Date   

Re: 49:1 End Fed antenna From 50 Watt Amp Parts

George Korper
 

Tom,

There is no comparison between a resonant full length End Fed  antenna and the MAXCOM. 
They are two very different ideas.

That being said, as I have discussed in other posts describing installations around the world
that are built to pick up signals from what you would call a dummy load, you may not have all the facts
on why such as system can and does prove useful.  It is a system and process that may not be suitable for Amateurs and the marketing
claims of companies outside their use in government can be exaggerated and are not the responsibility of government agencies to refute.

Best 73,
K3GK









Re: QLG1 GPS Receiver kit

Andrew Lenton
 

Hi Keeping it simple,

 

TTL is a positive going 5V or 3V3 signal (positive = 1)

RS232 is -12 of logic 1 and + 12 for logic zero. (this was used to get data through longish cables, no idea why -12 is a 1, historic)

 

If you invert TTL through a single transistor it will work on a RS 232 interface.

 

 

73 Andrew


Re: 49:1 End Fed antenna From 50 Watt Amp Parts

TomW4OKW
 

Gary, N3GO said:

A company in Florida once dazzled the Army back in the ‘70’s or 80’s with a compact 2-30 MHz dipole targeting the Manpack market as I recall. They made a similar claim... Something like 1.5:1 SWR over the entire range.

  It didn’t take a lot of effort to reverse engineer the design... essentially a short dipole as advertised, shunted at the feed point with a 50 ohm power dissipating resistor. i.e. a leaky dummy load of sorts. Indeed... no tuner required. Don’t you just love the creativity of marketing?   Truth in advertising at its best. LOL!

Tom sez:  The "MAXCOM automatic antenna matcher". And they sold millions of them to thegovernment, who wanted "no tune" antennas for Embassies, MARS and the military. They received OK, but most of your trasnsmit RF went up in heat!

73 Tom/W4OKW


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Re: kit GPS QLG1 #gps

KEN G4APB
 

Sorry Gilles, got interrupted before I finished...I was going to say for a first start-up of a new gps unit to need to give it a good clear view of the sky to allow a new almanac to download, can take 15 minutes or so. Also you need to be seeing at least 25db c/n values for good data. Only when you have satisfied these conditions can we start to investigate the pps connection. Also check your versions with Hans earlier posts, there were some issued with a firmware problem.

73 Ken G4apb


Re: kit GPS QLG1 #gps

KEN G4APB
 

Hi Gilles,
more info please. Are you getting a lat/long coordinates indication on your U3S? Four stats sounds too low, you should be seeing many more. 

73 Ken


Re: QCX 20 low output 5w at drain 1/3 w at output #problem

Ronald Taylor
 

Dan, many have found that removing a couple of turns from each of the toroids L1-L3 can raise the power output of the QCX20. If you are sure you have DC continuity through all of them and getting some power output and all the capacitors are right, then I’d try that step next. Before you do it, recount the turns you have in there. Many people find one extra turn because they forgot to count all the wires running through the center of the core as one turn. At any rate all you have to do is lift one wire of each toroid and unwind a couple turns and resolder it without cutting. That’s easier if you have to add a turn back on to get it right. When it’s right trim the excess wire and solder it back in place. I’ve built or fixed for others several 20 meter QCXs and have only found one get close to 5 watts output. The average I’ve seen is about 3.5 watts. And that is plenty of QRP power on 20 meters and only about 1.5 dB less than 5 watts, or about 1/4 of an S unit. 

Good luck .... Ron

On Mon, Apr 20, 2020 at 16:18 Daniel Curtin KF4AV <danieljcurtin42@...> wrote:
My QCX seems to work fine on RX. On TX I get 5 w (on the internal meter)at the drain of the BS 170s but  at the end of L1 about .3 w out. The instructions indicate the LC circuit would be suspect I do have DC continuity through the Low Pass filter. As best I can see I have the right capacitors in the right places and the right number of turns on the toroids.

