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J-pole antenna and wattage question

 
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J-pole antenna and wattage question
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jseabolt
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Post J-pole antenna and wattage question Reply with quote
Just got through mounting my J-pole antenna.



I built it out of 1/2" / 13mm copper tubing. My antenna is tuned to 92.1 I built using using a J-pole calculator.

I have it mounted to piece of water pipe which also secures a VHF TV/FM antenna. I did not have access to a taller ladder so it could have been mounted a bit higher (lke one meter higher).

I'm managing to get out approximately a 2 KM radius with this antenna using the PCIMAX3000.

Couple of questions. I could not find any definete info on wheather this type of antenna needs to be grounded or insulated. Based on a drawing I found I believe it supposed to be grounded which mine is. Correct?

Wattage question: The software I downloaded from this site says I am only pushing 0.8 watts and I have the software set to "100% power". If the card is rated for 3 watts then why is the software saying I am only transmitting at 0.8 watts?

How do I get the transmitter to push a full 3 watts?
Tue Mar 13, 2012 1:05 am View user's profile Send private message
pcs
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Location: Radio Land

Post Reply with quote
Hi,

the power meter in PCIMAX is not terribly accurate, it is kind of accurate when the antenna is tuned, but if your antenna is a bit off it will show too much of too little. Its probably a bit off so it shows 0.8W only although you are transmitting at much more I am sure. Your range is certainly decent.

I recommend that you use external mains power supply for your PCIMAX, use 15V supply. It gives a bit more power.

Also make sure pcimax is cooled properly as it will reduce power when it overheats, whenever that happens that program in windows turns on the red alarm button.

Definitely good job and nice range you're getting.

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Tue Mar 13, 2012 1:48 am View user's profile Send private message Visit poster's website
jseabolt
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Post Reply with quote
It's more of a 2.5 km radius. The signal starts to fade after about 2 km especially when I go into dips and valleys. The terrain here in East Tennessee is not flat and lots of hills and valleys and is surrounded by mountains so recieving an FM signal from even a commerical radio station is hit or miss.

I will try a 15 volt main and see if I can increase my range.

As of right now most of my town (about 5000 people) can here my signal if they are listening! I'm retransmitting a streaming feed from Absolute 80s from London UK.

The software says the temperature of the card is 47C. Does that sound normal?

It's 16C right now in my garage where I have my computer w/transmitter located.

The hottest it gets in my garage in the summer is about 35C in the summer.

I usually don't have any issues with my microprocessor overheating in the summer but I usually remove the side cover off my PC to help dissapate heat. I'm using a more "powerful" PC and still have the cover installed. I may remove it just to be safe.
Tue Mar 13, 2012 4:05 pm View user's profile Send private message
pcs
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Post Reply with quote
Things look good.

For more range you'll simply need more power, that's all. 15W might be enough.

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Best regards,
Marko - PCS Electronics
--------------------------------------------------------
Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Tue Mar 13, 2012 4:15 pm View user's profile Send private message Visit poster's website
jseabolt
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Post Reply with quote
pcs wrote:
Things look good.

For more range you'll simply need more power, that's all. 15W might be enough.


Correct me if I am wrong in case I misread someone's post but with this transmitter can you replace a resistor to bump the power up from 3 to 7 watts?

Should be the PCIMAX3000+ model I purchased last summer.
Tue Mar 13, 2012 5:48 pm View user's profile Send private message
pcs
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Post Reply with quote
That is definitely not true.

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Marko - PCS Electronics
--------------------------------------------------------
Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Tue Mar 13, 2012 7:20 pm View user's profile Send private message Visit poster's website
jseabolt
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Post Reply with quote
pcs wrote:
That is definitely not true.


Here's the thread:

http://www.pcs-electronics.com/phpBB2/viewtopic.php?t=2575
Wed Mar 14, 2012 1:51 am View user's profile Send private message
pcs
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Post Reply with quote
That is about stereo pilot level, not power.

And we were talking percents, not watts.

_________________
Best regards,
Marko - PCS Electronics
--------------------------------------------------------
Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Wed Mar 14, 2012 2:30 am View user's profile Send private message Visit poster's website
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