¿ªÔÆÌåÓý

Date

Re: Broke off screw mounts from screen

 

Hy Bob
The fact remains that in the world 6/7 billion people use the Decimal Metric System, that the ISO itself has established systems of multiples and submultiples related to the Decimal system ... I don't think that 400 or 500 million people, equal to only the 7% of the world population can continue to burden EXTRA COST over all the equipment, machinery and mechanics they import from the rest of the world with absurd costs for doubler the ingeniering for the rest of the world and maintain a measurement system that has been abandoned even by their own scientists ...
I know the inch metric comparison rules, but now, in the third millennium they are absurd and anachronistic !?it is time for the legacies of the past to be left in the past ... the future awaits us ! and the future does not belong exclusively to the USA, however big and important they may be, but to the whole world, from Europe to Asia and Africa and, not to forget, South America!
73 de
-------
IW4AJR Loris


Re: IRF510 sale

 

Ted,

You are likely getting more power on 20m than on 40 and 80 because of C81 and R83
in the emitter leg of Q90.? They increase the gain at high frequencies to compensate
for losses in the later stages.

Here's some old threads for those curious about tradeoffs in the uBitx PA.
Make sure you have some time before jumping in, there's lots going on here.
/g/BITX20/message/74038
/g/BITX20/message/57428
/g/BITX20/message/57506
/g/BITX20/message/58216
/g/BITX20/message/58856

Jerry, KE7ER


On Fri, Jan 1, 2021 at 11:04 AM, Ted wrote:
"Power from the 16db 2n3904 based driver stages falls off as the frequency goes up.
That may well be more of a factor than the IRF510's in your "much less on the higher bands".
?
I concur with Jerry and did follow Allison's lead that band performance upstairs can be improved by swapping 2N2222 cans for the original pre driver & driver 3904's with resistor halving as suggested.??
?
I've done that on one board and have been happy. On a separate board, I put in one 2N5109 for each pair of 3904's. That works especially well with 20v on the finals.? I'm getting around 20-25W SSB on 20 meters, and maybe 15 -20 on 80 & 40.??
?


Re: Ideas for "bulletproofing" the uBitx

 

I called the MPJA 800-number 800-652-6733 and did it over the phone for two packages of ten plus an impedance/capacitance meter (for $22.95) and had it all shipped for $6.95 and it took me only about five minutes. The link for the transistors? now shows an offer for resistors. The call attendant said she'd look to see if they had any left. She said they'd send them but I suspect they are sold out by now because the transistor link now shows resistors. You can call to see if any left.

It's such a common transistor that it's not hard to find them. Jameco has them for 99-cents each (10+ for 85-cents):







On Friday, January 1, 2021, 12:06:21 PM EST, Mike Morneau <ve3mic@...> wrote:


Not to mention RF parts availability.? IRF510s can be found almost anywhere.? Anyone that has tried to source RF transistors I'm sure can appreciate this -especially those living in remote areas.
73 de Mike


Re: IRF510 sale

 

"Power from the 16db 2n3904 based driver stages falls off as the frequency goes up.
That may well be more of a factor than the IRF510's in your "much less on the higher bands".

I concur with Jerry and did follow Allison's lead that band performance upstairs can be improved by swapping 2N2222 cans for the original pre driver & driver 3904's with resistor halving as suggested.??

I've done that on one board and have been happy. On a separate board, I put in one 2N5109 for each pair of 3904's. That works especially well with 20v on the finals.? I'm getting around 20-25W SSB on 20 meters, and maybe 15 -20 on 80 & 40.??



Ted
K3RTA?


Re: Ideas for "bulletproofing" the uBitx

 

Mad,

Name one name brand radio that uses a Nano clone.

Or better yet:
Name one name brand radio that sells for $160.

By your argument, we should just swap the whole thing out.
Which is a perfectly fine solution if what you want is a "real" RF appliance.

Jerry, KE7ER



On Fri, Jan 1, 2021 at 08:38 AM, MadRadioModder wrote:
Here¡¯s the tell.? Name one name brand commercial radio that uses IRF510¡¯s as RF transistors.


VARIATIONS IN SWR WHEN CONNECTING LINEAR AMP

 

HI GOOD DAY TO ALL.

NEW YEAR GREETINGS FROM INDIA.

