That is a good point Jerry.? I should look at the coax switch that this rig feeds into to see if it's open or shorted when not selected.? Did not think of that but it certainly makes sense as a possibility.? Especially since I have a T4C as well as the TR4C and the note on the switch is not very clear.
I've found myself selecting the wrong rig among these two a couple of times.? Maybe I won the lottery the last time and had the pleasure of the arc event as my reward for not paying attention to details.? And not taking time to properly label the switch positions.? Just the sort of thing Murphy loves to do here as well.
73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com
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Show quoted text
On 1/9/2025 12:16 PM, jerry wrote: I once had a tube transmitter arc across the tune cap when the output SO-239 was shorted to ground.
Apparently, the output PI network converted the short to an open at the
tube end.
??????????????????? - Jerry, KF6VB
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I once had a tube transmitter arc across the tune cap when the output SO-239 was shorted to ground.
Apparently, the output PI network converted the short to an open at the
tube end.
- Jerry, KF6VB
|
Re: 6HS6 Price and Availability
On 2025-01-09 09:40, Mark Davis via groups.io wrote: I tried to look up the Svetlana 6§¨5§±, on radiolamps.ru¡ my browser
says "You Are Not Connected to the Internet".
Now I think I'm on a government watchlist!
More likely you got a website that's trying to take over your computer. - Jerry, KF6VB
|
?
I'm looking for a Drake 2B parts radio that has the complete tuning knob shaft
that's not bent. If anyone has a 2B parts radio with that part, contact me off group at my
email address.
?
mikew5rkl at gmail dot com
?
Thanks
?
73
Mike W5RKL
?
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Re: 6HS6 Price and Availability
I tried to look up the Svetlana 6§¨5§±, on radiolamps.ru¡ my browser says ¡°You Are Not Connected to the Internet¡±.
?
Now I think I¡¯m on a government watchlist!
?
Mark - AD7EF
|
Re: 6HS6 Price and Availability
So - the completed replacement runs off the normal B+?
- Jerry, KF6VB
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Show quoted text
On 2025-01-08 13:50, Gary WB6OGD via groups.io wrote: It is pretty easy to make a solid state mixer. Unlike amplifiers, that
need just a certain amount of amplification, extra AVC inputs, etc.,
mixers are
basically non-linear choppers. They just need enough gain to chop and
enough voltage tolerance for the circuit they are in.
My very first experiment was a J-310 FET(the only FET I had) plugged
into the R-4A Pre-mixer socket. I only had to disconnect the +150V
plate supply resistor and hook it to about 18VDC(?). Worked fine
though hooking it to the T-4X and selecting XMTR control might have
blown it.
I researched more (stole designs and modded) and now have a plug in
tube replacement. Works great.
Attached is what I think I am running now. I also attached a 6AU6
replacement from the Collins site.
Beats trying to buy expensive, possibly bad old tubes. YMMV.
My 6HS6 is now safe and part of my 401K IRA.. hi hi...
73,
Gary
WB6OGD
Links:
------
[1] /g/DRAKE-RADIO/message/81765
[2] /mt/110491919/243852
[3] /g/DRAKE-RADIO/post
[4] /g/DRAKE-RADIO/editsub/243852
[5] /g/DRAKE-RADIO/leave/12260778/243852/767576506/xyzzy
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Re: 6HS6 Price and Availability
Continuing the 6AH6/6HS6 saga, I just ordered a sleeve of new Svetlana 6§¨5§±.
?
This purports to be the Russian equivalent of the 6AH6/6485. They are plentiful and less than $2 each in quantity shipped. I'll experiment with them as 6HS6 replacements and report back. I can't make sophisticated receiver performance measurements like Rob, but I can do direct comparison to the 6HS6 on air in my R-4x receivers.
?
Dave
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A while back a ham published an article discussing what he called the "free 3 dB". I can't find the article, but it essentially discusses when using the RF gain control is advantageous. Bill N0CU
Hello Earl. Thank you for clarifying that! I agree with your observation that above 10M, RF gain is far less important! In fact not really needed much. For FM mode... zero.
I asked if you were using "electricity" in a lighthearted way 100%. I monitor VHF/UHF quite a lot and I too NEVER need to touch the RF gain! For low band SWL, 120 meters - 13 meters I do use it as needed depending on the time of year and conditions/mode. S/N on the SWL bands is
often a struggle, and fiddling with receive antenna's, RF gain, is key especially on 120m-41m. Yeah, there is life outside the "honey baked ham bands".
J
On Wed, Jan 8, 2025 at 03:13 AM, Joseph K7CBR wrote:
Are you still using electricity?
On Wednesday, January 8, 2025 at 05:19:40 PM EST, N3 EG <n3eg@...> wrote:
The RF Gain control has always been the most useless thing to put on a radio.? It's like a high/low switch on a vacuum cleaner, which should be called "Clean/Less Clean."? In the case of HF radios, it should be called the Ignore Weak Signal Stations And Screw Up Your S-Meter Reading Control.?
