Re: [SPAM] Re: [SPAM] Re: [BITX20] IRF510 amplifier failures
Transmit into a resonate antenna where the SWR is close to 1:1.? Yes, a good thing.? I think most of the failures from high SWR mostly come from mistakes…. Not connecting an antenna, or transmitting into the wrong one.? Everyone makes a mistake like that once in a while… Hopefully no one knowingly transmits into a non-resonate antenna… ? There are other failure modes for these motor switches though too… but if the antenna match is good… most of those other failure modes are of no consequence. ? Remember until fold-back became popular, this was a problem with most commercial SS radios as well. ? ? 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: Like us on Facebook! ? ? email:? bill@... ?
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From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of David Wilcox via Groups.Io
Sent: Tuesday, January 30, 2018 6:35 AM
To: BITX20@groups.io
Subject: [SPAM] Re: [SPAM] Re: [BITX20] IRF510 amplifier failures? I may be off base here but using an antenna analyzer to tune ones antenna or tuner before applying power would prolong the life of the IRF510's. ?I know it doesn't allow one to move great distances from the first tuned frequency without rechecking but I have used that method for a few years and still have not blown a 510 (other than having a bad one or killing one with static electricity while installing it). ? I have a 3 way antenna switch that I use to switch to my little FG-01 analyzer as one of my options when I change frequency. Analyzers are now quite affordable and I feel a necessary part of any hams "must have" equipment. ?We ARE hams and do test things don't we? Carelessness has always been a costly issue..... Ask me about reverse voltages sometime. Thanks for the bandwidth but I see so much discussion about the IRF510's lately. ?They are cheap, simple, and do work if certain precautions are observed. ?And when I was in medicine, off label uses for certain meds were common and cost saving. ?They might be motor switches but do work in RF circuits. ?I just received 10 brand name 510's for $18.00 from DigiKey "just in case". Sorry if I made any mistakes in my comments. ?My education and experience was 44 years in family medicine. ?This hobby is part of my mental health therapy....... Has helped me keep my sanity since 1960. ?Ask my wife of 45 years. And as one local friend commented, "It is cheaper than a mistress, AND less stress."? This has been an interesting discussion, but still not sure which
might be the best way to insure a long and uneventful life for MOSFET power amplifiers.? Several ideas have been presented
by myself and other individuals.? All seem to have been rejected
by others for various reasons.? Makes me wonder if rejections
are based on reality or just a fear of using any switching device
as an RF amplifier.? The alternative of using real RF transistors or RF MOSFETs seems
to defeat the objective of designing and building low cost transceiver
from components that can be readily obtained at relatively low cost. Are the IRF510 failures because they are not suitable for the way we are attempting to use them, or because we are not being careful enough in how we use them?? Are IRF510 failures a real problem, or maybe being exaggerated?? Is there an acceptable way to make switching MOSFETs more robust in RF applications. Given the relatively high cost of RF rated devices it may be time to revisit something like Farhan's (Just a Bunch Of Transistors) design to see if that can be scaled up to the 5 to 10 watt range and ?? On Mon, Jan 29, 2018 at 4:48 PM, K9HZ <bill@...> wrote: ALC.? What a ghost from the past.? I’m not aware of anyone who designs RF amplifiers today that thinks ALC is a good idea today specifically it generates nasty products in the PA when it cuts in and makes a linear amplifier…nonlinear.? People used it years ago so that they didn’t over drive (read that blow the grids out of) their tube amplifiers.? Today we use more sophisticated algorithms, head room in over design, ?and compression to avoid the issue.? ? Of course current limited power supplies are not linear RF amplifiers. ? I think you should present your design, build it, and try it on the air… and have a look through a spectrum analyzer.? Maybe all of the theory I had in graduate school is bunk. ? ? 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: Like us on Facebook! ? ? email:? bill@... ? From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Arv Evans
Sent: Monday, January 29, 2018 12:49 PM
To: BITX20@groups.io
