Tag Archives: Palomar


Does the regulator in your radio run hot? Excessive heat from a transistor means the part is undersized for the circuit or that the circuit itself is not very efficient.
Changing the radio’s modulation circuit is impossible. But the solution for this problem is the Palomar MAX-MOD Transistor.

Photo: MAX-MOD transistor including mica insulator

Palomar is a famous old CB brand name from USA. The name is owned and used now by EKL Components, the mother company also for Magnum Radio’s and Motocomm helmet sets.
New in the Palomar program is the MAX-MOD, a special transistor.

The MAX-MOD is a replacement and upgrade PNP transistor for the modulation circuit in most radio’s. The MAX-MOD replaces the common 2SB and TIP parts.
The MAX-MOD works very well in 10M radio’s, including President models.

The MAX-MOD will give the RF section the current it needs and will increase the peak power by and average of 10% or more.
The MAX-MOD has the same lead spacing as the smaller transistors it replaces, making soldering very easy. The MAX-MOD uses a hughe TO-3PL package for improved heat dissipation, and comes with a mica insulator so you do not need to try to find one.
The MAX-MOD is available in single pack and 10-pack for technicians.

Photo: Palomar MAX-MOD Transistor  in single pack

• High Current / High Power PNP Power Transistor (AM Regulator)
• Replaces & Upgrades 2SB688, 2SB754, 2SB817, 2SB827 and other AM
• Regulator Transistors in CB and Amateur Radios
• Supplies Necessary Current Levels for Maximum Modulation
• Most Radios See a 10% Increase in Peak Power Levels
• Runs 40%* Cooler than Stock Regulators
• Massive TO-3PL Package for Improved Heat Dissipation
• Comes with Mica Insulator

Photo: Palomar MAX-MOD Transistor in 10-Pack


The  MAX-MOD Transistor is available from stock at Avera-Distributing.

For a datasheet of Palomar MAX-MOD Transistor click here.









 Photo: The Palomar SL41 comes in a beautiful packing

In the “old” days Palomar was a world famous brand in the world of CB and 10 meter. Most famous were the high quality products like linear amplifiers. From most famous brand names the ownership changed during the years. Also Palomar switched from owner. Until last year Mr Eric Lewis (USA) claimed back the name that his father, the founder of Palomar,  had made great in the past. Palomar is now back to the roots of the Lewis family.

The Palomar SL41 was introduced few weeks ago. It is a new technical concept for an electret microphone. Inside the housing is an alkaline battery that powers the microphone.

Photo: inside the housing is an alkaline battery

In Europe most CB’s have a 6-pin wiring and one of the pins supplies the voltage to the electret microphone. In USA most CB’s have a 4-Pin Uniden/Cobra wiring without a voltage supplied to one of the pins. That is why the battery is operated with an alkaline AAA battery.

For testing we connected the SL41 to a President Johnson-2. We have 2 very handy items to connect a 4-Pin Uniden/Cobra wired microphone to a 6-Pin President wired transceiver.

Photo: Adapter 4-Pin USA to 6-Pin President

C4PDF6 = Adapter, Converts 4-Pin Male to 6-Pin Female with Magnum DeltaForce/President Wiring.
CABLE 0008 = Microphone Adaptor Cable 4-Pin Male to 6-Pin Female with Uniden/President Wiring.

Photo: Uniden Adapter Cable 4-Pin Uniden to 6-Pin President

For the audio quality it made no difference whatever we used, the Adapter connector or the adapter cable.

First we tested the dynamic microphones RoadKing RK56 and Astatic 636. As these are dynamic types we were not surprised the quality was not so good on the electret type radio Johnson-2.

The Palomar SL41 is an electret type and it  gave a much better performance than the original microphone from Johnson-2.

To finish the test we connected a RD104 (Red Devil) and the DM104M6B4B. These are amplified microphones. The audio quality and the level of volume had not much difference with the Palomar SL41. That is a remarkable good result.

I heard many good reviews from Palomar SL41 and the only thing I can say now: “TESTED AND TRUE”.

The Palomar SL41 combines modern engineering and technology with time-tested design to provide the professional driver with the ultimate noise-cancelling microphone.