?Today(01.01.2021) I measured the SWR of my antenna system using ANTUINO ANALYZER. It is observed ?that there are very wide variations in the SWR values when the antenna is connected direct to the BITX rig (barefoot) and when connected through the linear amplifier(PUTTING THE LINEAR IN SWITCHED OFF CONDITION). The relevant details are as below

?? I am using uBITX V6 with a linear amplifier driving ?about 5w into linear amp.

?? Linear amp draws about 70 W power.

?? I am using inverted VEE antenna for 40 m and 20 m band ?with common coax feeder.

?? The linear amp has got provision such that when it is switched off, the antenna and ubitx rig are ?connected so that the output from the barefoot ubitx rig is getting pushed out to the antenna. This facilitates easy operation for changing QRP TO QRO or vice versa without unscrewing and screwing the connectors but by simply switching the linear on or off

? With the above set up I made the observations on SWR using Antuino and the observations are as below

LOWEST SWR VALUE AND CORRESPONDING FREQUENCY

  1. THE ANTENNA CONNECTED DIRECT TO THE ANTUINO ANALYZER ?

FREQUENCY? IN MHZ

SWR

?

7.140

1.5

?

14.250

1.2

?

?

??????? 2.THE ANTENNA CONNECTED TO THE ANTUINO ANALYZER ?THROUGH THE LINEAR

??????????? AMPLIFIER ?BUT THE LINEAR IS IN SWITCHED OFF CONDITION

FREQUENCY? IN MHZ

SWR

?

7.290

1.1

AT 7.140MHZ, SWR 1.4

14.100

4

AT 14.000MHZ SWR IS 5.8

AT 12.060 SWR IS 2.6

?

i)In the 7 MHZ band, if the linear is in series with TX ?and the linear IS IN SWITCHED OFF CONDITION , the SWR gets good improvement but at higher frequency ( outside ?the band)

ii) In the 14 MHZ band, if the linear is in series with TX ?and the linear IS IN SWITCHED OFF CONDITION, the SWR value rises ?up drastically (5.8 AT 14.000MHZ)

?As such I like to know the reason for the above SWR variations and to get guidance to bring the SWR values within 1.5 in both bands and in both linear on and off positions.

?. ???I appreciate, any one, kindly throw some light on the above and give some tips

?? Thanks a lot in advance

?????????????????????????????????????????????????????????????????????? ???With 73

? ?????????????????????????????????????????????????????????????????????????MUTHU?

??????????????????????????????????????????????????????????????????? ???????VU2LMN

???????????????????????????????????????????????????????????????????????? +919443114779


Re: Ideas for "bulletproofing" the uBitx

 

Thanks Jerry, that is reassuring, and maybe a bit of a warning too :)

HNY Scott


-----Original Message-----
From: Jerry Gaffke via groups.io <jgaffke@...>
To: [email protected]
Sent: Fri, Jan 1, 2021 12:13 pm
Subject: Re: [BITX20] Ideas for "bulletproofing" the uBitx

I haven't tried shorting my antenna,
but I don't recall any reports of uBitx damage due to such a short.

The only issue I see is heat internal to the IRF510.
Each IRF510 is only on 50% of the time, that helps.
I suspect that with a 12v supply, the load presented by T11 and the LPF's and the board traces
would keep the drain current down to where the IRF510 die can transfer ithe heat out to the tab.
And would expect it to take at least 15 seconds for the tab and heatsink to overheat.
Perhaps a shorted antenna never does damage the IRF510's if there is some air flow on the heatsinks.

I could be wrong.
Perhaps others have more information on this.

Jerry, KE7ER


I sincerely doubt it is instantaneous.

On Fri, Jan 1, 2021 at 08:29 AM, Scott McDonald wrote:
Jerry -?
?
This thread has been really helpful.? I haven't failed any 510's in the field yet, but....
?
When you mention a shorted antenna jack and heat-related failure, what kind of key-down times are you thinking about with the standard heatsinks- seconds, a minute, or???
?
I ask because I'm trying to relate it to how long it takes me to realize I have a problem operating portable, which is sometimes longer than I'd want it to be.
?
Thanks, Scott ka9p
?
?


Re: Ideas for "bulletproofing" the uBitx

 

Scott,

Here's a report from Allison regarding two IRF510's operating in push-pull
on 28v giving 50 Watts out.
They have survived years of abuse, including shorted antennas.
I sincerely doubt shorting the antenna on your uBitx with a 12v supply will cause any damage.
? ??/g/BITX20/message/55159

Jerry, KE7ER


On Fri, Jan 1, 2021 at 10:13 AM, Jerry Gaffke wrote:
I haven't tried shorting my antenna,
but I don't recall any reports of uBitx damage due to such a short.