I just got a digital scope (my first scope) so I tried to signal trace. I list here P-P rf voltage, the scope gives lots of other info:

DC input is about 14 V, for these readings.

On both sides of C29 40 V (including input to L3)
On the output side of L3 20 V
On the output of L2 10 V
On the output of L1 and at the BNC connector 7 V

Am I looking at the right things? Could my toroids be too poorly wound (I have not wound any in years and never any so small.)

Any help appreciated. I am having great fun with this excellent kit, and already have learned a lot.

73 Dan KF4AV


Re: Status of the All-Mode, Multi-Band Transceiver Kit?

@CurtisM
 

Well you may need to define up to date. The ubitx is a bit different than a ft817, and a hit lower receive current draw. I have a v4 and it operates decently. You might research who has adapted it to transvert on higher frequencies, but its a huge reach for those bands you mention. Neither rig is exceptional on cw, but they work. Ft817 probably better for getting to those higher bands, see if anyone has modified a ubitx to reach up into uhf.

You can customize the ubitx, a huge plus.

73 curt wb8yyy


Re: Nickel Metal Hydride Batteries for QCX

James Daldry W4JED
 

Hi, George

I like lithium (all types) because they are dead simple to charge. Limit the current and limit the voltage to 4.2 for most, 3.8 for LiFePO4. Also, for 18650's, 3 cells is 12 volts, close enough for gummint work.

NiCads are second, because most will take charging abuse - if overcharged and grabbed before too hot to touch they'll survive the assault. You can also trickle charge NiCads at 1/10 C or less. Fast charge can be accomplished by either thermal cutoff or looking for voltage dip.

NiMH are a nightmare to charge. Put one on a trickle charge and tomorrow it will be dead. Over current on charge, dead. Let it get warm enough to feel while charging, dead. Since voltage droop at charge end is too small to measure, you have to monitor cell temperature and stop the charge on the first measurable temperature rise.

I have my QCX in a homemade transparent ABS case with an aluminum front panel, with 2 - 6 volt NiMH battery packs in the bottom of the box. I have a 1N4148 diode with a 1K resistor in series buried in each pack, with the diodes wired in series, so the charge stops immediately when the forward voltage drops. So far I haven't hosed the batteries.

73

Jim W4JED

On 4/21/20 1:35 PM, George Korper wrote:
Hi,

I use Nickel Metal Hydride and alkaline batteries with the QCX. 
They are very cheap these days, and less hazardous that Lithium and 
not restricted to carry on by TSA. They have little memory, and are pretty cheap. 
I like they are AA.

I use 20 volt Lithium batteries for the amp and love 'em but for a barefoot
QCX, the Nickel Metal Hydride or Alkaline seem sufficient. 

My question what are members in the Group feelings about these vs. Lithium. I know Lithium
batteries are  popular these days, but there are some drawbacks. What do you think?


George


Re: Nickel Metal Hydride Batteries for QCX

Lawrence
 

I agree.  NiMH and the now less used NiCd batteries are more rugged than Lithium based batteries but they still need to be managed and maintained correctly.  Simple chargers do tend to cause the packs to become unbalanced after a number of cycles and heavy discharge of an unbalanced pack can cause one or more cells to be reversed, overheat and possibly burst.

NiMH cells tend to be capable of handing high currents, deep discharge and light overcharging well but ideally these packs should have the individual cells monitored and charged individually just like Lithium cells and you will get long life.  In the model car world it is common to buy matched cells and to have a jig to recharge them individually and monitor to ensure each cell comes up to full.  This then allows very heavy discharge during racing without damaging the cells.

Common NiMH chargers are often just a trickle charger with a circuit to look for the negative dv/dt that indicates full but this is unreliable since the first battery to become full will show this behaviour and it does not mean ‘all’ the batteries are full.  Repeated cycling can leave some batteries quite undercharged leading to early death.

