¿ªÔÆÌåÓý

Date

45M Filters

 

Folks!

Although this is the cheapest filter for 2 bucks, I hear only mention of people here
buying more expensive ones.



N2CBU has kindly listed more for sale as he says better under your bed than mine or
maybe basement!!

Cheers

--
Raj, vu2zap
Bengaluru, South India.


Re: Simple spur fix

 

I used a different filter
Best I could tell (googling) it's termination impedance is 1200. I used a 5:1 turns transformer with? BN61-2402s. I don't have the equipment to sweep the filter accurately but the spurs are for the most part gone, insertion loss was minimal, and I landed in the right spot relative to sidebands. Audio sounded very good over another radio- perhaps better than previously. As Warren points out this was assuming 50 ohm input and load impedance which is probably wrong. I had this filter so I used it but it may be better to stick with the 600 ohm filter everyone else is using. I grounded to C11 per Farhan's suggestion and used 26 magnet wire at the three connection points- seemed stout enough to support this very tiny board. I put a piece of kapton tape on the main pcb and up the back of the filter board for additional anchoring.

As usual- your mileage may vary! :)

John
KC9OJV


Re: Surprised by generous and kind act #bitx40

 

¿ªÔÆÌåÓý

This is TRUE ham radio.

Dave K8WPE

On Sep 9, 2018, at 12:15 AM, Robert D. Bowers <n4fbz@...> wrote:

Today I was greatly and pleasantly surprised.? I'd mentioned that I was thinking about converting my BITX20 to 40 meters, and I'd related some stories of frustration with the local ham community (generosity and willingness to help others seems to be a rarity in this area).

When I got our mail, there was a package in it - with a BITX40!? The housing it was in is very attractive as far as my wife and I are concerned - and perfect for our car.? The neat part was that you could see the circuitry in it - and the case also would lend itself to portable operation!

I won't embarrass the sender, but I will say it came from another state.? For many years, I've insisted that there was no such thing as Karma... but this suggests otherwise!

To the sender (not named) - a big Thank you! from both of us, and (laugh) no worry about "paying forward" - we do things all the time like that, whenever we can (we may not have much money, but we do have skills and knowledge we share).? Generosity and helping others is not a big price for gifts like this - in our opinion!


Re: uBitx Antenna #ubitx-help

 

On Sun, Sep 9, 2018 at 07:25 PM, Richard Spohn wrote:
Most radios actually have very diverse output impedances, but
overall are designed to deliver the most output power into 50 or 75
ohm coax
I like that statement. Was just reading an "authoritative" article repeating the standard "maximum power is transferred when the load matches the transmitter impedance" and that was why you had to match the load to the transmitter.?

Well if that was true it would be impossible to build a transmitter with greater than 50% efficiency. A transmitter with high efficiency may have an output impedance of a few ohms.?

I'd just got through reading the other article and saw this. Being fresh in my mind made the above sentence jump out at me. So, I'm agreeing with Richard's statement.

Tom, wb6b


Re: uBitx Antenna #ubitx-help

Vince Vielhaber
 

SWR and Wattmeters made for CB are often worthless in the ham bands, unless you're only using 10M. I picked up a Firebird SWR/Wattmeter a while back that was supposed to be good for 1.8-30 MHz. HAR! That thing won't even read accurately (or even semi-accurately) at 21 MHz and gets progressively worse the lower you go. It barely responds with almost 1KW going into it at 3.9MHz. Needless to say it's going back on ebay. It is fairly accurate on 10 meters, so it probably is on 11 too.

Vince.

On 09/09/2018 03:13 PM, Gordon Gibby wrote:
The only cb ones I have tried on 2 m are the long parallel rod pick up type, they were quite in accurate

For VHF/UHF I use ham products made for the purpose

Cheers

Gordon kx4z
On Sep 9, 2018, at 13:59, Bill Cromwell <wrcromwell@...> wrote:

Hi,

It might start to be a little shaky on the two meter band. And maybe will work there too.

73,

Bill KU8H

On 09/09/2018 05:37 AM, gonewiththeego@... wrote:
I was thinking about an Albrecht SWR 20 which I can see that is used
only for CB. Do you think it should work for 20/40m band ?
--
bark less - wag more


--
Michigan VHF Corp.


