The Ferrite Ring Combo Pack is a convenient solution for troubleshooting RFI/EMI from unknown frequencies or multiple frequencies that require multiple suppression mixes. Included in this combo pack are ten 2.4″ OD/1.4″ ID ring toroids as follows:
Mix 75 effective from .15-10 MHz including AM Broadcast band – quantity: 3
Mix 31 effective from 1-300 MHz for general purpose – quantity: 4
Mix 61 effective from 200-2000 MHz for cell phone, WIFI, HDTV, Cable TV interference – quantity: 3
Model BA-1-1000 is a 1:1 balun kit used to translate a 50 ohm
unbalanced input to 50 ohms unbalanced at power levels up to 1000 watts
PEP/100 watts continuous when used with a matched load. With a matched
load the SWR will not exceed 1.5 over the frequency range 1.8 to 61 MHz.
1,000 PEP watt rating on a 25% duty cycle. Will sustain about 100 watts RTTY or FT8 at 6 meters. (for higher power use the BA-1-1500 with 6-8 turns for higher frequencies).
Common mode impedance peaks
around 3,500 ohms at 10Mmhz.
With a matched 50 ohm load the SWR over the frequency range 1.8 to 61
MHz is shown in the following table measured with an AIM 4170 network
analyzer. Notice that the conversion from 50 to 50 ohms is very
consistent from 1.8-61 MHz and SWR is less than 1.3:1 over the range
allowing easy tuning by most radio internal antenna tuners or an
external tuner.
Ba-1-1000 1:1 Balun/Unun 1KW PEP 1-61 Mhz
The kit consists of a F140 ferrite toroidal core, enamel insulated
wire, a SO-239 connector with stainless steel hardware, and an
illustrated instruction manual with directions to connect the kit as a 1
to 1 balun/unun (unbalanced coax to unbalanced antenna or balanced
antenna like a dipole). Balun assembly time takes about an hour and is a
fun learning process.
Add a SO-239 Kit on output side to create a 1:1 unun (coax to coax line isolator) or add studs for a balun for use with dipole or beam antenna.
Use the recommwnded CB-Box-1 for a convenient enclosure.
The ring toroids are useful for AC/DC common mode choking with multiple turns as shown below
 AC Cable on F-240 Toroid – 7 turns |
 DC Cable on F240 – 4 turns |
The ring toroids can also be used on coax or signal lines as shown below:
 RG58 12 turns on FT240 |
 Ethernet Cable on F-240 Toroid – 7 turns |
For RFI/EMI wrap as many turns as possible for higher choking (under 30 mHz).