Subject: [SPAM] Re: [BITX20] IRF510 amplifier failures ? Maybe part of the point has been missed at several levels.? The proposed current limiter is not much different from current limiters in many commercial power supplies.? It is not active until some current value has been reached.? Up to then there is no current limiting or "modulation" or "compression".? Yes, the in-series current sensing resistance does allow an output voltage drop until voltage across this resistance reaches about 0.65 volts to forward bias the sensing transistor. If your power supply output is not stiff enough to hold a steady voltage this could add to the sensing resistance and cause voltage droop and in really bad cases
compression of RF output.? Question...is RF compression all that bad?? It is what most transmit ALC circuits do.? It would also be possible to make the proposed circuit driven by reflected power instead of current.? Then we could call it a transmit ALC to protect the It would be fairly simple to add a latching function to the limiter design so that it totally shuts down output when Imax has been reached.? This is possible but would then require a RESET button or power cycling to restore power to the RF PA stage. It is also possible to change the proposed design to put the current sensing ahead of the control MOSFET and make that MOSFET into a voltage control circuit.? This was my initial approach but the component count became just too high to be an internal modification for transceivers.? It would be more suitable for converting an unregulated power supply to a regulated one.? For those who are using modified PC power supplies it is possible to change the current sensing so that the switching regulator would shut down if Imax of 2 to 3
amperes is exceeded.? This approach would require power cycling to restore
operation.? Problem with using fuses is that they have a short but measurable heating period
before they go open.? When they do open they spark internally for another short
period.? Both the delay and the spark are potential problems for circuit components. Poly-fuse? or resettable fuse devices are intended to address a different issue.? Some are equivalent of FAST-BLOW fuses, and some are just conventional resettable circuit breakers. Suggestion here is that "if you can come up with something else that is adequate, please submit a circuit drawing and explanation of how it works"? We could all ? On Fri, Jan 26, 2018 at 11:27 AM, Tim Gorman <tgorman2@...> wrote: A current "limiter" which modulates the current, i.e. limiting the
current no matter the drive level, is like applying an ALC to the
exciter. Improper design can result in compression of the signal which
can then generate spurious responses in the output.
If the current limiter is of a "drop-out" style which requires
resetting then this won't happen, it will just shut down the exciter.
In that case, however, it doesn't provide much efficiency over a plain
old fuse!
tim ab0wr
On Fri, 26 Jan 2018 05:32:08 -0800
"n5ib_2" <n5ib@...> wrote:
> One other possibility to consider to protect against overcurrent
> situations is to use a current limiting power supply, or add a
> current limiter to an existing power supply or battery.
>
> The current limiter circuit whose link is at this site:
> <>
> will go up to 2.2 amps, and includes a low-dropout voltage regulator
> that also provides reverse polarity protection.
>
> There is a version, in a different package, of that same regulator
> chip that has an added "tracking" feature - being able to parallel
> multiple chips to increase the available current. Details are on the
> datasheet in the document.
>
> Jim, N5IB
>
>
>
?
?
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Re: IRF510 amplifier failures
I have not received my uBitx yet. I’ve been? reading this forum for about two weeks. Looks like PA failures is a huge problem. Are the two main causes reverse DC power and high SWR? For the DC polarity problem how about a full wave rectifier at the DC input? Two diode voltage drop a problem with this approach? What would be the best way to limit PA? power out to a very small value to allow a manual tuner to be used for the SWR issue? ? Tnx John WA8US ? ?
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Re: Second batch of uBITX shipping?
#ubitx
So glad somebody remembers all those marketing gimmicks of Howdy Doody and Captain Video days. My grandson doesn't even know the difference between an and and an or gate. Perish the thought of knowing what a transistor does.
Sent from my Verizon, Samsung Galaxy smartphone
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-------- Original message -------- From: Thomas Noel <tnoel@...> Date: 1/29/18 19:49 (GMT-05:00) To: BITX20@groups.io Subject: Re: [BITX20] Second batch of uBITX shipping?
