The two low band VHF signals appear to be strong enough to be received, but interference usually takes more signal margin than UHF.
Step one is to eliminate any possible source of interference to see if it is causing any problems. I would do this two ways;
1. tune your car radio to 530 or 540 KHz and drive past the house and listen for buzzing and note if the buzzing changes while you drive. If you hear buzzing, that is power line noise and might vary depending on the humidity and/if it has rained recently. Power line noise is best cured by the power company.
2. turn off every circuit in your house except the one for you TV set. Next unplug everything else on that circuit except for the TV and the preamp power supply. If the reception improves, turn things back on one at a time until you find the bad one.
Once you have eliminated interference, the next step gets you to improving the signal strength of the signal. Your idea of a second antenna might do the trick, but before you go that far, you can try moving the existing around to see if you can find an optimum spot. Here in the Adirondacks I have seen low band antennas several feet off the ground in a side yard. The optimum location will vary on your terrain. The goal is to find a height that uses the ground in front of the antenna to reflect the signal upwards toward the hill that is blocking the signal.
Step one is to eliminate any possible source of interference to see if it is causing any problems. I would do this two ways;
1. tune your car radio to 530 or 540 KHz and drive past the house and listen for buzzing and note if the buzzing changes while you drive. If you hear buzzing, that is power line noise and might vary depending on the humidity and/if it has rained recently. Power line noise is best cured by the power company.
2. turn off every circuit in your house except the one for you TV set. Next unplug everything else on that circuit except for the TV and the preamp power supply. If the reception improves, turn things back on one at a time until you find the bad one.
Once you have eliminated interference, the next step gets you to improving the signal strength of the signal. Your idea of a second antenna might do the trick, but before you go that far, you can try moving the existing around to see if you can find an optimum spot. Here in the Adirondacks I have seen low band antennas several feet off the ground in a side yard. The optimum location will vary on your terrain. The goal is to find a height that uses the ground in front of the antenna to reflect the signal upwards toward the hill that is blocking the signal.