Re: Tuning a pi-Network Output
The GE tubes are equivalent to the Sylvanias. No problems. Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana. Sent with [Proton Mail](https://proton.me/mail/home) secure email.
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Steve Wedge, W1ES/4
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#84138
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Re: PTO makes scraping sound
This weekend I should be able to figure it out because I have off on Saturday and Sunday. I will try to share with the group of what I find. Mark
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Mark N2DMI
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#84137
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Re: Tuning a pi-Network Output
This one has GE tubes. Not sure if those are considered the "good" ones (like the Sylvanias) or if they need more capacitance. Hopefully I'll get to the neutralization adjustment today or tomorrow.
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n4buq
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#84136
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Re: PTO makes scraping sound
Isould have my TR-4Cw RIT open next week. If you still need the info then I can get it and post here. Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana.
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Steve Wedge, W1ES/4
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#84135
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Re: Tuning a pi-Network Output
IIRC, you need a slightly higher value parallel cap with RCA tubes. Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana.
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Steve Wedge, W1ES/4
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#84134
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T-4XC "On" Decreases RX Performance?
Not really a big deal but thought I would check in to see if this is common. R-4C tied into T-4XC in normal transceive config. I'll listen around on the R-4C for a while, and I'll turn on the T-4 if I
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Craig W8CS
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#84133
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Re: Transceive with DDS VFO
OK, thanks.? I'm experimenting with one of the I0CG DDS-4 units. In the DDS-4 manual, one of the recommended uses is to run the DDS output to the INJ jack on the T4 transmitter, so that's what got me
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Ed G
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#84132
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Re: Identifying "Soft" Final Tubes
I think something else needs to be considered when there is discussion about how long the 6/12JB6 tubes will last is our present times. When a lot of the folks that are regular contributors to this
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Ron Magnus
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#84131
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Re: PTO makes scraping sound
Not on the PTO schematic but on the BIG schematic of the entire rig is where I want to know where the output of the PTO is connected to? Mark
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Mark N2DMI
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#84130
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Re: Transceive with DDS VFO
In order to do what you suggest, you would need a device to offset the ¡°T¡± VFO signal to the transmitter operating frequency since the 2-C has no local oscillator or mixer to convert the VFO
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Gary Follett
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#84129
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Re: Tuning a pi-Network Output
Well hey, it lasted 50 years! I have not heard of this failure before. It seems to me to be just an old age failure. Perhaps the collar had a weak spot or something. But by all means, do inspect it or
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Jim Shorney
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#84128
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Re: Tuning a pi-Network Output
Thanks, Jim. This is concerning:
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n4buq
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#84127
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Re: Tuning a pi-Network Output
I would say your PA is not neutralized, although IIRC the parallel capacitor needed to be changed for a certain brand of tube. Someone else probably knows. "n4buq via groups.io"
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Jim Shorney
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#84126
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Re: Tuning a pi-Network Output
Apples and oranges. The TR7 40M problem is a common mode feedback path through the high pass filter module. Tube neutralization deals with only the PA circuit (and occasionally the driver tube has its
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Jim Shorney
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#84125
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Re: For Sale: Drake TR-7 to R-7 interconnect cable
I've always appreciated that some will pay for convenience and for that, the price isn't out of line. I'm a pretty good carpenter but I'm also nearly 70, with anaemia and a bum foot. I'm starting my
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Steve Wedge, W1ES/4
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#84124
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Re: Another TR7 Journey begins
I am always suspicious when someone tells me a board is "bad". That seems to show a lack of enthusiasm to do the necessary component level troubleshooting. Fixing "bad" boards is just something a tech
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Jim Shorney
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#84123
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Re: Tuning a pi-Network Output
I took the PA cage off because it had a concavity to it that bothered me since it made the top of the cage that much closer to the plate caps. I then noticed the neutralization capacitor is fully
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n4buq
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#84122
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Re: Another TR7 Journey begins
Jerry, that¡¯s the plan.
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Bill NZ0T
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#84121
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Re: For Sale: Drake TR-7 to R-7 interconnect cable
Pretty sure mine cost me less than $20 to build and that includes two new Jones connectors. But I had the wire and cable I needed already. Cinch has Jones connectors still on their web site and they
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Jim Shorney
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#84120
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Re: Tuning a pi-Network Output
The neut procedure is but no mention is made of what happens on the lower bands. Neutralisation is most important at the highest frequencies, I have been told for years. Being a bit "off" on lower
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Steve Wedge, W1ES/4
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#84119
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