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Re: XTAL help is needed

 


Gary wrote:

> Old fashioned crystals are obsolete!?

But the whole radio is obsolete, isn't it?? That's not really the point of the exercise!


Steve? WD8DAS


Re: Another TR7 Journey begins

 

I don't think it really matters a whole lot. the TR7 wattmeter is not what I would call a precision instrument. Germanium was likely chosen for low forward voltage drop. A pair of decent Schottky diodes should work fine.

73

-Jim
NU0C

On Mon, 25 Mar 2024 17:28:39 -0700
"Bill NZ0T" <nz0tham@...> wrote:

Thanks again Jim,

I wonder if one or both of the AA119 diodes are bad in the wattmeter circuit.? They test OK in circuit with a multimeter but maybe they go leaky with more voltage applied.? Won't be easy to replace tho.? And I doubt they are easy to find tho I think the 1N60 is pretty close.? They are germanium diodes.

I'll try checking voltages in the circuit in the morning.

73, Bill NZ0T


Re: XTAL help is needed

 


Thank you to those who suggested AF4K Crystals.? I responded to an email from Nick earlier today regarding his need for a 10.0874 MHz crystal.? I let him know I can supply an inexpensive 10.080 MHz from stock in an HC-49 holder and this might be able to be pulled up in frequency to meet the target or at least get close.

73?? Steve? WD8DAS

sbjohnston@...??
??
/??
--------------------------------------------------------------------??
Radio is your best entertainment value.??
--------------------------------------------------------------------??





Re: Another TR7 Journey begins

 

Thanks again Jim,

I wonder if one or both of the AA119 diodes are bad in the wattmeter circuit.? They test OK in circuit with a multimeter but maybe they go leaky with more voltage applied.? Won't be easy to replace tho.? And I doubt they are easy to find tho I think the 1N60 is pretty close.? They are germanium diodes.

I'll try checking voltages in the circuit in the morning.

73, Bill NZ0T


Re: XTAL help is needed

 

¿ªÔÆÌåÓý

The March/April 2024 issue of Electric Radio has an article about using a ProgRock "programmable crystal" in the restoration of a Heathit HX-1681.? Interesting information on how to program it and integrate it into the circuit.

-- Art Delibert, KB3FJO


From: [email protected] <[email protected]> on behalf of Gary WB6OGD <winbladgary@...>
Sent: Monday, March 25, 2024 5:16 PM
To: [email protected] <[email protected]>
Subject: Re: [DRAKE-RADIO] XTAL help is needed
?
Or replace a whole bank of crystals(59?) for $14, see the Files section for:

$14 Homebrew FS-4B

Old fashioned crystals are obsolete!? hi hi...
73,
Gary
WB6OGD


Re: Various Finds

 

Dang Gary I might be interested in the R7 as a challenge if Steve is not. If available please email me off list echapm4@...?

Thanks,?
Eric?
K8cca?

On Mon, Mar 25, 2024, 3:37?PM Gary Follett <xntrick1948@...> wrote:
Steve:

Are you interested in an R7 project? I have one that is pretty good cosmetically, comes with the filters it originally came with, no noise blanker,

It is disassembled. The PTO is rebuilt, I will need to find it.

All boards are there, most tested in a working R7. However, two power supply boards are suspect and the DR7 I have is best described as a parts unit.

This will never a project but I simply do not have the time to put into it.