Re: Simple spur fix

 

rev.01


73


Re: Simple spur fix

 

Great Work GLENN!

My take, if it works, I'lll add it to my board offerings, say $1, or free with a LPF relay board....



73 Nick VK4PP


Re: Simple spur fix

 

approx. install position. R27 would be removed and short wires fitted. Hole was drilled into main board behind this adapter board.? There are two GND through holes, near R25 and to the right near the transformer also which might be useful. This assumes that R27 removal is the final idea.


Re: uBitX controller issues

 

Bill
Thanks for the reply. Someone told me how to check the voltages along the circuit path. Found a bad solder joint. (Damn trifocals ain¡¯t as good as young eyes!). Repaired the solder and fixed the problem.
Mark

On Sep 8, 2018, at 3:01 PM, Mark Rosenthal <marksro@...> wrote:

I searched for this problem to no avail. So I am posting in case someone has an answer.
I bought a new uBitX, and installed it in the case from Amateurradiokits.in.
Upon powering up the display shows:
uBITX v4.3
LSB A: 7.149.950

If I turn the encoder to change frequency, the display shifts from 7.149.950 to 7.149.900. back and forth as I turn, either CW or CCW.
If I push the encoder, the display shows Band Select >
Turning the encoder does nothing
Push encoder again and I get display showing Band Select:
Turning the encoder now changes display between 7.349.900 and 7.149.900.

If I power off, then back on, sometimes the frequencies shown in the display are a little bit different (some times when in band select, the display will change from 7.149.900 to 6.949.900, or similar).

With an antenna attached I can hear signals from the speaker (noise, occasionally someone¡¯s transmission). So I know the receiver works. If I push the PTT the relays click. I assume transmitter works too.

I thought I had a bad encoder, so I bought a new one from Digikey. Same results.

Power supply is 13.27 volts.
Power to raduino is 5 volts.
Someone suggested pin 3 may be shorted to ground causing raduino problems, but I checked and not grounded.
All wiring triple checked (or more).

Any thoughts are appreciated.

Thanks
73
Mark
W3MSR


Re: Simple spur fix

 

Hi Nick,
I made a simple single sided PCB for my install, but not installed yet.

I used ~0.2mm for the filter side winding (7T)? and ~0.5mm for the Low Z? winding (2T) to give the install a bit of mechanical stability. All parts vertically mounted.

PCB is 0.685" x 0.42" in size. The 3 pads on the bottom are spaced to allow very short connection to R27 (removed) and ground via a small hole drilled into the main board.

glenn vk3pe




Re: uBitx Antenna #ubitx-help

 

Dan, a CB swr meter will probably give you an incorrect reading on any
band except maybe 15 or 10 meters. A nice, relatively inexpensive new
SWR meter is the MFJ-818, correctly constructed for all the bands the
uBitx operates on. Many people on this list will tell you that the
uBitx cannot stand a high SWR for very long before the finals blow.
About output impedance, the radio output impedance is not as important
as using 50 or 75 ohm coax to connect your uBitx to your antenna
system. Most radios actually have very diverse output impedances, but
overall are designed to deliver the most output power into 50 or 75
ohm coax.

Keep reading everything you can lay your eyes on. After almost 50
years in the hobby, I still find great joy and inspiration in doing
this -- and I am still constantly adding to what I know. Welcome
again! 73, Rich WB2GXM<div
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font-size: 13px; font-family: Arial, Helvetica, sans-serif;
line-height: 18px;">Virus-free. <a
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On 9/9/18, gonewiththeego@... <gonewiththeego@...> wrote:
Thank you very much for your nice "Welcome aboard", indeed I appreciate all
of the answers above and I'm pretty sure that this topic will have some
"echo" throughout community. These are maybe the most common questions asked
by those with just the license of operation in hand and a few basic
knowledge of electronics. I can't wait to see the uBitx on my desk.
Meanwhile, I can't find some genuine information about the output impedance
of the uBitx itself. Is it 50 ohms ? Gordon Gibby previously sugested that a
CB SWR-Meter will do the job on HF also. I found one but it's rated to 11m
band only, or at least that's what on the label. Can someone tell me what
can go wrong it I start using it ? And by experiment, does anyone know how
much SWR can uBitx handle without permanent damage?




