Hyper-Cricket at 12 volts?


Kenneth Ketner
 

Will the little chirper take 12 volts for a bit more output? 

I recently saw a circuit, Tayloe simple tx at Hendricks kits, that got 4 watts on 3 parallel bs170 s.

Ken Ketner
KA5ELD
PO Box 65135
Lubbock, TX 79464-5135
Sent from my iPad


WA0ITP
 

GM Ken,  Yabut (always one of those isnt there).

W0EB just posted a coupla days ago that he found very little difference in output power from 9 to 12 increase.  Maybe Jim will chime in here.

The designer, NM0S, in a private email to me when I asked abt 12 volts, said that R6 would need to be changed to 150k or 220k. I was thinking abt the convenience of using a 3 cell LiPo, and having loong battery life.  Haven't done that yet.

Sure it could be redesigned for more power, VFO, more sensitivity, etc.  But then it would be a whole new rig and not a Cricket anymore.  Dave designed it as an inexpensive, minimalist, and fun entry level rig.

btw Ken, do you own a Cricket yet?  They're great fun.
72 WAØITP
I love this radio stuff.
www.wa0itp.com
www.4sqrp.com
On 5/3/2017 10:41 PM, Kenneth Ketner klaine@... [4sqrp] wrote:

 
Will the little chirper take 12 volts for a bit more output? 

I recently saw a circuit, Tayloe simple tx at Hendricks kits, that got 4 watts on 3 parallel bs170 s.

Ken Ketner
KA5ELD
PO Box 65135
Lubbock, TX 79464-5135
Sent from my iPad


wa2cky
 

The answer is 'maybe' but it brings up the question 'why???'.  The Cricket is what it is - a fun little, uncomplicated CW rig.  I personally figure on leaving it the way it is.  You know, somewhat before we start talking about 'overshoes' and the like.  Although a nice power amp with maybe 20 dB of gain would certainly do a bit to help the 'power urge' - 1 watt in, 100 watts out.  Boy, wouldn't my neighbors like that!  Not exactly QRP of course either. 

73 and grins
Bob Groh, WA2CKY


John Lonigro
 

As someone mentioned, the main reason for making the Cricket work on 12 volts is just to have it run in the shack without wasting 9 volt batteries. My suggestion is to build a simple 9 volt regulator that has a snap connector on the output and a powerpole (or whatever) on the input. There would be no mods made to the Cricket and, when desired, a 12 volt power supply could be used to power it. All the parts (regulator and a couple of capacitors) would easily fit into a 35 mm film can (remember them?) or a small pillbox. With the current levels we are talking about, no heat sinks would be required.

72,

John, AA0VE

On 05/04/2017 09:44 AM, bob.groh@gmail.com [4sqrp] wrote:

The answer is 'maybe' but it brings up the question 'why???'. The Cricket is what it is - a fun little, uncomplicated CW rig. I personally figure on leaving it the way it is. You know, somewhat before we start talking about 'overshoes' and the like. Although a nice power amp with maybe 20 dB of gain would certainly do a bit to help the 'power urge' - 1 watt in, 100 watts out. Boy, wouldn't my neighbors like that! Not exactly QRP of course either.


73 and grins
Bob Groh, WA2CKY


Curt
 

Possibly the drive level of the prior stage could be in play.  12 volts can allow higher power output, but there has to be enough drive level.  when there is enough drive (via an extra NPN transistor maybe) - then one can question if the 2N7000 can safely provide the dissipation.  using a BS170, perhaps again the drive level is in question. 

As I shared earlier, a companion board with VFO and an audio filter would be useful and easy, but more output power impacts the Cricket too much for most builders - and a 2X power increase isn't that noticed being about 1/2 an S-unit.  But with care one could home-brew a hyper cricket. 

One more thought - KC9ON may still sell multi-crystal boards that were intended for a Pixie - that may work fine with the Cricket.  Most shacks likely already have an audio filter (I did not ask Terry if he was using one when we QSO'ed half-way across NA. 

