Magnetic Long Wire Antenna Matcher (9:1) for SWL, 100 KHz-30 MHzProduct DetailsMPN: MLB-2Palomar Engineers Magnetic long wire antenna matche has been redesigned for shortwave listeners who listen to a broad frequency range from VLF to HF and others needing to match a long wire antenna to 50/75 ohm coax feed line cable.
Specifications: Frequency: 100 KHz – 30 MHz. Input: 50/75 ohms for coaxial cable. Output: High impedance. Connector: SO-239 (for cable), wingnut/solder lug wire lead (for antenna). Mounting: Stainless steel eyebolt. Size: 2.5” diameter. Case: White PVC sealed weatherproof. External ground bolt with wing nut for external counterpoise or separate ground.
The long wire antenna often has a high impedance in the 500-1000 ohm range and the MLB-2 transforms this high impedance close to efficiently couple the received signal to the receiver. A long wire antenna with a matching balun such as the MLB-2 often has a 12 db (2 “S” units) better signal than a long wire without a matching balun.
Typical Installation Diagram
MLB-1/MLB-2 Typical installation diagram
For best results we recommend that the coax feed line be at least 1/4 wavelength on the lowest operating frequency since the coax braid is used as a counterpoise if you don’t use the external counterpoise terminal on the matching unit. We also recommend a feed line choke at the end of the coax feed line near the radio to prevent RFI common mode current (from neighbor noise sources) from interfering with the radio – check out the info below on feed line chokes.
Also available as a complete ready to hang SWL antenna. (see related products).
Palomar Engineers Magnetic long wire antenna matche has been redesigned for shortwave listeners who listen to a broad frequency range from VLF to HF and others needing to match a long wire antenna to 50/75 ohm coax feed line cable.
Specifications: Frequency: 100 KHz – 30 MHz. Input: 50/75 ohms for coaxial cable. Output: High impedance. Connector: SO-239 (for cable), wingnut/solder lug wire lead (for antenna). Mounting: Stainless steel eyebolt. Size: 2.5” diameter. Case: White PVC sealed weatherproof. External ground bolt with wing nut for external counterpoise or separate ground.
The long wire antenna often has a high impedance in the 500-1000 ohm range and the MLB-2 transforms this high impedance close to efficiently couple the received signal to the receiver. A long wire antenna with a matching balun such as the MLB-2 often has a 12 db (2 “S” units) better signal than a long wire without a matching balun.
Typical Installation Diagram
MLB-1/MLB-2 Typical installation diagram
For best results we recommend that the coax feed line be at least 1/4 wavelength on the lowest operating frequency since the coax braid is used as a counterpoise if you don’t use the external counterpoise terminal on the matching unit. We also recommend a feed line choke at the end of the coax feed line near the radio to prevent RFI common mode current (from neighbor noise sources) from interfering with the radio – check out the info below on feed line chokes.
Also available as a complete ready to hang SWL antenna. (see related products).
TECH NOTE: We also stock RFI kits to protect effected devices such as garage door openers, computers (laptops, desktops), dsl/cable routers, ethernet hubs and many more devices. If you run a high powered RF amplifier in your ham station also consider a linear amp RFI kit which will cut down RFI transmitted by your station. Remember there is always a “transmitter” and a “receiver” of RFI and the quest is to find and choke the “path” the RFI has selected – you need to add ferrites to both the transmitting side and the receiving side to eliminate RFI problems. The RFI-HTS kit only helps suppress RFI on the receiving side.
Typical RFI Problem/Solution:
Hello, I am Larry, a ham operator and I am having interference issues with my Direct TV system. My station is a FT450D through an Ameritron ALS-600. From the amp through a coax switch to choose between an OCF dipole or an Hustler 5BTV vertical. Any power over 100 watts and my DTV goes off the air and must completly reboot/format. Coax is RG-8. The DTV dish is pointed away from the dipole and separated by about 25'. DTV was totally useless! They suggested I not talk on the radio while she is watching TV! Please help me with a reasonable, cost effective soultion. (The wife gets really pissed when I shutdown the tv!) Thank you, Larry
Hi Larry,
Your RFI problem is quite common and is usually a sign of either a radiating coax feed line or reception of your radiated signal (source) by the Direct TV (the victim) through either the AC power lines acting as “antennas” for your ham signal or the coax braid of the satellite antenna acting as an antenna for your signal.
The solutions are straight forward:
1. To make sure your feed line is not radiating you need a feed line choke at each antenna feed point (also makes your antenna work better since it is not using the coax as part of the antenna). You can use our simple Kit 110 with 5 snap on chokes on each antenna for this purpose. Part # Kit 110 at $27.50 each – one for each antenna. These chokes will keep your feed line from radiating and coupling into your ac power lines. INFO HERE
2. The radiation from your antennas themselves may also be getting into the ac power lines and coax braid of the Direct TV antenna so you need to protect the victim receiver. Depending upon the sophistication of your direct TV setup (e.g. home theater, dvd, tape player, sub woofer speakers, etc), the path of the RFI may be coming thru the AC power lines of any connected device to the video including the video monitor itself! To help solve this problem we have a home theater RFI kit for up to 5 devices (you need a minimum of two – one for the Direct TV receiver(AC and coax input) and another for the video monitor AC power lines and HDMI or video input cable. Our kit part # is RFI-HTS. INFO HERE
These items should help reduce the RFI and let you operate on the air while your wife watches TV.
Bob Brehm, AK6R
Chief Engineer