I ordered mine on 15th December. Received an email today saying it has been shipped.
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Re: Something has been blown
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 ?
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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.
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Show quoted text
On 01/26/2018 10:47 AM, John P wrote: _Here's a link! _
<>This
if the January flyer, so it doesn't show the sale price.
--
John - WA2FZW
--
Michigan VHF Corp.
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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
_._
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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
_._
|
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
|
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
|
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.
|
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: IRF510 amplifier failures
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
|
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
|
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: This if the January flyer, so it doesn't show the sale price.
--
John - WA2FZW
|
Re: Something has been blown
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
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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
toggle quoted message
Show quoted text
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
|
Re: IRF510 amplifier failures
?
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.
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
|
I sent a mail to hfsignals they said the next round is in about 2 weeks. I also ordered on the 23rd. -- David
?N8DAH
|
Re: uBitX - Replacement microphone
Thanjk you Michael
Let me check your suggestion.
|
Re: 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.
toggle quoted message
Show quoted text
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: BITX QSO Afternoon/Night, Sunday, January 28, 3PM/7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere
good call Ed. The GM (General Motors Employee/retirees) net operates on 7.277.5 - should NOT be a problem but can be used to check propagation during the week.? ? ? ? ? ? ? ? ? ? GM HF Net Mon thru Sat 1:00pm (HF 7,277.5 KHz).?
I think the mod to RLS 2 will help with the heterodyne we hear AM broadcasters in our 40M ham band in North America. I don't have the new uBITX built yet but I'm hoping it's not a problem too. Using an external DSP and/or notch filter does help a lot.
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Re: remote display was Apache Case on Sale
Jack and All,
attached 2 pix of remote display. Note that I used DuPont wires
that came as a flat-group, not the helter-skelter loose wires.
Probably helps reduce noise to some degree.
The ubitx is in an old Heathkit Frequency counter cabinet. When
fully assembled, the cabinet looks good, and has
plenty of room for add-ons, and has good cooling louvers.
I will install a fan just behind the finals. The fan will be
pulling air away from the finals, not blowing onto them.
Downside of using this case: the 12 inch Nano USB extension cable
will not reach the back panel; had to bring
it out through the front.
Rod KM6SN
On 01/26/2018 08:38 AM, Jack Purdum via
Groups.Io wrote:
toggle quoted message
Show quoted text
That's good
news! I'm thinking of using ribbon cable and grounding every
other wire.
Jack, W8TEE
From:
Rod Self <km6sn@...>
To:
BITX20@groups.io
Sent:
Friday, January 26, 2018 11:35 AM
Subject:
Re: [BITX20] remote display was Apache Case on Sale
Jack,
I
used 6 inch Dupont wires with no shield-no
apparent problems.
Rod
KM6SN
On
01/26/2018 06:43 AM, Jack Purdum via Groups.Io
wrote:
I
think there are a number of people who have
moved the display away from the main board to
give them some flexibility in terms of display
placement. Evidently, some shielding is
needed, but I think I recall someone simply
wrapping the cable in foil mitigated the
problem. I'd like to hear from anyone who has
moved the display and what their experience
is.
Jack,
W8TEE
I
love the idea of a "portable field
radio" with all the controls on the
top in a watertight case like this.
?I'm thinking of modeling it after a
bitX40 build I saw here, and this
case looks like the perfect size!
Is there any reason I couldn't do
that with the uBitx? ?It looks like
the LCD plugs directly into the
board, but would it give me noise
issues if I used a short length of
ribbon cable to move the LCD to face
upwards?
|
N8DAH
James Lawrie
