Keyboard Shortcuts
ctrl + shift + ? :
Show all keyboard shortcuts
ctrl + g :
Navigate to a group
ctrl + shift + f :
Find
ctrl + / :
Quick actions
esc to dismiss
Likes
- DRAKE-RADIO
- Messages
Search
|
Re: Drake R4/T4 rubber feet machine screws
¿ªÔÆÌåÓýSteve and the groupthose small rubber feet that screw into the bottom of the AC4 are in fact 6-32 thread. You can get the rubber feet from McMaster Carr, although I don¡¯t remember the part number off the top of my head
Mike, WB8VGE
|
|
Re: The mysteriously modified 7077 (and nothing else¡)
I believe the latest manual, available at WB4HFN, shows the pinout for the two mic inputs.
On Tuesday, February 4, 2025 at 12:15:34 PM EST, Steve Wedge, W1ES/4 via groups.io <w1es@...> wrote:
Thanks, Evan. ?It is a TR7A, so perhaps I¡¯ll do some experimentation. Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana. On Tue, Feb 4, 2025 at 10:09 AM, Evan via groups.io <k9sqg@...> wrote:
|
|
Re: TR-4C low power output on 15 & 10 meters
These are not new finals, correct? This appears to be finals that are at their end of life.? Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana. On Tue, Feb 4, 2025 at 11:12 AM, Dave KD5FX via groups.io <land.dave@...> wrote:
|
|
Re: Drake R4/T4 rubber feet machine screws
Pretty sure it¡¯s 10-24. Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana. On Tue, Feb 4, 2025 at 10:40 AM, Scott N1IA via groups.io <soakland5@...> wrote:
|
|
Re: The mysteriously modified 7077 (and nothing else¡)
Thanks, Evan. ?It is a TR7A, so perhaps I¡¯ll do some experimentation. Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana. On Tue, Feb 4, 2025 at 10:09 AM, Evan via groups.io <k9sqg@...> wrote:
|
|
Re: TR22C Repair
¿ªÔÆÌåÓýMike, thank you for your thoughts.? Your first paragraph mirrors my thoughts exactly. ? I don¡¯t have much test equipment other than VOM but I can get a can of contact cleaner and deoxit as well as reseating the crystals. ? Tony... WB8ZWI WRQJ370 ? Sent from my Compuserve Account ? From: [email protected] <[email protected]> On Behalf Of Mike Bryce via groups.io
Sent: Tuesday, February 4, 2025 9:48 AM To: [email protected] Subject: Re: [DRAKE-RADIO] TR22C Repair ? °Õ´Ç²Ô²â¡. ? Geeze, I don¡¯t want to pop your cork, but the bench time, lack of parts, and when you¡¯re done, you have a heavy 1W fixed freq transceiver with no PL tones for repeater access. ? I have about a dozen of these in the shop, from TR22, to TR33C including the Kenwood variants.? ? I have a TR33C that lives in the kitchen, and on friday nights, I check into the local repeater net. I¡¯m within the shadow of the repeater tower, so the 1W works fine. ? I was picking up these radios as hamfests for $20 and under. I usually purchased them if I needed a crystal for one that I had. ? Now that being said, I have now noticed that the asking price for these has went out of control, and for the life of me I can¡¯t understand it. ? Check to see if the crystal oscillator is running. Old crystals sometimes won¡¯t fire. Reset and clean the crystal¡¯s pins. You should hear a change in the static when you insert a crystal into its socket. No change means there¡¯s an issue with either the crystal of the oscillator. The ceramic filters go bad, and there are no replacements except for a parts radio. ? And of course always fall back with ¡®clean the contacts with deoxit.¡¯? ? ? Mike, WB8VGE ? ?
? |
|
TR-4C low power output on 15 & 10 meters
This is the same TR-4C that had the bad Xtals which were fixed by a baking. The problem now is the output is very low on 15 and 10 meters. Someone suggested I test the output on each band at the output of T9 which is on the driver. So I did and here is the results. Also, I re-tested the driver tube and the final, they all checked very good and I did a resistance test on the driver and finals as per the readings in the manual and they were all good.
Band? ?T9 out Power out
80? ? ? ?35V? ? ?130 W @ 0.4 amps
40? ? ? ?28V? ? ? ?90 W @ 0.375 amps
20? ? ? ?27V? ? ? 100 W @ 0.5 amps
15? ? ? ?35V? ? ? ? 30 W? @ 0.25 amps
10-1? ?30V? ? ? ? ? 5 W? @ 0.2 amps
10-2? ?30V? ? ? ? ? 5 W? @ 0.2 amps
10-3? ?30V? ? ? ? ? 5 W? @ 0.2 amps
There may have been some de-tuning from the scope probe in the circuit, I get about 25 W output on 10 without the probe there.?
