Date   

Re: AGC circuit to try?

Michael Shreeve
 

I have a Swan SS-200 with a perfectly working broadband amplifier, 10 to 15 watts input.200 watt peak out.  Might do pretty well with uBITX as an exciter. I believe it was built before the Tentec !


Re: AGC circuit to try?

Michael Shreeve
 

Yes Jerry, very narrow. Oh well, shouldn't work.


Re: boosting the power on 28 MHz #ubitx

ajparent1/KB1GMX <kb1gmx@...>
 

David the one published in QQ (QRPQuarterly) back in 2006 and was a 1W design SSB only.
I've done 5 others but those are not published and my notebooks while complete are not a
"here build this".

Doing 6m radios are not not going to use many 3904s save for an IF and audio stuff.  Once
you at 6M RF devices suitable are needed.

Allison


Re: AGC circuit to try?

Michael Shreeve
 

They say it will work at those frequencies but don't they say it's capable of a wider response. I'll look.


Re: AGC circuit to try?

Michael Shreeve
 

Yes, may be a problem for lower freq stuff, but I claims its dc to daylight


Re: AGC circuit to try?

Jerry Gaffke
 

That MA4VAT2007-1061T  has a little transformer in there.
Datasheet specs it for 1.7ghz to 2.0ghz.

JerryFri, Jun 1, 2018 at 02:41 pm, Michael Shreeve wrote:

I have picked up some of the MA4VAT2007-1061T MACOM SOIC-8 HMIC PIN DIODE VARIABLE ATTENUATOR  . 
If you look them up, you will see that it is a nice balanced dual pin diode attenuator on a chip. I thought it might work in the IF or just about anywhere . Work in progress, but definitely a very interesting chip. 


Re: boosting the power on 28 MHz #ubitx

Daniel Conklin <danconklin2@...>
 

Allison,
Do you have a schematic of your 6 meter radio available to share?


Amazon

Christopher Miller
 

I'm sure that it wouldn't have to be mutually exclusive. hfsigs could still sell them direct, but the effort to set up to sell them on Amazon for one person is probably too much. Maybe trade the Amazon gift cards to someone who is using them anyway and get cash?

kf4ftr


Re: Amazon

joe camilli
 

Unfortunately not with Amazon gift balance. :(

Joe N7QPP


Re: ND6T AGC implementation for uBIT-X

Tom Cooper
 

My AGC uses 3 simple PIN diode shunt attenuators.  An 0.1 cap connects to the circuit board and an MPN3404 goes to ground.  The attachments points I used are the connections between R27/R105, R47/C30 and R17/C216.  An AGC voltage derived from the audio or a manual "RF gain" voltage derived from RX both work fine.

I don't know what the control range is but it must be 40 db at least.  I can make really loud signals disappear.

Tom W1EAT


Re: ND6T AGC implementation for uBIT-X

Ralph Mowery
 

Mine works well.  Stuck it on one of the relays with a spot of hot glue.

S-meter is working with it after I played with the settings for it.Thanks to the KD8CEC software.

de ku4pt


On Fri, Jun 1, 2018 at 7:39 PM, M Garza <mgarza896@...> wrote:
I received mine also.
They are little works of art.

Thanks!

Marco - KG5PRT 

On Fri, Jun 1, 2018, 6:04 PM Daniel Conklin <danconklin2@...> wrote:
Kees,
I got mine today.  They are beautiful!  Thanks!
Dan, W2DLC



Re: ND6T AGC implementation for uBIT-X

M Garza <mgarza896@...>
 

I received mine also.
They are little works of art.

Thanks!

Marco - KG5PRT 

On Fri, Jun 1, 2018, 6:04 PM Daniel Conklin <danconklin2@...> wrote:
Kees,
I got mine today.  They are beautiful!  Thanks!
Dan, W2DLC


Re: ND6T AGC implementation for uBIT-X

Daniel Conklin <danconklin2@...>
 

Kees,
I got mine today.  They are beautiful!  Thanks!
Dan, W2DLC


Re: boosting the power on 28 MHz #ubitx

Michael Shreeve
 

If you use this one you will have a uBITX r4 . Although, he's putting them out with 510s, at this point, but used this mod In his own personal radio. Ashhar that is. 


Re: boosting the power on 28 MHz #ubitx

Doug W
 

Allard no need to be so modest.  It is not bragging to say you are the man behind the curtain pulling the robot's strings.  You have a very interesting site.
--
www.bitxmap.com


Re: boosting the power on 28 MHz #ubitx

Allard PE1NWL
 


Allard,
That image below, what is that from?
http://www.gooddx.net


Re: boosting the power on 28 MHz #ubitx

Michael Shreeve
 

Just checked, wasn't sure if I had the RD16 or the 15, and it is the 16 , awesome, will put this high on the project list. 


Re: New VK4PLN Audio Daughter Board + BCI

K9HZ <bill@...>
 

Not sure I agree with this being the wrong part for a preamp in the uBITx.  First I always design in a front end high pass filter on my preamps…(that should be a fairly obvious requirement for any preamp or amplification stage…don’t amplify things you don’t want amplified).  in this case I use a 5 pole chebby with a 3dB corner of about 18 MHz which works nicely for 12-10-6 meters.  Three 100pf caps in series and a two 330uH inductors to ground on the input is a decent design.  Second, variable gain control can easily be added.  The part has less than 0.5dB injected NF and therefore perfect as a preamp here IF DESIGNED RIGHT.   

 

You do know Elecraft uses it for their K3 preamp.  Must be something to it?

Dr. William J. Schmidt - K9HZ

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of ajparent1/KB1GMX
Sent: Friday, June 1, 2018 12:17 PM
To: BITX20@groups.io
Subject: Re: [BITX20] New VK4PLN Audio Daughter Board + BCI

 

The PGA-103 is nice utility amp but too much gain for uBitx.  It needs more like a grounded gate Jfet
(10db is enough).  A wideband high gain without band limiting(tuned) will cause all sorts of havoc.

Allison

 

Virus-free. www.avg.com


Re: boosting the power on 28 MHz #ubitx

Joe WB9SBD
 

Allard,
That image below, what is that from?


Joe WB9SBD

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com

On 6/1/2018 3:13 PM, Allard PE1NWL wrote:
On Fri, Jun 1, 2018 at 10:12 am, ajparent1/KB1GMX wrote:
I use the best tool I have for spotting 10 and 6M activity.

My radios
Yes. You're completely right.
Of course the best way is monitor the conditions on these bands is to listen 24/7 (and to call CQ frequently). Mono band BitX radios are a perfect choice for this purpose.

Most operators have a life next to ham radio though - For them an automatic alerting system that delivers alerts via email, SMS text, Twitter or push notifications, even when they're away from the rig, is very useful.

That Au and Eskip event didn't make it here, not yet.
Since my previous posting a few hours ago, MUF had been building and we even had 2m Eskip for about an hour. Perhaps it'll move to the US later today. So stay tuned!



73 Allard PE1NWL


Re: AGC circuit to try?

Michael Shreeve
 

I have picked up some of the MA4VAT2007-1061T MACOM SOIC-8 HMIC PIN DIODE VARIABLE ATTENUATOR  . 
If you look them up, you will see that it is a nice balanced dual pin diode attenuator on a chip. I thought it might work in the IF or just about anywhere . Work in progress, but definitely a very interesting chip.