• Get involved.
    We want your input!
    Apply for Membership and join the conversations about everything related to broadcasting.

    After we receive your registration, a moderator will review it. After your registration is approved, you will be permitted to post.
    If you use a disposable or false email address, your registration will be rejected.

    After your membership is approved, please take a minute to tell us a little bit about yourself.
    https://www.radiodiscussions.com/forums/introduce-yourself.1088/

    Thanks in advance and have fun!
    RadioDiscussions Administrators

RCA AM transmitter question

S

scappy

Several models of RCA AM transmitters have the plate current or the antenna current meters set back behind a second set of glass. Why did RCA do this? Did they not trust the insulation on the meters enough or was it more cost effective to just double up the glass? This quiestion popped into my head as I cleaned the dust that accumulated between the inner and outer glass on our BTA-1R2's plate current meter.
 
CCA also did that on some transmitters. I know the AM1000D had a plate current meter mounted that way.
The meter is HOT. It has the plate voltage on it. I would think it would be mounted like that for safety reasons. The front of the meters just seems like thin insulation for 3 or more kilovolts. I wouldn't want to touch it.
 
Too bad Harris didn't do that on the FM10H3. The Plate Current meter has 6-7KV on it, but no setback. That's the meter that tends to get static on it and tempts a person to clean the meter face.
 
It was more of a question to get the meter as close to the cavity as possible. You need to keep leads short and that's why they set them back. I'm sure a secondary effect was a bit of safety since the meters do have several thousand volts on them.
 
The reason RCA did that because the high voltage and the wattage sitting right there, it was purely for safety. Someone could get an RF burn being that close to one of those meters on an RCA if they didn't do that. The only RCA of the "umber grey" vintage that I have seen that did not have that is my RCA BTA 500M it used a transformer in the cabinet to drop the voltage and power so that it was safe and readable.
 
I realize that the plate current meter is in circuit. I just question why RCA's safety solution would look like an after-thought. One would think that they could design a meter that had additional insulation, or at least a 1-piece meter that didn't fill with dust between the panes.
 
Status
This thread has been closed due to inactivity. You can create a new thread to discuss this topic.


Back
Top Bottom