    • Classic Rugged Design
    • Active Circuit Microphone with Noise Cancelling Electret Element
    • 6 Conductor, Dual Shielded Cable – Custom Palomar Made Cable
    • 16″ Coiled Cable Section – Stretches to 9′
    • Over 1 Year Battery Life from Single AAA Battery
    • AAA Battery Included – Factory Installed
    • Industrial Grade Push-to-Talk Switch
    • Dual Mount – Machined Aluminum Button + Hanger
    • Wired for 4-Pin CB Radios

If you are interested in more technical information please read the document Technology and Design.

Photo: The Palomar SL41 – View from 4 sides


Under the name POWERBAND, the company PALOMAR in USA sells a line of
4 types of high power replacement final amplifier sections with high performance low pass filter for 10 meter amateur transceivers.

After RFX75 and RFX150 they now introduce the RFX85 and RFX85HD.


RFX75 is an Amplifier, 75 – 100 Watt PEP Output Power, RF Final Output Stage and Low Pass Filter, Designed as a replacement and/or upgrade for most 10 meter amateur transceivers.

The RFX75 is a RF final output stage and low pass filter designed as a replacement and/or upgrade for most 10-meter amateur transceivers.
The RFX75 features the latest Power MOSFET technology and a built in S-meter detection circuit.
The output power of the RFX75 varies depending on the transceiver that it is installed on. Most installations will see 75 – 100 watts PEP output power.


a) The RFX75 replaces the transceiver’s final amplifier stage and low pass filter section.
The RFX75 is NOT a standalone amplifier. The RFX75 mounts to the back of most transceivers with little or no modification to the transceiver’s chassis.

b) Once installed, the transmitted RF signal from the output of the transceiver’s driver stage (or pre-driver stage) is sent to the RFX75 via the coaxial cable marked RF IN.

c) The driver signal is then amplified through the RFX75‘s ERF2030 (FET1) and then again through the ERF7530 (FET2).

d) The amplified signal from the ERF7530 passes through the RFX75’s efficient low pass filter.

e) A small portion of the signal is sampled through C19 and rectified through D3 and D4. This is sent to the S-meter detection circuit in the transceiver through the yellow wire.

f) The final RF output signal of the RFX75 is sent back to the radio through the RF OUT coaxial cable where it is connected with the transceiver’s antenna connector*.

g) The incoming receive signal is sampled from C14 and connected to the receive strip of the transceiver through the RFX75’s coaxial cable marked RX OUT.

* It is possible to attach the RF OUT coax directly to the antenna connector. However, it is recommended to attach it to the transceiver’s PCB because some transceivers come equipped with antenna warning systems, or other circuits, that are on ancillary boards between the recommended connection point and the antenna connector.



RFX85 and RFX85HD

There are now 2 RFX85 Choices: the Standard RFX85 and the New RFX85HD High Drive.

The RFX85 Circuit includes driver stage, final amplifer stage and low pass filter. The RFX85 is your choice for 10 meter radio repairs and upgrades that require replacing the radio’s driver and final amplification stages.

The RFX85HD circuit includes only the final amplifier stage and low pass filter which makes for a much quicker and easier installation.

The RFX85HD is your choice for 10 meter radio repairs and upgrades when all your replacing is the final transistor or no transistors.

Both RFX85 units feature the new fan-ready heatsink design and variable bias controls for better tuning on SSB radio installations.


– Maximum Output: 100 Watts PEP.
– Drive Stage: ERF2030 MOSFET (x1).
– Final Stage: ERF7530 MOSFET (x1).
– Low Pass Filter: 3 Stage.
– Spurious Emission Suppression: 45 dB.
– Supply Voltage: 13.8 VDC.
– Power Consumption: 12 Amps Max.
– Dimensions: 5.1 x 8.3 x 4.2 cm (LxWxH).
– Weight: 235 gram.


– Maximum Input: 30 Watts PEP.
– Maximum Ouput: 100 Watts PEP.
– Final Stage: ERF7530 MOSFET (x1).
– Low Pass Filter: 3 Stage.
– Spurious Emission Suppression: 45 dB.
– Supply Voltage: 13.8 VDC.
– Power Consumption: 12 Amps Max.
– Dimensions: 5.1 x 8.3 x 4.2 cm (LxWxH).
– Weight: 235 gram.

It is necessarily to have good technical knowledge to install RFX types.
In USA these amplifiers are very popular and on the internet you can find many videos and reviews.
That might help to be prepared when installing the first RFX.

Here are some links, but many more can be found:

For many radios the installation instructions have been published on the following website:


All 4 models are available at Avera Distributing