Date   
Re: batch shipping

 

I sent a mail to hfsignals they said the next round is in about 2 weeks. I also ordered on the 23rd.
--
David

 N8DAH
Kit-Projects.com

Re: IRF510 amplifier failures

Thomas Sharka
 

On Friday, January 26, 2018 1:01 PM, James Lawrie <lawriejk@...> wrote:


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: batch shipping

Chris Clarke G3SQU
 

Is anyone up for maintaining a database of Bitx by serial no. to include purchaser, ordering, shipping and delivery dates, and info about subsequent issues and modifications?


For info, mine was ordered on 16-Dec (for shipping to UK via Indian P.O.), acknowledged by email from HFSignals on 31-Dec, and a couple of days ago (following my enquiry to HFSignals) I was informed it would ship in 2-3 days. No advice from PayPal as yet.


Chris

G3SQU


From: BITX20@groups.io <BITX20@groups.io> on behalf of N8DAH <Dherron@...>
Sent: 26 January 2018 18:13:24
To: BITX20@groups.io
Subject: Re: [BITX20] batch shipping
 
I sent a mail to hfsignals they said the next round is in about 2 weeks. I also ordered on the 23rd.
--
David

 N8DAH
Kit-Projects.com

Re: Something has been blown

César EA3IAV
 

It is very frustrating. I don’t have any watt showing up in my power meter even in the 2w scale
how do I know I blew the fets again? 
When ptt i get 0,5amp and adjustin It is too sensitive. Even one time it got crazy with a very loud beep coming through the speaker an i had to turn it off
when i whistle no extra power is drained

Re: Apache Case on Sale

John McFadden
 

I bought two 1800s, they would not fit my ubitx pcb at the bottom of the case by a fraction of an inch because of the orientation of the raduino and heat sinks on the short axis of the card, they must point to the sides. Leaving the long axis of the card to fit front to back in the case. 

Instead, I selected the Seahorse SE300, more expensive, but also has screw bosses molded into both the case and lid which means easily hanging the PCB from stand offs instead of puncturing the case. 

John

On Jan 26, 2018 10:48 AM, "John P" <j.m.price@...> wrote:
Here's a link! This if the January flyer, so it doesn't show the sale price.
--
John - WA2FZW

Caveat Emptor!

John P
 

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.
--
John - WA2FZW

Re: IRF510 amplifier failures

Arv Evans
 

Interesting comments thus far regarding IRF510 failures. 
  • Power supply current limiting (2.5 to 3A) seems to work.

  • Bias voltage shutdown on high current (3A) seems to work.

  • Driver impedance to IRF510 gate should be quite "stiff".  Use a 50 ohm pad.

  • Use small resistance (4.7 ohms) in series with each IRF510 gate lead.

  • Keep IRF510 leads short.

  • Impedance presented to the IRF510 drain should be 12.5 ohms.
    RF output transformer should be 1:2 windings for 1:4 impedance transition.
    Binocular core may work better...?

  • Avoid the problem by using some other MOSFET.

  • Use plastic fuses at 3A for self-healing action.

  • Fuse rig power at 2 to 3A to avoid IRF510 failures.
Some of the on-line information also mentioned low level background noise being
generated by MOSFET RF PA stages that remain powered during receive mode. 
Possible solution here might be to add a MOSFET switch in the DC power lead
going to the IRF510s so this power could be shut off during receive.

All good info.  Now how to keep within the original BITX objective of making rigs
that can be afforded by those with limited spare cash and still make them reliable
and inexpensive.  This solution(s) has potential for modification of existing
transceivers, and for future redesign of the similar units.  It also has application
for designing and adding homebuilt RF amplifiers for your BITX rig.

Arv  K7HKL
_._


On Fri, Jan 26, 2018 at 10:32 AM, 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: Caveat Emptor!

Ken
 

Contact the seller and have them replaced.