Gary

W0DVN

> On Mar 25, 2024, at 2:32?PM, Steve Wedge, W1ES/4 via <w1es=[email protected]> wrote:
>
> I should mention that the TR7 I sold was off QRZ.? No commission, I could use my choice in shipping and payment.? Yeah, I love it when you can sell at a profit with low overhead.
>
> Basically, I enjoy fixing these things, playing with them for awhile, finding better ones and selling the previous one.? I've been able to make enough to keep my hobby self-supporting.? I currently also have three Drake sets and a power supply on my "on-deck" circle that belong to other hams who pay me to work on them.
>
> Besides the TR7A with PS7 and 7077, my Drake stable has all three major sets of Twins, a TR-4Cw RIT, TR-6, 2-B, 1-A, an extra T-4XB and an L7.? I acquire them as I go along and lots of my ham friends know that I'm "into" Drake stuff and they send info along.
>
> Besides the Drake gear, I have a Collins S Line with amp, a TS-830S and a TenTec Omni VI with the Plus added on.? This group of gear came to me with an Omni V, another R-4A and a second 75S-3B and I got the whole pile, as-is, for $400.? I made more than that back when I fixed and sold the extra 75S-3B.? Then fixed and sold the R-4A and diagnosed the Omni V and sold it, as is, to a happy buyer.? Not that it matters but I still live in the same house and still drive the same 2015 car.
>
>
>
> Steve Wedge, W1ES/4
>
> Time flies like an arrow.? Fruit flies like a banana.
>
> Sent with Proton Mail secure email.
>
> On Monday, March 25th, 2024 at 3:11 PM, Jim Shorney <jimNU0C@...> wrote:
>
>> An old salesman once said "don't charge a fair price, charge what the market will bear". If someone wants to spend that kind of money on a 1-A, that's fine. If no one bites the price will be reduced.
>>
>> I have gotten most of my good deals locally and some are almost legendary. Minty one owner R7A for $450, gently used L4B offered to me for $450 by a local who knew that I like Drake, an estate purchase of a TR7 station that netted me an L7 for about $150 after I cleaned the rest up and re-sold it to another local. Picked up a lonely PS7 for $75 at a fest a couple years ago so now I have one for each of my TR7s. Another local who likes to deal in used radios offered me a nice NC300 for 40 bucks just because he wanted to get it gone. A list member sold me an R7 a few years back for $300 because no one else was interested. One of my TR7s also from a list member for $150 as a fixer-upper. I won't even mention my deal of the century on the pair of Alphas....
>>
>> Ebay? What's that? :D
>>
>> 73
>>
>> -Jim
>> NU0C
>>
>> On Mon, 25 Mar 2024 18:41:35 +0000
>> "Steve Wedge, W1ES/4 via " w1es=[email protected] wrote:
>>
>>> Why does it bother people when someone knows how to market something and makes a good profit? I don¡¯t understand the mindset.
>>>
>>> Having said that, such deals come up, even at hamfests. My first TR7 came from Shelby in 2019, for $350 and included a PS7 and the matching mic. Also an AUX-7 And fully-stuffed filter board. I was expecting to have to do some work on it but it fired right up and worked great!
>>>
>>> I still have the filter board in my TR7A (I swapped because I liked the selection better) and am using the PS7 and mic. Oh ¡ª and (Grumble! Grumble!) sold the TR7 for $550. It was in really nice shape and was worth that price.
>>>
>>> 73,
>>>
>>> Steve Wedge, W1ES/4
>>>
>>> Time flies like an arrow. Fruit flies like a banana.
>>>
>>> Sent from Proton Mail for iOS
>>>
>>> On Mon, Mar 25, 2024 at 13:56, Lyndon VE7TFX <[lyndon@...](mailto:On Mon, Mar 25, 2024 at 13:56, Lyndon VE7TFX <<a href=)> wrote:
>>>
>>>> Rick W4XA writes:
>>>>
>>>>> The down-side of it is, we'll spend pretty good money to get cool vintage s=
>>>>> tuff and when it's all over, if someone doesn't jump in and help to sell th=
>>>>> e "stuff" our "non-ham" kids will either "give" it away or haul it to a lan=
>>>>> dfill!
>>>>
>>>> Case in point: two weeks ago I landed a TR-7, PS-7, MS-7, and a
>>>> Drake desk might of unknown model number for CAD$250. That's about
>>>> $195 in real money.
>>>>
>>>> How did this happen? The back story: the fellow I bought it from
>>>> didn't want it because it was too big for his desk and he preferred
>>>> his smaller more modern rig. He obviously did not know what he
>>>> had, and just wanted to get rid of it.
>>>>
>>>> He bought it from the BCIT radio club (British Columbia Institute
>>>> of Technology). My guess is that the club shut down for a couple
>>>> of years because virus. When the new crop of 20-somethings arrived,
>>>> they likely looked at the radio and said "no SDR -- eeewww! no
>>>> touchscreen -- eewww! old -- eewww!!!" and sold it very cheap as
>>>> an old boat anchor. It had obviously been sitting on the shelf for
>>>> a long while. I had to have at it with the deoxit on the band
>>>> switch, the PBT switch, and the RV-7 connector to get it functioning
>>>> again. I still need to strip it down and give it a complete
>>>> scrubbing. But I got a complete working TR-7 (loaded with filters)
>>>> for a song.
>>>>
>>>> They don't all wind up in the landfill :-) And sometimes I have
>>>> no qualms about taking advantage of people's lack of knowledge of
>>>> history.
>>>>
>>>> At least it didn't go to an eBuy grifter who would immediately try
>>>> to resell it for $1200.
>>>>
>>>> And yeah, I'm still trying to figure out how to rewrite my will so
>>>> that my stack of gear doesn't end up on eBuy ... (or in the landfill)
>>>>
>>>> --lyndon
>>
>>
>>
>>
>> --
>>
>> 73
>>
>> -Jim
>> NU0C
>>
>>
>>
>
>
>
>
>







