Re: Drake MN7 Tuner Knobs
The lacquer coating on mine is shot. I was thinking about refinishing it but I don't know how they got that fine finish on the original. 73 -Jim NU0C On Mon, 04 Mar 2024 15:51:15 -0800 "K6OXN Bob" <bobk6oxn@...> wrote: Kevin, I am looking for a new skirt or replacement skirt for the RV-75 that I am working on. The knob is identical to the one on a TR-7. The skirt is just that a skirt, it has no function and fits the 1/4 inch shaft.? It appears you might have one in the picture shown or at least one that might work.? Most appreciated.
73? Bob
-- 73 -Jim NU0C
|
Re: Drake MN7 Tuner Knobs
I twiddled my MN2700 knobs several times during the contest. In all seriousness, I used to have several NOS big knobs with a 23 channel dial skirt for the Hy-Gain 623 CB rig. I have not seen them in decades so they are either deeply buried or I gave them away at some point. But they do exist. 73 -Jim NU0C On Mon, 04 Mar 2024 12:44:06 -0800 "Bill via groups.io" <billnopic@...> wrote: Well that turned into an interesting Contest discussion. Very Cool!
Let me hijack myself back to my knob issue Hi Hi.
Kevin,
Well I found my old knob and of course it had a good knob skirt. I just forgot I had?it. Such is my life ughhh
And the original is a 2 inch knob. So, yes if you have a 2 inch you can part with, I would appreciate it. You can contact me at billnopic@... and let me what you need for it.
Thank You Sir!
73
Bill
W4WCS
|
I had that issue recently on a radio in the shop for repair. It was the 24v regulator U2103. M78L24c Bob KF8IY
On Monday, March 4, 2024 at 03:14:08 PM EST, Adam W4AJF <adamf@...> wrote:
> Hi all, I have an issue with the display board in one of my Drake
> TR-7's and it's the board for sure because I installed the problem
> board in another TR-7 and it has the EXACT same issue: On the TR-7
> with the issue it was fine and not used for a while, turned it on and
> now the display shows 51.950 on all bands. The VFO will move it up and
> down but of course it will still be in that range on all bands but it
> does receive and transmit. I see this issue has been discussed on this
> web site but I don't see any answers?
Any help appreciated, I am hoping someone has figured out how to fix
this Specific issue.
> Adam Farber W4AJF
> Cooper City, FL
>
|
Re: Drake MN7 Tuner Knobs
Kevin, I am looking for a new skirt or replacement skirt for the RV-75 that I am working on. The knob is identical to the one on a TR-7. The skirt is just that a skirt, it has no function and fits the 1/4 inch shaft.? It appears you might have one in the picture shown or at least one that might work.? Most appreciated.
73? Bob
|
Those figures don't indicate a problem.? Ideally, TP2, with the preselector detuned, should read -1.35V? Your reading isn't terrible.? So now we need to see why you're getting S5 with no signal.? On the schematic, R41 and R89, in the meter bridge circuit, should be checked.
Steve Wedge, W1ES/4
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
On Monday, March 4th, 2024 at 3:53 PM, Michael Jensen <kavigal@...> wrote:
@Steve Tonight's numbers :).
Cold and detuned TP2=-1.335v
30 mins TP2=-1.267v
60 mins TP2=-1.259v
I get your point about "
The important part here is if the voltage at TP2 with respect to time."
Now what is the verdict? Too much voltage drop? What do you think?
Thanks, Michael.
On Sun, Mar 3, 2024 at 11:49?PM Steve Wedge, W1ES/4 via <w1es= [email protected]> wrote: Resistance is the most important here.
We now need to measure the TP2 voltage from startup to a point long after warmup. If this value drifts towards 0V then there is a chance that you have a gassy tube.
The important part here is if the voltage at TP2 with respect to time.
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
Sent with secure email.
On Sunday, March 3rd, 2024 at 12:50 PM, Michael Jensen < kavigal@...> wrote:
HI again!
Tak for linked Glenn, kunne godt minde lidt om mit problem :). Okay enough "Danglish" .. @Steve, Thanks for taking your time to reply! Detuned and with AVC ON, TP2 voltage is-1.26, right now, I did an adjustment cold, so seems to have dropped ever so slightly after proper warm up.
