8T & 8R
Locked
 
|
I'm pretty sure I now understand the operation of 8R and 8R HOLD.
Is 8T the inverse of 8R (ie goes high during transmit)? Is there a 8T HOLD option anywhere? At the moment I run 100% digital modes and I switch my linear via the RTS line on COM1 (which goes high on TX) and an opto-isolator. I would like to use the opto-isolator circuit for SSB and it looks as though the 8T line might do the trick. 73 Bob 2M0KDZ _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
Bob,
Yes, the 8T line is ALMOST opposite 8R - but not quite. 8R goes low prior to 8T being asserted and 8R can be held low after RF disappears for a period of time determined by the 8R HOLD menu parameter. The 8R line is usually the one used for external keying. There is an External Amp Keying Circuit schematic (and a partial kit) on the Elecraft website. Tom Hammond has an updated version of the circuit that you can find at www.n0ss.net - this is similar to the amp keying circuit found in the KPA100. There is no 8T hold menu parameter - the 8R signal goes low 15 to 20 ms prior to the onset of RF. 73, Don W3FPR > -----Original Message----- > > I'm pretty sure I now understand the operation of 8R and 8R HOLD. > > Is 8T the inverse of 8R (ie goes high during transmit)? > > Is there a 8T HOLD option anywhere? > > At the moment I run 100% digital modes and I switch my linear via > the RTS line on COM1 (which goes high on TX) and an > opto-isolator. I would like to use the opto-isolator circuit for > SSB and it looks as though the 8T line might do the trick. > > _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
In reply to this post by Bob Towers-3
Bob
The 8R line can be held on a little longer with the "hold" command in the menu, if you wish to use the 8R line with either an opto-isolator or a relay, I've got both circuits on my "boat anchor with a K2" article at: http://www.astromag.co.uk/k2/K2externalRX.pdf (end of blatant advert for my Drake R4A interface...) 73 Dave, G4AON >At the moment I run 100% digital modes and I switch my linear via the RTS line >on COM1 (which goes high on TX) and an opto-isolator. I would like to use the >opto-isolator circuit for SSB and it looks as though the 8T line might do the >trick. > >73 > >Bob >2M0KDZ _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
In reply to this post by Don Wilhelm-3
On Apr 20, 2006, at 8:27 AM, Don Wilhelm wrote: > There is no 8T hold menu parameter - the 8R signal goes low 15 to > 20 ms > prior to the onset of RF. One question on this -- how does this work for SSB? Is there a 15-20ms delay circuit that allows the VOX to key before the RF makes its way out, or does the K2 simply clip 15ms or so of audio before it is transmitting? I can see how this works for CW, since the K2 can delay the keying waveform by 15ms. How about SSB? Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email] Quote: "Not within a thousand years will man ever fly!" -- Wilbur Wright, 1901 _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
Bill,
My opinion is showing, but VOX will clip leading syllables no matter what - and that goes for any transceiver. It may or may not be important - not much intelligibility will be lost in most instances, but the use of VOX leads to operating practices on SSB that contain phrases like: "Ahhh - I am ...." - I prefer using PTT. 73, Don W3FPR > -----Original Message----- > > One question on this -- how does this work for SSB? Is there a > 15-20ms delay circuit that allows the VOX to key before the RF makes > its way out, or does the K2 simply clip 15ms or so of audio before it > is transmitting? > > I can see how this works for CW, since the K2 can delay the keying > waveform by 15ms. How about SSB? > > _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
Don,
Your statement about VOX clipping is true of most transceivers. The one exception that I know of is the STAR transceiver by G3XJP. With this design the audio from the microphone is delayed in DSP until all of the RF changeover etc has been accomplished. This gives a very clean and precise VOX operation. 73 Stewart G3RXQ On Sat, 22 Apr 2006 16:29:28 -0400, Don Wilhelm wrote: > Bill, > > My opinion is showing, but VOX will clip leading syllables no matter what - > and that goes for any transceiver. It may or may not be important - not > much intelligibility will be lost in most instances, but the use of VOX > leads to operating practices on SSB that contain phrases like: "Ahhh - I am > ...." - I prefer using PTT. > > 73, > Don W3FPR > >> -----Original Message----- >> >> One question on this -- how does this work for SSB? Is there a >> 15-20ms delay circuit that allows the VOX to key before the RF makes >> its way out, or does the K2 simply clip 15ms or so of audio before it >> is transmitting? >> >> I can see how this works for CW, since the K2 can delay the keying >> waveform by 15ms. How about SSB? >> >> > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
In reply to this post by Dave, G4AON
On Thu, 20 Apr 2006 20:26:24 +0100
Dave <[hidden email]> wrote: > Bob > > The 8R line can be held on a little longer with the "hold" command in the menu, if you wish to use the 8R line with either an opto-isolator or a relay, I've got both circuits on my "boat anchor with a K2" article at: > http://www.astromag.co.uk/k2/K2externalRX.pdf (end of blatant advert for my Drake R4A interface...) > > 73 Dave, G4AON > Dave, Many thanks for the article. The ideas will do me very nicely and I'll be able to use the opto-isolator circuit which I originally used for keying the K2 via the RTS line from COM1 on my PC. I have a very quick and dirty setup at the moment which is a 10K resistor from the 8T line to the opto-isolator. I seems to work well for digital modes and SSB, which is all I need at the moment. I'll make up your more elegant solution when I get the 8-pin connectors for J13. 73 Bob 2M0KDZ _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
Dave,
I have to say that your Drake R4A is a neat looking bit of kit. I was a SWL 40-odd years ago and in those days - apart from Collins - the Drake line was the bees-knees. All I could afford was a HRO-MX and no bandspread coils! Great way of learning how to tune SSB signals with backlash on the main tuning.... 73 Bob 2M0KDZ _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
«
Return to Elecraft
|
1 view|%1 views
| Free forum by Nabble | Edit this page |