True for casual operating but when chasing rare DX every dB counts! :D

73

-Jim
NU0C

On Fri, 08 Mar 2024 11:22:13 -0800
"amfone via groups.io" <amfone20000@...> wrote:

True Rick the Drake gear used carrier control output in the AM mode ( no agc when using AM ) and the amp really? thinks its looking at an SSB signal. I've done this too with? good reports. And yes on the db difference you noted, at 100watts you have to get to 200 watts to just get 3db of signal difference on the receive end and to 400 watts to get an S-Unit.
73 Tim
WB8UHZ

On Friday, March 8, 2024 at 02:12:38 PM EST, Rick W4XA <myr748@...> wrote:

On Tue, Mar 5, 2024 at 11:21 AM, amfone wrote:

//////I normally tune for about 500 watts on the meter, this is below of course the ratings for the tube noted by Drake in the manual. If I run AM phone with the amp using a modern rig I will have a carrier output of not more that 125 watts,///////73 and thanks again.?Tim?WB8UHZ???

Tim,

You mentioned running AM with the L-4B and I thought I would share my experience running AM with my? C-Line.?? I think just about everyone here know that Drake used screen modulation with carrier control in the TR-3/4/6 transceivers and the T-4x A/B and maybe others.

It's interesting how really inefficient it is (using Drake tube transceivers and transmitters)? considering (IIRC) that they either screen modulated the driver (12BY7... TR-4/T-4X) or the final 12JB6's in the TR-3 etc.

So using an L-4B (or L-7) driving with a T-4X or TR-4 you could conceivably be running a screen modulated AM signal through 2 linear amplifiers (2 or 3 6JB6)? or just the 12JB6's in the TR-3

But it would appear that Drake intended the L-4/L-4B on AM to be operated using a Drake "driver" which would loosely approximate the average and peak power of driving with SSB.

And so I have actually used my T-4XB (that I bought new) to drive the L-4B on AM. (In the SSB MODE)

All tuned up, the "resting" carrier (controlled)? level is not quite 150W.?

Running the amp on 240 AC, It "talks" up to around 1400W PEP (output)? measured with both the? Array Solutions Power Master II and the peak reading watt-meter in the Palstar HF-Auto tuner.

I get signal reports similar to what the Viking 500 guys get in the Pacific NW

Driving it with any other NON-carrier controlled AM driver would require up to 375W of "resting" (or steady ) carrier to even come close to the above PEP

The 3-500's do also show some "color" when operating on AM.? I also tried a pair of 3-400's (that I have for my Loudenboomer) and they produced identical results.

Now having said all that, I never do "Lock-to-Talk" AM for 20min or even 10min like some of my "Verbose" friends do!? In fact, when I pause, I drop the carrier.?

But if I stop talking the power output still drops to a little less than 150W

I don't think anyone has ever told me that they could tell I was using Carrier Controlled AM unless I mentioned it.

And I actually would rather use my Viking Valiant anyway.?
Besides, 450W PEP with the Valiant and the 1300-1400W PEP running the C-Line / L-4B is only about a 5db difference and not really worth it.

73/Rick
W4XA
*Every post is created using Linux

--

73

-Jim
NU0C

It is all relative. An Alpha 374A sold here recently at an estate sale for $400. I probably should have bought it because it was a working amp that I had actually used multiple years at a multi-op SS shack. But I am full up on amps now anyway. I paid $450 for my L-4B from another local almost 20 years ago, gently used with original tubes. OTOH I see $1K+ prices for Drake amps in online forums. An old salesman once said "don't charge a fair price, charge what the market will bear".

Eric: Pull the top cover off and inspect the condition of the tuning caps, band switch, and tubes. Offer the guy $1200 cash if it meets the description and go from there. Ham radio is all about dickering over over price.

73

-Jim
NU0C

On Fri, 08 Mar 2024 10:10:05 -0800
"Rick W4XA" <myr748@...> wrote:

Eric,

About 3 or 4 years ago, I bought an L-4B for $700.? I got a really "smokin" deal? I would expect a nice L-4B to be worth around $1000.? Possibly more.

About 6mo ago, a friend of mine bought an L-7 for $700.?? And although it was completely stock (original caps etc) He got a REALLY "Smokin" deal.

They should also be worth North of $1000.? Maybe closer to $1500

But here's the bottom line.?? They're only worth what someone will pay.? If you see them SELL on eBay for $1600 (plus shipping) and there's a LOT of bidders near that final price then? there's a good chance one or more of them will give near to that kind of money for one.

If you make a comparison to used Ameritron AL-82's or other (2) 3-500 amps $1600 might not be far off.

Right now, on QTH I found 2 Kenwood TL-922's for around $1200-1300,? an AL-82 for $1600 and an L-4B for $1200 (shipped)

Another bottom line, if you walk up to the front door of the owners of the above amps with cash in your hand, they will likely take less.? You don't know until you try.

