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The harmonics are not just VHF, they are HF. If you are on 7 MHz the TR switch will generate 14, 21, 28, and so on. I'm not saying that is a problem that will "bite" everyone, but it will certainly

Thanks, Tom! I am encouraged to know I should be OK with the 3.5V to the RX. As I can increase my TX output to 20 watts, that should make the RX even happier by cutting off a bit more signal than 10

The capacitors will not be perfect, they will have leakage. Usually it is a slow-charge leakage. Some years ago, probably the 1980s when I was doing a QSK switch for Heathkit, I looked at the Johnson

Hello Mike. I have one but have never tried to connect it. There are a few little dings in the paint, but overall, it looks pretty good. I can send a few photos if you

I'll take it. Russ [email protected]> wrote:

Hello?? Free for USPS Postage, probably Medium Flat rate box, to the lower 48.Insured. Let us know how much insurance you need for this meter. We use lots of bubble wrap !! This meter is not

Update: The output of the TR switch to the receiver is a bit more manageable driving it with 30 watts (see photo) than with the 10 watts I ran in my previous post: Assuming the maximum safe input to

I am looking for a Johnson Signal Sentry, Part No. 250-25. Thanks! Mike Harmon, WB0LDJ mharmon at att dot net

Work to be done ... ? About 10 watts into the TX jack and then on to a 50Ω dummy load from the Antenna jack ? Yields about 9.8 Vpp / 3.5 Vrms? across 50Ω into my scope (thankfully not my

*For Sale: Johnson Viking Valiant 1* This radio is in good overall shape and appears to be complete. It is untested. Condition is commensurate with age with some “patina”, especially on the rear

Hi Sully , No, I have (3) of the Johnson TR switches. I’m talking about a device called the Signal Sentry. It’s basically a keying monitor, but it has other benefits as well. I’d like to find

Anyone contemplating using the EF Johnson T/R switch with anything other than a tube-type receiver should read Tom Rauch W8JI's comments: https://www.w8ji.com/johnson_tr_switch.htm Not wanting to

Could you be talking about the Johnson T/R switch? I have one of those and am in the process of setting up an AM station with a Viking I transmitter and this switch. Right now I am trying to decide

Mike, Have you ever heard of a Johnson Signal Sentry? I just found out about them today, and the operation sounds intriguing. Apparently, the gadget mutes the receiver during transmit and sends an

OK – noting that you’re thinking of using the HV FET to open the B+, I would ask two questions, please. If you’re inclined to do it this way, might you consider just killing the audio output

For break-in, I’m thinking that opening and closing circuits with the lowest voltage and least current along with not having capacitors that need to discharge to fully mute the receiver would be

Hi Mike, I’ve been thinking of alternative ways of doing what I wanted to accomplish. As constructed, the Collins R-388 receiver has a terminal strip on the rear apron that is connected to a DC

Hmmm. Interesting idea ! Please allow me to share two thoughts. If you sense voltage across the key rather than at the “Probe” port, you’ll preclude any even small delay in reducing receiver

Hi, Mike, I share your thoughts. I was thinking of rectifying the voltage from the "Probe" port on the TR Switch to turn on a transistor, which would apply a control voltage across a small relay.

Thanks for the reply, Mike. Both sections of C12 were horrible. I had restuffed the can with new caps which explains the OPEN and supports your theory. Jeff W8KZW