VHF/UHF Generic Base Transceiver RFI KitProduct DetailsMPN: RFI-VHF-BASEType: NwCountry/Region of Manufacture: United StatesFilter Power Rating (PEP watts): 500RFI Suppression Range (MHz): 25-300 MHzPalomar Engineers RFI Filter Kit for VHF/UHF Base Radio Transceivers up to 2 GHz uses a combination of ferrite mixes useful from 1-2000 MHz.
BUY THIS KIT NOW TO SOLVE YOUR RFI/EMI NEEDS! WORKS WITH MANY BRANDS OF HAM/COMMERCIAL RADIO RIGS
Purpose
The RFI kit is designed to be installed on your radio transceiver to reduce Radio Frequency Interference (RFI) caused by common mode current on the outside of the coax braid at the output of your radio. Additional chokes are included to reduce common mode currents on the amp relay keying line (7 pin Din), rear audio in/out for digital modes (13 pin Din), computer control line (DB-9) and the DC power cord.
This kit will help reduce or eliminate:
1. “Hot mic” RFI caused by poor grounding of antennas or common mode currents from linear amps feeding unbalanced (coax fed) antennas without baluns/line isolators.
2. RFI to neighbor’s electronic devices including audio/video systems, computers, telephones, garage door openers, etc.
3. RFI to your other radios, audio/video systems, computers, telephones, etc.
A side benefit is a reduction in noise floor in your receiver depending on the amount of noise being introduced by common mode currents (which are blocked/reduced by the chokes in this kit).
These chokes use a special mix of ferrite core material that is effective in suppressing radio frequency interference from Ham Radio amplifiers.
The split beads beads are easy to use, don’t require modification of the protected equipment and work in almost all cases, even when plug-in filters fail.
This kit is designed to choke common mode currents going into or exiting from your transceiver. Chokes are supplied for the RF Out (1 antenna only), Amp Relay Cable (7 pin DIN), Computer Control Cable (DB-9), PSK31/Digital Mode Cable (13 pin Din) and DC power line. Use of the chokes often helps cure SWR problems between transceiver and a linear amp and between transceiver and antenna tuner or direct to antenna. The DC power line choke helps keep common mode current out of the power line which could cause interference to other devices connected to the same power line if not suppressed.
Included are the following chokes and installation guidelines:
RF Input: F240 Ring Toroid for noise reduction – 3-5 turns of RG-58/RG-8X size coax cable through center
DC Input: F240 Ring Toroid – 3-7 turns of DC power cable
I/O Cable 1: FSB-1/2 – multiple turns through choke – ½” diameter hole
I/O Cable 2: FSB-1/2 – multiple turns through choke – ½” diameter hole
I/O Cable 3: FSB-1/2 – multiple turns through choke – ½” diameter hole
Also make sure you connect a good RF ground to the transceiver ground post.
For additional RFI suppression, use a feed line choke at the antenna to suppress common current on the coax feed line – see our store for feed line choke alternatives for use at the antenna.
If you use a linear amplifier we have RFI kits for linear amplifiers that help suppress RFI in your shack or in your neighbor’s house.
Super-Choker™ Common Mode Feed Line Chokes
Palomar Engineers RFI Filter Kit for VHF/UHF Base Radio Transceivers up to 2 GHz uses a combination of ferrite mixes useful from 1-2000 MHz.
BUY THIS KIT NOW TO SOLVE YOUR RFI/EMI NEEDS! WORKS WITH MANY BRANDS OF HAM/COMMERCIAL RADIO RIGS
Purpose
The RFI kit is designed to be installed on your radio transceiver to reduce Radio Frequency Interference (RFI) caused by common mode current on the outside of the coax braid at the output of your radio. Additional chokes are included to reduce common mode currents on the amp relay keying line (7 pin Din), rear audio in/out for digital modes (13 pin Din), computer control line (DB-9) and the DC power cord.
This kit will help reduce or eliminate:
1. “Hot mic” RFI caused by poor grounding of antennas or common mode currents from linear amps feeding unbalanced (coax fed) antennas without baluns/line isolators.
2. RFI to neighbor’s electronic devices including audio/video systems, computers, telephones, garage door openers, etc.
3. RFI to your other radios, audio/video systems, computers, telephones, etc.
A side benefit is a reduction in noise floor in your receiver depending on the amount of noise being introduced by common mode currents (which are blocked/reduced by the chokes in this kit).
