Klein Communications

Klein Communications Repair of Commercial FM 2-Way Radios, CB Radios & Amps - Design & Repair of Power Back-up Systems

08/01/2025

*Education and Career Resume*>>>

Attended the DeVry Technical Institute in Woodbridge, New Jersey from 1976-1977.

Attended the Westchester Community College in White Plains, New York from 1977-1978.

Received a Diploma in March of 1980 from the Cleveland Institute of Electronics in their 2-year course of "Electronics Technology and Advanced Troubleshooting" (Levels 1 and 2).

Worked as the service-manager and repair-technician for "East-Coast-Stereo" and then "Old-Greenwich-Stereo" in Greenwich, Connecticut (1978-1980).

Then moved (in 1980) from Greenwich, Connecticut to Stephentown, New York (25 miles east of the New York State capitol city of Albany).

Became lead-technician for a Motorola company-owned, service-center in Pittsfield, Massachusetts (1980-1986).

Possess an FCC 1st Class Radiotelephone License (which is required to repair broadcast transmitters of 10,000 watts and above) along with a Radar endorsement (required to repair ship-board, Microwave-Radar systems) issued in 1980 (which was a total of 4 exams, all taken at the "Jacob K. Javits Federal Building" in "lower Manhattan", which was just a mile north of "Battery Park" (at the lower tip of NYC).

Later became NABER certified (National Association of Business and Educational Radio) which was an FCC sanctioned exam in 1985, and also became a holder of two (2) FAA avionics certifications in 1982 (from Logan International Airport in Boston Massachusetts), and then four (4) equipment, model-specific certifications by 1986, from the Motorola National Service Training center, in Schaumberg, Illinois.

Started a "sole-proprietorship" of Klein Communications, in the East Nassau / Stephentown / New Lebanon, NY area in 1987, and have continued servicing many types of Municipal-sector and Private-sector "Commercial, 2-Way Radio" communications equipment to present day, including various types of audio amplifiers (vintage stereo and guitar amplifiers) along with small to large whole-house, battery-powered, power back-up systems.

Then moved here to the center of America's hard-wood forested mountains of West "by God" Virginia in 2007 (about 5 miles east of the GREAT little town of Buckhannon.!)

Also an "Extra-Class" Amateur-Radio Operator as KY8E

PS: I figured that after being a "professional" for over 35 years., that it was "high-time" to finally become an "amateur".! 😉

Regards / 73
Eric Klein
Klein Communications
https://www.facebook.com/radioman55
Also as KY8E
https://www.qrz.com/db/KY8E

12/28/2024

Concerning "voice intelligibility", microphone positions, and microphone types.

The following 13 minute video is the result of taking four (4) videos, which were first edited down a bit, and then "joined" together, to make one continuous lesson concerning both the "hows and whys" of human speech "intelligibility", and also explains how different types of microphone cartridges operate (ie: "dynamic" versus "electret-condenser"), along with how the placement of a microphone effects its frequency response.

The company who made the individual videos from which this one was created, is a VERY "high-end" microphone manufacturer by the name of DPA

This company (DPA microphones) is based in the country of Denmark ("kissing-cousins" to the north of Germany) and is just as well known for its quality of electronics products as is Germany.! :)

As their home-page states:

They have over 60 years of experience in the design and manufacturing of "world class" microphones. And that designing microphones with amazing sound, exceptional consistency and outstanding durability is no easy process. DPA has a long history of precision and perfection which continues to define their "Electret-Condenser" microphones to this day., with pristine sound and technical innovation being at the heart of everything they do.

Their home-page web-link:
https://www.dpamicrophones.com

BTW: "These guys know what they're doing" (and talking about.!) as ALL of their microphones are for TRUE "professional-use" and therefore are EXTREMELY expensive (ie: $600 to $2000)., and certainly NOT for the "weary hearted".! ;)

FYI: The "headset" mic he is using in the video, sells for about $800 😲

This is a web-link to their "Mic University" page with MUCH information:
https://www.dpamicrophones.com/mic-university

*The main "take-away" of the video presentation concerning "voice intelligibility", is "two-fold"...