I have checked and double checked all the fingers on the band switch.?
What should I look at next? Some component is out of spec somewhere. |
|
Re: TR22C Repair
¿ªÔÆÌåÓý°Õ´Ç²Ô²â¡.Geeze, I don¡¯t want to pop your cork, but the bench time, lack of parts, and when you¡¯re done, you have a heavy 1W fixed freq transceiver with no PL tones for repeater access. I have about a dozen of these in the shop, from TR22, to TR33C including the Kenwood variants.? I have a TR33C that lives in the kitchen, and on friday nights, I check into the local repeater net. I¡¯m within the shadow of the repeater tower, so the 1W works fine. I was picking up these radios as hamfests for $20 and under. I usually purchased them if I needed a crystal for one that I had. Now that being said, I have now noticed that the asking price for these has went out of control, and for the life of me I can¡¯t understand it. Check to see if the crystal oscillator is running. Old crystals sometimes won¡¯t fire. Reset and clean the crystal¡¯s pins. You should hear a change in the static when you insert a crystal into its socket. No change means there¡¯s an issue with either the crystal of the oscillator. The ceramic filters go bad, and there are no replacements except for a parts radio. And of course always fall back with ¡®clean the contacts with deoxit.¡¯?
Mike, WB8VGE
|
|
Re: The mysteriously modified 7077 (and nothing else¡)
Yes for the TR-7A and possibly late production TR-7. ?One pin is for "high output high impedance" while the other is "low output low impedance"; ?basically just a resistor between the two pins. ?
On Tuesday, February 4, 2025 at 09:39:44 AM EST, Steve Wedge, W1ES/4 via groups.io <w1es@...> wrote:
Indeed.? I thought I¡¯d heard that there are two audio inputs to the TR7. I¡¯m going to have to look at the service manual, as the owner¡¯s manual only shows pin 4 as n/c. Perhaps this low level element could directly feed the low-level input, if it exists¡ Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana. Sent from for iOS On Tue, Feb 4, 2025 at 08:01, James Barrie via groups.io <barrie43@...> wrote:
|
|
Re: Drake R4B vs R4C
Has anyone done a sensitivity / selectivity test between a R4B VS a R4C? Bill N1WL
On Monday, February 3, 2025 at 08:26:57 PM EST, Steve Wedge, W1ES/4 via groups.io <w1es@...> wrote:
I prefer the C in tight quarters on CW. You can get crystal filters down to 250 Hz stock and 125 Hz if you search. In pileups, these are the equal to newer rigs¡¯ receivers.? For everyday, casual CW, the B sounds quite nice.? Understand that the shape factors of the two rigs¡¯ filters are fairly different. Some prefer one over the other.? The CW subbands aren¡¯t as crowded as they were 20 years ago, so take that into consideration.? 73, Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana. Sent from for iOS On Mon, Feb 3, 2025 at 15:17, Craig W8CS via groups.io <craig_severson@...> wrote:
|
|
Re: The mysteriously modified 7077 (and nothing else¡)
Indeed.? I thought I¡¯d heard that there are two audio inputs to the TR7. I¡¯m going to have to look at the service manual, as the owner¡¯s manual only shows pin 4 as n/c. Perhaps this low level element could directly feed the low-level input, if it exists¡ Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana. Sent from for iOS On Tue, Feb 4, 2025 at 08:01, James Barrie via groups.io <barrie43@...> wrote:
|
|
TR22C Repair
Hello all!? I've been going through my old 2m radios thinking I might sell them but not wanting to sell a broken one.? I have a couple of TR22C's.? One was my fathers and the other was mine.? We used them for a few years when we got in the hobby prior to switching to some HTs (IC2AT) with VFOs.? In any case that is another story.??
One of the radios seems to have a receive issue.? I only get noise and static when I power it up.? It does transmit, at least according to my external RF meter and the vu meter on the radio itself. The only mods might be a light behind the dial (which isn't lighting, so I am not sure I remember) to indicate what channel it's on and the earphone plug was modified to accept a standard DTMF pad from a touchtone phone. (Good old autopatch days!) ?
I am trying to find out is someone or someplace still repairs these.? I am located just outside of Dallas, TX.? I am willing to ship for the repair.? Any help would be appreciated.??
?
