Date   
Re: End whistling into the mic

chris gress <Chrisg0wfh@...>
 

You could always use this so you could have built in swr/rf out on your bitx the 51ohm resistors I use 2x 100 ohm 3watt I picked this up from the internet 

On 27 Jan 2018 09:32, "gw4akz via Groups.Io" <gw4akz=aol.com@groups.io> wrote:
On Thu, Jan 25, 2018 at 01:20 pm, David wrote:
Instead of whistling into the mic when using an antenna tuner on SSB, we could easily add a tone generator and switch to do that for us. Thoughts?
I have fitted a switchable -6db pad between the output of the pcb and the anttena socket. With the circuit switched in the worst case swr is about 1.65 to 1 with an open or short circuit, this prevents the finals from ever seeing a poor swr. tune is easily achived with the key down and reduced radiated power when tunning up. I use 2 watt carbon resistors 33 ohms in a t attenuator circuit. 2 in parrarlel to give 16.5 ohms which is close enough to the callculated value. I use a relay to switch this attenuator in and out.

Re: End whistling into the mic

chris gress <Chrisg0wfh@...>
 

Built on back of a switch low power atu to the right chris

On 27 Jan 2018 11:45, "chris gress" <Chrisg0wfh@...> wrote:
You could always use this so you could have built in swr/rf out on your bitx the 51ohm resistors I use 2x 100 ohm 3watt I picked this up from the internet 

On 27 Jan 2018 09:32, "gw4akz via Groups.Io" <gw4akz=aol.com@groups.io> wrote:
On Thu, Jan 25, 2018 at 01:20 pm, David wrote:
Instead of whistling into the mic when using an antenna tuner on SSB, we could easily add a tone generator and switch to do that for us. Thoughts?
I have fitted a switchable -6db pad between the output of the pcb and the anttena socket. With the circuit switched in the worst case swr is about 1.65 to 1 with an open or short circuit, this prevents the finals from ever seeing a poor swr. tune is easily achived with the key down and reduced radiated power when tunning up. I use 2 watt carbon resistors 33 ohms in a t attenuator circuit. 2 in parrarlel to give 16.5 ohms which is close enough to the callculated value. I use a relay to switch this attenuator in and out.

Re: Caveat Emptor!

John P
 

On Fri, Jan 26, 2018 at 11:47 am, John P wrote:
I just received 3 of the MCUFriend 3.5" TFT displays purchased from "accecity2006" on eBay. One of the 3 worked correctly; one was cracked and another one was not displaying text correctly.
I did get a refund quickly from the seller. That won't get my project up and running any faster though! Anyone have any recommendations on a reliable provider of the MCUFriend 3.5:" TFTs?
 
--
John - WA2FZW

Re: Second batch of uBITX shipping? #ubitx

Arvo W0VRA
 

Got a shipping confirmation last night for my December 15 order. Better start working on the case!

ubitx - pads under toroids

MAc B
 

There are nice 6 hole plastic pads under toroidal transformers.

Are they from the shop or custom made?

 

MAc

Re: Second batch of uBITX shipping? #ubitx

Laurence Oberman
 

If you paid with PayPal, PayPal will notify you when it ships.
Always better to pay the DHL extra as it's fully tracked.



On Jan 27, 2018 7:53 AM, "Arvo KD9HLC via Groups.Io" <arvopl=yahoo.com@groups.io> wrote:
Got a shipping confirmation last night for my December 15 order. Better start working on the case!

Re: Second batch of uBITX shipping? #ubitx

chris gress <Chrisg0wfh@...>
 

Mine is via India post I don't use dhl the take the pee with the extra charges had to pay £24 last time chris

On 27 Jan 2018 13:22, "Laurence Oberman" <oberman.l@...> wrote:
If you paid with PayPal, PayPal will notify you when it ships.
Always better to pay the DHL extra as it's fully tracked.



On Jan 27, 2018 7:53 AM, "Arvo KD9HLC via Groups.Io" <arvopl=yahoo.com@groups.io> wrote:
Got a shipping confirmation last night for my December 15 order. Better start working on the case!

Re: IRF510 amplifier failures

K9HZ <bill@...>
 

I don’t think it’s so much a matter of if they will work or not.  Both will work fine at 50 MHz (and above actually)… the issue is that the RD15HVF1 is a little flatter across the spectrum and from that perspective easier to design around and match.  I use them all the time and they are very easy parts to make work.  A pair will easily put out 30 watts 1-54 MHz if the rest of the design is correct.