1: Without having enough upper mid-range frequencies (and at the proper level) in your spoken voice being heard by the "listener" (ie: being received)., the ability of the listener to hear the difference between certain words can (at times) become quite difficult to understand. Especially if the volume (ie: signal-strength) of the speech is not loud / strong enough.

2: BUT also., "on-the-other-hand"., if you have too much low-range frequencies in your spoken voice, which are being transmitted to the "listener"., the same problem occurs (ie: less "voice intelligibility"), as then those lower voice frequencies begin to "cover-up" / "drown-out" the higher frequencies, which are essential to your words being CLEARLY understood.!!

This is the reason to actually lessen the "level" of the lower frequencies being transmitted (in relation to the upper frequencies) when attempting to make "DX" (distant) radio contacts., especially if you do NOT know how strong of a signal the receiving station is getting from you.!!

Actually., most "high-end" (ie: "digital") microphone "equalizer-boxes" (designed for radio transmitting) will have a setting for "DX"., which automatically reduces some of the lower frequencies of your speech, in order to help "cut-through" the noise and "pile-ups" to distant stations which may not be getting a strong enough signal from your station.

*Case-in-point:

I have a customer, who after purchasing a relatively high-end audio speech-processor (designed just for Ham / Amateur use), is that once he had it adjusted just perfectly for talking to "his locals"., they ALL said it sounded "awesome".! :)

Though on a number of occasions, when attempting to make "long-shot" DX-contacts, he would have difficulty in getting some stations to "come-back" to him :(

BUT., once he would either switch "equalizer box" into the "DX-mode" (which cuts-out some of the "bass" frequencies)., or just simply switch the "box" into the "bypass-mode"., then those stations would call back to him.! :)

Though I will say, that this particular customer already has quite a "deep-voice", and even with the added "bass" (along with a "touch" of audio "compression") was FANTASTIC sounding to his locals (along with a strong "local-signal") (y) BUT., when it came time to contact distant / DX stations., it actually became a "hindrance" to "making-contacts" :(

++++++++++++++++++++

*This is the most compelling reason as to why the famous D-104 "Lollipop" desk microphone has always been "the-go-to" base-station microphone for long-distance / DX transmitting (for most folks that is.!).

That is, as long as the 30+ year-old cartridge / "head" is still in OK condition., and not damaged from either "droppage" (which can crack the internal ceramic element, or damage the aluminum diaphragm), or damaged caused to the ceramic element by im-proper, long-term storage, at either very high or very low temperatures :(

The internal ceramic element in them (ie: "piezo-electric") has a naturally, high-frequency-response, but because of the large diameter aluminum "diaphragm" (2-1/2 inch), it also produces just the right amount of mid-range frequencies, with very little "low-end" frequency response, making it one of best "DX" microphones around.

This is why the D-104-M6B "hand-mic" does NOT sound as good as the full-size "Lollipop" (it sounds much "thinner" / "tinny"), because even though it also contains a ceramic / piezo element, both the element and the diaphragm are much smaller, and therefore results in generating even more high-end frequencies, and less mid-range frequencies :(

*Now, don't get me wrong., there are other desk-microphones out there that can easily "rival" (and surpass.!) the 2-1/2 inch Lollipop, but they incorporate a high-quality "Electret-Condenser" cartridge (with a "flat frequency-response" from 50 Hz to 15 Khz), followed by a well-designed, "frequency-shaping" preamp circuit., with some even having user-adjustable, frequency roll-off, and tone-shaping controls.! :)

++++++++++++++++++++

Bottom line.?

Your speech / voice "EQ" (ie: frequency equalizing) and "compression" is TOTALLY dependent on BOTH what your "natural voice" is., AND the strength of the signal reaching the station., of which you want them to hear AND understand you clearly.!!!

