Blonder-Tongue BAVM-Z
 

I have two of these. Yesterday I made a test with the Ch. 10 one.

It is hooked to a vertical dipole.

I used my new Sony Watchman and started walking around with the poer all
the way up. Oh my, the illegality! I gave up at quarter mile still
with a very strong picture.

At all the way down it still is perfect around the apartment
and starts visibly getting snowy only at 100 feet outside.
Of course that's B&W on a teensy screen.

Hey, surprised no one has replied to this thread. I am using (3) Blonder Tongue AM-60-550Bs and (1) AM-60-860 with add-on stereo audio board.

Perhaps the biggest improvement I have seen with these, in the quality and range of broadcast, is to make a 'frequency-specific' dipole which correlates to the channel you are using it on.

There is a tutorial on youtube on how to use an RF analyzer to maximize the output level and reduce noise.

On my channel 12 unit, for instance, I have each leg of 18awg solid core cabling at ~13", terminated into an RG-6 run of around 30 feet.

With a portable color TV in my car, running off twelve volts DC, I have snowy coverage at almost 1 block away. Beyond that, my little Quasar portable can not receive the signal in color anymore, and the sound gets snowy. The antenna for broadcast is 3 stories up in an attic area, and RF output level is maxed out.

Think I will settle on about a halfway power level setting, since I do not need to cause interference. Also, these run quite hot with the power at maximum.

I suppose your antenna is roof-mounted to still be usable at a quarter mile!

I hope these Tongues are not AM transmitters, as they may go right across the bands without filters .

No, my antenna is a twin-lead 300 ohm antenna fed from a balun,
hung from the blinds in a window. Its vertical polarization. This is second floor
in an apartment. Its cut to the usual 95% length at center channel. Lradin is
about three feet.

The Blonder-Tongue modulators were designed for CATV and LPTV use so are VSB.

They will go a lot farther with a cable trunk amplifier. This was a common trick for FM broadcast pirates.