I have started testing on 800 khz using the Talking House am transmitter.
I have started testing on 800 khz using the Talking House am transmitter.
One serious problem with my particular model (TH 2) is the hum and low modulation. I am sure after spending some time digging around here on Part15.us a solution will be found to over-come these two problems.
The hum is probably the wall wart supplied with the TH and can be fixed by using a different power supply. Perhaps a regulated power supply.
Fixing the low modulation is my main concern and after tinkering with a few circuits I have come to the conclusion that a matching transformer is the only way to go. So far i have been experimenting with a graphic equalizer made by Teac. This has helped with controlling the tinny audio by limiting the highs and increasing the bass.
It is a shame that the digital audio storage chip has better modulation than the line input jack. The input jack sounds like about 50% modulation while the digital audio chip seems to transmit at or close to 80% modulation.
Hard to tell without a modulation meter but that is a educated guess none the less. So anyway, thats what i am up to these days.
Hope everyone is doing great.
p.s. testing may not be restricted to 800 khz but right now it seems there is less hum there.
Similar problem
How do you tell which model you have?
I have two, and they each have much different audio inputs and internal speaker controls. The one I use every day sounds pretty good if the signal is clear. It has a stereo mini-jack input, which I assume takes care of mono matching internally. In that processing, I figure it must also take care of modulation, too. It isn’t perfect, with a bunch of processing before it goes to the internet, it sounds pretty good. It also has a thumbwheel control for internal speaker volume.
Now the other one must be an earlier model. It sounds tinny and trebley. If I up the processing and volume to try for better modulation, it simply distorts. It has a single RCA input jack for a line in and another for recording which doesn’t connect to its live audio input. I have to build a little stereo to mono mixer for it if I use it. I’d be willing to do that, but impedance-matching will likely still be an issue. I guess I should get what I can for it or pitch it, and get another one like the one in use.
But I don’t know how you can reliably tell which model is which on eBay.