The only issue I see is heat internal to the IRF510.
Each IRF510 is only on 50% of the time, that helps.
I suspect that with a 12v supply, the load presented by T11 and the LPF's and the board traces
would keep the drain current down to where the IRF510 die can transfer ithe heat out to the tab.
And would expect it to take at least 15 seconds for the tab and heatsink to overheat.
Perhaps a shorted antenna never does damage the IRF510's if there is some air flow on the heatsinks.

I could be wrong.
Perhaps others have more information on this.

Jerry, KE7ER


Re: Ideas for "bulletproofing" the uBitx

 

I haven't tried shorting my antenna,
but I don't recall any reports of uBitx damage due to such a short.

The only issue I see is heat internal to the IRF510.
Each IRF510 is only on 50% of the time, that helps.
I suspect that with a 12v supply, the load presented by T11 and the LPF's and the board traces
would keep the drain current down to where the IRF510 die can transfer ithe heat out to the tab.
And would expect it to take at least 15 seconds for the tab and heatsink to overheat.
Perhaps a shorted antenna never does damage the IRF510's if there is some air flow on the heatsinks.

I could be wrong.
Perhaps others have more information on this.

Jerry, KE7ER


I sincerely doubt it is instantaneous.


On Fri, Jan 1, 2021 at 08:29 AM, Scott McDonald wrote:
Jerry -?
?
This thread has been really helpful.? I haven't failed any 510's in the field yet, but....
?
When you mention a shorted antenna jack and heat-related failure, what kind of key-down times are you thinking about with the standard heatsinks- seconds, a minute, or???
?
I ask because I'm trying to relate it to how long it takes me to realize I have a problem operating portable, which is sometimes longer than I'd want it to be.
?
Thanks, Scott ka9p
?
?


Re: IRF510 sale

 

Here's an excellent post from Allison regarding the use of IRF510's vs the RD16HHF:
? ??/g/BITX20/message/53765
The IRF510's can work fine up through 30mhz.
At 50mhz I'd go with something better, but Allison finds a way.

Power from the 16db 2n3904 based driver stages falls off as the frequency goes up.
That may well be more of a factor than the IRF510's in your "much less on the higher bands".

Jerry, KE7ER



On Fri, Jan 1, 2021 at 09:13 AM, Howard Fidel wrote:
I have 19V and on 40 meters, about 20 watts. Much less on the higher bands. The IRF510 is a poor choice for higher power and higher frequencies, it is slew rate limited.


Re: Broke off screw mounts from screen

Gregg
 

That makes sense, I should have gotten out my calipers


On Fri, Jan 1, 2021, 4:37 AM Bob Lunsford via <nocrud222=[email protected]> wrote:
If you measure the screws' length with a millimeter scale, you will find there are two sizes, a longer one and a slightly shorter one. Use the shorter one and it will work OK. Just because a screw happens to screw into the thread does not mean it is the right screw.

The parts list that comes with the radio shows this, there are two screw sizes but of two different length. Time to break out that millimeter scale.

Bob ¡ª KK5R

On Friday, January 1, 2021, 5:31:58 AM EST, Gregg <greggahorton@...> wrote:


I was attaching the screen and the screws weren't sitting flush and the bottom two nuts snapped off as I tightened. Is there anyway to repair? The screen isn't loose but I'd rather those not be snapped.


Re: IRF510 sale

 

I've never tried going much beyond 12v on the uBitx.
If I were to do it, I'd start with the qrp-labs 10W PA that I have built up.

Power out should be proportional to the square of the supply voltage,
so if you get 8 watts out at 12v, should get 32 Watts from 24v.
Most seem to be going with around 19v (perhaps an old laptop power supply),
applied only to the IRF510's, the rest of the radio still gets 12v.
At 19 volts, we should get something like?10 * ((19/12)**2) = 25.0 Watts.
Reports on the uBitx seem to be more like 20 Watts max.

On the uBitx, this would be on some very thin ice, it's intended for use at 12v.
Pushing it from 10W to 20W only gives an extra half of an S unit of signal, hardly noticeable.
You definitely need a much better heatsink on those IRF510's.
The capacitors in the LPF's likely don't have sufficient voltage rating,
and the currents might be an issue for them too.
T11 and the transmit LPF inductors don't have sufficient wire size, and the cores can saturate.?
The 20 Watt final would be an inch away from some very low low level IF signals, adding spurs.
The driver doesn't have enough power for the gates on the upper bands when running at 12v,
and the power required of the driver goes up proportional to power out.