73 CUL

Curt


Jim, N5IB
 

Consider this doodad for providing 9V to your Cricket
follow the "Current Limiter" link at

http://n5ib.net/Index.xht

Easy perfboard or DIY PC board.
Has the extra feature of adjustable current limiting to keep the smoke in.

N5IB




---In 4sqrp@..., <jonigro@...> wrote :

As someone mentioned, the main reason for making the Cricket work on 12
volts is just to have it run in the shack without wasting 9 volt
batteries. My suggestion is to build a simple 9 volt regulator that has
a snap connector on the output and a powerpole (or whatever) on the
input. There would be no mods made to the Cricket and, when desired, a
12 volt power supply could be used to power it. All the parts
(regulator and a couple of capacitors) would easily fit into a 35 mm
film can (remember them?) or a small pillbox. With the current levels
we are talking about, no heat sinks would be required.
72,
John, AA0VE


Kenneth Ketner
 

Greetings:
Thanks for the reply.

Gottacricket. Finished it yesterday. As promised, got .7 watt out directly on my official Oak Hills qrp wattmeter at first smoke test. It retains smoke. Nice sidetone but had  clunk on key release. Will research same. I am running my straight key into the adapter. Got RX noise, but no-one about at the ColorBust frequency just then.

I wanted to ask the experts about 12 volts before trying it. Fried cricket is not appetizing. So I will try more juice, maybe try the resistor change. I would prefer a whole watt if possible.

Wouldn't the cricket be as joyful at 1 watt as it is at .7?
1 is the master number. 1 + 1 is 2, 2 + 1 is 3. 1/2 is a number, 23/32 is some kinda number....   Therefore, 1 is important, numberwise.

73
Ken Ketner
ARS KA5ELD
ARRL, RSGB, G-QRP
PO Box 65135, Lubbock, Texas 79464-5135

On May 04, 2017, at 08:17 AM, WA0ITP wrote:

GM Ken,  Yabut (always one of those isnt there).

W0EB just posted a coupla days ago that he found very little difference in output power from 9 to 12 increase.  Maybe Jim will chime in here.

The designer, NM0S, in a private email to me when I asked abt 12 volts,
said that R6 would need to be changed to 150k or 220k. I was thinking abt the convenience of using a 3 cell LiPo, and having loong battery life.  Haven't done that yet.

Sure it could be redesigned for more power, VFO, more sensitivity, etc.  But then it would be a whole new rig and not a Cricket anymore.  Dave designed it as an inexpensive, minimalist, and fun entry level rig.

btw Ken, do you own a Cricket yet?  They're great fun.
72 WAØITP
I love this radio stuff.
www.wa0itp.com
www.4sqrp.com
On 5/3/2017 10:41 PM, Kenneth Ketner klaine@... [4sqrp] wrote:
 
Will the little chirper take 12 volts for a bit more output? 

I recently saw a circuit, Tayloe simple tx at Hendricks kits, that got 4 watts on 3 parallel bs170 s.

Ken Ketner
KA5ELD
PO Box 65135
Lubbock, TX 79464-5135
Sent from my iPad


Kenneth Ketner
 

Did some additional tests with stock cricket recently built, no circuit changes. I fabricated a thin copper heatsink with about .5 x 1 inch surface area, formed its bottom around pa transistor, used some heat goo. With a battery reading 9 v open circuit, measured .7 watt out into oak hills qrp wattmeter with a dummy load. Checked temp of pa using a radio shack infrared no contact thermometer, got 79 f. Ambient temp of bench table read 77 f.

Next connected a lithium battery in 9 v box showing 10 v. Got 1 watt out. Temp at 82 f. Connected a battery of 8 1.5 v cells showing 11.5 v, got 1.5 w at 83 f. Pa not warm to touch. 

In the tests I sent some random key chatter into the dummy load for about 1 minute. 

It appears this particular gryllidae member can go with a standard shack 12 v supply, at least into a dummy load. Performance on air not tested yet. 

Would the increase in power cause failure of FCC emission standards?

Ken Ketner
KA5ELD
PO Box 65135
Lubbock, TX 79464-5135
Sent from my iPad