Re: 1-A on eBay

 

On 2024-03-25 14:25, John K5MO wrote:
On Mon, Mar 25, 2024 at 12:11 PM, Jim Shorney wrote:
I just sold three vacuum tubes
The three sold quickly enough to pay for half the cost of a new
FTDX101D I now have on order. :-)
*** Many moons ago, I got three TV7D/U tube testers at the ham swap
for $20 each. The price those things get on Ebay now.... is eye-watering.

I think it's driven by audiophiles.

- Jerry, KF6VB


Re: 1-A on eBay

 

On 2024-03-25 13:24, Ralph Mowery via groups.io wrote:
It is easy to start off asking for a high price and lowering the
asking price. At hamfests I have bought and sold things at a price I
wanted or walked away
*** I generally start walking way when the seller says "On Ebay these go for...."

- Jerry, KF6VB


Re: 1-A on eBay

 

John...nice going.? May we ask what the tubes were?? I fear I have a few "finds" lying dormant and lost in my tube stash too.

73
Peter
VE7PS

On Mon, Mar 25, 2024 at 2:25?PM John K5MO <johnk5mo@...> wrote:
On Mon, Mar 25, 2024 at 12:11 PM, Jim Shorney wrote:
An old salesman once said "don't charge a fair price, charge what the market will bear". If someone wants to spend that kind of money

I just sold three vacuum tubes (old Western Electric) that I had found in one of the boxes of random pulls and NOS that I bought? 20+ yrs ago and never opened. They'd been lying on the garage floor since last November when I ran across them and I thought I should toss them on the 'Bay before I forgot about them for another 3 months.

?

The three sold quickly enough to pay for half the cost of a new FTDX101D I now have on order.? :-)

John K5MO


Re: 1-A on eBay

 

On Mon, Mar 25, 2024 at 12:11 PM, Jim Shorney wrote:
An old salesman once said "don't charge a fair price, charge what the market will bear". If someone wants to spend that kind of money

I just sold three vacuum tubes (old Western Electric) that I had found in one of the boxes of random pulls and NOS that I bought? 20+ yrs ago and never opened. They'd been lying on the garage floor since last November when I ran across them and I thought I should toss them on the 'Bay before I forgot about them for another 3 months.

?

The three sold quickly enough to pay for half the cost of a new FTDX101D I now have on order.? :-)

John K5MO


Re: XTAL help is needed

 

Or replace a whole bank of crystals(59?) for $14, see the Files section for:

$14 Homebrew FS-4B

Old fashioned crystals are obsolete!? hi hi...
73,
Gary
WB6OGD


Re: Another TR7 Journey begins

 

Great! I've come to the point that 10-turn pots are a necessary upgrade. Those little trimpots can go off if you look at them wrong. They may have been primo parts in the day but time marches on.