73 Lawrence Harris VA7EDU




On Apr 21, 2020, at 15:55, Shirley Dulcey KE1L <mark@...> wrote:

I have used them. My experiences are very different from yours. I have always recharged them individually, which may help, and I don't run them down all the way.

That said, my current main field battery is a BioEnno 3000 mAh LiFePo4.

On Tue, Apr 21, 2020 at 6:10 PM ajparent1/KB1GMX <kb1gmx@...> wrote:
Have you  actually used them?
I have and they are better but claims have not been fully met.
4 of the 12 never recharged after abut 30 cycles and one leaked.

Allison
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Re: Nickel Metal Hydride Batteries for QCX

ken fest <disklog@...>
 

I have used Eneloop for years ( the original white ones ) in both AA and AAA sizes and have had zero failures. I like them so much
I now have them in all my devices that take AA or AAA.
At lease two dozen in use at this time with half dozen charged and sitting on a shelf waiting to be used. No leaks yet.
Ken

On Tuesday, April 21, 2020, 06:10:43 PM EDT, ajparent1/KB1GMX <kb1gmx@...> wrote:


Have you  actually used them?
I have and they are better but claims have not been fully met.
4 of the 12 never recharged after abut 30 cycles and one leaked.

Allison
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Re: Nickel Metal Hydride Batteries for QCX

ajparent1/KB1GMX
 

I try tnot to run them down and the charger was the one
supplied that charges 2  or 4,.  The failed cells were replaced
without explanation.

Rather annoying as it was in the field.  Fortunately I carried spares.
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Re: Nickel Metal Hydride Batteries for QCX

Shirley Dulcey KE1L
 

I have used them. My experiences are very different from yours. I have always recharged them individually, which may help, and I don't run them down all the way.

That said, my current main field battery is a BioEnno 3000 mAh LiFePo4.

On Tue, Apr 21, 2020 at 6:10 PM ajparent1/KB1GMX <kb1gmx@...> wrote:
Have you  actually used them?
I have and they are better but claims have not been fully met.
4 of the 12 never recharged after abut 30 cycles and one leaked.

Allison
-------------------------------
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Re: Nickel Metal Hydride Batteries for QCX

ajparent1/KB1GMX
 

Have you  actually used them?
I have and they are better but claims have not been fully met.
4 of the 12 never recharged after abut 30 cycles and one leaked.

Allison
-------------------------------
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Re: Nickel Metal Hydride Batteries for QCX

Shirley Dulcey KE1L
 

Eneloop (2100 mAh, 2000 charge cycles, 70% charge after 10 years) and Eneloop Pro (2550 mAh, 500 charge cycles, 85% charge after one year) are both readily available on Amazon. The Pro are better if you want maximum run time, but the non-Pro are better in other ways (longevity and charge retention) and are significantly cheaper. The non-Pro ones are also available in red and blue, but those are identical to the white ones except for the color. I have never seen the Pro in any color other than black.

You will also need to get a suitable charger for NiMH cells to go with them. The best ones control the charge of each cell individually, which I recommend if you want to fast-charge, but they are more of a nuisance to use because you have to remove the cells from their holder and put them in the charger one at a time.

I have used them to power QRP radios successfully. The best choice for most gear is a pack of 10: 15V maximum at full charge, 12.5V for most of the discharge cycle, 10V minimum. It's hard to find a holder for 10 AAs, but you can get then in both flat (one row of 10) and brick (2 rows of 5) configurations on Amazon and eBay. Radios that can run on lower voltage can use a pack of 8: 12V at full charge, 9.6V for most of the discharge cycle, 8V minimum. I also like to use a pack of 6 to demo Arduino projects in the field.

It's hard to buy exactly 10 in a cost-effective way. Get extras and put them in your LED flashlights or whatever.


On Tue, Apr 21, 2020 at 5:16 PM George Korper <georgekorper@...> wrote:
Thank you Shirley...got confused. 