I wouldn't sell my L-4B for less than about 1300......but I probably wouldn't sell it at all.? It matches my C-line (that I bought new)

--
*73/Rick* *W4XA
* * Every post is created using Linux *
*

--

73

-Jim
NU0C

On Tue, Mar 5, 2024 at 11:21 AM, amfone wrote:

//////

I normally tune for about 500 watts on the meter, this is below of course the ratings for the tube noted by Drake in the manual. If I run AM phone with the amp using a modern rig I will have a carrier output of not more that 125 watts,

///////

73 and thanks again.

?

Tim

?

WB8UHZ

?

?

?

Tim,

You mentioned running AM with the L-4B and I thought I would share my experience running AM with my? C-Line.?? I think just about everyone here know that Drake used screen modulation with carrier control in the TR-3/4/6 transceivers and the T-4x A/B and maybe others.

It's interesting how really inefficient it is (using Drake tube transceivers and transmitters)? considering (IIRC) that they either screen modulated the driver (12BY7... TR-4/T-4X) or the final 12JB6's in the TR-3 etc.

So using an L-4B (or L-7) driving with a T-4X or TR-4 you could conceivably be running a screen modulated AM signal through 2 linear amplifiers (2 or 3 6JB6)? or just the 12JB6's in the TR-3

But it would appear that Drake intended the L-4/L-4B on AM to be operated using a Drake "driver" which would loosely approximate the average and peak power of driving with SSB.

And so I have actually used my T-4XB (that I bought new) to drive the L-4B on AM. (In the SSB MODE)

All tuned up, the "resting" carrier (controlled)? level is not quite 150W.?

Running the amp on 240 AC, It "talks" up to around 1400W PEP (output)? measured with both the? Array Solutions Power Master II and the peak reading watt-meter in the Palstar HF-Auto tuner.

I get signal reports similar to what the Viking 500 guys get in the Pacific NW

Driving it with any other NON-carrier controlled AM driver would require up to 375W of "resting" (or steady ) carrier to even come close to the above PEP

The 3-500's do also show some "color" when operating on AM.? I also tried a pair of 3-400's (that I have for my Loudenboomer) and they produced identical results.

Now having said all that, I never do "Lock-to-Talk" AM for 20min or even 10min like some of my "Verbose" friends do!? In fact, when I pause, I drop the carrier.?

But if I stop talking the power output still drops to a little less than 150W

I don't think anyone has ever told me that they could tell I was using Carrier Controlled AM unless I mentioned it.

And I actually would rather use my Viking Valiant anyway.?
Besides, 450W PEP with the Valiant and the 1300-1400W PEP running the C-Line / L-4B is only about a 5db difference and not really worth it.

73/Rick

W4XA
*Every post is created using Linux

Eric,

About 3 or 4 years ago, I bought an L-4B for $700.? I got a really "smokin" deal? I would expect a nice L-4B to be worth around $1000.? Possibly more.

About 6mo ago, a friend of mine bought an L-7 for $700.?? And although it was completely stock (original caps etc) He got a REALLY "Smokin" deal.

They should also be worth North of $1000.? Maybe closer to $1500

But here's the bottom line.?? They're only worth what someone will pay.? If you see them SELL on eBay for $1600 (plus shipping) and there's a LOT of bidders near that final price then? there's a good chance one or more of them will give near to that kind of money for one.

If you make a comparison to used Ameritron AL-82's or other (2) 3-500 amps $1600 might not be far off.

Right now, on QTH I found 2 Kenwood TL-922's for around $1200-1300,? an AL-82 for $1600 and an L-4B for $1200 (shipped)

Another bottom line, if you walk up to the front door of the owners of the above amps with cash in your hand, they will likely take less.? You don't know until you try.

I wouldn't sell my L-4B for less than about 1300......but I probably wouldn't sell it at all.? It matches my C-line (that I bought new)


--

73/Rick

W4XA
*Every post is created using Linux

Hey guys, I have a perhaps silly question.? I am working to fill out my TR7 station and? found an L7 that is super clean, supposed to have had the PS rebuilt with Harbach board and good tubes.? Asking price is 1600.? Is that reasonable these days?? In person transaction, so no shipping.? I have a really nice L4B that I would likely sell, what would a fair price be for that one???

Thanks guys!
Eric
K8CCA

I am fairly new to Drakes and antique radio repair/service and have now got two(TR-4 and T-4XC(w/R-4C) receiving and transmitting.? (In face checked into a net with each so very happy with that)These maybe questions that have been answered before so thanks in advance.? On the Tr-4 when I turn on and tubes heat up receive audio strong as the tubes seem to warm up the receive audio gets quieter to the point I have the RCVR Gain all the way up, RF Gain all the way up and you can hear the audio but very low.? I have tried on MS-4, MC-4 and RV-4 speakers and same issue.? Is there a particular tube I should check, adjustment I should look at?? Also, when transmitting the microphone gain is quite low not pushing much power on SSB.? I have tried a couple different mics which have Hi-Z output(I purchased a Heil GM Elite Vintage-Single Element High Impedance Microphone)and have also used a Shure KCB4.? Both have been reported with good audio quality but have to almost yell into them to get enough input/output to move the Watt Meter to generate enough power to get out.? I could run them into a mixer and/or mic pre-amp and crank up the volume which might work but feel I shouldn't have to do that.? Same with audio on the TR-4 and output to a mixer/amp into other external speakers to get enough volume.? The T-4XC-R-4C puts out plenty of audio and don't have to turn up a couple of notches and it quite loud.??

