[rabbit73]

It sounds like you are willing to try a few more tests. You have been so thorough so far that I'm kind of running out of ideas, but I'll stay with you as long as you are willing. Maybe ADTech can think of something that I missed. It might not be possible to do any better with KTMF, but I'm not ready to give up yet.

In regards to moving the antenna, I don't have the pieces to do a portable set-up like you demonstrated on the AVS Forum (shown in photo above).

I understand; I was just trying to demonstrate that moving the antenna might find a location where the signal is better.

it appears Sadelco is no longer producing new products

Yeah, that makes me sad because they are my favorite. There are refurbished meters available from the repair facility that did repairs for them. I have a 719E which measures down to -35 dBmV, equal to -84 dBm, where most tuners drop out. My newer DisplayMax 800 and 5000 don't measure below -20 dBmV (-69 dBm), so I need to add a preamp before them when hunting for channels that were missing from a scan.



The 719E is on the left, the 800 on the right. The 719E was designed to measure analog signals, but is useful to make comparative measurements of digital signals. There aren't many good meters like the 719E left on ebay. The other tool that can be used to hunt for and measure missing channels is a spectrum analyzer, but they are expensive.

Is it possible to manually tune a TV tuner to a channel (23.1 in my case) and use the channel strength indicator to get a rough guess on signal strength? Or does one need to go through the tv's "scan" feature for each re-position?

Most TVs require a scan, but some will pick up a missing channel if you enter the virtual channel number or the real RF channel number. You can test your TV by trying each way.

You can also do a scan without the antenna connected to erase all channels and then reconnect the antenna and enter a virtual channel number or a real channel number of a channel that you know you can get to see if it picks it up.

If manually re-positioning the antenna on the roof, do I need to prop/secure the antenna or can a person hold it?

Try to keep it from moving during a scan; secure it or have a person hold it still with a prop.

Approximately how long should it be held at a particular height/rotation to allow for the capture (if using the channel signal strength listed in #1)?

It depends upon how long it takes your TV to lock on to the signal. Unfortunately, the channel will not show unless the tuner locks on to it. With my signal level meter I can hold the antenna in my hand and watch the signal reading as I move the antenna because the meter can measure a signal even if the tuner scan isn't able to find it.