On Tue, Apr 21, 2020, 4:13 PM George Korper via groups.io <georgekorper=gmail.com@groups.io> wrote:
Ask  and you get results. I would never have known that the Eneloop Pro is 2500
mAh and last 10 years with only 30% depletion. Amazing. A little pricey but obviously worth it.  Thanks  again Allison. And available in MX on Amazon with charger! Just Google Eneloop.

On Tue, Apr 21, 2020, 3:51 PM George Korper via groups.io <georgekorper=gmail.com@groups.io> wrote:
Thanks Allison. I will look them up.

 Eneloop. 

When I find them  I will post a link. 

On Tue, Apr 21, 2020 at 4:40 PM Shirley Dulcey KE1L <mark@...> wrote:
You can solve that by using NiMH cells that are designed for long shelf life without discharging, such as Eneloop. You do pay a bit more for them than for standard NiMH cells, but they work very well. The size and weight equations aren't quite as favorable as lithium, but if you don't mind that drawback they are a viable alternative.

On Tue, Apr 21, 2020 at 2:19 PM ajparent1/KB1GMX <kb1gmx@...> wrote:
I use them when the weight and power they afford is reasonable.
Decent ones are fairly cheap and with a good charger they last a 
fair number of recharge cycles.

They fail for fully charged shelf life.  If I'm using them they are fresh
out of the charger or by 15 days out they are 20% down.

I di use them in two HTs that use AA cells. The internal battery for
the FT817 as they need to be charged often.  Various devices that
are already accepting AA sized cells.

AA size I use are 2200mah  the same capacity in Lithium is about 
a bit more than twice the weight.  If I have to carry enough to run
a larger amount of time lithium is still the way to go.

I still use NiCd and Lead acid (gelled and AGM) as well.  They have a 
place for applications and sometime low cost power.

Allison
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Re: How much power is too much?

Allan Nelsson
 

Alan,

 Sorry I made a typo in the $ comparison, QRPlabs GPS, but it doesn't change the total. It should have been:

U3S: 33 + 23 (GPS http://qrp-labs.com/qlg1.html) + 16 (OCXO) = 72 $ + time to assemble and calibrate the kit.

 

RFzero: 62 + 4 (GPS ant) + 2 (LCD) = 68 $ - ready to use.

eBay parts: <30 $ (Arduino, GPS, Si, PA) + time to integrate parts

It is true that the RFzero offers freedom on how to connect "modules" and the U3S only has 1 way to do it. The RFzero documentation has a good description on how to use this freedom to connect PA, relays, filters and antennas: https://www.rfzero.net/examples/wspr-transmitter/ then go to Filter mode, bits and control.

 

For several reasons I still go for the RFzero, not least because the drift problem is eliminated. :-)

73, Allan OZ5XN. 

 


Re: Nickel Metal Hydride Batteries for QCX

George Korper
 

Thank you Shirley...got confused. 


On Tue, Apr 21, 2020, 4:13 PM George Korper via groups.io <georgekorper=gmail.com@groups.io> wrote:
Ask  and you get results. I would never have known that the Eneloop Pro is 2500
mAh and last 10 years with only 30% depletion. Amazing. A little pricey but obviously worth it.  Thanks  again Allison. And available in MX on Amazon with charger! Just Google Eneloop.

On Tue, Apr 21, 2020, 3:51 PM George Korper via groups.io <georgekorper=gmail.com@groups.io> wrote:
Thanks Allison. I will look them up.

 Eneloop. 

When I find them  I will post a link. 

On Tue, Apr 21, 2020 at 4:40 PM Shirley Dulcey KE1L <mark@...> wrote:
You can solve that by using NiMH cells that are designed for long shelf life without discharging, such as Eneloop. You do pay a bit more for them than for standard NiMH cells, but they work very well. The size and weight equations aren't quite as favorable as lithium, but if you don't mind that drawback they are a viable alternative.