On the other hand, IRF510's are cheap, and the uBitx is meant to be an experimenter's radio.
So have at it if so inclined.?
Maybe borrow the transformer core and LPF's from the WA2EBY amp
Add an extra driver stage.? ?
Consider moving the final over to a different PCB.?
Figure out how to check for spurs and IMD.
? ?
A?WA2EBY style amp can put out around 50 Watts from 28v using?a push-pull pair of IRF510's.?
Reliably, if done right.

Jerry, KE7ER


Re: IRF510 sale

 

I have 19V and on 40 meters, about 20 watts. Much less on the higher bands. The IRF510 is a poor choice for higher power and higher frequencies, it is slew rate limited.


Re: Ideas for "bulletproofing" the uBitx

 

Not to mention RF parts availability.? IRF510s can be found almost anywhere.? Anyone that has tried to source RF transistors I'm sure can appreciate this -especially those living in remote areas.
73 de Mike


Re: Ideas for "bulletproofing" the uBitx

 

"Name brand commercial radio" does not describe the uBITX which is designed to be less expensive and more desirable by people in India and other countries, even here. This includes me and is the reason I have bought the V4, V6 (twice) and the BITX40. It is affordable.

If Ashar had used the better, higher cost components, the price would have been much higher, putting it out of the range of many hams either on a budget or budget challenged. The IRF510 works as intended, no problem. The number of people interested in replacing it with a different transistor are either wanting to milk more watts out of the BITX box or they think it is more reliable. I notice that those who are bent this way are low numbers of people, the vast majority are "getting along" with the IRF510 and are satisfied with the way it works.

Due diligence in the design of the antenna/load are incidental factors in the mostly satisfied users of the BITX radios. One this is done, which should be done for any ham station, the problems seem to belong to other people who do not practice that due diligence.

If the cost of the V6 had been $250, I would just buy the Xiegu G1M even though the G1M covers only 80-15M and is only 5W output. However, the V6 has a very sensitive receiver system...

Bob ¡ª KK5R

On Friday, January 1, 2021, 11:38:59 AM EST, MadRadioModder <madradiomodder@...> wrote:


Here¡¯s the tell.? Name one name brand commercial radio that uses IRF510¡¯s as RF transistors.

?

From: [email protected] <[email protected]> On Behalf Of Jerry Gaffke via groups.io
Sent: Friday, January 1, 2021 9:17 AM
To: [email protected]
Subject: Re: [BITX20] Ideas for "bulletproofing" the uBitx

?

Mad,

Thousands of stock uBit's are operating with no trouble at all.
If the IRF510's die at all, It is almost certainly because of overheating.
Perhaps when running some digital mode, inside an enclosure, with zero airflow..

Many of the reports of blown IRF510's can be attributed to people fiddling with the gate bias pots
without first spending 10 minutes to figure out what they are doing.?
The "clockwise is minimum" pot rotation plays a big factor.
Going to RD16HHF1's will only make this mistake much more expensive.

The uBitx is designed to be a minimalist SSB rig for all of HF at minimum cost, and succeeds wildly.
If it is to be used continuously at full power in digital modes, the minimalist heatsinks should be improved.

I can imagine that a shorted antenna jack (thus infinite SWR) could play a role.
But only because the IRF510's might heat up after some period of time.

Many in the forum run the IRF510's at around 20 volts for increased power.
With an adequate heatsink, this works reliably.
If you insist on telling them they should switch over to "real" RF devices such as the RD16HHF1,
you should also warn them?not to run at much beyond 12 volts.

The qrp-labs 10W PA blows away the many claims over the years in this forum
that the IRF510's are not suitable as RF transistors.?
It simply works, flat and clean, from 3.5 to 30mhz.
And is bulletproof when operated at 12v, even when presented with a worst case SWR.
The uBitx IRF510's can be just as reliable if given a suitable heatsink.

Jerry, KE7ER




On Fri, Jan 1, 2021 at 01:31 AM, MadRadioModder wrote:

Don¡¯t understand the point.? Why would you want to operate excellent RF transistors designed specifically for the 12-14V mobile world at a higher voltage?? They make all of their power in that range.

?