So., for those who have taken the time to read (and re-read.?) another one of my "mini-novel" explanations., I say thank you.!! (it requires MUCH time & effort to create them), and hope it (along with the video.!) was helpful to get a better understanding of "speech intelligibility"...
..and a person should be VERY "questioning" and / or skeptical of those who "push" the idea of "more bass is better"., AND the related $$$ of cost to achieve such results., especially when spending all those $$$ for just one (1) single radio...
..when compared to purchasing a separate / external (and high-quality) EQ-box, with "variable-compression" (something the "customized" radios do NOT have), and thereby having the ability to customize the "EQ curve" AND "compression" for use with MANY different radios, and MANY different microphones., along with the MANY different "voice-profiles" of each different "end-user" / operator that will be using it.!!

*There's NO such thing as "one-size-fits-all"...

I'm truly sorry if I "ruffled any feathers" here (ie: those that "customize" individual radios for their frequency-response)., but "Facts are Facts"., and believe they were explained (IMHO) very well in the video done by the spokesman of that 60 year old company (DPA), of which that company has enough knowledge and experience to build (and have a market for) some of the world's most expensive microphones.!!

(??.and hopefully my added "mini-novel" also gave a bit more understanding.??)

Regards / 73
Eric Klein
Klein Communications
Also as KY8E

Regarding: "The Four-Times Power Nightmare"(and accompanying demonstration video)The following Ham / Amateur exam-questi...
09/27/2024

Regarding: "The Four-Times Power Nightmare"
(and accompanying demonstration video)

The following Ham / Amateur exam-question (for the "General-Class" level of license) along with its answer AND the accompanying demonstration-video (made by another YT content producer) is a VERY well explained AND demonstrated example of how LARGE of a power / wattage increase your station must produce, in order for the station you're talking to., to see even a small difference in their receiver "S-meter".!

In other words (as the video explains)., if you're already generating 250w of PEP power (1/2 capacity of the RM of Italy BLA-703 amplifier), you would need to increase your power to 1,000w PEP to gain just 1 S-unit on the station you're talking to.

And when operating that RM of Italy BLA-703 at "full-bore" (ie: 500w PEP) you would then be required to generate a whopping 2,000w of PEP to gain just that single (1) S-unit more on the receiving station's meter.!! 😲

So what's the "bottom line" as it pertains to CB radio output power in general.?

All that's really needed for that extra "healthy-help" to be heard at greater distances., is to simply "get away" from what I call the "4-watt dead-key doldrums"., which in "textbook-terms" (for "symmetrical-modulation") equals about 16w PEP.

And once you're able to get your station up to that 250-500w PEP level., all else (within reason of course.!) becomes nothing more than just "bragging-rights"., 10-4 there good-buddy".?!? ;)

Just a little something to think and consider about...

Regards,
Eric Klein
Klein Communications
Also as KY8E

09/14/2024

Concerning the subject of the MOSFETs used in CB / Export radios: (another one of my "mini-novel" length write-ups, but hopefully worth your time to read...)

First and foremost, the TO-220 case-style of MOSFETs which are used in virtually all CB and Export radios are / were NEVER specifically made for RF purposes., and is evidenced by the fact that there are absolutely NO specifications within their datasheets to back-up such claims for RF use.!

While on the contrary., when dealing with actual / real RF devices (whether BJT transistors, or Enhanced-mode MOSFETs)., right at the top of their respective datasheets., they will always CLEARLY state the three (3) main characteristics which are specifically intended for RF amplification purposes.!

1: Their RF operating frequency range (in Mhz) whether it's the HF, VHF, UHF, etc. frequency bands.

2: Their stated PEP wattage output at a stated voltage.

3: Their typical RF-gain factor given in dB (their "Gp" rating) which can then be easily converted (via chart) as to the ratio of output watts versus input watts.