RF GAIN Pot measures ~12Ohms(seem to be some capacitance) with wires attached, so guess that is quite okay.
Thanks, Michael-oz8abr
On Sun, Mar 3, 2024 at 2:11?PM Steve Wedge, W1ES/4 via <w1es= [email protected]> wrote: Michael, what is the voltage at TP2? There are other resistors in the bridge circuit and I have seen them go out of tolerance.
What is the resistance reading across the RF GAIN pot?
73,
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
On Sun, Mar 3, 2024 at 07:09, Glenn, OZ1HFT < glenn.mh.dk@...> wrote: Hi Michael
See this thread:
/g/DRAKE-RADIO/topic/r_4b_agc_issues_part_trois/103544827
--
best regards,
Glenn, OZ1HFT
|
Re: Drake L7 Power output
True statement Jim! Some sort of protection is definitely needed to prevent arcing the power switch on "make" (or break) ? I'm using a solid state relay to completely eliminate stress on the "un-obtanium" switch .? (I also put one in my AC-4 too....no more thumps or bangs inside the AC-4,? nor sparks inside the T-4XC switch)   3-500's are good up to 4000V.? I'm thinking that 2700V probably won't? "hurt" them. And when tuning for maximum output, the tubes should be tuned at the voltage and (max) current they'll be drawing at peak for lowest grid current and best linearity.??? Grid current is also a little lower at the at the higher voltages.? Drake only did the "tune" position to meet the FCC max power (single-tone/CW 1KW input)? of the time. If you want to be "easy" on the amp, just drive it to a lower power output. (lower drive = lower grid/plate current and output) I am re-building the power supply for my Hallicrafters HT-45 Loudenboomer (single 3-400) using a plate transformer out of a Drake L-4PS. ? ? It'll get the same SSR and won't be wired for switchable plate voltage.
On Mon, Mar 4, 2024 at 10:39 AM, Jim Shorney wrote:
Personally I like having the low power switch. You have less inrush current at power on (regardless of whether or not you have a soft start installed) and it is easier on the tubes for initial tune-up and when testing an amp.
73
-Jim
NU0C
--
73/Rick
W4XA
*Every post is created using Linux
|
@Steve Tonight's numbers :).
Cold and detuned TP2=-1.335v
30 mins TP2=-1.267v
60 mins TP2=-1.259v
I get your point about "
The important part here is if the voltage at TP2 with respect to time."
Now what is the verdict? Too much voltage drop? What do you think?
Thanks, Michael.
On Sun, Mar 3, 2024 at 11:49?PM Steve Wedge, W1ES/4 via <w1es= [email protected]> wrote: Resistance is the most important here.
We now need to measure the TP2 voltage from startup to a point long after warmup.? If this value drifts towards 0V then there is a chance that you have a gassy tube.
The important part here is if the voltage at TP2 with respect to time.
Steve Wedge, W1ES/4
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
On Sunday, March 3rd, 2024 at 12:50 PM, Michael Jensen < kavigal@...> wrote:
HI again!
Tak for linked Glenn, kunne godt minde lidt om mit problem :). Okay enough "Danglish" .. @Steve, Thanks for taking your time to reply! Detuned and with AVC ON, TP2 voltage is-1.26, right now, I did an adjustment cold, so seems to have dropped ever so slightly after proper warm up.
RF GAIN Pot measures ~12Ohms(seem to be some capacitance) with wires attached, so guess that is quite okay.
Thanks, Michael-oz8abr
On Sun, Mar 3, 2024 at 2:11?PM Steve Wedge, W1ES/4 via <w1es= [email protected]> wrote: Michael, what is the voltage at TP2? There are other resistors in the bridge circuit and I have seen them go out of tolerance.
What is the resistance reading across the RF GAIN pot?
