Muting receivers

[iw5ci]

I have just completed the AM shack you can see in the Photo:

the antenna connector enters in the ART-13 and the receiver connection from art-13 is rerouted to a coaxial switch that delivers the signal to one of the receivers (SP-600 , National NC-303, Rhode & S. ED/07-D2).

When the trasmitter is in TX mode the internal vacuum relay of the ART-13 disconnect the receivers from antenna , but i have no provision of muting receivers.

I would like to know if it is dangerous for the receivers such arrangment because i have no proper connector to utilize the muting function of the art-13 .

[iw5ci]

the correct photo is this one..

[N8ETQ]

Nice Rack...

  J106 has a SPDT relay contact.

Pin 23    common
Pin 24    N.C.
Pin 25    N.O.

  I just tin some #16 wire and shove it in
the connector. J106 is the conector for the
remote control box.


/Dan

BTW: What was the resolution with the "No grid/Pegged plate
Issue?

[iw5ci]

Hi Dan, the "No grid/Pegged plate Issue" is on the 2nd ART-13
and at this moment i am still investigating.
I have found that the oscillator doesn't' work so maybe this issue is the cause
of the no grid current problem.

Nice Rack...

  J106 has a SPDT relay contact.

Pin 23    common
Pin 24    N.C.
Pin 25    N.O.

  I just tin some #16 wire and shove it in
the connector. J106 is the conector for the
remote control box.


/Dan

BTW: What was the resolution with the "No grid/Pegged plate
Issue?

[N8ETQ]

  OK,

  Didnt know you had two of 'em.  That 837 is the osc tube
and the 1625's are multipliers/buffers depending on freq.
Thats your lack of grid issue. 

   The OSC. runs between 1.0 and 1.5 mc in 2 bands. A
padder cap is switched in and out via control "A" depending
on band. (make sure the knob is on there in the correct position
as I think it will still key up even if it is not "ACCURATELY
ALIGNED" unlike the other knobs)

   With just FIL. and LV. you should be able to find the OSC.
signal with headphones plugged in and switched to CALIBRATE.

GL
/Dan

Hi Dan, the "No grid/Pegged plate Issue" is on the 2nd ART-13

[iw5ci]

That's the point Dan.. i cannot ear the OSC signal on the nearby receiver.. but all the tubes in that section have been tested on the first ART-13 and works good.
Now the problem is troubleshooting the oscillator... no idea to start from...

[N8ETQ]

  Ok,,

   Just FYI I can hear my OSC at 1300kc with knob "A" at
position 4 and tunning knob "B" at 680.  I guess just verify
400 VDC on the plate of the 837. Also a set of contacts
on the Antenna relay ground the cathode of the 837 via 2.5
mh choke and a 10k R. The 837 gets screen E  (190v or so) from
a bunch of 5k ohm R's  R117 - R120 and C126.

   Hope you find the problem there as it could get ugly
if the PTO is goofed up.

GL
/Dan

 

   The OSC. runs between 1.0 and 1.5 mc in 2 bands. A
padder cap is switched in and out via control "A" depending
on band. (make sure the knob is on there in the correct position
as I think it will still key up even if it is not "ACCURATELY
ALIGNED" unlike the other knobs)

 

[Opcom]

Very nice rack& stack! I find it hard to get at the ones near the floor, but there is something to be said for lying around and SWLing.

[iw5ci]

yes! i like lying on the floor with earphones and radio sound... asap i will replace the NC303 with a Collins 390 receiver.

[N8ETQ]

    RX audio is a bit of "Pet Peave" with me.. "I don't need no Stinkin'
Speaker".  Most RX's (even gud ones) have "CRAP" audio stages.
Try a free download of some audio spectral analysis software and
you will see that even an R-390 (NO "A") won't pass much above
5kc through the audio amp even when set to 16kc BW!  You pretty
much NEED to hook up to the "Diode Load" and feed that to a nice
"Station Audio" system. I use an old Pioneer SX950 and a pair of
JBL studio monitor speakers.  "Rock the House".

     Room acustics is what I need to pay attention to now.  I found a
gud "Instructional" video on that topic here:

http://exposed.ethanwiner.com/852x480.htm

Good info and it works both ways, RX and TX.  I'm mainly concerned with
RX since I seldom TX.  Anyway I won't "Critique" any ones audio
with my FT857,

73

/Dan

Another problem you will run into with some of the older receivers is that you will get a very loud pop! thru the speaker when muting them during transmit. I had this problem with both my HRO-50 and HRO-60 receivers.

[W2PFY]

the correct photo is this one..

I have to lay on my side to view it

[KB2WIG]

no, just put the monitor on it's side


klc

[ke7trp]

I just found one of those amperex relay tubes.  How much delay do they have?  This was says 11505 on it so I maybe 115volts and 5 seconds? 

On the Sp600, There is a huge inrush.  The mute has 276 volts DC and 44ma of current but when you first close the mute line there is a really big hit.  We tried using a mosfet to switch this. We used a 450 volt 4amp device. It died right away.

So maybe a real big mosfet or a vac relay is really the best way.  I tried PB relays but after a month, The contacts are shot.

C

[ke7trp]

Thats going to squeeeeeeeeel for 1 second everytime I key up...  Not sure that would work unless you guys like the browning ping from two 304TLs at full volume

C

[ke7trp]

This one is 115 volt Normaly open and 5 seconds. 

5 second is way to long. I need an instant one.  I will use this for some other project.

C