Re: Antenna Loops #off_topic

M Garza
 

Nothing to be sorry for.
This is good info!

Marco - KG5PRT?

On Sun, Sep 9, 2018, 12:31 PM David Posthuma <davep@...> wrote:

Sorry.

?

David A Posthuma, WD8PUO

1 (616) 283-7703

?

From: [email protected] <[email protected]> On Behalf Of Arv Evans
Sent: Sunday, September 09, 2018 1:14 PM
To: [email protected]
Subject: Re: [BITX20] Antenna Loops #ubitx-help #ubitx #antennas #loops

?

David

A copy of your post to the uBITX group has been forwarded to the [email protected]?discussion group.??
This group was formed to move the long and multiple off-topic posts, mostly about EFHW antennas,? to a
place where antennas would be?more on-topic.? If not already on that group you can join at
and post to [email protected]?.

Arv? K7HKL
_._


Re: K5BCQ uBITX Relay Switched LPF/BPF board

 

¿ªÔÆÌåÓý

Kee¡¯s, are you referring to relay K3 that is used to switch M1 and M2. Is that relay on your board now or are you revising your board to include it.?

Skip Davis, NC9O

On Sep 9, 2018, at 20:07, Kees T <windy10605@...> wrote:

It looks like great progress is being made on spur reduction, so back to LPF switching and a few other things. Received the first set of boards and have already made some modifications for better wireability.

1) I decided to eliminate R3 off the uBITX board and instead add it to the LPF Relay Board because it frees up space on the uBITX and allows more efficient RF wiring for receive. Since the "old R3" also switches M1 to M2, I'm changing that to how it's wired on the V4 uBITX by adding a 2N7000, changing R70 to 1K, add a 1K R78, add a 1uF C79, add a D14, and driving the 2N7000 with a line over to T/R (a 2N7000 driven directly by T/R is faster than any speeding relay contact).

2) Replace 3 sets of dual 2N3904 Transistors in the PA driver with 3 sets of dual 2N2222A Transistors. Allison had suggested changing the emitter resistors from 22 ohms to 10 ohms (for dual 2N2222A's ??

3) Add a three 1N4148 diode-OR from TxA,TxB, and TxC driver inputs to a TxD driver to pick that relay, which removes the 10m/12m/(15m) LPF when inserting the proper (A/B/C) LPF during Tx. Yes, that means 4 relays are active during TxA,TxB, or TxC transmit. All four of the LPFs use the existing inductor/capacitor components off the uBITX board. They are just moved over to a small 1.5" x 0.5" bare LPF board (that footprint is also the one QRP labs has for their LPF/BPF filters, but they don't sell blank boards.

4) uBITX Antenna will be wired to either one of two SMA connector pads.

5) T11 will be connected to the RF input on the LPF Relay Board with about 1" of coax.

8) Will provide pictures later.

73 Kees K5BCQ?

_._,_

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Re: Simple spur fix

 

HI John, Details please? And the results?

Thanks
Nick


Re: uBitx Antenna #ubitx-help

 

¿ªÔÆÌåÓý

If I may add to the conversation - my experience of using CB meters is if they're the parallel-strip kind (very common), they may loose some sensitivity at the low end.? Otherwise, they did a fair to good job checking the SWR, which is a ratio anyway.? (At the upper end of the 'usual' spectrum - sometimes TOO sensitive, but I've used them with reasonable accuracy on 6m.)

Power measurements are a different story... but in those cases, I'd rather use something more accurate.? The way many of them are made, they are still accurate for measuring power between 15m and 10m only (my experience is that they're usually rather accurate at the upper end of the HF spectrum if they're made for 11m).



On 09/09/2018 12:51 PM, Arv Evans wrote:

Output of the uBITX is 50 ohms.? Your CB SWR meter should work for the upper end of?
HF range (20M through 10M) and maybe acceptably good for 80M through 10M.? Many?
of those old CB SWR meters were just copies of ham radio SWR meters of the era.??