BUT., the IRF-520, FQP-13N10, IRFZ-24N, etc., do NOT state even one of the above three (3) specifications., and are all designed to be nothing more than a high-speed "switch".!

The ONLY reason some of them DO work for RF power-amplification purposes (up at the 30 Mhz range) is because some of those "generic" switching MOSFETs have a fast enough on / off switching speed to then "pump" current (on and off) into an LC network (ie: "tank-circuit") to form a "clean" sine-wave at those frequencies.

These specs can be seen in their respective datasheets, and are listed as their "Turn-on Delay-Time" PLUS their "Rise-Time"., and also equally important., their "Turn-off Delay Time" PLUS their "Fall-Time". If those parameters are "fast-enough"., along with designing the correct "support-circuitry" around them, in order to "match" the MOSFETs input AND output capacitance (also spec-sheet listed)., it WILL work just fine.! :)

*Now yes., there certainly are some "fake" / "Bootleg", TO-220 case-style, MOSFET devices out there., BUT., sometimes the cause of getting poor-performance from your (designed for switch-mode application) MOSFET can be something entirely different, than it just simply being some type of fake / Bootleg device.!!

There's also another caveat / qualification that NEEDS to be addressed, and is why even some "genuine" / "real-deal" MOSFETs (even from a reputable / certified re-seller) that will operate at sub-par levels.!

This is because these originally NOT designed for RF / switching-type MOSFETs are intended to operate in the context of "switch-mode" circuits, in which the "Gate" of the MOSFET is typically "driven" at some quite high voltage levels in order to "reach" their full stated Rds (minimum stated resistance between the "Drain" and "Source" leads), and is why the maximum "Gate" voltage for most all of these devices is +/- 20v.

Virtually all of these MOSFETs have a datasheet stated "Rds" (when they reach their "saturation" point) of 10v., and in some situations (as in using them for RF circuits) is a LOT of voltage to reach, in order to also have them reach their maximum through-put current.!

*Remember., a BJT transistor is a "current-driven" device., while a MOSFET is a "voltage-driven" device.!!

I've had MANY "real-deal" MOSFETs here (IR, Vishay, Fairchild, etc.) from MAJOR country-wide "supply-houses" (pick your name.!) where most of the MOSFETs operated just fine., BUT., will occasional get a "batch" that just reacts "weak"., or what I like to call, a "soft, turn-on ramp".

This is because, although the MOSFET is within their datasheet specs., if the Rds voltage is at the "upper-end" of its factory stated 10v level., it will work., but it'll be with lack-luster results :(

The same goes for the stated "Vgs" (Gate Threshold Voltage) of the datasheets for all the above MOSFETs, which give a range of 2v to 4v., and that's a WIDE range (~100%.!) when compared to a BJT transistor, which is typically between 0.6 to 0.7v (~17%) depending on how "hard" one wants to "idle-current" the device.

Then to add another parameter "to-the-mix"., is that because a MOSFET is a voltage amplifying device (somewhat equivalent to a vacuum tube) there's also the factor of the "Gm" (Transconductance) rating of the MOSFET to consider (most datasheets do not specify it, because it's not a pertinent spec to their switch-mode applications)., which is the ratio of Gate voltage change versus the Drain current change.

And the manufactures of these CB / Export radios know (or should know.!) all of these things, and will pick / specify a "production-run" (from whatever company they purchase from) to get MOSFETs that have inherently lower Rds saturation voltage and higher Gm ratings.

*Now there is a "test-jig" that can be made to SAFELY test ("non-destructively") such a parameters, but that would be a whole other discussion... ;)

Bottom line.?? One can just purchase a large quantity of devices from a "reputable re-seller"., but I prefer to 1st purchase just a hand-full., testing them in "the-real-world" (or in my test-jig)., and if all is good., THEN and only then, will I purchase a large quantity from the same reseller, BUT the re-seller must also assure me, that I'll receive the same "lot" (ie: factory-run) so I know I'll be getting the same results.!! (y)

Hopefully my little "mini-novel" was of some value and understanding...