On Tue, Apr 21, 2020 at 2:19 PM ajparent1/KB1GMX <kb1gmx@...> wrote:
I use them when the weight and power they afford is reasonable.
Decent ones are fairly cheap and with a good charger they last a 
fair number of recharge cycles.

They fail for fully charged shelf life.  If I'm using them they are fresh
out of the charger or by 15 days out they are 20% down.

I di use them in two HTs that use AA cells. The internal battery for
the FT817 as they need to be charged often.  Various devices that
are already accepting AA sized cells.

AA size I use are 2200mah  the same capacity in Lithium is about 
a bit more than twice the weight.  If I have to carry enough to run
a larger amount of time lithium is still the way to go.

I still use NiCd and Lead acid (gelled and AGM) as well.  They have a 
place for applications and sometime low cost power.

Allison
-------------------------------
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No direct email, it goes to bit bucket due address harvesting in groups.IO


Re: Nickel Metal Hydride Batteries for QCX

George Korper
 

Ask  and you get results. I would never have known that the Eneloop Pro is 2500
mAh and last 10 years with only 30% depletion. Amazing. A little pricey but obviously worth it.  Thanks  again Allison. And available in MX on Amazon with charger! Just Google Eneloop.

On Tue, Apr 21, 2020, 3:51 PM George Korper via groups.io <georgekorper=gmail.com@groups.io> wrote:
Thanks Allison. I will look them up.

 Eneloop. 

When I find them  I will post a link. 

On Tue, Apr 21, 2020 at 4:40 PM Shirley Dulcey KE1L <mark@...> wrote:
You can solve that by using NiMH cells that are designed for long shelf life without discharging, such as Eneloop. You do pay a bit more for them than for standard NiMH cells, but they work very well. The size and weight equations aren't quite as favorable as lithium, but if you don't mind that drawback they are a viable alternative.

On Tue, Apr 21, 2020 at 2:19 PM ajparent1/KB1GMX <kb1gmx@...> wrote:
I use them when the weight and power they afford is reasonable.
Decent ones are fairly cheap and with a good charger they last a 
fair number of recharge cycles.

They fail for fully charged shelf life.  If I'm using them they are fresh
out of the charger or by 15 days out they are 20% down.

I di use them in two HTs that use AA cells. The internal battery for
the FT817 as they need to be charged often.  Various devices that
are already accepting AA sized cells.

AA size I use are 2200mah  the same capacity in Lithium is about 
a bit more than twice the weight.  If I have to carry enough to run
a larger amount of time lithium is still the way to go.

I still use NiCd and Lead acid (gelled and AGM) as well.  They have a 
place for applications and sometime low cost power.

Allison
-------------------------------
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Re: QLG1 GPS Receiver kit

Jonathan Dog
 

Hi David

There are essentially two main RS-232 level converter chips, with RS-232 voltages on one side and TTL voltages on the other. They are excellent chips, originally from Maxim but now multisourced. Essentially they are dual charge pump converters to make +ve and -ve 10ish VDC for the RS-232 signals, along with a buffer (which inverts voltages because logic 1 is -ve voltage in RS-232 and +ve in TTL.) They have two RS-232 to TTL "receivers" and two TTL to RS-232 "transmitters". Excellent chips. (And you can use them just as low-power twin-rail supplies for op-amps if you're as nasty as I am.)

If you search on Ebay/Amazon/Banggood/Alibaba etc for max232 module or max3232 module you will find what you need in any number of packages. Note that most have only TXD and RXD connected (and not the second transmitter or receiver). Mine is like this.

If you want to use the PPS signal on RS-232 you might consider a converter with handshake transmitter connected.

The most expensive of those is about USD 15, the cheapest about USD 1.

