Hallicrafters HT-40 PTT modification

[KK4RF]

I recently acquired a HT-40 and have heard  that some have modified it for push-to-talk on the microphone so that the function switch does not have to be manually turned each time from transmit-to-receive. Does anybody have this information? I want to use mine to switch an external T-R relay and also to mute a rcvr and key the SB-201 linear. Any ideas would be greatly appreciated. I may check into the DX-60 net in the AM Sunday and see what I can find. Many thanks.
                           ---Marty, KK4RF---

[K4TLJ]

A DX-60B but you might get some ideas.
http://www.amwindow.org/tech/htm/dx60ptt.htm

[KK4RF]

Terry,
     Thanks for the link. I just printed the article and I'll be reading it shortly. Hopefully I can make this all work with the D104's built in PTT switch. Thanks again.
                                    ---Marty, KK4RF---

[wb1ead]

Hi Marty..and all..this is an interesting topic for me..I've also obtained an HT-40..and for sure used to have a DX60B with HG10 VFO and HR10b rcvr..this was many many years back Marty..however I do recall making the whole thing work by keying the CW jack and using a Shure 444 mic..there were multiple cables(and lots of tie-ins in the guts of that mic) coming out the back of the mic base..some were diode protected..one to mute the rcvr..one going to the mic jack on the DX60..and one tripping the CW jack..all I can say was that it most definetly worked..there was a slight clink/clunk if the paddle on the mic was too fast down..other than that I enjoyed many years of trouble free AMing..the Heath is long ago sold..buuuuttt I was planning on using just that scheme on my TX with the SX140rcvr..having said all that..in short could you please keep me informed as to how you make out with ur plans on this..maybe what I plan will not work on this one..by the way if you need a link to the "audio mods" for this rig..give me a holler..tnx and have a good holiday!!
                                                            73 de DAVE

[KK4RF]

Dave,
     Thanks for the reply. I'm actually impressed at how well made the HT-40 rig actually is. I'm hoping someone has a cook-book approach to this with maybe an article from an old QST or CQ mag. That's an idea. I may do a search of the QST archives and see if maybe there was a mod there.
     In any event, I don't think it should be too hard to figure it out. I'm hoping not to have to "re-invent the wheel" as it were.
     You mentioned the SX-140 rcvr. That was my Novice rcvr back in the late 60s. Had a lot of fun with it.
                    ---73s, Marty, KK4RF---

[KK4RF]

     Got my PTT mod done. I did use the DX-60 suggestions for the voltage (6.3 volt filament AC, rectified with a single diode and filtered with a single 100 uF electrolytic) and the 12 volt relay worked great. My mod won't let me use the HT-40 on CW, but I'm interested only in AM for this rig anyway. Might try some of the audio mods suggested for this radio, but for now am having fun with my HT-40 into a SB-201 linear. Thanks again to all who replied.---Marty, KK4RF---