 

I’ve been thinking about and have had requests for a nice linear amplifier for the uBITx and these parts are cheap enough to use for that purpose too.  I originally designed one using two RD70HVF1 parts but the cheapest I’ve found them is $18 each.  Not a show stopper but the little brothers are cheaper.  If The parts were under $15 in large quantity, it would be a no brainer.  The auto tuner must be finished first though.  Oh, did I mention, the RD series devices are real RF transistors?

 

 

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ

 

Owner - Operator

Big Signal Ranch – K9ZC

Staunton, Illinois

 

Owner – Operator

Villa Grand Piton – J68HZ

Soufriere, St. Lucia W.I.

Rent it: www.VillaGrandPiton.com

Like us on Facebook! facebook icon

 

 

email:  bill@...

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Lawrence Galea
Sent: Saturday, January 27, 2018 3:34 AM
To: BITX20@groups.io
Subject: Re: [BITX20] IRF510 amplifier failures

 

Good morning.

I was thinking about the RD15HVF1 so that it would be easier for people who want to try 50MHz and perhaps 70MHs where available with suitable mods to the μbitx.

 

The RD16HHF1 appears to be  used in the Ukraine transverters as a PA in the 50MHz, 70MHz and 144 MHz transverters while the RD15HBF1 appears to be used in the 222MHz and 432MHz transverters. http://transverters-store.com/50mhz.htm

I have the 50MHz and 70MHz transverters and they do work.
Two years ago I worked more than 40 stations on 70MHz (see my log on QRZ dot com) with a simple dipole at about 4M high on the roof fed with some 50 feet of RG58 coax.

Last year I built a 5 element LFA Yagi for 70MHz but didn't have time to get on the air. 

Regards

Lawrence

 

On Sat, Jan 27, 2018 at 3:41 AM, James Lawrie <lawriejk@...> wrote:

Hello,

 

That’s why I bought 10 ea... for the uBitxs I’ll probably get the others rated at over 30 MHz. Always nice to stock up on useful parts. Out of all listed on there website what would you recommend for HF/VHF use?

James Lawrie


On Jan 26, 2018, at 19:56, K9HZ <bill@...> wrote:

The RD15HVF1 has a bit of a flatter input capacitance curve with frequency so its easier to keep constant gain over 1-54 MHz… but the RD16HHF1 is certainly a worthy part too.  Oh, did I mention, they are both real RF transistors?

 

 

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ

 

Owner - Operator

Big Signal Ranch – K9ZC

Staunton, Illinois

 

Owner – Operator

Villa Grand Piton – J68HZ

Soufriere, St. Lucia W.I.

Rent it: www.VillaGrandPiton.com

Like us on Facebook! <image001.gif>

 

 

email:  bill@...

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of James Lawrie
Sent: Friday, January 26, 2018 2:01 PM
To: BITX20@groups.io
Subject: Re: [BITX20] IRF510 amplifier failures

 

On same site I found these, made for 30 MHz RD16HHF1. Sooo I bought 10 of them, plan to try in Bix40 first. Data sheet even shows a reference amp design, and they are 12 volt like the other one. If it works I’ll let everyone know.

 

James Lawrie


On Jan 26, 2018, at 11:32, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:

The RD15HVF1's should be operated at not much more than 12v.
At 12v, the IRF510's would survive just fine with no antenna connected.
That's an infinite VSWR.

So not obvious that this is a solution to blown FET's.
Though I do think the the Ids curves go up more slowly as Vgs increases on the RD15HF1's,
which makes RV2,RV3 not so touchy.
And the RD15HF1's might be easier to drive at 30mhz.
If you do swap them in, let us know how much power you get at 30mhz.

Jerry, KE7ER

On Fri, Jan 26, 2018 at 03:54 am, KD8CGH wrote:

Wouldn't it be better to change to a RD15HVF1 for high VSWR

 

Re: Second batch of uBITX shipping? #ubitx

Dgyuro
 

Dec 17 order date will ship in 2 days. 