Thanks,
Tony... |
|
Re: The mysteriously modified 7077 (and nothing else¡)
What a mess On Mon, Feb 3, 2025, 21:06 Steve Wedge, W1ES/4 via <w1es=[email protected]> wrote:
|
|
Re: TR4310 HF Transceiver
On my 4310, just like my TR-7A and L4B, I keep the power switches in the "on" position and use an external switch on a surge suppressor for powering up/down. ?Replacing/repairing the potentiometers, switches, etc. is not something I look forward to. While I might not prefer 110 vac inside a rig, I do like the cooling that the FA-7 provides, especially for the 4310 that seems to. be rated at slightly higher power output than the TR-7A based upon the limited documentation that I have. ?Still, I keep the output around 60-65 watts PEP since that is all I need for the L4B. Enjoy that 4310!
On Tuesday, February 4, 2025 at 05:39:52 AM EST, atlasstuff <g4fph@...> wrote:
On trying to use a Drake SP75 Speech Processor with the TR4310 Communications Transceiver.
?
I'm pleased to report that the TR4310 has been working flawlessly since it's recent major surgery. I have been using it on 160, 80 and 40 with a Shure 444 microphone, which I find always produces great results with any TX or TRx from the same era. I've replaced the Drake FA-7 110 Volt AC cooling fan with a 12 Volt DC computer-type one - about 5 Volt DC gets it spinning nicely without screaming. I don't like the US practice of routing AC primary mains into radios for on/off switching, or fans, especially where the radio is otherwise fully low-voltage DC powered.
?
?
The job lot of Drake I bought some while ago included an SP75 Speech Processor. The SP75 is a proper RF Clipper, with a compression stage on the front. I'm a big fan of the Datong 'ASP' Automatic RF Speech Processor units, made in the UK many years ago. The SP75 uses the filter method (at 459 kHz) to create it's SSB, while the Datong uses the phasing method. I thought the SP75 would make a nice companion for my TR7 / TR4310 and free-up a Datong for use with other vintage radio here.
?
On plugging the Drake processor into the TR4310, it behaved rather strangely. The 'on' LED would only illuminate when the microphone PTT was pressed. It passed audio when it did that sounded not too bad. When the case of the processor touched the case of the transceiver, the transceiver went into transmit!?!
?
I pulled the processor apart and checked it's jumper settings, microphone socket and microphone plug wiring against the schematic. All in agreement.
?
Next I put the manuals for the TR7 and TR4310 side by side. Surely Drake would not wire the microphone sockets differently between amateur and commercial versions of, largely, the same product, would they. The cynic in me thought they just might, in order to add a barrier to commercial users trying to cheap-out and use accessories from the amateur line. No! I banished my cynical thoughts - the wiring was specified as identical.
?
That left only one possible cause: The wiring of the microphone socket in the TR4310 was wrong / not as designed. I flipped the TR4310 over and put it side-by-side with the flipped-over TR7 that had been supporting it all these weeks. The microphone socket in the '4310 was mirror image vertically of that in the TR7. So, what should have been ground on the connector was wired as PTT and vice versa. What should have been hi-level mic audio was wired as lo-level and vice versa. The soldering did not look too bad, but less good than I would have expected ex-factory. I re-wired it to be correct against the schematic and concluded that the wiring error was introduced when someone had the front panel off previously. I can see that the movable photo interrupter, part of the tuning dial, has been changed. If the fixed one has been changed too, that would have necessitated front-panel removal.
?
Now to try the processor to see how it performs!
?
Regards,
?
Mark, G4FPH.
?
|
|
Re: Drake TR7, TX issue any ideas?
Thanks Jim! I'll get on it asap and keep the thread updated :). /Michael. On Tue, Feb 4, 2025 at 2:25?AM Jim Shorney via <jimNU0C=[email protected]> wrote:
|
|
Re: TR4310 HF Transceiver
On trying to use a Drake SP75 Speech Processor with the TR4310 Communications Transceiver.
?
I'm pleased to report that the TR4310 has been working flawlessly since it's recent major surgery. I have been using it on 160, 80 and 40 with a Shure 444 microphone, which I find always produces great results with any TX or TRx from the same era. I've replaced the Drake FA-7 110 Volt AC cooling fan with a 12 Volt DC computer-type one - about 5 Volt DC gets it spinning nicely without screaming. I don't like the US practice of routing AC primary mains into radios for on/off switching, or fans, especially where the radio is otherwise fully low-voltage DC powered.
?
?
The job lot of Drake I bought some while ago included an SP75 Speech Processor. The SP75 is a proper RF Clipper, with a compression stage on the front. I'm a big fan of the Datong 'ASP' Automatic RF Speech Processor units, made in the UK many years ago. The SP75 uses the filter method (at 459 kHz) to create it's SSB, while the Datong uses the phasing method. I thought the SP75 would make a nice companion for my TR7 / TR4310 and free-up a Datong for use with other vintage radio here.
