Ham Nation Pine Board Project discussion

Discussion in 'Homebrew and Kit Projects' started by KD8YQC, Mar 25, 2017.

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  1. K9EID

    K9EID Ham Member QRZ Page

    Right on, Steve! This is the way to do it and will be the direction for the transmitter. Even have the switch mounted as you will see next week. I am called away for this week so will start the transmitter next week. Thanks for being here in bringing your ideas for all...
     
  2. K9EID

    K9EID Ham Member QRZ Page

    Hi
    Hi Loren.... thanks for being here and appreciate your input and questions. The reason i started with 150 volts is that I wanted to use a tube rectifier....just to get some of the new fellows iinto building and understanding the technology. I do hope you saw George's explanation of the power supply a few weeks back. We will have the clip up oin the site at www.heilsound.com soon.
    The transmitter has turned out really well and I will present that next week. Unfortunately I have been called away for tomorrow's show but next week it all happens. When we get a few weeks into it I have things you can do with the power supply. I mounted a SS bridge into an octal plug. Replaced the 6X5 and we will have nearly 300 volts.....again, thing for all to learn from. Also, ,the value of the caps are not all that important for what we are doing as you read on one of the above posts. Working voltage is important but 20, 22, 47 mfd are all fine for this project.
    Keep in mind I am trying to select parts from Antique Electronic Supply as they now are putting each of the module parts together in their catalog ! Keep the iron hot and stay in touch. Thanks
     
  3. K9EID

    K9EID Ham Member QRZ Page

    Hi Don....keep up the good work. Have the transmitter finished after going through several designs with Richard. We get on the air each morning - 200 miles away- and have a great path to test and check these little jewels. The 6AG7 and 6V6 are really the best especially with my 12AX7 preamp and equalizer. Stay in touch, my friend.
     
  4. N2EY

    N2EY Ham Member QRZ Page

    This can be done with a 3PDT relay:

    1 pole switches the antenna
    1 pole grounds the RX antenna connection
    1 pole mutes the RX and turns on your VFO (moving contact is grounded, RX is set up so that the MUTE line must be grounded for receiver to receive, VFO is set up so that VFO key line must be grounded to turn on VFO.)

    With a hollow-state superhet receiver, one end of the RF Gain control usually goes to ground. Unground it and bring it out of the receiver and you have a mute connection.

    Another approach is to use multiple relays with their coils in parallel or series, as appropriate. A simple DPDT for antenna switching and another DPDT, 3PDT or whatever, as needed.

    Some folks think you need a fancy Dow-Key relay for TR switching, but for HF work up to a couple of hundred watts, that's just not true.

    73 de Jim, N2EY
     
  5. K9EID

    K9EID Ham Member QRZ Page

    5"]This can be done with a 3PDT relay:

    1 pole switches the antenna
    1 pole grounds the RX antenna connection
    1 pole mutes the RX and turns on your VFO (moving contact is grounded, RX is set up so that the MUTE line must be grounded for receiver to receive, VFO is set up so that VFO key line must be grounded to turn on VFO.)

    With a hollow-state superhet receiver, one end of the RF Gain control usually goes to ground. Unground it and bring it out of the receiver and you have a mute connection.

    Another approach is to use multiple relays with their coils in parallel or series, as appropriate. A simple DPDT for antenna switching and another DPDT, 3PDT or whatever, as needed.

    Some folks think you need a fancy Dow-Key relay for TR switching, but for HF work up to a couple of hundred watts, that's just not true.

    73 de Jim, N2EY[/QUOTE]
    You are correct, Jim. Have built many antenna switching relay systems over the years with just simple 12 volt relays from Radio Shack. Miss those guys ! Gateway electronics in St Louis has a good supply of 12 volt and 110 volt relays. Interesting, Jim that the transcievers use small relays to switch the RF - sometimes 200 watts and certainly not a Dow Key. Under ten meters- no problem. Thanks for being with us and keep on bringing good information to the Pine Board Project.

    BOB HEIL, K9EID
     
  6. KE4OH

    KE4OH Ham Member QRZ Page

    Just FYI, Amazon has quite a selection of inexpensive relays that are just dandy for this type of use.
     
  7. KF5FEI

    KF5FEI Ham Member QRZ Page

    Somewhere I have a box of ginormous 24-volt multi-pole relays we got as surplus from one of the local companies that closed their facility.
     
  8. KE4OH

    KE4OH Ham Member QRZ Page

    Jim, I don't want to beat a dead horse, but a 4PDT relay costs the same as a 3PDT relay. And I have a Millen VFO with a hot chassis, so I don't want to ground the thing to turn it on. (Yes, I use an isolation transformer, but I still don't want to route the cathode circuit to actual ground - Just to the VFO chassis ground.) Maybe there are other VFOs like that out there.

    73 de Steve KE4OH
     
    N2EY likes this.
  9. N2EY

    N2EY Ham Member QRZ Page

    Depends on what kind of relay you use. The 11 pin based KP style relays max out at 3PDT.

    The "Variarm 150" (see QST for January 1941) doesn't have a hot chassis if properly built and used. But, yes, the cathode circuit needs its own contacts.

    So, what you do is this:

    1 pole switches the antenna
    1 pole grounds the RX antenna connection on transmit and grounds the RX mute line on receive
    1 pole turns on the VFO

    The "Millen" is unique in that respect. (They actually took the QST article and manufactured copies of it, sold as the 90700. There was an improved version too.)

    Every amateur VFO besides the Millen that I know of is transformer-powered, or meant to be powered by an external, transformer-type supply. Heath VF-1, HG-10, Eico 722, Johnson 122, Globe 755, Hallicrafters HA-5.......

    73 de Jim, N2EY
     
  10. KE4OH

    KE4OH Ham Member QRZ Page

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