Sent from my iPhone

On Jan 27, 2018, at 6:33 AM, chris gress <Chrisg0wfh@...> wrote:

Mine is via India post I don't use dhl the take the pee with the extra charges had to pay £24 last time chris

On 27 Jan 2018 13:22, "Laurence Oberman" <oberman.l@...> wrote:
If you paid with PayPal, PayPal will notify you when it ships.
Always better to pay the DHL extra as it's fully tracked.



On Jan 27, 2018 7:53 AM, "Arvo KD9HLC via Groups.Io" <arvopl=yahoo.com@groups.io> wrote:
Got a shipping confirmation last night for my December 15 order. Better start working on the case!

Re: Second batch of uBITX shipping? #ubitx

bill richardson
 

Got my shipping notice this morning. Looks like it shipped out on Thursday and will arrive on Monday. I ordered on 15 December.

Sent from my iPhone

On Jan 27, 2018, at 7:53 AM, Arvo KD9HLC via Groups.Io <arvopl@...> wrote:

Got a shipping confirmation last night for my December 15 order. Better start working on the case!

Re: IRF510 amplifier failures

philip yates
 

So if they are " real RF transistors" probably worth the extra then ?

Phil - G7BZD

On Sat, Jan 27, 2018 at 1:36 PM, K9HZ <bill@...> wrote:

I don’t think it’s so much a matter of if they will work or not.  Both will work fine at 50 MHz (and above actually)… the issue is that the RD15HVF1 is a little flatter across the spectrum and from that perspective easier to design around and match.  I use them all the time and they are very easy parts to make work.  A pair will easily put out 30 watts 1-54 MHz if the rest of the design is correct.

 

I’ve been thinking about and have had requests for a nice linear amplifier for the uBITx and these parts are cheap enough to use for that purpose too.  I originally designed one using two RD70HVF1 parts but the cheapest I’ve found them is $18 each.  Not a show stopper but the little brothers are cheaper.  If The parts were under $15 in large quantity, it would be a no brainer.  The auto tuner must be finished first though.  Oh, did I mention, the RD series devices are real RF transistors?

 

 

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ

 

Owner - Operator

Big Signal Ranch – K9ZC

Staunton, Illinois

 

Owner – Operator

Villa Grand Piton – J68HZ

Soufriere, St. Lucia W.I.

Rent it: www.VillaGrandPiton.com

Like us on Facebook! facebook icon

 

 

email:  bill@...

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Lawrence Galea
Sent: Saturday, January 27, 2018 3:34 AM


To: BITX20@groups.io
Subject: Re: [BITX20] IRF510 amplifier failures

 

Good morning.

I was thinking about the RD15HVF1 so that it would be easier for people who want to try 50MHz and perhaps 70MHs where available with suitable mods to the μbitx.

 

The RD16HHF1 appears to be  used in the Ukraine transverters as a PA in the 50MHz, 70MHz and 144 MHz transverters while the RD15HBF1 appears to be used in the 222MHz and 432MHz transverters. http://transverters-store.com/50mhz.htm

I have the 50MHz and 70MHz transverters and they do work.
Two years ago I worked more than 40 stations on 70MHz (see my log on QRZ dot com) with a simple dipole at about 4M high on the roof fed with some 50 feet of RG58 coax.

Last year I built a 5 element LFA Yagi for 70MHz but didn't have time to get on the air. 

Regards

Lawrence

 

On Sat, Jan 27, 2018 at 3:41 AM, James Lawrie <lawriejk@...> wrote:

Hello,

 

That’s why I bought 10 ea... for the uBitxs I’ll probably get the others rated at over 30 MHz. Always nice to stock up on useful parts. Out of all listed on there website what would you recommend for HF/VHF use?

James Lawrie


On Jan 26, 2018, at 19:56, K9HZ <bill@...> wrote:

The RD15HVF1 has a bit of a flatter input capacitance curve with frequency so its easier to keep constant gain over 1-54 MHz… but the RD16HHF1 is certainly a worthy part too.  Oh, did I mention, they are both real RF transistors?

 

 

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ

 

Owner - Operator

Big Signal Ranch – K9ZC

Staunton, Illinois

 

Owner – Operator

Villa Grand Piton – J68HZ

Soufriere, St. Lucia W.I.

Rent it: www.VillaGrandPiton.com

Like us on Facebook! <image001.gif>

 

 

email:  bill@...

