440 antenna trimming ?

[Se7en]

Would like to use this, but can it be trimmed to cover 420-450?

http://www.theantennafarm.com/catal...ct_info&cPath=191_192_196_214&products_id=813

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[Se7en]

Hope someone has an answer I am sick n tired of the diamond cr320a...time to put it in the pile and use a "real" antenna...

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[KC9Q]

Being designed for 450 to 470 MHz, it will be too short to use on 420 to 450 MHz. Maybe you can find a longer whip (20" or so) to replace the current one, or find an antenna model that covers below 450 MHz?

Looked at AES. They have a NMO440C that covers 440 to 450. http://search.cartserver.com/search...&maxhits=1200&keywords=larstuff&go.x=8&go.y=8

I would think that the maximum bandwidth for a UHF mobile is 10 MHz for TX. It will be OK for receiving the 420 to 450 MHz range.

 

[Se7en]

Being designed for 450 to 470 MHz, it will be too short to use on 420 to 450 MHz. Maybe you can find a longer whip (20" or so) to replace the current one, or find an antenna model that covers below 450 MHz?

Hi thank you for the reply. Can u look on there and see...if I have this right longer the whip the higher the MHz....? Or shorter....this sucks trying to find a 5/8 440 black antenna for my mobile. Shoulda bought American antenna before spending soo much money on this diamond junk

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[W5LZ]

The longer the whip the lower the frequency (Mhz). It wouldn't take much at all to drop that lower frequency limit to 420 Mhz, probably an inch or less (in addition to the whip that comes with the antenna).
- 'Doc

 

[Se7en]

The longer the whip the lower the frequency (Mhz). It wouldn't take much at all to drop that lower frequency limit to 420 Mhz, probably an inch or less (in addition to the whip that comes with the antenna).
- 'Doc

Soo....I'll have to get a longer whip ? If I bought that antenna ?

 

[Captain Kilowatt]

Hi thank you for the reply. Can u look on there and see...if I have this right longer the whip the higher the MHz....? Or shorter....this sucks trying to find a 5/8 440 black antenna for my mobile. Shoulda bought American antenna before spending soo much money on this diamond junk

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Absolutely nothing wrong with Diamond antennas at all as thousands will attest. you just ended up either with a faulty unit which happens to all companies or you messed something up. What is the big hang-up on wanting a 5/8 wave on 440 MHz anyway? Everyone knows (well apparently not quite everyone) that on 440 MHz it is easy to achieve more gain from the antenna by using phased sections. Almost nobody bothers to make a simple 5/8 wave on 440 MHz when it is a simple matter to stack a couple of 5/8 wave sections for some extra gain which is what 99% of the people want.

 

[Se7en]

Absolutely nothing wrong with Diamond antennas at all as thousands will attest. you just ended up either with a faulty unit which happens to all companies or you messed something up. What is the big hang-up on wanting a 5/8 wave on 440 MHz anyway? Everyone knows (well apparently not quite everyone) that on 440 MHz it is easy to achieve more gain from the antenna by using phased sections. Almost nobody bothers to make a simple 5/8 wave on 440 MHz when it is a simple matter to stack a couple of 5/8 wave sections for some extra gain which is what 99% of the people want.

I would rather run LARSEN monobanders than the all in one antenna. Even kb0g said the cr320a isn't the best choice.... since all our local agency's run larsen, antenex, maxrad, laird. Without any problems maybe I should make the switch. I have a triplexer that I should use...just wanted a 440 ant that had some gain and no coils on the whip. I'll find what I want for the mobile.

 

[Captain Kilowatt]

No doubt about the quality of the Larsen brand. I was just wondering what the hang up was with you looking for a 5/8 wave 440 MHz antenna. Any multiband antenna is a compromise in some fashion however having several antennas on the same vehicle can and usually does lead to some sort of interaction that degrades performance as well. Personally if I wanted 2m/220MHz/440MHz I would use a dual band antenna for 2m/440 and a monobander for 220MHz if I could find one. Up here however 220 MHz is not an issue as it is never used and is basically a waste land.

 

[Se7en]

No doubt about the quality of the Larsen brand. I was just wondering what the hang up was with you looking for a 5/8 wave 440 MHz antenna. Any multiband antenna is a compromise in some fashion however having several antennas on the same vehicle can and usually does lead to some sort of interaction that degrades performance as well. Personally if I wanted 2m/220MHz/440MHz I would use a dual band antenna for 2m/440 and a monobander for 220MHz if I could find one. Up here however 220 MHz is not an issue as it is never used and is basically a waste land.

Do they make a duplexer for that type of setup ? All I have is the triplexer and duplexer (2m/70cm).
Id be more than happy to use the ANLI dualband and a 220 ant.