Ken VA3ABN

On Fri, Jan 26, 2018 at 2:47 PM, John P <j.m.price@...> 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.
--
John - WA2FZW


Re: Lost in Customs?

DJ2AG
 

Last tracking information for mine was „2017-12-19 00:19 Germany, FRANKFURT/FLUGHAFEN, Receive item at office of exchange (Inb), Air“

On 29th I got a letter from local customs office (Zollamt) that a parcel ist waiting for me. Paid VAT and fetched it. But this last step doesn’t show up in tracking. Maybe your Zollamt is a bit slower than mine, and 
you just have to wait. Gut Ding will Weile haben.

Re: Caveat Emptor!

Dennis Zabawa
 

It is quite possible that the vendor is selling slightly defective culls from the production line.  Reputable manufacturers clearly mark such items to prevent them from being sold as fully working items.  Others sell them off with no warning, while others destroy them.  Luck of the draw

Re: Caveat Emptor!

Arv Evans
 

John

My experience with high density displays is not any better.  I have 5 of the small 0.92 inch
displays but have not been able to get any of them to work.  These are TWI or I2C interface
and my Arduino does not recognize any.  I have tried the example code, the TWI address search
code, and my own TWI interface code, all to no avail.    At present I seem to be limited to using
the old standard 1602 LCDs, 4-line 16 char LCDs, and using the ttl/USB interface to show Arduino
outputs on my PC. 

Given my non-success experience with the 0.92 inch screens I have been hesitant to invest in
larger wire-bus connected displays.  Your experience seems to say it is good that I have not
purchased larger displays.

I wonder who, if anybody, has had good luck with these type screens?  The wire.h library
seems straight-forward and easy to use, but it just does not work with displays I have tried.
I even used the example code without making any modifications and it still doesn't work.

Arv
_._


On Fri, Jan 26, 2018 at 12:47 PM, John P <j.m.price@...> 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.
--
John - WA2FZW


Re: Caveat Emptor!

Sr Shobe
 

Have done business with same person....the way they are packed and handled by China mail, it is a miracle that anything makes it thru to the US....Mine made it okay......so far!!! Knock on lotsa wood!
Steve/N0AAH

On Fri, Jan 26, 2018 at 2:07 PM, Arv Evans <arvid.evans@...> wrote:
John

My experience with high density displays is not any better.  I have 5 of the small 0.92 inch
displays but have not been able to get any of them to work.  These are TWI or I2C interface
and my Arduino does not recognize any.  I have tried the example code, the TWI address search
code, and my own TWI interface code, all to no avail.    At present I seem to be limited to using
the old standard 1602 LCDs, 4-line 16 char LCDs, and using the ttl/USB interface to show Arduino
outputs on my PC. 

Given my non-success experience with the 0.92 inch screens I have been hesitant to invest in
larger wire-bus connected displays.  Your experience seems to say it is good that I have not
purchased larger displays.

I wonder who, if anybody, has had good luck with these type screens?  The wire.h library
seems straight-forward and easy to use, but it just does not work with displays I have tried.
I even used the example code without making any modifications and it still doesn't work.

Arv
_._


On Fri, Jan 26, 2018 at 12:47 PM, John P <j.m.price@...> 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.
--
John - WA2FZW



Re: Caveat Emptor!

Jack, W8TEE
 

Do you have the correct I2C address for the displays? You might check that. See:




 Jack, W8TEE



From: Arv Evans <arvid.evans@...>
To: BITX20@groups.io
Sent: Friday, January 26, 2018 3:08 PM
Subject: Re: [BITX20] Caveat Emptor!

John

My experience with high density displays is not any better.  I have 5 of the small 0.92 inch
displays but have not been able to get any of them to work.  These are TWI or I2C interface
and my Arduino does not recognize any.  I have tried the example code, the TWI address search
code, and my own TWI interface code, all to no avail.    At present I seem to be limited to using
the old standard 1602 LCDs, 4-line 16 char LCDs, and using the ttl/USB interface to show Arduino
outputs on my PC. 