Regards / 73
Eric Klein
Klein Communications

Just as a "for-example" PS: I've installed a number of "the-real-deal" MOSFETs (ie: non-bootleg) in radios which have "dual-finals" (along with separate "bias trim-pots" for each final), in which if I would set Final #1 for an "idle-current" of even just 50ma., that once I would then attempt to bring Final #2 up to the same 50ma of idle current., that once that 2nd setting would get even above 25ma., then the pair of MOSFETs would just WAY over-shoot in current., which in some cases., would "jump" to a full Amp (or more) of current.! :(

*And here's a "factory-fresh" example: Some years back (8-9 years.?) I had received a brand-new / factory-fresh "case of 6", Ranger SS-3900-EGHP radios, in which EVERY radio (right from the factory) had the Dual-Finals set to only about 12ma each (24ma total) so I figured I would "set-them-right"., but boy was I mistaken.!

This is because, once I would set the 1st Final to even 25ma, and then attempted to set 2nd Final to the same (for a total of 50ma)., that once the 2nd Final got past about 15ma., the combined current would "shoot-to-the-moon" (over 600ma+)., and these were the factory-installed, clearly marked, "Vishay" brand of MOSFETs.

Conclusion.?? Whatever "batch-lot" of MOSFETs that the factory had purchased from Vishay (for that "run" of radios) were apparently (for whatever cause) ended-up being VERY "squirrely" in their behavior., and instead of just rejecting the MOSFETs, they (Ranger) decided to just factory-adjust the idle-currents all the way down to 12ma each (24ma total), which is just enough to keep the SSB transmissions somewhat clear-sounding., thereby "curing-the-problem"., and then simply, just "send-em-out-the-door".! :(

Vintage tube-type linear-amplifier >> converted to solid-state :) About 6 months ago (during a "short breather" from my ...
06/24/2023

Vintage tube-type linear-amplifier >> converted to solid-state :)

About 6 months ago (during a "short breather" from my regular repair business) I finally was able to finish a bit of a hobby-project of mine, which had been sitting on the shelf for over 10 years.! (y)

It was an obscure, mid-1970s, Italian-made, tube-type, linear-amplifier ("Tenko" is the brand-name, and the model name is "Derby") which had 1 driver-tube and 3 final-tubes (all 6KG6)., in which although it was quite "clean" within the upper chassis., the bottom of the PCB (printed-circuit-board) had been SO butchered by a previous, self-proclaimed "tech", that it was deemed un-repairable, as couldn't even begin to "reverse-engineer" (ie: draw) a schematic diagram, because of the "butchered-board" :(

So., I finally had the time to "gut-it" (remove all remnants of the tube-type amplifier) and then make it into a self-contained (with power-supply) solid-state, Italian-made, class-AB, linear-amplifier (RM of Italy, KL-503) with a few extra "bells & whistles" :)

1: Along with removing / re-wiring the factory-stock, 6-position attenuator control to the amp's front panel, I also added an extra attenuation circuit, to facilitate using the "Hi / Low" switch on the amp's front panel, resulting it having 12 positions (2 x 6) of attenuation control, giving it a true "high-drive" capabilities.

2: The stock "all or nothing" (ie: on / off) receiver preamp was re-designed to be a variable gain and attenuation preamp, and wired to the front panel control, in which when the front k**b is placed at about the 12:00 position, it renders the preamp as "neutral" (as if it's not on). Then as the k**b is turned clockwise, the gain of the preamp is increased, and when the k**b is turned counter-clockwise (from the 12:00 position) makes the control operate as an "RF gain" / attenuator control.

3: I also wanted the original front-panel meter to read "relative-watts", in which when the meter would reach its maximum deflection (to the right), it would then correspond to the Amplifier's maximum output (~250 PEP). To that end, I then designed an adjustable "RF-sniffer" circuit (between amplifier output and the meter) to make it possible.! :)

I've also attached 2 "screen-captures" (full-page and close-up) of the only place I found any information about the original amplifier, which was an advertisement from a 1977 edition of an Italian CB / Electronics magazine, and still have the full PDF file of the entire magazine (74 illustrated pages) if someone would like to have a copy of it, just contact me.