You are correct¡­ that most people won¡¯t get much out of replacing IRF devices with the RDs¡­? until they blow out a set or two of them.? Then it will start to matter, because the RD devices survive much better under bad circumstances like infinite SWR.? Again, real RF transistors designed for load mismatch tolerance ?(read the app note, load tolerance spec).? Bullet-proof.

?

You are also correct that most people won¡¯t spend the time to replace the IRF devices for the RD devices even after they kill a few sets.? They will just keep killing IRF510¡¯s.

?


Virus-free.

--

¡­_. _._


Re: Ideas for "bulletproofing" the uBitx

 

That is a very neat and interesting idea. However, another commenter here stated that doing this could affect the higher (15/10M) output power for the V6 which is already challenged by lower power output.

For me, since I do not plan to use it on those higher bands, I would only do this if the FETs blew and had to be replaced because it would make replacement much easier and faster.

Bob ¡ª KK5R

On Friday, January 1, 2021, 9:40:03 AM EST, Gerard <kabupos@...> wrote:


Sorry,

here an idea for the IRF510


Re: Ideas for "bulletproofing" the uBitx

 

¿ªÔÆÌåÓý

Here¡¯s the tell.? Name one name brand commercial radio that uses IRF510¡¯s as RF transistors.

?

From: [email protected] <[email protected]> On Behalf Of Jerry Gaffke via groups.io
Sent: Friday, January 1, 2021 9:17 AM
To: [email protected]
Subject: Re: [BITX20] Ideas for "bulletproofing" the uBitx

?

Mad,

Thousands of stock uBit's are operating with no trouble at all.
If the IRF510's die at all, It is almost certainly because of overheating.
Perhaps when running some digital mode, inside an enclosure, with zero airflow..

Many of the reports of blown IRF510's can be attributed to people fiddling with the gate bias pots
without first spending 10 minutes to figure out what they are doing.?
The "clockwise is minimum" pot rotation plays a big factor.
Going to RD16HHF1's will only make this mistake much more expensive.

The uBitx is designed to be a minimalist SSB rig for all of HF at minimum cost, and succeeds wildly.
If it is to be used continuously at full power in digital modes, the minimalist heatsinks should be improved.

I can imagine that a shorted antenna jack (thus infinite SWR) could play a role.
But only because the IRF510's might heat up after some period of time.

Many in the forum run the IRF510's at around 20 volts for increased power.
With an adequate heatsink, this works reliably.
If you insist on telling them they should switch over to "real" RF devices such as the RD16HHF1,
you should also warn them?not to run at much beyond 12 volts.

The qrp-labs 10W PA blows away the many claims over the years in this forum
that the IRF510's are not suitable as RF transistors.?
It simply works, flat and clean, from 3.5 to 30mhz.
And is bulletproof when operated at 12v, even when presented with a worst case SWR.
The uBitx IRF510's can be just as reliable if given a suitable heatsink.

Jerry, KE7ER




On Fri, Jan 1, 2021 at 01:31 AM, MadRadioModder wrote:

Don¡¯t understand the point.? Why would you want to operate excellent RF transistors designed specifically for the 12-14V mobile world at a higher voltage?? They make all of their power in that range.

?

You are correct¡­ that most people won¡¯t get much out of replacing IRF devices with the RDs¡­? until they blow out a set or two of them.? Then it will start to matter, because the RD devices survive much better under bad circumstances like infinite SWR.? Again, real RF transistors designed for load mismatch tolerance ?(read the app note, load tolerance spec).? Bullet-proof.

?

You are also correct that most people won¡¯t spend the time to replace the IRF devices for the RD devices even after they kill a few sets.? They will just keep killing IRF510¡¯s.

?


Virus-free.

--

¡­_. _._


Re: Broke off screw mounts from screen

 

Loris, I grew up in Brazil and finished secondary school there. I used the Metric System as did all my classmates.

People here either shy away from the metric system or they act as if it does not exist. They are not aware of the fact that most mechanical rotary bearings used on cars are in the metric system, the long decimal numbers in their measurement equates to even one-hundredths of a millimeter, a relatively small number. Fafnir and Bruening do this.

The list of materials delivered with the uBITX kid shows the screws on the list. a simple scale, a measuring tool like a ruler but is usually in stainless steel, can be easily obtained with both inches and millimeters on the ruler/scale. Scale, by the way, is the name of the mechanical/machine shop measuring device which is usually carried in the pocket of a tool & die maker. Here are examples of "scales"and by the way, I attended IBM's Tool & Die program.

