Antenna /coaxial upgrade

ihregistry

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Christmas in April. After many hours of debate and evaluation I decided to upgrade my set up. Thank you to all who have given advice and recommendations. My antenna was a Tram 1410 and super cheap cable. My son kinda reminded me of issues with the antenna when treading the coaxial to the antenna connector that it spun and was loose. This along with the coaxial cable lose made me scrap the set up.

Purchased 75 feet of LMR400 coaxial cable.



I chose this set up after reviewing my scanning frequencies. I have nothing above 469mhz. So I figured if something changes that I monitor 700 800mhz I can add a antenna just for those frequency. Due to rain I wasn't able to install this today so going to shot for Tuesday. I'll post here the results. Be advised I don't own a analyzer so it will be how good the signals are to the ear.
 

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MDScanFan

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You made a good decision on the coax. Does that dual band antenna cover all you need? Your original Tram works quite well for FM through mid to upper UHF.
 

ihregistry

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County Police/Fire/EMS use 150 to 160MHz the EMS use 450 to 460MHZ
The state P25 on 150's
2 aircraft frequency at 118 and 124Mhz

So I figured limit antenna to what I monitor.
 

mmckenna

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The dual band antenna has gain on the frequencies of interest, so it'll easily outperform the discone. As the OP said, if his needs change, he can add an additonal antenna.

Likely you'll find that antenna will work well, and probably perform well on VHF Low band if you want to sniff around down there.
 

ihregistry

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A while back I did set and ran the scanner to continuously scan Ham frequency but got nothing. I also monitor the International space station And best I was able to get was static a couple times.
 

mmckenna

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A while back I did set and ran the scanner to continuously scan Ham frequency but got nothing. I also monitor the International space station And best I was able to get was static a couple times.
A discone wasn't doing you any favors. You still may not hear anything depending on your location, but with a good antenna and better cable, you might see some big improvements.
 

Ubbe

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Purchased 75 feet of LMR400 coaxial cable.
At that lenght you'll need a good coax, RG6 or better like LMR400. Try that new coax with your current discone before taking it down. The LMR400 will have 2dB attenuation at 460Mhz and RG6 3dB and if you earlier had RG58 then that had 8dB loss.

It looks as if you have the proper lenghts for the ground plane elements for VHF. That antennas gain are specified in dB without any reference to anything but could be dBi. That 1.6dB gain for VHF are in the tuned band of 150-154MHz and will be a lot less in VHF air where your discone will probably do much better. I recommend to try your discone first with the new coax to be used as a reference when you compare to your new narrow band antenna.

/Ubbe
 

ihregistry

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At that lenght you'll need a good coax, RG6 or better like LMR400. Try that new coax with your current discone before taking it down. The LMR400 will have 2dB attenuation at 460Mhz and RG6 3dB and if you earlier had RG58 then that had 8dB loss.

It looks as if you have the proper lenghts for the ground plane elements for VHF. That antennas gain are specified in dB without any reference to anything but could be dBi. That 1.6dB gain for VHF are in the tuned band of 150-154MHz and will be a lot less in VHF air where your discone will probably do much better. I recommend to try your discone first with the new coax to be used as a reference when you compare to your new narrow band antenna.

/Ubbe
I didn't order a adapter for to connect the lmr400 n connectors to the discone and I believe the 259 connector on my discone is bad and allowing moisture to get inside the antenna. My son reminded me of the 259 connection turning when connecting cable. So rather then chance taking mast up and down couple times I've decided to replace the entire antenna.
 

Ubbe

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My son reminded me of the 259 connection turning when connecting cable.
The connector are protected inside a tube from the discone so should probably not be an issue with moist and the ground are probably fine and it's just the nut holding it in place that are loose. When taking down the discone you could try the antenna at ground or roof level with the new coax, or just a short lenght of coax if you bring your scanner to the antenna. If you have a PL-to-BNC female adaptor then that will also work to push the N connector to from the new coax and check if the discone are still functional.

Then you'll know if the discone can be reused at another time or place.

/Ubbe
 

ihregistry

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WOW. Completed my replacement/upgrade. My scanner is awakened. I am picking up things I never dreamed.of. my scanner is truly overwhelming with communications. I wouldn't never have dreamed that a little antenna would allow me to receive so much. The coaxial cable (LMR400) I admit is like wrestling a steel pipe.

I am in the process of monitoring all transmission and keeping notes to either remove or keep or adjust the Attenuation settings and AGC in my programming software. Thank you everyone.
 
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