Y'all are all so spoiled. I remember ordering from the back of comic books and cereal boxes and having to wait "allow 6-8 weeks for delivery" for my "Amazing X-Ray Glasses" or "Secret Decoder Ring". No email, no tracking numbers.? Just endless faith and optimism. And that was just from Kalamazoo? or Battle Creek Michigan. If you got it at all you were amazed! Tom
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Hi Hiro san,
what resistor value are you using for the CW CARRIER mod?
Originally (in v1), it was recommended to use 10K. But in some cases this
will not give sufficient drive. In that case you need to reduce the
resistor value. In the latest updated instructions, it is recommended to
use 4.7K:
You can experiment even smaller values. But never use less than 1K!
73 Allard PE1NWL
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On Tue, January 30, 2018 07:12, JH1OJY wrote: I changed?? software V1.27.3 to??V2.03.
I noticed that??LSB CW output power is slightly down to 3w from 5w than
before.
I tried to ajust BFO freq and VFO??High/Low and so on??for output power up
but I could not.
There is VFO Drive Level control setting??on V1.27.3 but no??V2.03.
All??I need is to modify VFO Drive Level in sketch or driver?? level
volume up in hardware.
Please let me know??how to get?? output power up.
Hiro JH1OJY
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Re: [SPAM] Re: [BITX20] IRF510 amplifier failures
I may be off base here but using an antenna analyzer to tune ones antenna or tuner before applying power would prolong the life of the IRF510's. ?I know it doesn't allow one to move great distances from the first tuned frequency without rechecking but I have used that method for a few years and still have not blown a 510 (other than having a bad one or killing one with static electricity while installing it). ?
I have a 3 way antenna switch that I use to switch to my little FG-01 analyzer as one of my options when I change frequency.
Analyzers are now quite affordable and I feel a necessary part of any hams "must have" equipment. ?We ARE hams and do test things don't we? Carelessness has always been a costly issue..... Ask me about reverse voltages sometime.
Thanks for the bandwidth but I see so much discussion about the IRF510's lately. ?They are cheap, simple, and do work if certain precautions are observed. ?And when I was in medicine, off label uses for certain meds were common and cost saving. ?They might be motor switches but do work in RF circuits. ?I just received 10 brand name 510's for $18.00 from DigiKey "just in case".
Sorry if I made any mistakes in my comments. ?My education and experience was 44 years in family medicine. ?This hobby is part of my mental health therapy....... Has helped me keep my sanity since 1960. ?Ask my wife of 45 years. And as one local friend commented, "It is cheaper than a mistress, AND less stress."?
Dave K8WPE
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On Jan 29, 2018, at 8:31 PM, Arv Evans < arvid.evans@...> wrote: This has been an interesting discussion, but still not sure which
might be the best way to insure a long and uneventful life for
MOSFET power amplifiers.? Several ideas have been presented
by myself and other individuals.? All seem to have been rejected
by others for various reasons.? Makes me wonder if rejections
are based on reality or just a fear of using any switching device
as an RF amplifier.?
The alternative of using real RF transistors or RF MOSFETs seems
to defeat the objective of designing and building low cost transceiver
from components that can be readily obtained at relatively low cost.
Are the IRF510 failures because they are not suitable for the way
we are attempting to use them, or because we are not being careful
enough in how we use them?? Are IRF510 failures a real problem,
or maybe being exaggerated?? Is there an acceptable way to make
switching MOSFETs more robust in RF applications.
Given the relatively high cost of RF rated devices it may be time to
revisit something like Farhan's (Just a Bunch Of Transistors)
design to see if that can be scaled up to the 5 to 10 watt range and
cover up to 30 MHz.
Arv? K7HKL
_._
|
Re: Perfect speaker grill
hello Jim have you link for find case for ?nitx , Best regards
jo?l f6cht lovely case!!
Le 29/01/2018 à 17:37, Jim Sheldon a
écrit?:
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This really worked well. ?I needed something a bit smaller
(2" speaker) and I found one that had 3/32" holes in the kitchen
so I used that. ?I slipped on one hole in the center so it's
slightly off but all-in-all it still looks okay - building this
thing should include a cosmetic error or two anyway just to
prove you built it and not some factory - LOL!