Inline image

Bob ¡ª KK5R

On Friday, January 1, 2021, 10:06:04 AM EST, Loris IW4AJR via groups.io <lorisbollina@...> wrote:



?
Hey Bob ???
Why "Time to break out that millimeter scale"?
I'm not understanding well ???
The Decimal scales (of which the millimeter scale is a representative)?are the only true scientific and world "standards", your method of measurement, based on reports of anatomical parts of "men" from the distant prehistoric past, remained the only representative of this "Pleistocene Dinosaur"!
Come on, come on .. adapt! the world has gone on light years, if the English have changed, now it's time for you to adapts to the "new" ... leaves your "inchs" to the past and try to enumerate in a little less prehistoric way!
--?
IW4AJR Loris


On Fri, Jan 1, 2021 at 01:37 PM, Bob Lunsford wrote:
?
If you measure the screws' length with a millimeter scale, you will find there are two sizes, a longer one and a slightly shorter one. Use the shorter one and it will work OK. Just because a screw happens to screw into the thread does not mean it is the right screw.
?
The parts list that comes with the radio shows this, there are two screw sizes but of two different length. Time to break out that millimeter scale.
?
Bob ¡ª KK5R
?
On Friday, January 1, 2021, 5:31:58 AM EST, Gregg <greggahorton@...> wrote:
?
?
I was attaching the screen and the screws weren't sitting flush and the bottom two nuts snapped off as I tightened. Is there anyway to repair? The screen isn't loose but I'd rather those not be snapped.


Re: Ideas for "bulletproofing" the uBitx

 

Jerry -?

This thread has been really helpful.? I haven't failed any 510's in the field yet, but....

When you mention a shorted antenna jack and heat-related failure, what kind of key-down times are you thinking about with the standard heatsinks- seconds, a minute, or???

I ask because I'm trying to relate it to how long it takes me to realize I have a problem operating portable, which is sometimes longer than I'd want it to be.

Thanks, Scott ka9p




-----Original Message-----
From: Jerry Gaffke via groups.io <jgaffke@...>
To: [email protected]
Sent: Fri, Jan 1, 2021 9:16 am
Subject: Re: [BITX20] Ideas for "bulletproofing" the uBitx

Mad,

Thousands of stock uBit's are operating with no trouble at all.
If the IRF510's die at all, It is almost certainly because of overheating.
Perhaps when running some digital mode, inside an enclosure, with zero airflow..

Many of the reports of blown IRF510's can be attributed to people fiddling with the gate bias pots
without first spending 10 minutes to figure out what they are doing.?
The "clockwise is minimum" pot rotation plays a big factor.
Going to RD16HHF1's will only make this mistake much more expensive.

The uBitx is designed to be a minimalist SSB rig for all of HF at minimum cost, and succeeds wildly.
If it is to be used continuously at full power in digital modes, the minimalist heatsinks should be improved.

I can imagine that a shorted antenna jack (thus infinite SWR) could play a role.
But only because the IRF510's might heat up after some period of time.

Many in the forum run the IRF510's at around 20 volts for increased power.
With an adequate heatsink, this works reliably.
If you insist on telling them they should switch over to "real" RF devices such as the RD16HHF1,
you should also warn them?not to run at much beyond 12 volts.

The qrp-labs 10W PA blows away the many claims over the years in this forum
that the IRF510's are not suitable as RF transistors.?
It simply works, flat and clean, from 3.5 to 30mhz.
And is bulletproof when operated at 12v, even when presented with a worst case SWR.
The uBitx IRF510's can be just as reliable if given a suitable heatsink.

Jerry, KE7ER




On Fri, Jan 1, 2021 at 01:31 AM, MadRadioModder wrote:
Don¡¯t understand the point.? Why would you want to operate excellent RF transistors designed specifically for the 12-14V mobile world at a higher voltage?? They make all of their power in that range.
?
You are correct¡­ that most people won¡¯t get much out of replacing IRF devices with the RDs¡­? until they blow out a set or two of them.? Then it will start to matter, because the RD devices survive much better under bad circumstances like infinite SWR.? Again, real RF transistors designed for load mismatch tolerance ?(read the app note, load tolerance spec).? Bullet-proof.
?
You are also correct that most people won¡¯t spend the time to replace the IRF devices for the RD devices even after they kill a few sets.? They will just keep killing IRF510¡¯s.
?


Re: IRF510 sale

 

Curious what power out do you get with 18-22VDC?


--
Frank, KG9H