?I have learned a lot from this forum(including solving my SSB frequency issue I had) Thanks in advance for any advice or suggestions!

Mark

Hi Bill & George

How about injecting the Crystal Eliminator signal via the "XTAL LOCK" socket? The Crystal Eliminator signal via the "XTAL LOCK" socket must be AC-coupled via a 1 nF capacitor - and the signal might need to be attenuated and terminated with 50 ohm?

If so, the square wave will be bandpass filtered and a fine sine wave will appear on V2 cathode. C59 might be disconnected, so V8 do not oscillate - maybe it is not necessary?

Schematic:
http://www.ve6kq.com/drake.html

--
best regards,

Glenn, OZ1HFT

The earlier amps were built under the 1 Kilowatt DC input rule, which translates to 600-ish Watts CW output. That's what they would have been doing in the ads run during that period. A 1500 Watt carrier output would have been above the legal limit in those days.

73

-Jim
NU0C

On Thu, 07 Mar 2024 14:44:28 -0800
"Benton W4JBA" <uoba@...> wrote:

Like Rob said, Alpha did market their own dummy loads. One was a Model 2000, and the other was a Model 2100. Both were capable of 6KW burst of between 1 and 2 minutes, and both were capable of 1500 watts legal limit key down forever. Just like their amps!
73,
de Benton

开云体育

Any demonstrations I saw at Dayton were sending dits. ?Rob, NC0B?

Like Rob said, Alpha did market their own dummy loads. One was a Model 2000, and the other was a Model 2100. Both were capable of 6KW burst of between 1 and 2 minutes, and both were capable of 1500 watts legal limit key down forever. Just like their amps!
73,
de Benton

On Thu, Mar 7, 2024 at 12:49 PM, jerry-KF6VB wrote:

I guess if you were in one of the cheap-water states you could just hook it up
to a hose and run water through it to a drain or out to the lawn.? - Jerry, KF6VB

For amp testing I use either a 1KW Bird oil-cooled load or the Altronic Omegaline shown below.? It's a compact 5KW no-time-limit test load, good up to 2 GHz provided there's ample water flow.? At 2KW, the output water is lukewarm.? For permanent installations, a flow switch can be added to kill transmitter power if the outlet water volume drops below the switch's flow threshold.? If flow drops or is impeded in any way, the switch prevents the internal glass resistor from shattering.? ? ?

Paul, W9AC

?

?

Mine is 600 Watt CCS oil cooled. There is a note in the Bird catalog that the oil cooled loads can take a 10 dB peak to average ratio. So in theory I could hit it with kilowatts for very short periods. I'm not inclined to test that claim.

73

-Jim
NU0C

On Thu, 07 Mar 2024 12:31:41 -0800
"Steve Wedge, W1ES/4 via groups.io" <w1es@...> wrote:

I have a water-cooled Bird load that can take a kW for long enough to measure, when it’s dry. I’ve never run it water-cooled and have tested many L-4/L-7/LK-500/SB-220 type amps over the years. If I ran it water-cooled, it could take 2500W, CCS.

Steve Wedge, W1ES/4

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

Sent from [Proton Mail]() for iOS

On Thu, Mar 7, 2024 at 2:34 PM, Jim Shorney <[jimNU0C@...](mailto:On Thu, Mar 7, 2024 at 2:34 PM, Jim Shorney <<a href=)> wrote:

Probably a biga$$ Bird. At the 1KW DC input level I have one that would handle it.

73

-Jim
NU0C

On Thu, 07 Mar 2024 11:03:01 -0800
"jerry-KF6VB" <jerry@...> wrote:

I wonder what they used for a dummy load?

- Jerry, KF6VB

p.s. It's probably time to get the Beast ( Alpha 78 ) out of the shed
and give it
some exercise before the electrolytics dry out.

--

73

-Jim
NU0C

--

73

-Jim
NU0C

Remember Alpha sold a legal limit dummy load. There was the original and then a follow-up version.

Rob, NC0B

Too bad they couldn't have simply connected it back to the local electrical grid and called it a wash.

Barry - N4BUQ

开云体育

I was lucky a couple of years ago, when I was helping a widow with her SK's ham radio gear.? I was able to get a like new 5 kw Bird dummy load for $600.? She was happy, I was happy...

I guess I need to build a bigger amp now...

Steve, NR4M