Jim Sheldon - W0EB
------ Original Message ------
Sent: 1/24/2018 1:31:35 PM
Subject: [BITX20] Perfect speaker grill
To get a tidy speaker grill on your EF01 enclosure or
what ever you are using have a rummage in the kitchen
utensil draw you may find the perfect template.? I used a
plastic sifter lid as the holes were the size I wanted.
Draw a center line where you want it positioned, line up
the template, drill one hole on the outer circle, insert
nut and bolt, drill hole opposite end of template, insert
nut and bolt, now drill rest of holes in perfect place.?
Hot glue speaker in place on underside of lid.
Peter G4NJJ
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Re: MAX9814 mic preamp and DC bias capacitor
Just decrease the value of R63 for more gain!
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At 30/01/2018, you wrote: uBITX Mic Audio
I think that the rig only needs slightly more gain in the existing Mic PreAmp.? I believe adjusting values to add gain is really all that is needed.? Don't need 40 dB extra gain.
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Re: [SPAM] Re: [BITX20] IRF510 amplifier failures
Hi Jerry,
I was going to build an rtx for 7MHz using 7400 N AND gates but having no test equipments except a good scope I could not experiment much. Discussing with some friends we came to the ending expecting high noise figures from such components. I used them as mixer for VFOs.
73
Gian
I7SWX
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Re: Inkits India QRP kits
A great idea Alan
I have made the page template ... now the hard part in putting it
all together.? You don't want to volunteer do you?
A list of all products (WORD table you send me),? supplier,
website (if there is one) and email address for contact.
73
Mike
On 30/01/18 10:43 AM, Alan de G1FXB via Groups.Io wrote:
We need a who is who,
on the uBIX.net page.
So we easily know who is selling what:-
Raduino clones,
Improved Raduino's, Touchscreens, AGC, S-meter, Mic Amp, Speech
Processor, PA protection circuits, SWR Bridge, Auto ATU.
forgotten anything?
it's ALL TOO MUCH......? :-)
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Re: uBITX Firmware (CEC) 0.30 released (Test version).
#ubitx
Nic
I like your thinking, if you add the swr function, generate a low level tone and thus low level rf out. Arrange for the nano to sweep a range of frequencies, ta dah cheap and cheeful antenna analyser.
looking forward to your mods
chris
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Re: Bitx Delivered..YAY!!
the board numbers within the batch are all topsy-turvey. so, don't bank on them to be shipped serially. the numbering is done at the output of the SMD pick and place which tests it with 'flying probes'. the ok are marked with the number and kept stacked in trays. the THT insertion girls grab any rack and start to populate them. The second test further scrambles them. Then, Uma sits to test the boards, and further muddles up the sequence of numbers. Within this flow, the boards might be taken out of the line-up for rework at smd stage, THT stage or at final test and alignment by Uma.?
On Tue, Jan 30, 2018 at 3:26 AM, B C <k9wis@...> wrote: ok ... that makes sense...thanks...now to get this thing working...the shipping time once it hit the system was amazing..
Brian K9WIS
---- Dave Bottom <ars.kd6az@...> wrote:
> uBITX Deliveries
>
> I believe 319/2 would be board #319 of Run #2
> My board 359/1 (#359 of Run #1 - 1,000 boards?) was ordered on Dec 10th,
> shipped Dec 20th DHL received in CA Dec 22nd.
>
> I probably won't see my second order (January) until March.? I wonder if
> any other HF radio (including commercial ones) has sold so many in such a
> short time.
>
> Thoroughly enjoying my first uBITX. 4 Countries (3 Continents) with just a
> Dipole (including Russia on 80M no less) so far in casual operating on
> Sundays. Thank You Farhan!
>
> Dave WI6R
>
> On Mon, Jan 29, 2018 at 11:37 AM, B C <k9wis@...> wrote:
>
> > The DHL man delivered my Ubitx package this morning here in Wisconsin..I
> > ordered it on Dec 14, was notified last Friday by Pay PAl that it will
> > ship..
> > So use this as a gauge.
> >
> > My board was marked 2 of 319..So I must have just missed the cut off on
> > that first shipment..
