Magnetic Long Wire Antenna Matcher (9:1) for SWL, 100 KHz-30 MHz
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).
Testimonial
Hi Bob,
Radio: Flex-6700 running barefoot -10 to 100 Watts max.
Antenna: MFJ-1216 – 160/80 meter OCFD wire antenna with matching network.
Elevation: Over 60 feet AGL – fully extended.
Installed: Mid November 2013
I operate mainly on the digital modes running less than 50 Watts. All of the sudden after a few days operating with this antenna, I start to have RFI and my radio was acting up; such as changing bands, SWR changing values, radio failures and turning off. However, when I used my Hy-Gain 18 HT vertical on the same band none of the abnormality occurred.
I contacted MFJ and confirm that what I was noticing was a failure of their “matching network” AKA balun. They offered no solutions. Then I contacted Palomar Engineers and bought the 1:1 new toroid RF beads. I called Palomar Engineers and I happened to talked to you directly; regarding the on going issue with the MFJ antenna. I found out that the 1:1 balun was not what I needed (I was miss-informed by MFJ that it was 1:1 matching network.)
You offered to make the required balun 4:1 and the rest is history.
Here are my findings:
- No more RFI displayed on the monitors.
- Radio not acting up or turning off.
- The SWR at 160/80 meter is 1.2:1
- No antenna tuner required. (radio goes to Bypass automatically.)
- Worst SWR is on 10 meter with a 2:1 but still usable, with antenna tuner 1.5.
- One happy OCFD user!
Thanks to Palomar Engineers design and engineering for solving this issue.
73, Ernest – W4EG