?
On plugging the Drake processor into the TR4310, it behaved rather strangely. The 'on' LED would only illuminate when the microphone PTT was pressed. It passed audio when it did that sounded not too bad. When the case of the processor touched the case of the transceiver, the transceiver went into transmit!?!
?
I pulled the processor apart and checked it's jumper settings, microphone socket and microphone plug wiring against the schematic. All in agreement.
?
Next I put the manuals for the TR7 and TR4310 side by side. Surely Drake would not wire the microphone sockets differently between amateur and commercial versions of, largely, the same product, would they. The cynic in me thought they just might, in order to add a barrier to commercial users trying to cheap-out and use accessories from the amateur line. No! I banished my cynical thoughts - the wiring was specified as identical.
?
That left only one possible cause: The wiring of the microphone socket in the TR4310 was wrong / not as designed. I flipped the TR4310 over and put it side-by-side with the flipped-over TR7 that had been supporting it all these weeks. The microphone socket in the '4310 was mirror image vertically of that in the TR7. So, what should have been ground on the connector was wired as PTT and vice versa. What should have been hi-level mic audio was wired as lo-level and vice versa. The soldering did not look too bad, but less good than I would have expected ex-factory. I re-wired it to be correct against the schematic and concluded that the wiring error was introduced when someone had the front panel off previously. I can see that the movable photo interrupter, part of the tuning dial, has been changed. If the fixed one has been changed too, that would have necessitated front-panel removal.
?
Now to try the processor to see how it performs!
?
Regards,
?
Mark, G4FPH.
? |
|
Re: AC-4 Power Supply 10K Bias Trimmer Replacement
¿ªÔÆÌåÓýHi Joe,Try oldradioparts.net. Mark Oppat stocks literally thousands of potentiometers in every possible configuration, and will even customize them for you if needed. Very reasonable prices for unobtainium parts. 73, Graham N6GH On Feb 3, 2025, at 3:17?PM, Joe W7BWA via groups.io <W7BWA@...> wrote:
|
|
Re: 7077 Mic
Mostly agreed but has nothing to do with distortion. Passive microphones, which include crystal, ceramic, magnetic, moving coil, ribbon are generators. They look like voltage sources. They do have a characteristic electrical impedance, which is stated in their specs, but they are voltage sources, as the OP states, not power sources. Non generator microphones, which include condenser and carbon microphes, are not generators. Carbon microphones are "valves" where the carbon acts as a variable resistance. There is a current source which is varied by the microphone resistance, which in turn, depends on the pressure on the resistive element by the diaphragm. Carbon microphones have the property of being amplifiers and for that reason were almost universally used in telephone systems where power is important. A condenser microphone is a variable condenser. It is used to either vary a voltage charge put on it by a voltage supply, or to vary the frequency of an oscillator. Condenser microphones always need some sort of electronic amplfier, or rather an impedance matcher or else a combination oscillator/detector.
toggle quoted message
Show quoted text
An electret microphone is a condenser microphone with a permanent charge. It is the condenser equivalent of a permanent magnet. Electret microphones, like condenser mics, need an amplifier or impedance matcher. They are very simple and can be made with very high fidelity. Electret mics require very little power and have supplanted condenser mics for many purposes and carbon mics for almost all purposes. The required load impedance for generator microphones (crstal, dynamic) is, essentially infinite, since they are voltage sources. In some cases the load impedance will affect the frequency response. This is the case for ribbon and directional moving coil mics where _matching_ the impedance will cause a loss of low frequency response as well as an overall loss of level. The British (BBC) actually prefer to load microphones. Where the frequency response is of interest the microphone is built with internal damping and equalization. I have had some arguments with British sound engineers over the virtues of loading. They are wrong about this. BTW, Western Electric did much the same thing their speech imput amplifiers mainly to avoid expensive input transformers. Condenser and electret mics are essentially electronic so the source impedance is an electronic circuit and can be made whatever is desirable for the application. Many European condenser mics require a given load impedance to eliminate resonances in the transformers. But, because the signal to noise ratio is determined by the amplifier and not the microphone element, the levels vs load impedance is of no consequence. At some point On 2/3/2025 6:26 PM, jerry-KF6VB wrote:
On 2025-02-03 17:12, Jim Shorney via groups.io wrote: --
Richard Knoppow Los Angeles WB6KBL SKCC 19998 |
Tony WB8ZWI
Scott N1IA
to navigate to use esc to dismiss