> >
> > Brian K9WIS
> >
> >
> >
> >
>
>
> --
> 73 Dave WI6R
|
I changed? software V1.27.3 to?V2.03.
I noticed that?LSB CW output power is slightly down to 3w from 5w than before.
I tried to ajust BFO freq and VFO?High/Low and so on?for output power up but I could not.
There is VFO Drive Level control setting?on V1.27.3 but no?V2.03.
All?I need is to modify VFO Drive Level in sketch or driver? level volume up in hardware.
Please let me know?how to get? output power up.
Hiro JH1OJY?
|
Re: Inkits India QRP kits
The website inkits.in has been made to take orders only for customers in India.? the website is still not fully populated for products and some sections are still to be added. I think I am a bit lazy on the site as the sales are not much with my Indian customers.
Our main website for world wide customers is
Our new site under construction?
Our new website ubitx.com aim is to provide complete complete info and updates about ubitx,taking into sharing of info by all ubitx builders.
Our website is just like other group websites like ubitx.net? promoting ubitx info.?
The website aim is also to inform the achievement of HF Signals contribution in bringing out such a affordable equipment and ushering an era of excitement among hams world wide.?
BTW our website new website ?is under construction.?
Should be a valuable site for all ubitx builders.?
best of 73s
Sunil VU3SUA
?
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Re: uBITX Firmware (CEC) 0.30 released (Test version).
#ubitx
Thanks!
And A0: Voltmeter!
So:
RX will be S-metre and Volts: S_________ 12.45v (16 chars)
TX will be SWR and PWR: SW:1.2?? P:10.5w (16 chars)
being displayed on top line of LCD.
A bit like a FT817 clone... lol...
73 Nick, VK4PLN
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Re: uBITX Firmware (CEC) 0.30 released (Test version).
#ubitx
nickpullen
awosome!!!?I learned how to apply variously because of you.?I was thinking about S.Meter and Power Meter space. I will write the code to print the sample on the top line. You will be able to check in a few hours.
Thanks for your information
Ian KD8CEC
Hi Ian. This work you are doing on the FW is incredible. Many thanks for your efforts, and to every one else for their contibutions.
I plan on doing the following to your version once you are "done" with the non-hardware mod version..
1: Convert to I2C LCD, free up 6 digital I/O.
Move keyer jack to D8 for DIT and D9 for DAH, should work well as there is a GND connection between the 2 on the OLD LCD header (pin 4,5,6)
Move PPT to D10 (pin 11)
Move Button to D11 (pin 12 and 16 for GND)
Move ENC to D12/13 (pin 13,14 and 16 for GND)
Also gives easy access to +5v on pins 2 and 15 for my I2C TPA2016 AGC and SSM2167 MIC Amp.
I2C breakout as per Jim Sheldon's method, I need 2 of each for AGC (+3.3v) and LCD.
Now what to do with all those free Analog ports?
A7: S-Meter. (vk3YE AGC with out the AGC part, only the SIG meter...)
A6: SWR bridge rev (Kitsandparts.com)
A3: SWR bridge fwd (Kitsandparts.com)
A2: Array of buttons (via different resistors) for direct access to: Band up/down, RIT, VFO A/B...
A1: Potentiometer to for ACG control (via the I2C AGC module)
A0: ...
Hope to get the FW to display s-meter on RX and the SWR and PWR on TX on the top line.
Thanks again.
-- Best 73 KD8CEC / Ph.D ian lee kd8cec@...
(my blog)
|
Re: UHF/VHF uBITx equivalent
But, this is not much of a homebrew. The challenge would be to build something from scratch.
- f
On Tue, Jan 30, 2018 at 9:56 AM, <nickpullen@...> wrote: Hi Fred.
This is also on my project list. I have both the V and U version of the DRA818. I am planning on a simply desktop unit powered by arduino and a nokia 5110 lcd.
a cheap baofen mic/speaker. Just for experimentation and local repeater access as these modules are only 1W... maybe even do APRS...
In the end though, If all you want is a cheap V/U radio, just buy a $30 UV5R...
