CB causing central A/C to come on

[tshows]

Okay guys, I am going to make this as short as possible. Here is the situation. The evaporator coils, furnace, blower unit and associated control circuitry of my HVAC unit is located in the attic of my house. Because of the covenants of our subdivision we are not allowed to have exterior antennas. I have Double Bazooka dipole antenna mounted in an inverted V configuration in the attic. I only use the 11 meter band channels 1 thru 40 am and ssb. I am running a Galaxy DX 949 radio with a Palomar TX-150B amp (vintage 80's model transistor amp a real Palomar I have been told) Now finally to the problem I am having. I have noticed that when I am using the radio on channel 38 LSB and the amp(talking skip, using the amp on low power output on ssb of 80 to 120 watts) and the A/C is off that the A/C unit will come on even though the temperature is below what the thermostat is set for. The unit does have a programmable thermostat. I can supply more detailed info about the HVAC if it would help. I don't talk skip much on AM so I don't know if that affects the HVAC unit as well and I always run barefoot when talking locally on AM. One last thing I have moved the dipole antenna as far away from the A/C unit and the programmable thermostat as I can. I would say it is a good 15' to 20' away from the unit at this time. Any help or suggestions to resolve this problem would be greatly appreciated. Thank you in advance.

 

[Beetle]

Simply put, the HVAC circuitry is obviously susceptible to RF, and your 15-20 foot separation between it and the antenna is not enough.

Lose the amplifier, first of all. See what effect legal power has on the HVAC. The HVAC manufacturer may have a fix for legal powered CB RFI, but even at 12W PEP, the antenna may just be too close.

 

[tshows]

Thanks Beetle. From the testing I have done when running the radio barefoot, (legal 12W on SSB) it does not effect the HVAC unit. It's kind of hard to talk very far though on 12 watts and a dipole antenna in the attic.

 

[Wire Weasel]

You can also try some shielded replacement thermostat cable. This will not be available at HVAC supply but through the wire & cable industry. Many internet sellers of wire and cable. Individual wires need to be 18 gauge wire just as they are now with the standard thermostat wire.

Shielded wire is sold for audio, computer and other technical industries.


Good luck!

 

[tshows]

Thanks, Wire Weasel. Sounds like a good idea. I will see what I can find.