Proper ALC depends on proper operation of the wattmeter circuit. Get the wattmeter working right. It's pretty much the same circuit as a W4. You can disconnect the FWD WM and REFL WM inputs from the ALC board if you want to isolate it, just watch your drive level.

73

-Jim
NU0C

On Mon, 25 Mar 2024 13:56:06 -0700
"Bill NZ0T" <nz0tham@...> wrote:

Progress!? I went all the way back to the 10V setting which had moved to 9.1V for some reason - I can see why the 10 turn pots are a popular mod.? Got the oscillators? and VCXO within spec even the? 8.05 (just barely) without any cap padding.

So now I'm back to the transmitter alignment issues. I can get through the wattmeter null adjustment but the ALC adjustment is still wonky and, possibly because of that, the wattmeter is not working nor will it adjust. Will see what I can do tomorrow.

73, Bill NZ0T


Re: Another TR7 Journey begins

 

Progress!? I went all the way back to the 10V setting which had moved to 9.1V for some reason - I can see why the 10 turn pots are a popular mod.? Got the oscillators? and VCXO within spec even the? 8.05 (just barely) without any cap padding.

So now I'm back to the transmitter alignment issues. I can get through the wattmeter null adjustment but the ALC adjustment is still wonky and, possibly because of that, the wattmeter is not working nor will it adjust. Will see what I can do tomorrow.

73, Bill NZ0T
?


Re: 1-A on eBay

 

On Mon, 25 Mar 2024 20:17:47 +0000 (UTC)
"Paul Ellis via groups.io" <paulz67@...> wrote:

Disclaimer: Your reality may vary.
You kill me, man! I'm not sure I want to know about your reality.... :D

I forgot to mention the nice R-390/A with original meters that I bought from Evan (NOT the Evan in this group) for $150.

--

73

-Jim
NU0C


Re: grounded grids vs stock Drake

 

W8JI did a good analysis of this idea:



Scroll down to 'A Common "Bad Grid Idea" Super Cathode Drive'.

One take-away is that at some frequency in the HF spectrum that grid circuit is parallel resonant. That just seems like a bad idea. Of course this is not the only point in his analysis.

73

-Jim
NU0C

On Mon, 25 Mar 2024 20:21:46 +0000
"Clyde K2UE" <clydewashburn1@...> wrote:

The mechanism of feedback is the capacitive divider formed by the plate
to grid capacitance and the grid to ground capacitance. The average of
the various 3-500Z data sheets suggest plate to grid is 4.4 pF and each
tube has 600 pF of grid to ground capacitance, so it is a a roughly
136:1 voltage divider. Taking the 2500V case, the RMS plate voltage at
600W per tube is 1440V, which causes 10.6V to be applied to the grid, in
opposition to the cathode. The driving power without feedback is 46W
into 100 ohms, or 67.8V, so the feedback has increased that to 78.4 V,
or 61.5 W (ignoring the grid current loading). So so in the simple case
33% more power is required for the same output. Note that max output is
not reduced -- it just takes more power to get there. But if you have a
100W driver you are not able to supply more drive, and conclude that
grounding the grids "makes more power". With a 150 or 200W driver you
crank up the power, get the same output as before, but reduced
distortion due to the feedback.

You can imagine the linearity enhancing effect by noting that the grid
current shoots up at the peak of the drive cycle and is very non-linear.
So when the grid current is reaching peak it is shunting the feedback,
i.e there is less negative voltage on the grid opposing the drive,
helping the tube reach the peak current needed to accurately reproduce
the peak -- in other words, better linearity.

The above calculations are obviously an approximation, ignoring that the
reactance of grid-to-ground capacitance changes by 16:1 over the various
ham bands, and the grid input impedance in in shunt with it. But that
is the mechanism in a nutshell.

______________________________________________________________
Clyde Washburn
ClydeWashburn1@...

"It is better to light one candle than to curse the darkness"


------ Original Message ------
From "Paul Kraemer" <elespe@...>
To "[email protected]" <[email protected]>
Date 3/25/2024 3:23:29 PM
Subject [DRAKE-RADIO] grounded grids vs stock Drake

Curious as to what should actually be expected regarding power gain going from the "floating" grids in L4B / L7 vs strapping the grids directly to ground. I see 200 watt increase on one L7. Increases from 1kw to 1200w, same drive level and power supply. Is that believable? Seems a bit high but that is what I am seeing on one amp.

