I was browsing around and I found that you can get small e-ink displays for very reasonable prices:



They have very low power consumption, especially standby power (they essentially only draw current when changing the display), and are easily readable in direct sunlight, so may make a good option for a display for an outdoor radio.

The disadvantage is that they have a pretty slow refresh time and don't handle moving images well, so fast tuning or an s-meter may not work well.

Thoughts?

开云体育

I burned a new uP with 3.12a. It runs but it sloooow.. It legs the clock, and the screen is refreshing very slowly. I can navigate bit is very different than it was with the previous chip (3.10a)
I used ATmeg328P (!).

叠é濒补

You have not set the fuses? /g/QRPLabs/message/24845

73 Alan G4ZFQ

I burned a new uP with 3.12a. It runs but it sloooow.. It legs the clock, and the screen is refreshing very slowly. I can navigate bit is very different than it was with the previous chip (3.10a)
I used ATmeg328P (!).?

Any idea??

73 de 叠é濒补 HA4BM?

开云体育

Not a very nice person then!

Thanks, Hans.? I will proceed assuming everything is working, even if a bit strangely!

73,
Steve VE3SMA

Hi?
Last year I asked if there was someone who could assemble a fully fledged ultimate3s kit for me because visually impaired.
A nice person responded and told me he could do, so I ordered, and paid the full kit with his address for the delivery.
unfortunately, I had now news since then, and also no replies to my Emails from this person.
is there someone among you who would sell an unused unit me?
Thank you in advance
Daniel

Hi Karlis,

that's because the preamp must show a low resistance to the terminals of
the loop, in order to get a _broadband_ antenna (i.e. "no-tune").

Reason is: If You have same field strength at, say, 3 and 30 MHz, with an
open loop You will get 10 times the voltage on 30 MHz than on 3 MHz across
the loop's terminals. (That is, because induced voltage is proportional to
frequency.) But, if You place a resistance at the terminals of the loop,
which has a much lower value than the impedance of the loop for all
frequencies, the voltage for 3 and 30 MHz will be the same. (That is,
because inductive reactance increases proportional to frequency.)

For a broadband-antenna, all transformations must be broadband, hence
gamma match would not work.

Kind Regards,
Axel


On Thu, 28 Mar 2019 09:21:22 +0100, Kārlis Goba <karlis.goba@...>
wrote:

Haven't yet read his article, but why focus so much on the input
resistance of an amp as a limiting factor when you can just transform
the loop impedance first hand? Use a (almost lossless) smaller coupling
loop/gamma match to get close to 50 ohms or any other practical input
impedance and work from there.

Haven't yet read his article, but why focus so much on the input resistance of an amp as a limiting factor when you can just transform the loop impedance first hand? Use a (almost lossless) smaller coupling loop/gamma match to get close to 50 ohms or any other practical input impedance and work from there.

--
Karlis YL3JG

Thank you for pointing me to the magnetic-loops group, didn't know of
this. I took a short overview on the topics of this group, and they have a
huge amount of infos for me, for further readings.

As to the radiation resistance: Unfortunately, SNR seems to be limited by
other resistances (losses and differential input resistance of the
preamp). Values are (for reasonable loop size):

0.5 Ohms: Losses in Loop (LZ1AQ's article)
3 Ohms: Preamp's differential input resistance (LZ1AQ's article; but
this is not comparable to the other resistances: higher value means better
SNR)
0.030 Ohms: radiation resistance (14 MHz;
)

After reading LZ1AQ's article, I want to look into the magnetic-loops
group, if it is possible to have a preamp with higher SNR at 14 MHz and
above.

LZ1AQ states, that the noise floor of his preamp is (a lot) higher than
atmospheric noise. He explains, that this is due to the _low_ differential
input resistance of the preamp (3..7 Ohms). He explains, that increasing
this resistance has adverse effects (lower bandwidth and others). And he
says, that the noise temperature of the differential input resistance is
290K. - At present, I think, maybe there are two possibilities to improve
SNR of the preamp: Increase differential input resistance and sacrifice,
for example, bandwidth. And, I know, properly build (narrow band) preamps
can have input resistances which are at noise temperature much below 290
K, but I don't know if this is useable for the given purpose.

73 Axel DF1ET

John K5MO? ? Thanks for the kind words, It has been a lot of fun .. and aging myself, I? appreciate the kind of vicarious travel adventure these experiments can furnish from the comfort of my couch..hihi..
OF COURSE..., without Hans's clever firmware and design, this easy world coverage tracking would be impossible.? Kudos to Hans.

Casey KC7IBT... I used to be a welder (among other things) so still have a relationship with the welding shop and can buy hydrogen.? Hydrogen can be made at home but after generation, you need to wash it by bubbling it through some water in a preserving jar ( as the caustic electrolyte could damage the balloon) and then into a dryer with crystal cat litter ( silica gel ) (again a preserving jar and some aquarium hoses and fittings) and then into some kind of storage unless you are filling the balloon directly.... all can be done fairly easily but it takes a bit of time to generate the .08 cubic meters of gas, unless you use high power and that could be problematic I understand.
For balloons I believe the search terms (clear balloon party foil 36" ) should work on aliexpress.

Dave VE3KCL

I managed to test my trim pot off of the rig and it works fine. I think I just had a solder bridge under the plastic I couldn't see. I connected it with wires since I lost the internal conductor out of the through holes. The trim pot reads fine now but my IQ amplitude is still unaffected. It might move 2 bars when I crank it clockwise all the way about 10 times. It's a shame. I wish I could figure out the problem.

And I just found the following :??
which is probably an even better choice as it can easily be sprayed on.

Cheers

Michael VE3WMB?

Related to this topic, I just by chance found something from MG Chemicals that might fit the bill. It is called Super Corona Dope.
See attached file.?

Cheers

Michael VE3WMB

P.S. I would be tempted to try a few coats of clear spray Krylon as suggested.?

I guess I should have mentioned that the GPS threshold parameter is set to zero, to minimize the step size.

73,
Steve VE3SMA

Dave,

Congratulations on these remarkable flights. You've really stuck with this and allowed us to vicariously participate in these flights.

Thanks for creating this fun and much continued success!

John K5MO