Great Toolbox serial ports For serial connections, I almost entirely use "Cisco Console Cabling", with RS-232 on an RJ-45 socket. Toolbox has lots of USB to RS-232 with Cisco RJ-45 pinout, which makes all wiring really easy. Search for cisco usb console cable, it's a light blue cable with a USB-A plug at one end (goes into laptop) and RJ-45, goes into Cisco equipment RS-232 console ports, and a great way to avoid the Hell Of Understanding RS-232 Cabling.

RS-422 Alternative As I mentioned in my other post, I'm considering using RS-422/RS-485 drivers from the QLG1, so I can run long twisted-pair cable and put the QLG1 outside in a plastic box, rather than run a long cable to the antenna. I'm happy to write this up if it interests anyone.

FTDI232 Alternative Lastly, As Gregg suggested, you might also consider instead an adaptor which is a USB device, containing a FTDI USB serial interface. (Search for ftdi usb to serial in usual suppliers, his was https://www.sparkfun.com/products/9716) This gives you a USB socket on your GPS, and when you plug your computer in it acquires a serial port. These are TTL on the device side, and would wire straight to the QLG1's TTL pins. For toolbox purposes, I prefer to have actual RS-232 voltages, but what's best depends on what you want to do, of course.

Kind regards
Jonathan.

PS. No connection with any firms mentioned.


Re: Nickel Metal Hydride Batteries for QCX

George Korper
 

Thanks Allison. I will look them up.

 Eneloop. 

When I find them  I will post a link. 

On Tue, Apr 21, 2020 at 4:40 PM Shirley Dulcey KE1L <mark@...> wrote:
You can solve that by using NiMH cells that are designed for long shelf life without discharging, such as Eneloop. You do pay a bit more for them than for standard NiMH cells, but they work very well. The size and weight equations aren't quite as favorable as lithium, but if you don't mind that drawback they are a viable alternative.

On Tue, Apr 21, 2020 at 2:19 PM ajparent1/KB1GMX <kb1gmx@...> wrote:
I use them when the weight and power they afford is reasonable.
Decent ones are fairly cheap and with a good charger they last a 
fair number of recharge cycles.

They fail for fully charged shelf life.  If I'm using them they are fresh
out of the charger or by 15 days out they are 20% down.

I di use them in two HTs that use AA cells. The internal battery for
the FT817 as they need to be charged often.  Various devices that
are already accepting AA sized cells.

AA size I use are 2200mah  the same capacity in Lithium is about 
a bit more than twice the weight.  If I have to carry enough to run
a larger amount of time lithium is still the way to go.

I still use NiCd and Lead acid (gelled and AGM) as well.  They have a 
place for applications and sometime low cost power.

Allison
-------------------------------
Please reply on list so we can share.
No direct email, it goes to bit bucket due address harvesting in groups.IO


Re: Nickel Metal Hydride Batteries for QCX

Shirley Dulcey KE1L
 

You can solve that by using NiMH cells that are designed for long shelf life without discharging, such as Eneloop. You do pay a bit more for them than for standard NiMH cells, but they work very well. The size and weight equations aren't quite as favorable as lithium, but if you don't mind that drawback they are a viable alternative.


On Tue, Apr 21, 2020 at 2:19 PM ajparent1/KB1GMX <kb1gmx@...> wrote:
I use them when the weight and power they afford is reasonable.
Decent ones are fairly cheap and with a good charger they last a 
fair number of recharge cycles.

They fail for fully charged shelf life.  If I'm using them they are fresh
out of the charger or by 15 days out they are 20% down.

I di use them in two HTs that use AA cells. The internal battery for
the FT817 as they need to be charged often.  Various devices that
are already accepting AA sized cells.

AA size I use are 2200mah  the same capacity in Lithium is about 
a bit more than twice the weight.  If I have to carry enough to run
a larger amount of time lithium is still the way to go.

I still use NiCd and Lead acid (gelled and AGM) as well.  They have a 
place for applications and sometime low cost power.

Allison
-------------------------------
Please reply on list so we can share.
No direct email, it goes to bit bucket due address harvesting in groups.IO