73,
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
On Sun, Mar 3, 2024 at 07:09, Glenn, OZ1HFT < glenn.mh.dk@...> wrote: Hi Michael
See this thread:
/g/DRAKE-RADIO/topic/r_4b_agc_issues_part_trois/103544827
--
best regards,
Glenn, OZ1HFT
|
Re: Drake MN7 Tuner Knobs
Well that turned into an interesting Contest discussion. Very Cool! Let me hijack myself back to my knob issue Hi Hi. Kevin,? Well I found my old knob and of course it had a good knob skirt. I just forgot I had?it. Such is my life ughhh And the original is a 2 inch knob. So, yes if you have a 2 inch you can part with, I would appreciate it. You can contact me at? billnopic@...?and let me what you need for it. Thank You Sir! 73 Bill W4WCS ?  
|
Hi all, I have an issue with the display board in one of my Drake TR-7's and it's the board for sure because I installed the problem board in another TR-7 and it has the EXACT same issue: On the TR-7 with the issue it was fine and not used for a while, turned it on and now the display shows 51.950 on all bands. The VFO will move it up and down but of course it will still be in that range on all bands but it does receive and transmit. I see this issue has been discussed on this web site but I don't see any answers? Any help appreciated, I am hoping someone has figured out how to fix this Specific issue. Adam Farber W4AJF
Cooper City, FL
|
Re: Why a pentode mixer in Drake 4x-line receivers?
It may be in a location where noise is important. Pentagrid mixers have some advantage in the isolation of the signal and oscillator but they are the noisiest form or mixer. Pentodes have less isolation but are much quieter and triodes even less noise. I don't know off hand of a good tutorial on tube mixers and converters but they exist.
I don't know why Drake made the choice but I think cost had little to do with it.
toggle quoted message
Show quoted text
On 3/4/2024 10:12 AM, Glenn, OZ1HFT wrote: [Edited Message Follows]
Why do?Drake 4x-line receivers use a pentode in 1. mixer?
Why not a true pentagrid/hexode converter mixer - e.g. ECH81?
Yes a pentode is cheaper, but are a pentagrid/hexode tube not way better? What are the trade-offs?
--
best regards,
Glenn, OZ1HFT
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
|
New here and trying to help a friend sell off his estate
Good afternoon everyone. I¡¯m helping a friend sell off his Drake equipment as he is moving into a retirement home. I figured this would be the best place to post this gear so it lands in the hands of the people who appreciate it. He has a?
R-4B
TR-4CW
MS-4/AC-4
W-4
He stated that they haven¡¯t been turned on in 5 years and I have not attempted to bring any of them online. If anyone is interested in picking all of this up from my QTH in Mount Airy, Maryland, please shoot me a message. They all look to be complete with the exception of the TR-4CW, which is missing the top cover. He is asking for $400 for the whole lot. I can provide pictures but I¡¯m having trouble posting them here.
I¡¯ll do my best to answer any questions but I¡¯m more familiar with Collins and National radios.
Thank you in advance,
Adam?
|
Re: Drake L7 Power output
Some things to know/ realize:
With new tubes and the plate voltage on the high setting and with a reasonable dummy or antenna load, you will easily get 1200 Watts.
It is typical that the higher frequencies are lower output power.? This is also a useful, broad based measure of your tubes.? Aged tubes have less power on the higher frequencies.? Tubes that are new and presently available?are, in my opinion, generally of poorer quality that the originally used and intended tubes.
Your watt meter?needs to be?calibrated to a known stable standard if your mode of effectiveness is output?power measurement.
There is very little difference between 1000 watts and 800 watts or less on the other end.? Having a signal at the other end of 10 over S9 is just as effective for a normal qso as S9.? Striving for full max on every tune up will have you also buying new tubes more often.? I run mine no more than 800 watts because I do not need to go higher?to make and hold a qso.??
Use the lower?plate voltage/power setting of the?initial?tune up.? If that power is ok for your purposes, no need to go higher.? But if you then need more, go to the higher plate voltage setting and do a slight adjustment on the tuning.
The L7 is a good amplifier.? Care for it and your tubes and you should have good service.
Good luck.
David Assaf III W5XU, VP8RXU ?
Hi,
I own a Drake L7 received from a silent key. The L7 seems to be in a very good condition from optical inspection. I am unsure if the tubes are in a good condition considering power output (Eimac 3-500Z).
The manual of the l7 says 1kW input on CW. So, what HF output should I measure on tuned amplifier?