These chokes use a special mix of ferrite core material that is effective in suppressing radio frequency interference from Ham Radio amplifiers.
The split beads beads are easy to use, don’t require modification of the protected equipment and work in almost all cases, even when plug-in filters fail.
This kit is designed to choke common mode currents going into or exiting from your transceiver. Chokes are supplied for the RF Out (1 antenna only), Amp Relay Cable (7 pin DIN), Computer Control Cable (DB-9), PSK31/Digital Mode Cable (13 pin Din) and DC power line. Use of the chokes often helps cure SWR problems between transceiver and a linear amp and between transceiver and antenna tuner or direct to antenna. The DC power line choke helps keep common mode current out of the power line which could cause interference to other devices connected to the same power line if not suppressed.
Included are the following chokes and installation guidelines:
RF Input: F240 Ring Toroid for noise reduction – 3-5 turns of RG-58/RG-8X size coax cable through center
DC Input: F240 Ring Toroid – 3-7 turns of DC power cable
I/O Cable 1: FSB-1/2 – multiple turns through choke – ½” diameter hole
I/O Cable 2: FSB-1/2 – multiple turns through choke – ½” diameter hole
I/O Cable 3: FSB-1/2 – multiple turns through choke – ½” diameter hole
Also make sure you connect a good RF ground to the transceiver ground post.
For additional RFI suppression, use a feed line choke at the antenna to suppress common current on the coax feed line – see our store for feed line choke alternatives for use at the antenna.
If you use a linear amplifier we have RFI kits for linear amplifiers that help suppress RFI in your shack or in your neighbor’s house.
Sometimes you need a high power common mode choke that is super effective and the Super-Choker™ products fill this need very well. All Super-Choker™ chokes use multiple turns through ferrite cores for higher choking impedance compared to our multi-bead sleeve chokes which only use one turn through multiple cores. Different ferrite mixes and turns ratios are used to optimize choking impedance in the selected product frequency range.
Super-Choker™ chokes are manufactured with 1/2″ 52 ohm coax cable (rated for full amateur radio legal limit of 1500 watts continuous (or the capacity of the coax cable at the selected frequency – good for over 5KW on 4 MHz into a matched load for example) with PL-259 connectors that can be connected to your coax feed line with simple double female barrel connectors.
Super-Choker™ chokes are ideal for high power stations and are very effective for keeping common mode current off the feed line on verticals, dipoles, and loop antennas at their feed point and also for choking coax lines at the station input to reduce common mode noise picked up by the outside of the coax braid between the feed point and the station entrance.
Ferrite core kits are available separately if you want to supply your own coax feed line.
Super Choker™ Case History:
I run an 80 meter loop antenna about 30 feet in height and have previously been using a coaxial balun common mode choke of 25 turns of RG-213 on a 6 inch form attached about 6 feet under the corner feed point of the loop (configured in a triangle). Using a Dentron 3000 antenna tuner I was able to tune all the ham bands and the lowest SWR was about 1.4 on most bands. The antenna feed line was led away from the corner of the loop and was not under the loop. Feed line length was about 105 feet as measured on the Aim 4170-TDR function.
I first placed a Super Choker™ 8010 at the antenna tuner leaving the coaxial balun in place. As I retuned the antenna tuner, the first thing I noticed was that I could now tune down to 1.1:1 on 80, 40 and 20 meters and I could not do that before. The noise level which had been running about S7 on 40 meters during the day had dropped to about S6 on my TS-870 receiver. I was pleased that the reflected power was now almost nil and the noise level was lower.
I then took the next step and replaced the coaxial balun and Super Choker 8010 with a Super Choker™ 16040 in series with a Super Choker 4010 for maximum choking power from 80-10meters. The antenna tuning was about the same but now the SWR was 1.0:1 on 80-10 meters and the noise level on 40 was down to S5. I tuned up on 20, 15 and 10 meters and worked a couple of JA’s and noticed that the noise level on 10 and 15 was not even S1 – something I had not experienced before on the 5 acre plot of land we call home.
What a welcome relief to find such a simple solution to RF feedback I had experienced and I got a lower noise level to boot!
Now to plan that 160 meter loop! I wonder what Krusty ole Kurt would use?
Bob, AK6R