Given my non-success experience with the 0.92 inch screens I have been hesitant to invest in
larger wire-bus connected displays.  Your experience seems to say it is good that I have not
purchased larger displays.

I wonder who, if anybody, has had good luck with these type screens?  The wire.h library
seems straight-forward and easy to use, but it just does not work with displays I have tried.
I even used the example code without making any modifications and it still doesn't work.

Arv
_._


On Fri, Jan 26, 2018 at 12:47 PM, John P <j.m.price@...> 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.
--
John - WA2FZW



Re: Apache Case on Sale

Vince Vielhaber
 

The coupon is in the "Final Attempt" flyer for Feb and March. I've yet to see an electronic version of the flyer. It's possible it'll show up after the first of the month on the HF site. I'll post it when I see it.

Vince.

On 01/26/2018 10:47 AM, John P wrote:
_Here's a link! _
<https://www.harborfreight.com/1800-watertight-protective-case-9-316-in-63518.html?utm_source=publitas&utm_medium=monthly-ad&utm_campaign=012018>This
if the January flyer, so it doesn't show the sale price.
--
John - WA2FZW

Re: Something has been blown

Arv Evans
 

Ceasar

It might be worthwhile to make up a little test jig for evaluating IRF510 devices. 
Maybe just a pot to vary the gate bias and a 1K resistor in the drain lead.  Ground
the source lead.  Monitor drain voltage as you vary the gate bias.  At between 3
and 4 volts on the gate you should see drain voltage decrease indicating that the
device is drawing current.  If this current is not adjustable it might indicate a defective
device.  Of course this is just a DC test and not fully representative of RF performance.




In BJT (Bipolar Junction Transistors) we are used to seeing the base draw current
to forward bias the device, but with MOSFETs there is no gate current.  They are
only affected by voltage at the gate.  Once we accept that it is easier to troubleshoot
circuits that have these devices.

An oscilloscope or RF Detector Probe could be used to measure RF at various points
around the IRF510 devices.  You should have at least a couple of volts RF on the
gate lead, and more RF volts on the drain lead.  If nothing on the gate then you could
use the probe or scope to verify presence or absence of RF voltage in the drive section.

Arv
_._


On Fri, Jan 26, 2018 at 9:23 AM, César EA3IAV <Cesarleon@...> wrote:
Thank you Arv

It is weird. I was adjusting the pa with the blue squares and the fuse blew. I changed the fuse and it happened again. It was like that until i changed the transistors... i have quite a few.
now still no power out visible through power meter even in lowest selectir (2w mode)
0,5amps while ppt but as i speak there is no increase on that 
i can hear myself in a close receiver  though...
i feel like these fets are bad

what else could br the reason to not output power?
what is that round blue trimmer for?

i do receive fine btw

i am going tonmy local electrinic shop to buy more fets and fuses 😟


Re: batch shipping

Alan G4NMA
 

I ordered mine on 15th December. Received an email today saying it has been shipped.

Re: Second batch of uBITX shipping? #ubitx

Alex
 

Email this morning to say that mine has been shipped India post.

Ordered 15th December, they're slowly getting through them. Looking forward to getting it!

Alex

Re: Caveat Emptor!

John P
 

On Fri, Jan 26, 2018 at 12:01 pm, Ken wrote:
Contact the seller and have them replaced.
Did that! But thanks for the reminder! Waiting for a response.
 
--
John - WA2FZW

Re: Second batch of uBITX shipping? #ubitx

Alan G4NMA
 

Same for me, ordered 15/12, notified of shipping today. 

Re: Caveat Emptor!

John P
 

On Fri, Jan 26, 2018 at 12:21 pm, Jack Purdum wrote:
Do you have the correct I2C address for the displays?
They're not I2C displays; they're the 3.5: TFTs for the analyzed.
 
--
John - WA2FZW