Thanks

Paul K0UYA













--

73

-Jim
NU0C


Re: grounded grids vs stock Drake

 

My homebrew single 3-500Z amp from the 1970s used directly-grounded grids. I see nothing wrong with Drake having added some negative feedback, but it wasn't consistent with frequency due the three 200pF capacitors per tube. Possibly this somewhat flattened out the drive requirement from 80 - 10 meters. (A supposition only)

My amp used a 10-volt 50-watt zener diode grounded to the chassis for bias on SSB (likely a bit higher than optimum for linearity) with 2800 volts key down on the plate. During RX or on CW I switched in a 30-volt zener which was biased modestly beyond cutoff.

For this project I purchased the 3-500Z from Drake for $35.00. Those were the days!

Rob, NC0B

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Jim Shorney
Sent: Monday, March 25, 2024 2:14 PM
To: [email protected]
Subject: Re: [DRAKE-RADIO] grounded grids vs stock Drake


It seems worth noting that in recent years amplifier manufacturers have returned to the idea of directly grounding the grids.

73

-Jim
NU0C

On Mon, 25 Mar 2024 19:37:22 +0000
"Steve Wedge, W1ES/4 via groups.io" <w1es@...> wrote:

I've been considering doing this, after a long stretch of keeping the grids slightly above DC ground. I've also been considering changing the bias to the stack o'zeners. I have a Harbach power supply board but I'm not sure if that has the alternative biasing on it. Currently, the amp idles at about 200 mA, which just seems excessive to me. I can get about 1200W out before the grids get overdriven (I like to keep the combined Ig below 300mA).

74,

Steve Wedge, W1ES/4

Time flies like an arrow.? Fruit flies like a banana.

Sent with Proton Mail secure email.

On Monday, March 25th, 2024 at 3:23 PM, Paul Kraemer <elespe@...> wrote:

Curious as to what should actually be expected regarding power gain
going from the "floating" grids in L4B / L7 vs strapping the grids
directly to ground. I see 200 watt increase on one L7. Increases from
1kw to 1200w, same drive level and power supply. Is that believable?
Seems a bit high but that is what I am seeing on one amp.

Thanks

Paul K0UYA


Re: 1-A on eBay

 

It is easy to start off asking for a high price and lowering the asking price.? At hamfests I have bought and sold things at a price I wanted or walked away or? kept the items if the price was not to my liking.? As the day goes on the prices often get less.


Probably the most expensive thing on earth for size or weight is totally useless.??
An old used postage stamp last sold for 8.3 million dollars.

I think that is the only remaining one in the world.
?British Guiana 1c Magenta






Ralph ku4pt




On Monday, March 25, 2024 at 03:11:34 PM EDT, Jim Shorney <jimnu0c@...> wrote:



An old salesman once said "don't charge a fair price, charge what the market will bear". If someone wants to spend that kind of money on a 1-A, that's fine. If no one bites the price will be reduced.

I have gotten most of my good deals locally and some are almost legendary. Minty one owner R7A for $450, gently used L4B offered to me for $450 by a local who knew that I like Drake, an estate purchase of a TR7 station that netted me an L7 for about $150 after I cleaned the rest up and re-sold it to another local. Picked up a lonely PS7 for $75 at a fest a couple years ago so now I have one for each of my TR7s. Another local who likes to deal in used radios offered me a nice NC300 for 40 bucks just because he wanted to get it gone. A list member sold me an R7 a few years back for $300 because no one else was interested. One of my TR7s also from a list member for $150 as a fixer-upper. I won't even mention my deal of the century on the pair of Alphas....