On 20m connected to a dummy load, I measure 600W on the L7 meter and approx 480W on a Power meter connected in between to the DL. The HV drops from 1880V idle to 1500V load.
This calculates to approx. 50% efficiency in CW mode. From literature readings, Class B amplifier should have up to 80% efficiency ...
Should I expect a higher efficiency? Is 380V HV drop ok or should I check the capacitance of the filter caps?
Maybe an expierenced OM could give me some explaination.
Regards, Johann
|
Re: Drake L7 Power output
Personally I like having the low power switch. You have less inrush current at power on (regardless of whether or not you have a soft start installed) and it is easier on the tubes for initial tune-up and when testing an amp. 73 -Jim NU0C On Mon, 04 Mar 2024 07:55:00 -0800 "Rick W4XA" <myr748@...> wrote: Hi Johann,
I have an L-4B which is electrically similar to the L-7 (and uses the same power supply)
50-60% efficiency is not all that uncommon for? L-4/L7 amplifiers.? (or any 3-500 Class AB amp) 75+% can be expected with Class C amps though.
Eimac indicates about 330W output (single tube) @1500V and 400mA.... so around 600W for a pair wouldn't be totally out of line.
Depending on how well calibrated your "Power Meter" is, and if it is not , you're basically using 2 unknown wattmeters for measurement.........? You may not have any problem at all!
How much power are you getting when tuning in the SSB "mode"? (I get about 1200-1300w running the amp on 240VAC line voltage)? Measured with a Bird 43 wattmeter and 2500W "slug" and verified with an Array Solutions Power Master II
That CW/TUNE mode was included because Drake needed to provide a plate voltage that wouldn't exceed 1000W power input when that was the limit for US amateurs.? It's really not needed anymore.? I stopped using the "CW/TUNE" voltage selection long ago.? And when I clean up my power switch and install a solid state relay to protect it, I'll probably permanently bypass the switch wire it for "SSB"
Bottom line, get another watt meter to verify your outboard meter and try tuning it in the SSB position.
You're likely going to get infinite opinions on all this.
-
*73/Rick* *W4XA
* * Every post is created using Linux *
*
-- 73 -Jim NU0C
|
Why a pentode mixer in Drake 4x-line receivers?
Why do?Drake 4x-line receivers use a pentode in 1. mixer?
Why not a true pentagrid/hexode converter mixer - e.g. ECH81?
Yes a pentode is cheaper, but are a pentagrid/hexode tube not way better? What are the trade-offs?
--
best regards,
Glenn, OZ1HFT
|
Re: Drake L7 Power output
Hi Johann,?
I have an L-4B which is electrically similar to the L-7 (and uses the same power supply)
50-60% efficiency is not all that uncommon for? L-4/L7 amplifiers.? (or any 3-500 Class AB amp) 75+% can be expected with Class C amps though.
Eimac indicates about 330W output (single tube) @1500V and 400mA.... so around 600W for a pair wouldn't be totally out of line.
Depending on how well calibrated your "Power Meter" is, and if it is not , you're basically using 2 unknown wattmeters for measurement.........? You may not have any problem at all!
How much power are you getting when tuning in the SSB "mode"? (I get about 1200-1300w running the amp on 240VAC line voltage)? Measured with a Bird 43 wattmeter and 2500W "slug" and verified with an Array Solutions Power Master II
That CW/TUNE mode was included because Drake needed to provide a plate voltage that wouldn't exceed 1000W power input when that was the limit for US amateurs.? It's really not needed anymore.? I stopped using the "CW/TUNE" voltage selection long ago.? And when I clean up my power switch and install a solid state relay to protect it, I'll probably permanently bypass the switch wire it for "SSB"
Bottom line, get another watt meter to verify your outboard meter and try tuning it in the SSB position.
You're likely going to get infinite opinions on all this.?
-
73/Rick
W4XA
*Every post is created using Linux
|
Hi,
I own a Drake L7 received from a silent key. The L7 seems to be in a very good condition from optical inspection. I am unsure if the tubes are in a good condition considering power output (Eimac 3-500Z).
The manual of the l7 says 1kW input on CW. So, what HF output should I measure on tuned amplifier?