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of James Lawrie
Sent: Friday, January 26, 2018 2:01 PM
To: BITX20@groups.io
Subject: Re: [BITX20] IRF510 amplifier failures

 

On same site I found these, made for 30 MHz RD16HHF1. Sooo I bought 10 of them, plan to try in Bix40 first. Data sheet even shows a reference amp design, and they are 12 volt like the other one. If it works I’ll let everyone know.

 

James Lawrie


On Jan 26, 2018, at 11:32, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:

The RD15HVF1's should be operated at not much more than 12v.
At 12v, the IRF510's would survive just fine with no antenna connected.
That's an infinite VSWR.

So not obvious that this is a solution to blown FET's.
Though I do think the the Ids curves go up more slowly as Vgs increases on the RD15HF1's,
which makes RV2,RV3 not so touchy.
And the RD15HF1's might be easier to drive at 30mhz.
If you do swap them in, let us know how much power you get at 30mhz.

Jerry, KE7ER

On Fri, Jan 26, 2018 at 03:54 am, KD8CGH wrote:

Wouldn't it be better to change to a RD15HVF1 for high VSWR

 


Re: Second batch of uBITX shipping? #ubitx

Joe Puma
 

I ordered mine on Jan 17th. I was just emailed and was told 2-3 weeks for shipping.  :(



Sent from my iPhone

On Jan 27, 2018, at 8:33 AM, chris gress <Chrisg0wfh@...> wrote:

Mine is via India post I don't use dhl the take the pee with the extra charges had to pay £24 last time chris

On 27 Jan 2018 13:22, "Laurence Oberman" <oberman.l@...> wrote:
If you paid with PayPal, PayPal will notify you when it ships.
Always better to pay the DHL extra as it's fully tracked.



On Jan 27, 2018 7:53 AM, "Arvo KD9HLC via Groups.Io" <arvopl=yahoo.com@groups.io> wrote:
Got a shipping confirmation last night for my December 15 order. Better start working on the case!

Re: uBITx.net website

 

Mike :

This is an awesome idea !  

Right away I can see that over time, this could really help to reduce group traffic from "uBITX newbies" looking for 
solutions to problems that have already been resolved.

Can I suggest that where possible, sections on the website provide a link to the associated discussions in the
Bitx20 Group? As Groups.IO allows a search based on message number, just including the number of the initial message for a given
topic would allow website readers to go back  to the Bitx20 group and read through the complete discussion on that topic if they want the full story. 

Many thanks for doing this ! 

Cheers

Michael VE3WMB 

Re: No TX #ubitx

César EA3IAV
 

I am experiencing the same issue. I see no needle movement on the power meter but i get heard on a nearby receiver.

i have changed seceral times the transistors just in case. The same results 

Re: UBITX Touch Control TFT Display

Jerry Gaffke
 

I had never heard of elegoo.com, that looks like a good steer.
They have some nice Arduino starter kits.
However, their 2.8" TFT display is not well documented, and burns an awful lot of pins.

Here's a reply to a question up on Amazon:  https://www.amazon.com/ask/questions/asin/B01EUVJYME/4/ref=ask_ql_psf_ql_hza?isAnswered=true
      I just went through all of the pins marked on the board and the code for the support libraries.
      It appears that the display hogs all of the pins with the exception of the A5 and the serial I/O pins 0 and 1.
      This pretty much precludes the use of any other peripheral devices using Wire, SPI, or I2C.
      The SD card uses digital pins 10 through 13, so if you don't need the SD card, you can snip those pins off
      (and don't include the SD library in your project). Otherwise the options are limited.

Not what I'm looking for.  
I'd prefer a display with just a 4 wire SPI interface, and power and ground.
Recommendations solicited.

Regarding the si5351 PLL chip breakout board, in addition to adafruit.com, there is also etherkit.com and qrp-labs.com
Hans of qrp-labs is active on this forum, a kit for his board is $7.75
    https://qrp-labs.com/synth.html
The others come fully soldered up, which some may prefer.

Jerry, KE7ER




On Fri, Jan 26, 2018 at 06:42 pm, Joe wrote:
Brein,
 
I use the following: HARDWARE
 
DISPLAY - Optimum size - 2.8inch TFT - I have tried several types and sizes from various companies - hit and miss. some work but poor clarity etc.
 
