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Re: BITX QSO Night, Sunday, August 6, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere

Karl Schwab
 

Oops, in my previous post, for QSO's with KN4AAG and VA2NB, the time was 7:00p, not 8:00 as I indicated.? Karl, KO8S, MI


On Sunday, August 6, 2017 8:20 PM, Tom VE3THR <ve3thr@...> wrote:


hearing a lot of stations since 2300 UTC. Confirmed bitx40 qso's with VA2BB Mike, W4DML Doug and KC4LRR Robert so far.Don't give up that easily - keep calling CQ!
73 Tom


Re: BITX QSO Night, Sunday, August 6, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere

Tom VE3THR
 

hearing a lot of stations since 2300 UTC. Confirmed bitx40 qso's with VA2BB Mike, W4DML Doug and KC4LRR Robert so far.Don't give up that easily - keep calling CQ!
73 Tom
Re: BITX QSO Night, Sunday, August 6, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere

Karl Schwab
 

I called CQ BITX at 8:00p tonight and was called by KN4AAG, Kevin in NC, and then by VA2NB, Michael in Quebec for my first DX!? Heavy QSB, but, hey, it was still great fun using a 135' dipole with 450 ladder line feeders.? My PA was warming up to my surprise, so I think a heat sink will be added very soon!? Just think how much fun a two element Yagi for 40 meters would be?? I had a friend that had one once, until a storm took it down.? 73, Karl, KO8S, Warren, MI.


On Sunday, August 6, 2017 8:00 PM, Michael Babineau <mbabineau.ve3wmb@...> wrote:


I was only able to get on the air for about a half hour tonight. QSB was pretty bad, but I did manage to make my first three BITX40 to BITX40 SSB QSOs with :?

KC8WBK - Paul
KO8S - Karl?
VE3THR - Tom?

FWIW, ?I am running a BITX40 @5w with all of the PE1NWL suggested mods & firmware into a double-sized G5RV (i.e. 204 ft doublet) at 50 feet.
I am using a Koss CS-100 computer headset and I am really enjoying the SOTABeams DSP filter module that I just integrated into the rig
(2.4 Khz SSB & 300 Hz CW).?

Cheers

Michael VA2NB / VE3WMB ?(Note: I use my VA2 call from my cottage located about 30 mi NW of Ottawa in the Gatineau Hills of QC)


Re: BITX QSO Night, Sunday, August 6, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere

 

I was only able to get on the air for about a half hour tonight. QSB was pretty bad, but I did manage to make my first three BITX40 to BITX40 SSB QSOs with :?

KC8WBK - Paul
KO8S - Karl?
VE3THR - Tom?

FWIW, ?I am running a BITX40 @5w with all of the PE1NWL suggested mods & firmware into a double-sized G5RV (i.e. 204 ft doublet) at 50 feet.
I am using a Koss CS-100 computer headset and I am really enjoying the SOTABeams DSP filter module that I just integrated into the rig
(2.4 Khz SSB & 300 Hz CW).?

Cheers

Michael VA2NB / VE3WMB ?(Note: I use my VA2 call from my cottage located about 30 mi NW of Ottawa in the Gatineau Hills of QC)
Re: VK3YE AGC questions, description of how it works? and how to make it more effective?

Vince Vielhaber
 

Are you referring to me? Failure to include any context with your comment makes it like coming into the middle of a conversation.

Vince.

On 08/06/2017 02:14 PM, Dexter N Muir wrote:
Hi Vince

To the thread's title: /g/BITX20/message/30479 gives
the basic 'splainin'. I think the author asked about the 4k7 following
the diode: the 6.8uF needs R there so it can hold a charge briefly,
lowering that reduces the 'decay' time.

If you read my comment - *all* of it, it's self-explanatory. The key
phrase is "photo *and* gain!"

I've been doing a bit more t'inking, including my earlier suggestion of
RF AGC (same idea, but different details). How about this:
Tap off the output of Q1 (RF Amp) to drive the first BC548 (caps in and
out small ceramics, maybe a darlington or extra stage if more 'loop
gain' needed?). Second BC548 then drives another to reduce Q1's power
from +RX, does the job of the RF Gain pot. between R15 and R16; no
'photo' needed. The 'feed forward' loop is DC, using the amplitude of
the signal (filtered by the BPF it should detect strong sigs and QRN).

I haven't been able to get valid RX yet, let alone enough to need this,
but in the words of a 'Cheezels' ad: "Worth a crack, Nigel ... "? (I'm
more than half convinced it's my antenna giving the headaches)

Hopefully helpfully ... Dex, ZL2DEX

--
Michigan VHF Corp.

Re: BITX QSO Night, Sunday, August 6, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere

 

Antennas are very important with low power radios.
Re: BITX QSO Night, Sunday, August 6, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere

John P
 

Called and listened from 7PM until 7:30. Nada! I have to do something about my antenna situation!
--
John - WA2FZW
Re: VK3YE AGC questions, description of how it works? and how to make it more effective?

 

That second link with the N8DAH schematic has an extra 10k resistor after the diode,
not found in Farhan's original version of the circuit. ?
The extra 10k might help by reducing the load to the preceding NPN.
Will hinder by increasing the amount of time it takes to respond to a strong signal.



On Sun, Aug 6, 2017 at 03:10 pm, Jerry Gaffke wrote:
Here's Farhan's blog post on a simple audio derived AGC:
? ??
The comments suggest replacing the first 100k resistor with a diode, which should help it engage faster.?
Here's a thread describing a board available for it, including a redrawn schematic:
? ??/g/BITX20/message/30731
Re: BITX QSO Night, Sunday, August 6, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere

 

Calling CQ Bitx from Chicago KC9OJV
7.277
Re: uBitx almost finished by Bore Lezaic into CM2KMK PCB

 

Looks great
I am also working on a board?

