Does any body know how to build an antenna Matcher for CB radio that can explain or have picture I want to build a small simple one using trimmer pots / air caps?
-
You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
build a cb antenna Matcher?
- Thread starter sanjosebay21
- Start date
Google pi network antenna tuner.
The Pi network is most versatile allowing matching over a wide range. Use something like a pair of 100 or 200 pF caps to ground and a tapped coil in the series leg. Make the coil about 10 turns and about two inches in diameter from 14 gauge wire or larger. Tap the coil at one, two, three, five, eight and ten turns. Should tune more than you would ever encounter on CB.
There are other types of tuners such as the SPC Match (series parallel capacitor) the L network or the T network but the Pi is likely the most useful for what you want.
The Pi network is most versatile allowing matching over a wide range. Use something like a pair of 100 or 200 pF caps to ground and a tapped coil in the series leg. Make the coil about 10 turns and about two inches in diameter from 14 gauge wire or larger. Tap the coil at one, two, three, five, eight and ten turns. Should tune more than you would ever encounter on CB.
There are other types of tuners such as the SPC Match (series parallel capacitor) the L network or the T network but the Pi is likely the most useful for what you want.
Last edited:
There is an easier way than building one for yourself; but perhaps not as satisfying as building your own.
MFJ makes the MFJ-949 tuner that can be had for as cheap as $50/used and will work right now. It also has a built-in cross-needle SWR meter - which is the best way to have an SWR meter - IMO. Not to mention other cool features, such as a built-in antenna switch and other goodies too. Will handle up to 300 watts . . .
http://www.mfjenterprises.com/Product.php?productid=MFJ-949E
MFJ makes the MFJ-949 tuner that can be had for as cheap as $50/used and will work right now. It also has a built-in cross-needle SWR meter - which is the best way to have an SWR meter - IMO. Not to mention other cool features, such as a built-in antenna switch and other goodies too. Will handle up to 300 watts . . .
http://www.mfjenterprises.com/Product.php?productid=MFJ-949E
This simple tapped L match works well for me. The input from the radio is at the coil end, the output to the antenna is alongside the capacitor.
I made a coaxial vertical dipole, cut for 11 meters, fed with 50 ohm RG-213. The antenna doesn't present a 1.1 swr match, so I built the tuner to match the antenna to the radio.
I made a coaxial vertical dipole, cut for 11 meters, fed with 50 ohm RG-213. The antenna doesn't present a 1.1 swr match, so I built the tuner to match the antenna to the radio.
Attachments
Last edited:
Hi dc2rf i have a half wave dipole that has a swr 1.5. whilw it is not bad, iwould like to bring it down to a 1:1 match. i found your matcher and would like to try it. unfortunatly you do not show much detail. Re the coil size, wire size, length, dia etc. i would like to see a close up of the matcher so as to enable me to build it. I can not remove the antenna as it is up 9 meters. So the easist way is the matcher. Hoping to hear from you soon. Jimbobre
A half wave dipole has a natural match around 1.5. That is normal for that antenna design, and if it were any lower you would need to look into it and see why.
Once you get to a certain SWR, getting it lower doesn't actually help you any, and depending on how you get it lower, might actually hurt your signal. You are beyond that point of a safe SWR. If you really want to tune your antenna further you need an antenna analyzer... Or at the least a field strength meter.
To many people get over obsessed with SWR. Do yourself a favor and don't follow that path.
The DB
I have one of these and it is a great and quick way to reduce your swr readings. This meter is the easiest to use and it is quick.There is an easier way than building one for yourself; but perhaps not as satisfying as building your own.
MFJ makes the MFJ-949 tuner that can be had for as cheap as $50/used and will work right now. It also has a built-in cross-needle SWR meter - which is the best way to have an SWR meter - IMO.
http://www.mfjenterprises.com/Product.php?productid=MFJ-949E
A field strength meter and take readings with is the best way to tell you if your antenna is really putting out. I use my spectrum analyzer to monitor signal strength when I tuneup.
I also have it's BIG Brother MFJ-989 that is rated for 3 KW pep. You can find these cheap if you hunt for a little while.