Ebay? What's that? :D

73

-Jim
NU0C


Re: grounded grids vs stock Drake

Clyde K2UE
 

The mechanism of feedback is the capacitive divider formed by the plate to grid capacitance and the grid to ground capacitance.? The average of the various 3-500Z data sheets suggest plate to grid is 4.4 pF and each tube has 600 pF of grid to ground capacitance, so it is a a roughly 136:1 voltage divider.? Taking the 2500V case, the RMS plate voltage at 600W per tube is 1440V, which causes 10.6V to be applied to the grid, in opposition to the cathode.? ?The driving power without feedback is 46W into 100 ohms, or 67.8V, so the feedback has increased that to 78.4 V, or 61.5 W (ignoring the grid current loading).? So so in the simple case 33% more power is required for the same output.? Note that max output is not reduced -- it just takes more power to get there.? But if you have a 100W driver you are not able to supply more drive, and conclude that grounding the grids "makes more power".? With a 150 or 200W driver you crank up the power, get the same output as before, but reduced distortion due to the feedback.

You can imagine the linearity enhancing effect by noting that the grid current shoots up at the peak of the drive cycle and is very non-linear.? So when the grid current is reaching peak it is shunting the feedback, i.e there is less negative voltage on the grid opposing the drive, helping the tube reach the peak current needed to accurately reproduce the peak -- in other words, better linearity.

The above calculations are obviously an approximation, ignoring that the reactance of grid-to-ground capacitance changes by 16:1 over the various ham bands, and the grid input impedance in in shunt with it.? But that is the mechanism in a nutshell.

______________________________________________________________
Clyde Washburn

"It is better to light one candle than to curse the darkness"


------ Original Message ------
From "Paul Kraemer" <elespe@...>
Date 3/25/2024 3:23:29 PM
Subject [DRAKE-RADIO] grounded grids vs stock Drake

Curious as to what should actually be expected regarding power gain going from the "floating" grids in L4B / L7 vs strapping the grids directly to ground.? I see 200 watt increase on one L7. Increases from 1kw to 1200w, same drive level and power supply. Is that believable?? Seems a bit high but that is what I am seeing on one amp.
?
Thanks
?
Paul K0UYA
?
?
?
?
?
?
?


Re: 1-A on eBay

 

This. The market for cool vintage gear has certainly shifted, as experienced hams are moving on and/or dying off, as always... In the meantime, pricing on new/shiny/SDR flavored gear has gotten insanely cheap, relative to the capabilities and performance -- which has increased dramatically over the past ten years or so. Will there be a market for classic gear in the future? Of course--not unlike the classic car hobby.?

A few months back I posted my 1A for sale here, and all I heard was crickets. I'm pretty much over selling anything on eBay, so it also was marketed on Facebook Marketplace and Craigslist. I ultimately did a cash + trade for a Ten-Tec setup (locally-ish, with another member on this group) as a result of the Marketplace ad. The Ten-Tec setup, while it exceeded my expectations, will be hamfest fodder in the months ahead.

Disclaimer: Your reality may vary.

Paul
KA0JQF


Re: grounded grids vs stock Drake

 

It seems worth noting that in recent years amplifier manufacturers have returned to the idea of directly grounding the grids.

73

-Jim
NU0C

On Mon, 25 Mar 2024 19:37:22 +0000
"Steve Wedge, W1ES/4 via groups.io" <w1es@...> wrote:

I've been considering doing this, after a long stretch of keeping the grids slightly above DC ground. I've also been considering changing the bias to the stack o'zeners. I have a Harbach power supply board but I'm not sure if that has the alternative biasing on it. Currently, the amp idles at about 200 mA, which just seems excessive to me. I can get about 1200W out before the grids get overdriven (I like to keep the combined Ig below 300mA).

74,

Steve Wedge, W1ES/4

Time flies like an arrow.? Fruit flies like a banana.

Sent with Proton Mail secure email.

On Monday, March 25th, 2024 at 3:23 PM, Paul Kraemer <elespe@...> wrote:

Curious as to what should actually be expected regarding power gain
going from the "floating" grids in L4B / L7 vs strapping the grids
directly to ground. I see 200 watt increase on one L7. Increases from
1kw to 1200w, same drive level and power supply. Is that believable?
Seems a bit high but that is what I am seeing on one amp.

Thanks

Paul K0UYA