On 20m connected to a dummy load, I measure 600W on the L7 meter and approx 480W on a Power meter connected in between to the DL. The HV drops from 1880V idle to 1500V load.
This calculates to approx. 50% efficiency in CW mode. From literature readings, Class B amplifier should have up to 80% efficiency ...
Should I expect a higher efficiency? Is 380V HV drop ok or should I check the capacitance of the filter caps?
Maybe an expierenced OM could give me some explaination.
Regards, Johann
|
Re: Drake Technical Net - 3 March 2024
Bill, ? I tried to call in twice with my barefoot TR5 but we¡¯re probably one too many ionospheric hops away from Milwaukee.? The guys up in the Carolinas seemed to do much better.? Daytime 40m propagation from Florida is a bit of a stretch too.? I¡¯ll try again next week.? Now to find a matching L75 amp! ? Paul, W9AC? ?
toggle quoted message
Show quoted text
From: [email protected] <[email protected]> On Behalf Of William Shadid
Sent: Monday, March 4, 2024 8:33 AM
To: [email protected]
Subject: Re: [DRAKE-RADIO] Drake Technical Net - 3 March 2024? Steve,
Sorry we missed you. I was completely surprised that we had zero interference from the ARRL International DX SSB Contest. We only had one time with any problem and that was internally generated. We had one participant who was interfered with by a POTA station that, from what I could tell, no one else heard. His comments to the offending POTA station caused a lot of QRM to a couple of our members trying to talk when it was their turn. He was well intended, I am sure.?
From my point of view in the Milwaukee area, conditions were pretty good - but some QSB seemed present on some stations.
See (hear?) you next week.?
73,
-Bill Shadid, W9MXQ
Drake Technical Net, Net Control for 3 March 2024
|
Re: Drake Technical Net - 3 March 2024
Steve,
Sorry we missed you. I was completely surprised that we had zero interference from the ARRL International DX SSB Contest. We only had one time with any problem and that was internally generated. We had one participant who was interfered with by a POTA station that, from what I could tell, no one else heard. His comments to the offending POTA station caused a lot of QRM to a couple of our members trying to talk when it was their turn. He was well intended, I am sure.?
From my point of view in the Milwaukee area, conditions were pretty good - but some QSB seemed present on some stations.
See (hear?) you next week.?
73,
-Bill Shadid, W9MXQ
Drake Technical Net, Net Control for 3 March 2024
|
Re: Drake MN7 Tuner Knobs
Yeah, I gave up SSB contesting long ago. It just have me a headache. I used to be very much into it.?
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
On Sun, Mar 3, 2024 at 22:30, Steve Bookout, NR4M < steve@...> wrote:
If you do it on CW,
it's almost a pleasurable thing.
I listened for about 10
minutes just to take in all the HORRIBLY WIDE and distorted SSB
signals.
Steve NR4M
On 3/3/2024 10:13 PM, Jim Shorney
wrote:
I worked 60 DXCC entities on 10m alone over the weekend. At least 40 on each of the three other bands I worked. This is what sunspots can do. :)
73
-Jim
NU0C
On Sun, 03 Mar 2024 16:19:48 -0800
"Bill via groups.io" <billnopic@...> wrote:
Back in the house. I was amazed at the "contest" DX today. I barely heard 3 stateside stations calling CQ everyone was DX.....:-)
I must of led a sheltered Ham Life hi hi
|
Re: Drake Technical Net - 3 March 2024
Actually, you¡¯d be surprised. Not peak time but the multi transmitter stations are still active.?
Anyway, I wasn¡¯t able to make it so glad everyone had a good time.?
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
On Sun, Mar 3, 2024 at 21:26, Jim Shorney < jimNU0C@...> wrote:
It was a DX contest. Not much DX on 40 daytime...
73
-Jim
NU0C
On Sun, 03 Mar 2024 23:57:00 +0000
"Steve Wedge, W1ES/4 via groups.io" <w1es@...> wrote:
> I was over at the granddaughter's place and thought that, in the midst of the ARRL SSB contest that there'd be no room.
>
> Steve Wedge, W1ES/4
|
Jim Shorney
Bill
David
Paul Christensen