?
I've never found a good reason to use it in at least 52 years of HF listening, and it's totally useless on 10 meters and up.
|
Re: 6HS6 Price and Availability
Lee, many thanks for posting this. I've been looking for a 7-pin plug that I can wire a mechanical AM filter to for the 75A-4, and this will be perfect.
?
Dave
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Re: R4C Sherwood audio mod questions
Well, I decided to go ahead with the R4C transformer rotation and completed it this morning.? I was able to locate a new 5/8" Greenlee punch on eBay for a good price.? Took a lot of photos and notes so everything went back together properly.? There's definitely an improvement when listening to the calibrator at both ends of the bands.? I never noticed the same problem with CW signals and am wondering if the proximity of the calibrator board to the transformer might have something to do with the calibrator effect.? I don't have the equipment to look closely at the signal as Rob and others have done.? One slight oversight by me in the process: after removing the transformer, I removed the calibrator board so not to accidentally damage it while drilling and punching.? I reinstalled the transformer in it's new orientation and found that I couldn't get the calibrator board plugged in again due to mechanical interference with the transformer shell and the fact that the calibrator has rather long pins on the connector.? Replace the calibrator first!
?
Since this is essentially a no-cost modification (if you already have the Greenlee punch), it's probably worth doing but I don't consider it a vast improvement, at least not to me.? Thanks to all who commented on the mod.
?
73, Floyd - K8AC
?
?
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Re: 6HS6 Price and Availability
Gary, I live in Tucson, and I've been buying stuff from Elliott Electronic Supply for almost 50 years. And they are still there in the same place!
?
It's kind of amazing to me also but a welcome resource that I want to keep around, so if any of you need something they are on-line and will ship it out to you. When I went in there yesterday I saw 5 guys working behind the counter -- that they have that much business to employ so many people is doubly amazing. Much of the stock now is the usual Chinese products you can buy on eBay or Amazon, but the convenience of it being 20 minutes away is worth using them for me.
?
And next door they have Elliott Surplus which seems to be a rotating hamfest of consignment items, it's always different each visit. Quite a few boatanchor receivers in stock, as if I needed any more projects. Last month they had an RME-70 and now a National NC-2-40D, among many others. It's worth a visit if you're ever passing through on I-10.
?
Dave
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Re: Using the PLJ-6LED digital display with the R4C
Hi Mark.? With the T4X connected to the injection line, are you able to get an accurate and stable readout on the counter on 10 and 15 meters?? I see you're in Doylestown - used to ride the bicycle to Doylestown through Rogues Hollow.? I was located in Jackson Township at that time.
?
73, Floyd - K8AC
|
Re: 6HS6 Price and Availability
YES!
W7GZ,? where in the world(and which world) are you?? Maybe you are a time traveler??? hi hi...
73,
Gary
WB6OGD
?
|
Good morning?
i'm interested if the ac-4's are recapped....
?
Let me know your best price
?
Paul IK1QHB
?
please via email at ik1qhb@...
|
Re: Using the PLJ-6LED digital display with the R4C
Floyd,
The width of the display has not changed since I wrote the article many years ago. The unit does not touch the front panel but is mounted next to the inside panel behind the display plastic window.? Since it is mounted some distance from the front panel window, you can easily see the first and last digit by adjusting your viewing angle by moving your head left or right. I have my displays positioned slightly more towards the center of the radio giving preference to the last digit. I've installed maybe 10-15 of these in this manner and have had no issues other than I have had to play around with the value of the coupling cap. Using a scope I monitored the INJ level and used a cap that did not load it down. I've not had to use a buffer amp, but that would be a good fix and probably eliminate having to play around with cap values.?
?
Good luck and be interested in what you end up having to do to fix yours.?
73's,
Mark, WB0IQK
?
?
|
Re: 6HS6 Price and Availability
The most remarkable part of this, is that you have a local electronics store that stocks tubes!? Thanks for the report.
?
John K5MO
|
Hello Earl. Thank you for clarifying that! I agree with your observation that above 10M, RF gain is far less important! In fact not really needed much. For FM mode... zero.
I asked if you were using "electricity" in a lighthearted way 100%. I monitor VHF/UHF quite a lot and I too NEVER need to touch the RF gain! For low band SWL, 120 meters - 13 meters I do use it as needed depending on the time of year and conditions/mode. S/N on the SWL bands is
often a struggle, and fiddling with receive antenna's, RF gain, is key especially on 120m-41m. Yeah, there is life outside the "honey baked ham bands".
J
On Wed, Jan 8, 2025 at 03:13 AM, Joseph K7CBR wrote:
Are you still using electricity?