20170807_070301.jpg

Re: VK3YE AGC questions, description of how it works? and how to make it more effective?

 

I have parts on order to build the VU2ESE AGC.? Now that I have this one working, I am not sure if I will build it.?
Re: VK3YE AGC questions, description of how it works? and how to make it more effective?

 

Thanks Jerry. Like I said, I'm just t'inking - I'm just a t'inker. Working on the antenna at present, a different balun. I might get enough 'stoke' out of my LSG-11 sig gen to get an indication of SWR from a bridge on a toroid around its lead to the (OCF) antenna feed, but likely not actual impedance (though I've got a dummy load to calibrate against). What an adventure this HF lark is! :)? 73 ...
Re: Finished to build but LCD noise.

 

I missed something here.? Do you have a schematic of? the circuit you used?? Did you also do the other mod using the resistor and the 2200uF caps or did this absolutely fix the problem?? I am at that stage of my build and want to use the best option

Virus-free.

On Fri, Aug 4, 2017 at 4:39 PM, <qrper72@...> wrote:
OK Bill,
thanks again.

ja9mat Hidehiko.




--
Paul Mateer, AA9GG
Elan Engineering Corp.

NAQCC 3123, SKCC 4628
Re: VK3YE AGC questions, description of how it works? and how to make it more effective?

 

Here's a webpage for the W7ZOI AGC scheme.
Takes two schematic pages, looks nearly as complicated as a complete Bitx40
? ??

A good example of the tradeoffs Farhan makes to create such a popular easily hacked,
easily understood, low-cost rig for experimenters. ?And amazingly enough, the Bitx40
can still give better than average performance. ?Just not quite up to W7ZOI's standards.

Jerry


On Sun, Aug 6, 2017 at 03:10 pm, Jerry Gaffke wrote:
Farhan recommends W7ZOI's hybrid cascode IF amp as a good implementation of AGC:
? ??/g/BITX20/message/15460
Re: VK3YE AGC questions, description of how it works? and how to make it more effective?

 

Here's Farhan's blog post on a simple audio derived AGC:
? ??
The comments suggest replacing the first 100k resistor with a diode, which should help it engage faster.?
Here's a thread describing a board available for it, including a redrawn schematic:
? ??/g/BITX20/message/30731

Farhan recommends W7ZOI's hybrid cascode IF amp as a good implementation of AGC:
? ??/g/BITX20/message/15460

Dennis and Jack are working on a board with RF derived AGC,
? ? /g/BITX20/message/24379
but it's not out yet.
? ??/g/BITX20/message/28026

And of course, we have the current thread wit VK3YE audio derived AGC.
Quite similar to Farhan's circuit, primary difference is the use of an LED and LDR instead of a FET:
?
You don't want to ask me how best to implement AGC, as I have not built one.
Lots of different ways to do it.
Lots of different ways to screw up.

Jerry, KE7ER


On Sun, Aug 6, 2017 at 01:51 pm, Dexter N Muir wrote:

True, Jerry. Tap off at Q3C then?

Farhan's circuit? Where? In this thread, or elsewhere? URL please? I must have poked my nose in late in the piece; I've only seen VK3YE's and derivatives.
Re: VK3YE AGC questions, description of how it works? and how to make it more effective?

 

True, Jerry. Tap off at Q3C then?

Farhan's circuit? Where? In this thread, or elsewhere? URL please? I must have poked my nose in late in the piece; I've only seen VK3YE's and derivatives.
Re: VK3YE AGC questions, description of how it works? and how to make it more effective?

 

Neither.
I was responding to Dexter's post regarding where to add an RF derived AGC circuit.


On Sun, Aug 6, 2017 at 12:36 pm, KC8WBK wrote:
Which one are you running?
Re: BITX QSO Night, Sunday, August 6, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere

 

Conditions were pretty good last night.? I suggest calling on the :15's, every quarter hour give a call or two.

A lot of us are monitoring throughout the evening.? Things tend to get interesting after sunset.
Re: VK3YE AGC questions, description of how it works? and how to make it more effective?

 

Jerry;

Which one are you running?
Re: VK3YE AGC questions, description of how it works? and how to make it more effective?

chris gress
 

I built the vk3 AGC its low cost and works well and I like that I can control it not just on/ off or on all the time if one is better than the other I don't know ?chris?

On 6 Aug 2017 20:02, "Jerry Gaffke via Groups.Io" <jgaffke=[email protected]> wrote:
The BPF passes the entire 40m band and more.? A strong SWL station at 7.4mhz will bring on the AGC action if the AGC is done up front.? AGC wants to be after the crystal filter, where it's only the signal of interest present.

By the way, where the Bitx40 schematic shows BC849's, but it's 2n3904's that get stuffed.

Does anyone have reason to select the VK3YE AGC over Farhan's AGC? ?
Perhaps some find the transition region of a 2n7000 FET to be too quick?
I haven't tried either, but Farhan's seems the more obvious, 2n7000's are cheap and easy to obtain.
If you want a light that blinks with each lightning bolt, could add an LED to Farhan's and forget the LDR.

Jerry

On Sun, Aug 6, 2017 at 11:14 am, Dexter N Muir wrote:

I've been doing a bit more t'inking, including my earlier suggestion of RF AGC (same idea, but different details). How about this:
Tap off the output of Q1 (RF Amp) to drive? the first BC548 (caps in and out small ceramics, maybe a darlington or extra stage if more 'loop gain' needed?). Second BC548 then drives another to reduce Q1's power from +RX, does the job of the RF Gain pot. between R15 and R16; no 'photo' needed. The 'feed forward' loop is DC, using the amplitude of the signal (filtered by the BPF it should detect strong sigs and QRN).

?
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