me talk about 3/4 of a mile further, so when pulkling in weak signals or getting into a repeater really count, it helps a little bit.
Posted: Tue Nov 13, 2001 8:38 pm
by Astro_Saber
i wish motorola would get off there ases and make the threading so it can fit a regular saber also
Posted: Thu Nov 15, 2001 1:25 pm
by Will
Astro,
Refer to my prior post, as the Saber uses that thread on it's antennas too!!!!!!
Posted: Fri Nov 16, 2001 3:35 pm
by /\/\y 2 cents
The regular saber does not have the "waveguide" SMA type connector, it has the regular one as on an MT1000 or HT600. The ASTRO saber has this type of connector. I am almost positive on this. Maybe there is a Saber SP that has this type of connector, but I have never seen one.
Posted: Sun Nov 18, 2001 8:47 pm
by RFdude
I use a VHF XTS3000 both as a portable and sometimes in the vehicle with an outside quarter wave antenna. I'd like to leave the SMA to BNC adapter in place and use a BNC based rubber duck antenna. Wideband like the Motorola version would be nice. Any suggestions?
Posted: Sun Nov 18, 2001 9:02 pm
by /\/\y 2 cents
You could use a HT90/HT440 antenna w. BNC jack on it. Those are pretty good antennas...pretty much the same thing as a MT1000/ht600/p200 molded neoprene antenna w/sort of a little bulge on bottom where the antenna is wound and molded to the BNC. Look through the Motorola Portable radio parts bible to see if they made an HT90/440 High gain VHF antenna, that would be your best bet if they ever made it. But if they don't id say the slickest alternative is the HT90/440 regular VHF rubber duck