On Wednesday, January 8, 2025 at 05:19:40 PM EST, N3 EG <n3eg@...> wrote:
The RF Gain control has always been the most useless thing to put on a radio.? It's like a high/low switch on a vacuum cleaner, which should be called "Clean/Less Clean."? In the case of HF radios, it should be called the Ignore Weak Signal Stations And Screw Up Your S-Meter Reading Control.?
?
I've never found a good reason to use it in at least 52 years of HF listening, and it's totally useless on 10 meters and up.
|
Re: 6HS6 Price and Availability
>¡±I remember in the 70s hams experimenting with various tubes to "soup up" the front ends of their radios. These new types had higher transconductance and lower noise than what the factory supplied -- 6BZ6/6CB6/6GM6/6HS6, etc., and were all sharp-cutoff pentodes.¡± ? Several years ago, I purchased Electric Radio Magazine¡¯s 75A-4 Modification Compendium.? It¡¯s 240 pages of modifications in a 3-ring binder, many of which are related to optimizing the RF and mixer stages.? Collins chose a 6DC6 for the 75A-4¡¯s RF amp, although I believe 75A-4 production in 1955 may have pre-dated the 12BZ6 and 6HS6.? ? As Dave points out, most mods were primarily focused on noise and transconductance.? However, Bob Stankus, W2VCZ, heavily modified his 75A-4, beginning with a 6GM6 in the RF stage, followed by 7360s in the IF stages.? I believe his is one of the few mods that seriously consider dynamic range and front-end overload.? His modification is one of several in the Compendium.? ? Paul, W9AC
|
Re: 6HS6 Price and Availability
you guys seen this?
Lee, w0vt
_skw=10+pc+small+PCB+for+CMC+EIZZ+7+pins+tube+socket+adapter+7+pin+6Z4+6X4+6J1+6X4&itmmeta=01JH4R5JHHM35XZ770SEXGXNEY&hash=item41e46a6e90:g:AXgAAOSw4aZbH0-N&itmprp=enc%3AAQAJAAABMHoV3kP08IDx%2BKZ9MfhVJKlv%2BlvtfMcQEgaCtq6PEiXweii%2B1NhAyPxF97xLiUzHy2fFv5C9SMvyt5px%2BrLz45F1JNbnLID8qrvX4vqEJJkNIE9eT7nY4%2BtiAAHLxugfXxQLy2egBGJtEj6dV8eHlB%2BX9XJ486Ten90LuJLGLNrBmgj7MH29KgWfoRRiLIpUpLrLZCoGqwvq3M3G2697N%2FvX2U1rPIxBbmygnFqWqdeeTRQZw4tfU88dwabARBxpixG9v4LEq5m641Qq7qSsudiE9qtGCRSYdJAO%2B9Ju3vBNs%2BKKXztBb3cwoy3iPCPR7ObxCKcQugTuxRPhjDpwDkRP2IuGt0P3u7dmBRM6SbapF%2Bs4wEm2etOXZ0ba%2B5uqW5z2GpoKuD%2FWvyxRmf0JtYU%3D%7Ctkp%3ABk9SR_ColpiJZQ
On 1/8/2025 3:50 PM, Gary WB6OGD via
groups.io wrote:
toggle quoted message
Show quoted text
It is pretty easy to make a solid state mixer. Unlike
amplifiers, that need just a certain amount of amplification,
extra AVC inputs, etc., mixers are
basically non-linear choppers.? They just need enough gain to
chop and enough voltage tolerance for the circuit they are in.
?
My very first experiment was a J-310 FET(the only FET I had)
plugged into the R-4A Pre-mixer socket.? I only had to
disconnect the +150V plate supply resistor and hook it to about
18VDC(?).? Worked fine though hooking it to the T-4X and
selecting XMTR control might have blown it.
?
I researched more (stole designs and modded) and now have a
plug in tube replacement.? Works great.
Attached is what I think I am running now.? I also attached a
6AU6 replacement from the Collins site.
?
Beats trying to buy expensive, possibly bad old tubes.? YMMV.
My 6HS6 is now safe and part of my 401K IRA.. hi hi...
73,
Gary
WB6OGD
?
?
|
Re: AFG/RFG controls R4C (W1ES)
On 2025-01-08 17:18, Steve Wedge, W1ES/4 via groups.io wrote: Funny thing is, lately, my TR7 is the rig that most benefits from
lowering the RF gain a tad. Lots of popping on fast AVC, otherwise.
The A's and B's areen't as bad. The C is in between... *** My latest boat anchor project REALLY wants the RF gain set down. It's a Signal/One CX7A. Signal One messed up the injection to the product detector, and if you have the RF gain all the way up, it distorts. Voices sound harsh. There's a fix - you change one resistor. Waiting for me to get a round tuit. - Jerry, KF6VB
|
Mark Davis
Floyd - K8AC
Gary WB6OGD
Paul Christensen