73s
Eric Klein
Klein Communications
(also known as KY8E )
https://www.qrz.com/db/KY8E
++++++++++++++++++++

01/27/2023

👉Here's why there's always a diode wired across the "coil" of a relay.!

So., why is there always some type of standard silicon diode placed across the magnetic activating coil of a relay (known as a "fly-back" or "snubber" diode) when the relay is being switched on and off by a low-power / low-voltage, solid-state control circuit.? 🤔

This is a GREAT video (made by another "content-producer") which talks about the "how and why" of the dangerously high voltages (from the standpoint of low-voltage, transistor) which are generated from the "speed-of-light" collapse of the magnetic energy that's stored in the magnetic coil of a relay when it is switched off. 😲

It explains how a standard / typical silicon diode can easily protect the low-power / low-voltage electronics (transistors) from being damaged by these high voltages, and is shown / displayed (on a 4-channel oscilloscope) as voltage and current measurements being made to an actual "bread-boarded" circuit, in order to see the real-world effects of when you do have, and do not have a diode placed across the magnetic coil, of a standard relay.! (y) :)

10/22/2022

👉 Career Résumé 👈
Started as the service-manager & repair-technician for "East-Coast-Stereo" and then "Old-Greenwich-Stereo" in Greenwich, Connecticut (1977-1980)

Became lead-technician for a Motorola-owned service-center in Pittsfield, Massachusetts (1980-1986)

Possess an FCC 1st Class Radiotelephone License with a Radar endorsement, issued in 1980, and later became NABER certified in 1985, became a holder of two (2) FAA avionics certifications in 1982, and six (6) equipment-model-specific certifications by 1986, from the Motorola schooling center, in Schaumberg, Illinois.

Started a "sole-proprietorship" of Klein Communications (Stephentown / New Lebanon, NY in 1987) and have continued servicing many types of private-sector, and municipal-sector "Commercial, 2-Way Radio" communications equipment to present day (including various types of audio amplifiers & small to large power back-up systems).

Then moved here to the center of America's hard-wood forested mountains of West "by God" Virginia in 2007 (about 5 miles east of the GREAT little town of Buckhannon.! 🙂 )

Also an "Extra-Class" Amateur-Radio Operator @ KY8E (https://www.qrz.com/db/KY8E)
PS: I figured that after being a "professional" for over 35 years., that it was "high-time" to finally become an "amateur".! 😉

👉The mysterious, Ranger branded, "RT-1", RF-power MOSFET...The mysterious & secretive "Ranger" branded part-number RT-1 ...
12/03/2021

👉The mysterious, Ranger branded, "RT-1", RF-power MOSFET...

The mysterious & secretive "Ranger" branded part-number RT-1 of their RF-power output / final MOSFET, is actually just an IRFZ-24N underneath the OEM "scrubbed" / ground-off labeling.!

In comparison., both the IRF-520s and the FQP-13N10s are rated at about 9 to 10 amps of Drain current (about 0.2 ohm "on" resistance), and have a Drain to Source "break-down voltage" rating of about 100 volts.

And although the IRFZ-24Ns are rated at a whopping 17 amps of Drain current (because of the lesser "on" resistance of about 0.07 ohms), the Drain to Source "break-down voltage" rating is unfortunately, only about 55 volts...

This is how those RT-1 devices can achieve about 40+% more output power (ie: watts) than the 520s or 13N10s. This is because with less internal "on" ohms, they will then allow more amps to flow, which then equals more watts (Ohms Law states: "Volts times Amps, equals Watts").