73, Nick. VK4PLN
|
Re: UHF/VHF uBITx equivalent
Hi Fred.
This is also on my project list. I have both the V and U version of the DRA818. I am planning on a simply desktop unit powered by arduino and a nokia 5110 lcd.
a cheap baofen mic/speaker. Just for experimentation and local repeater access as these modules are only 1W... maybe even do APRS...
In the end though, If all you want is a cheap V/U radio, just buy a $30 UV5R...
73, Nick. VK4PLN
|
Re: Second batch of uBITX shipping?
#ubitx
I ordered mine on Dec 14 and received it this morning...
Brian K9WIS
---- James Tate <kw4sz@...> wrote:
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Just to let you all know, I ordered mine in the 4th. When I inquired about status, I did not even get an ETA. I am patiently awaiting confirmation of shipping on a slow boat. LOL
From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Joe Puma
Sent: Monday, January 29, 2018 7:44 PM
To: BITX20@groups.io
Subject: Re: [BITX20] Second batch of uBITX shipping?
I ordered one Jan 17th. I recently emailed them and they said it will ship in 2-3 weeks. Glad I ordered DHL.
Sent from my iPhone
On Jan 29, 2018, at 7:37 PM, David Robertson <kd1na363@...<mailto:kd1na363@...>> wrote:
Ordered on the 16th and no responce
--
Dave Robertson KD1NA
|
Re: uBITX Firmware (CEC) 0.30 released (Test version).
#ubitx
Hi Ian. This work you are doing on the FW is incredible. Many thanks for your efforts, and to every one else for their contibutions.
I plan on doing the following to your version once you are "done" with the non-hardware mod version..
1: Convert to I2C LCD, free up 6 digital I/O.
Move keyer jack to D8 for DIT and D9 for DAH, should work well as there is a GND connection between the 2 on the OLD LCD header (pin 4,5,6)
Move PPT to D10 (pin 11)
Move Button to D11 (pin 12 and 16 for GND)
Move ENC to D12/13 (pin 13,14 and 16 for GND)
Also gives easy access to +5v on pins 2 and 15 for my I2C TPA2016 AGC and SSM2167 MIC Amp.
I2C breakout as per Jim Sheldon's method, I need 2 of each for AGC (+3.3v) and LCD.
Now what to do with all those free Analog ports?
A7: S-Meter. (vk3YE AGC with out the AGC part, only the SIG meter...)
A6: SWR bridge rev (Kitsandparts.com)
A3: SWR bridge fwd (Kitsandparts.com)
A2: Array of buttons (via different resistors) for direct access to: Band up/down, RIT, VFO A/B...
A1: Potentiometer to for ACG control (via the I2C AGC module)
A0: ...
Hope to get the FW to display s-meter on RX and the SWR and PWR on TX on the top line.
Thanks again.
|
Re: Cheap Harbor Freight Case for MBITX
I've been working on a plastic one that fits both the Pelican 1150 and the Apache 1800. I actually bought the Pelican without the pick-n-pluck.
I still need to thin it some since I found it can actually be used on the top as well if you're not putting anything real thick in it. Some LCD displays will fit in the top with a plastic panel.
Vince.
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On 01/29/2018 05:39 PM, Ken Hansen wrote: This 'pelican-style' case is also nice - I'd love to figure out a front
panel that snaps over the bottom half of the case (remove all
pick-and-pluck)...
Ken, N2VIP
On Jan 29, 2018, at 3:47 PM, wishbone_aaa <dlmock@...
<mailto:dlmock@...>> wrote:
Just place my order for a MBITX and have been looking for an
enclosure. I spotted in my workshop a Harbor Freight plastic ammo box
that looks like it will do the job. With the lid open, the box is 6
inches deep,9 3/4 wide and 4 1/2inches high. Price $6.99 (even
cheaper when there's a coupon).
<>
--
Michigan VHF Corp.
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K9HZ
Leland Lannoye
Allard PE1NWL
Joel Fournol
Raj vu2zap
Giancarlo - I7SWX
Sunil Lakhani
Nick VK4PP