If the CB SWR meter is not performing well, it does provide a case, meter, and knob to?
use in building a more modern bridge type SWR and power meter.

Arv
_._

On Sun, Sep 9, 2018 at 1:12 AM, <gonewiththeego@...> wrote:
Thank you very much for your nice "Welcome aboard", indeed I appreciate all of the answers above and I'm pretty sure that this topic will have some "echo" throughout community. These are maybe the most common questions asked by those with just the license of operation in hand and a few basic knowledge of electronics. I can't wait to see the uBitx on my desk. Meanwhile, I can't find some genuine information about the output impedance of the uBitx itself. Is it 50 ohms ? Gordon Gibby previously sugested that a CB SWR-Meter will do the job on HF also. I found one but it's rated to 11m band only, or at least that's what on the label. Can someone tell me what can go wrong it I start using it ? And by experiment, does anyone know how much SWR can uBitx handle without permanent damage?



Re: Simple spur fix

 

45 Mhz filter installed with impedance matching transformers. PCB made with islands created with a x-acto hobby saw.

John
KC9OJV


Re: Simple spur fix

 

George also modified the main 45MHz filter by adding transformer coupling ...........on?Sep 8???

73 Kees K5BCQ


Re: Simple spur fix

 

Warren, my plot of the TOYOCOM 45E2BF filter using your 7 : 2t on BN43-2402 also.

Clearly my filters have a different impedance than yours as loss is higher and ultimate rejection worse. But I guess it shows that buying 'other' filter types than yours might still be usable. I didn't do any further checks on actual impedance of my filters.

glenn
vk3pe


Re: K5BCQ uBITX Relay Switched LPF/BPF board

 

It looks like great progress is being made on spur reduction, so back to LPF switching and a few other things. Received the first set of boards and have already made some modifications for better wireability.

1) I decided to eliminate R3 off the uBITX board and instead add it to the LPF Relay Board because it frees up space on the uBITX and allows more efficient RF wiring for receive. Since the "old R3" also switches M1 to M2, I'm changing that to how it's wired on the V4 uBITX by adding a 2N7000, changing R70 to 1K, add a 1K R78, add a 1uF C79, add a D14, and driving the 2N7000 with a line over to T/R (a 2N7000 driven directly by T/R is faster than any speeding relay contact).

2) Replace 3 sets of dual 2N3904 Transistors in the PA driver with 3 sets of dual 2N2222A Transistors. Allison had suggested changing the emitter resistors from 22 ohms to 10 ohms (for dual 2N2222A's ??

3) Add a three 1N4148 diode-OR from TxA,TxB, and TxC driver inputs to a TxD driver to pick that relay, which removes the 10m/12m/(15m) LPF when inserting the proper (A/B/C) LPF during Tx. Yes, that means 4 relays are active during TxA,TxB, or TxC transmit. All four of the LPFs use the existing inductor/capacitor components off the uBITX board. They are just moved over to a small 1.5" x 0.5" bare LPF board (that footprint is also the one QRP labs has for their LPF/BPF filters, but they don't sell blank boards.

4) uBITX Antenna will be wired to either one of two SMA connector pads.

5) T11 will be connected to the RF input on the LPF Relay Board with about 1" of coax.

6) Found some of the smaller 12V 10 pin DPDT bifurcated contact relays on ebay for about $1 each. They fit nicely.

7) Leave all the traces, just make a cut and remove 1/16" of the trace where needed.

8) Will provide pictures later.

73 Kees K5BCQ?



Re: More PA Putzing ..

jim
 

Did Change the output transformer (T11) to 2 FB43-801's like a binoc core ..3 T pri, 5 T sec ..just to start ..The other one was kinda making the waveshape look like a triangle wave generator (lotsa 3x harmonics I assume)

Jim

On Sunday, September 9, 2018, 8:55:06 AM PDT, ajparent1/KB1GMX <kb1gmx@...> wrote:


? It should be a 2:3?
[maybe 4:6 turns] where 2:3 ratio nets about 22ohm drain load and it likely to have a chance at
10W IMD?being acceptable at 12V.??


Things you have to do to generate /clean/ power.


Allison