Having used the elegoo 2.8 inch  TFT Display with pen - from "amazon" has resulted in 100 percent working, clear, clean, crisp displays.
I have ordered 4 over time and quality is persistent. Price  around $15.00 shipped.  Best choice
 
 
Arduino Module : Atmega 2560 - Ebay is cheapest source at less then $10.00...  Any Atmega 2560 will work..
I have many different company modules and have found they all work great...
 
DDS module -  SI5351  module (not just the chip)- available from Ebay or Adafruit direct or amazon around $11.00
 

Re: uBITx.net website

Joe Puma
 

Great job on the website 


Sent from my iPhone

On Jan 27, 2018, at 10:35 AM, Michael Babineau <mbabineau.ve3wmb@...> wrote:

Mike :

This is an awesome idea !  

Right away I can see that over time, this could really help to reduce group traffic from "uBITX newbies" looking for 
solutions to problems that have already been resolved.

Can I suggest that where possible, sections on the website provide a link to the associated discussions in the
Bitx20 Group? As Groups.IO allows a search based on message number, just including the number of the initial message for a given
topic would allow website readers to go back  to the Bitx20 group and read through the complete discussion on that topic if they want the full story. 

Many thanks for doing this ! 

Cheers

Michael VE3WMB 

Re: No TX #ubitx

philip yates
 

Easy to check TX, put the µBitx into TX CW mode with a power meter and dummy load attached.

If the output is ok, the power meter should show power.
I used this method as my mike was not connected properly. All sorted now.

Phil - G7BZD

On Sat, Jan 27, 2018 at 3:38 PM, César EA3IAV <Cesarleon@...> wrote:
I am experiencing the same issue. I see no needle movement on the power meter but i get heard on a nearby receiver.

i have changed seceral times the transistors just in case. The same results 


Re: No TX #ubitx

Arv Evans
 


If an oscilloscope is not available you can use a diode probe to measure RF level at various points
in your circuits.  N5ESE has documented a nice probe along with how it works and how to use it.

  http://n5ese.com/rfprobe1.htm

Arv  K7HKL
_._

On Sat, Jan 27, 2018 at 2:58 AM, David Beal <aardvarq@...> wrote:
Hi Joe, 
I'm experiencing similar symptoms as captured here: https://groups.io/g/BITX20/topic/7878333?p=Created,,,20,1,40,0 

Current draw indicates that it's making power, but nothing is making it to the antenna. FWIW, my initial bias current was 380 mA. 
 
I validated with a separate receiver that the radio is transmitting. I had concluded that K3 was bad; replaced it tonight (it did measure with open coils), but still no output.  

Tomorrow, I'll follow Ashhar's suggestions in this thread to check around the toroids and I'll run some DC checks on the relay paths. 

--
Dave Beal
AE6RQ


Re: IRF510 amplifier failures

K9HZ <bill@...>
 

Well it’s this way.  You can either spend a little more on the transistor (with the nice input characteristics) and design with minimal parts (e.g. one set of broad band impedance matching transformers and bias network) to work over a large frequency range (1-54 MHz)…. Or you use a cheap motor switch like the 510 and live with the gain roll-off from mismatch (large del C / del Freq) with a fixed set of broad band I/O transformers…. OR you spend more $$$ to build band switchable compensation networks to improve the matching (Can be bulky and expensive but not always).  Pay me now of pay me later.  Many commercial SS Amps that cover 1-54 MHz complete still utilize some sort of compensation network in them to cover the large frequency range and it’s not apparent to the user… even with very good RF transistors (sometimes driven by the transformer material).   All depends on the part.  Best to Simulate from the S params first.  It will tell you a lot.

 

 

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ

 

Owner - Operator

Big Signal Ranch – K9ZC

Staunton, Illinois

 

Owner – Operator

Villa Grand Piton – J68HZ

Soufriere, St. Lucia W.I.

Rent it: www.VillaGrandPiton.com

Like us on Facebook! facebook icon

 

 

email:  bill@...

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of philip yates
Sent: Saturday, January 27, 2018 10:17 AM
To: BITX20@groups.io
Subject: Re: [BITX20] IRF510 amplifier failures

 

So if they are " real RF transistors" probably worth the extra then ?

 

Phil - G7BZD

 

On Sat, Jan 27, 2018 at 1:36 PM, K9HZ <bill@...> wrote:

I don’t think it’s so much a matter of if they will work or not.  Both will work fine at 50 MHz (and above actually)… the issue is that the RD15HVF1 is a little flatter across the spectrum and from that perspective easier to design around and match.  I use them all the time and they are very easy parts to make work.  A pair will easily put out 30 watts 1-54 MHz if the rest of the design is correct.

