VHF Base station antenna

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prcguy

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Since the antenna is responsible for most of your reception, using the highest gain you can and putting it as high in the air as possible is key to distant reception. If you can't find a single antenna to satisfy the gain requirements then using individual single band high gain antennas and a low loss combiner will give you the performance edge.

If VHF is your problem band and UHF is close in stuff then you might get away with a single high gain VHF antenna that has poor performance on UHF, but you will neve know how good or bad it is until you try it. Same with 800MHz, that's a problem band for many that needs a gain antenna up high but if your close to the transmitting stations it might work good enough on a VHF antenna.

If you have space, time and $$ you could make it a multi step process and get a VHF antenna first and see how it does on all bands. If it doesn't work out then supplement with a UHF and finally an 800 with suitable combiners as needed.

I guess your right nd5y and it makes much more sense to run one cable. I get it, but if not using the correct splitters, diplexers, cable ect than your just wasting your time by not getting the receiving results that you should. To answer your question prcguy, 800mhz not a big deal. I for the most part lock out MSP & Worcester that are all on that state 800 thing. I occasionally listen to state with no problem. Worc little garbled with their voices, but I worked for the city and even their own radios were a little garbled. Isn't it better to have one antenna for vhf tuned to 158-162 that I listen to and one antenna for 460-470 that I listen to as well? Or just cut A Diamond F23H to the VHF 158-162 and hope for the best on UHF?
 

Rawkee1

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If I use the diplexer for two antennas on the roof, can I use a signal splitter to split the signal inside the house to use two separate scanners?
 

prcguy

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If your going to use a preamp somewhere before the splitter then you can split without any loss provided the preamp doesn't degrade reception in other ways. Wtihout a preamp a 2-way splitter will loss at least half your signal and a four way will loose at least 75% of your signal to each receiver.

If I use the diplexer for two antennas on the roof, can I use a signal splitter to split the signal inside the house to use two separate scanners?
 

Ubbe

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can I use a signal splitter to split the signal inside the house to use two separate scanners?
Try first connecting the scanners directly with a T adapter. If one scanner are in the 400MHz band it will have a high impedance in the 800Mhz band and will have very little impact on the signal level if the other scanner are in the 800Mhz band. If both scanners are in the same frequency band they will load the signal to half. When not using a 20dB isolating CATV splitter the scanners will interfere and sometimes send out a carrier or distorted signal to the other scanner that will then stop scan and monitor that interference. If using a splitter it will always be a 3,5dB or more attenuation of the signal but it will be more or less totally free from interference problems from the other scanner.

If you use the antenna amplifier you can as well get a 1-4 port splitter or more, to be prepared if you get another receiver like a SDR dongle. I use a 1-6 splitter and with a FM trap filter I do not need any additional attenuation, but that's my location and are probably different for anyone else. That variable 0-20dB attenuator will let you know what the best setting will be.

/Ubbe
 

Rawkee1

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I'm also inquiring on a good low loss diplexer with PL259 port connections to connect two antennas.
 

Rawkee1

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I was given an F23 antenna with no cutting instructions. I would like to tune it to 160Mhz. I was told you have to cut both elements and not just the center or the top element. Does anyone out there that can tell me how much I have to cut off each element. Is it possible that I could possibly just cut one of the elements instead of both.
 

Rawkee1

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I am not splitting the signal. I have two antennas. I'm running two sets of coax. One for each antenna. LMR400
 

Ubbe

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Does anyone out there that can tell me how much I have to cut off each element. Is it possible that I could possibly just cut one of the elements instead of both.
Prcguy gave it to you in message #49. The antenna consists of three antenna elements that are stacked on top of each other. If you tune only one element, the top one, it will be optimized for one frequency and the other two elements for another frequency and with more gain. It will run at an overall reduced gain but will be more broadbanded in its frequency range. There's always a relationship between how narrow in frequency a vertical antenna works and how much gain it gives. More broadbanded will always have less gain.

/Ubbe
 

kmartin

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I've been looking at the tram 1400 aluminum 6dbd gain antenna on the Amazon site. I know that there are some tram haters out there however there are some good reviews on this antenna
 

mmckenna

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however there are some good reviews on this antenna

Before you put a lot of stock in those reviews, you'd need to know the actual real world experience of the person writing the review, and if they'd actually compared performance to a different antenna in the exact same location, exact same coaxial cable, exact same radio, exact same…….

What you'll often find is that someone buys the antenna, and it works well for them. That gets translated in the reviews to "Best antenna ever built in any universe". When you start talking to these guys, they often have never had another antenna that they can do a side by side comparison with.


And, after all, antenna design is not magic. It's easy to do the physics behind it and make a good antenna. Lots of people build their own antennas with good results.
Where the issue comes up is how long the antenna survives.
Not hard to make an antenna last a few years. But compare that to a LMR/Public Safety antenna that gets installed on a tower on a mountain top with hurricane force winds, ice loading, etc. It just doesn't compare.

To be fair, most hobbyists don't need antennas that will survive that, and a Chinese antenna might work fine on top of their home.

Whatever works, and whatever you can afford is the right choice.
 

Md116

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Before you put a lot of stock in those reviews, you'd need to know the actual real world experience of the person writing the review, and if they'd actually compared performance to a different antenna in the exact same location, exact same coaxial cable, exact same radio, exact same…….

What you'll often find is that someone buys the antenna, and it works well for them. That gets translated in the reviews to "Best antenna ever built in any universe". When you start talking to these guys, they often have never had another antenna that they can do a side by side comparison with.


And, after all, antenna design is not magic. It's easy to do the physics behind it and make a good antenna. Lots of people build their own antennas with good results.
Where the issue comes up is how long the antenna survives.
Not hard to make an antenna last a few years. But compare that to a LMR/Public Safety antenna that gets installed on a tower on a mountain top with hurricane force winds, ice loading, etc. It just doesn't compare.

To be fair, most hobbyists don't need antennas that will survive that, and a Chinese antenna might work fine on top of their home.

Whatever works, and whatever you can afford is the right choice.
My Tram 5/8 wave dual band antenna blows my Laird 1/4 wave antenna away as far as receiving goes. It does have gain of course compared to Laird and I compared both antennas using the same mag mount, same location, same scanner. The Laird is built much better though and would survive the outdoors much longer than the Tram would ,If I chose to use it outdoors.
 
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