But because of that lower Drain-to-Source break-down voltage of the IRFZ-24Ns (aka: RT-1s) they are not as resistant to "fly-back" voltages as the 520s or 13N10s., especially when encountering high SWR coming back from a faulty antenna or its coax., and especially from bad / loose / intermittent coax connectors & switches.!!

The other problem., which at times there can be nothing done about (within reason of course), has to do with what happens when they are used in an amplifier which has a mechanical antenna output relay (ie: the newer style RCI-2995s using the four (4) MOSFET amplifier).

The antenna relay does NOT change-over from receive to transmit positions (ie: go "click") instantaneously. There is a very short, but very significant moment which occurs when the relays' contacts are in mid-air between their receive contacts and their transmit contacts.

Needless to say., the SWR during that very short moment in time (50 milli-seconds or less), is VERY high (almost infinite SWR.!)., and although it's certainly not for long., at times, maybe just for long enough for the "device" with the lower breakdown-voltage rating to exceed its limit, and "self-destruct" :(

This is why it's VERY important to NOT "push" your output power "to-the-max & beyond".! But instead., to keep it at least about 15% below its factory-rated maximum. That is., if you'd like to keep all that expensive "factory-installed-smoke" from escaping your radio... ;)

But the older "built-in, power-amp" models which use a pair of ceramic 2SC-2290 transistors (aka: "pills"), such problems are really not much of an "issue", because of their HIGH resilience to short-term SWR.

This is because such "devices" (aka: "pills") utilize something that's called "diffused emitter ballasting", which results in GREATLY improved ruggedness & reliability, and are capable of withstanding high "short-period" SWR load mis-matches (at all phase angles) up to as much as 30:1 depending on the manufacture's design.!! :)

*** Notes on the proper set-up and biasing of "paralleled" MOSFETS...

The Gate to Source turn-on threshold voltage, is the point at which the conduction of current between the Source and Drain starts, and can be anywhere from 2 volts to 4 volts in value, which is quite a WIDE range.!

A "Peak" brand, Atlas DCA-75 tester (or something equivalent) will permit one to measure the Gate to Source turn-on, threshold voltage (denoted as VGS-on or VGS-th) of each MOSFET.

Doing one's best to "match" pairs, quads, etc. of MOSFETs, which are controlled by same / common bias-control, trim-pot (ie: as in the RCI-69 base station or RCI-2995) will not only give one a "cleaner" output (ie: less spurious emissions) but can also make the devices last longer.! :)

But., this Gate-bias adjustment should NOT be set by simply adjusting the Gate voltage., as it NEEDS to be set by the amount of "idle-current" (in milliamps) that the Drain(s) pass, with no RF or signal of any sort being applied to its Gate.! (ie: the transmitter in SSB mode, and the mic-gain turned-down all the way).

Though unfortunately., attempting to measure that current, can at times (depending on the circuit's physical design)., be easier said than done :(

Hope the above info will be of a least some help to others.....

Regards & 73s,
Eric Klein (KY8E)
https://www.qrz.com/db/KY8E

Tram D-201-(A) receiver un-key "click" eliminatorFor those of you who may have a problem (though not all units manifest ...
09/17/2021

Tram D-201-(A) receiver un-key "click" eliminator

For those of you who may have a problem (though not all units manifest it) with hearing a LOUD click / snap sound from your Tram's internal speaker every time the transmitter is un-keyed (to go back into the receive mode) here's a simple circuit (which needs just a bit of component-value tweaking) to eliminate just that.! :)

Of course, you'll still have the key-up (PTT) speaker click / snap., though that one is less than half the volume of the un-key "pop", which is the most annoying.!

Address

Heavner Grove Rd
Buckhannon, WV
26201

Opening Hours

Monday 8:30am - 6pm
Tuesday 8:30am - 6pm
Wednesday 8:30am - 6pm
Thursday 8:30am - 6pm
Friday 8:30am - 6pm
Saturday 9am - 5pm
Sunday 10am - 4pm

Website

https://www.qrz.com/db/KY8E

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