 

I’ve been thinking about and have had requests for a nice linear amplifier for the uBITx and these parts are cheap enough to use for that purpose too.  I originally designed one using two RD70HVF1 parts but the cheapest I’ve found them is $18 each.  Not a show stopper but the little brothers are cheaper.  If The parts were under $15 in large quantity, it would be a no brainer.  The auto tuner must be finished first though.  Oh, did I mention, the RD series devices are real RF transistors?

 

 

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ

 

Owner - Operator

Big Signal Ranch – K9ZC

Staunton, Illinois

 

Owner – Operator

Villa Grand Piton – J68HZ

Soufriere, St. Lucia W.I.

Rent it: www.VillaGrandPiton.com

Like us on Facebook! facebook icon

 

 

email:  bill@...

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Lawrence Galea
Sent: Saturday, January 27, 2018 3:34 AM


To: BITX20@groups.io
Subject: Re: [BITX20] IRF510 amplifier failures

 

Good morning.

I was thinking about the RD15HVF1 so that it would be easier for people who want to try 50MHz and perhaps 70MHs where available with suitable mods to the μbitx.

 

The RD16HHF1 appears to be  used in the Ukraine transverters as a PA in the 50MHz, 70MHz and 144 MHz transverters while the RD15HBF1 appears to be used in the 222MHz and 432MHz transverters. http://transverters-store.com/50mhz.htm

I have the 50MHz and 70MHz transverters and they do work.
Two years ago I worked more than 40 stations on 70MHz (see my log on QRZ dot com) with a simple dipole at about 4M high on the roof fed with some 50 feet of RG58 coax.

Last year I built a 5 element LFA Yagi for 70MHz but didn't have time to get on the air. 

Regards

Lawrence

 

On Sat, Jan 27, 2018 at 3:41 AM, James Lawrie <lawriejk@...> wrote:

Hello,

 

That’s why I bought 10 ea... for the uBitxs I’ll probably get the others rated at over 30 MHz. Always nice to stock up on useful parts. Out of all listed on there website what would you recommend for HF/VHF use?

James Lawrie


On Jan 26, 2018, at 19:56, K9HZ <bill@...> wrote:

The RD15HVF1 has a bit of a flatter input capacitance curve with frequency so its easier to keep constant gain over 1-54 MHz… but the RD16HHF1 is certainly a worthy part too.  Oh, did I mention, they are both real RF transistors?

 

 

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ

 

Owner - Operator

Big Signal Ranch – K9ZC

Staunton, Illinois

 

Owner – Operator

Villa Grand Piton – J68HZ

Soufriere, St. Lucia W.I.

Rent it: www.VillaGrandPiton.com

Like us on Facebook! <image001.gif>

 

 

email:  bill@...

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of James Lawrie
Sent: Friday, January 26, 2018 2:01 PM
To: BITX20@groups.io
Subject: Re: [BITX20] IRF510 amplifier failures

 

On same site I found these, made for 30 MHz RD16HHF1. Sooo I bought 10 of them, plan to try in Bix40 first. Data sheet even shows a reference amp design, and they are 12 volt like the other one. If it works I’ll let everyone know.

 

James Lawrie


On Jan 26, 2018, at 11:32, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:

The RD15HVF1's should be operated at not much more than 12v.
At 12v, the IRF510's would survive just fine with no antenna connected.
That's an infinite VSWR.

So not obvious that this is a solution to blown FET's.
Though I do think the the Ids curves go up more slowly as Vgs increases on the RD15HF1's,
which makes RV2,RV3 not so touchy.
And the RD15HF1's might be easier to drive at 30mhz.
If you do swap them in, let us know how much power you get at 30mhz.

Jerry, KE7ER

On Fri, Jan 26, 2018 at 03:54 am, KD8CGH wrote:

Wouldn't it be better to change to a RD15HVF1 for high VSWR

 

 

Re: My ubitx Finally shipped

B C
 

The ubitx I ordered on Dec 14th shipped yesterday according to the email I just got from paypal.
Let the adventure begin..I had added DHL shipping so I will keep you posted..
Brian K9WIS