Date   
Re: ubitx mobile in a car

Ted
 



I'd like to hear more about this 40m "center fed" design.  I figured 80m mobile is a pipe dream at BEST for a variety of reasons. If I could get 40 and 20 to work, I'd be fine is it tends to only get easier from there on upward. I built a base loading coil that works well with an 8 foot CB whip back in the early 80s for 40m and which had a tap for 20m. That was out of the ARRL 1977(?) Handbook and worked fantastically. I still have that coil even today. I could try it again though I'd rather try to move to some newer materials; that, and it didn't look so terrible in the back of a 1969 Plymouth Fury III. I'm pretty sure my dear, lovely spouse would not want that on the family's RAV4.

On a different note, about 12 years ago I took a VHF low-band antenna and used the base of the coil as a mount at the bottom of a length of 1.25" PVC pipe.  I then attached a 48-inch whip to the top of that coil form (using the original antenna's cap & set screw) with about 32 ft of wire. A shunt came from the center of the base (from within the PVC form, near the bottom out to the side) - that being an NMO mount for the original low-band antenna - which was used to tap to the external coil at a point found to resonate well on 14.25mHz or thereabouts. This antenna was used exclusively with an MFJ9420 and it kicked a$s. This one, I know to still be in inventory... :)  Also in inventory is an 80m hamstick that could be shortened, shunt-fed, or otherwise repurposed for a different band.

So, please do share, in as much detail as you wish to give, the design on this center-fed 40-meter deal. I'd like to know what was done and what worked. And if nothing else, I've got a known, working 20 meter band base mounted antenna that I can simply use with another hatchback lip mount as was before.

All else being equal, I 'd prefer to have 40m in the car for daytime driving and which I could switch to 20m when the band's open. Sure, I'd like to have 80m as well but I might as well just put a coat hanger out the window and pray. That doesn't cost much.

Thanks much and 73,

Ted
K3RTA

Re: Nextion Saga

Michael Mitchell <mitchellmichaelh@...>
 

Or a circular firing squad. Have you looked at uBitx.net

Nextion Saga

W2CTX
 

Now don't flame me guys....

Reading all these questions about what build goes with what Nextion size and
what options are supposed to be activated reminds me of Abbot and Costello -
Who's on First.

rOn

i2c signal meter/analyser/dsp/cw decoder

Sourav
 

Hi,

 

Can anybody pl confirm which firmware .hex to run the DSP signal meter & CW decoder option .

I use nextion adv 3.5”.

Fyi, the S-meter function works normally, but DSP1 & CW setup buttons don’t appear on the control menu ??!!

 

I’m using –

#for 1st Arduino (ubitx):            UBITX_CEC_V1.200_NX_S.hex  (tried v1.097 & v1.10 too !!)

 

#for 2nd Arduino (sig.sensor):   I tried all the below found online, but w/o success

CEC_I2C_Meter_V0.8.hex

DSPMeter1_V0.7.hex

i2cmeter1.ino.hex

 

In dspmeterv1-master uploaded few days back ( https://github.com/phdlee/dspmeterv1) there’s no .hex files !!

 

All wiring as per-

Standalone Signal Analyzer (I2C Type Signal-Meter) for uBITX #2 - Nextion LCD

Standalone Signal Analyzer (I2C Type Signal-Meter) for uBITX #3 - Advanced and FFT

 

73s,

Vu3Cgb- Sourav

 

A circuit board

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A picture containing black, top

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Finally started construction #ubitx

estwing W
 

My XYL purchased an Ubitx for me late last year. It is a V4. Board. I had time to start on the recommended fixs this weekend. I have replaced the relays with the Axicoms. Does anyone in the U.S. have the SMD inductors for L5 and L7 for sale? I hope to put this in a pelican style case with a tuner and power source to use for portable ops. Thanks to everyone here for their vast wealth of knowledge. I have learned so much about these radios and electronics in general reading this board.
Russell Ward W8ARD
Columbus Ohio

Re: Kit-Projects ND6T Ubitx AGC

Lee Weifenbach <wb3acc@...>
 

Hi David, would you please email me the updated switch diagram for my agc I just received from you a week or two ago.  I did question the supplied diagram.  thanks  Lee   wb3acc@...    73


On April 14, 2019 at 11:55 PM N8DAH <Dherron@...> wrote:

I have restocked mic's, paddles and AGC's. The AGC doc's have been updated with the correction for the DP3T.

73
--
David

 N8DAH
Kit-Projects.com

Shop is open!

Re: ubitx mobile in a car

ajparent1/kb1gmx
 

The reality of mobile ops is they antennas used will be inefficient for bands below 20mhz.
Reason is loading coils are a required thing to tune out the reactance of a short antenna.
There is no way around that. 

FOr 20M antenna efficiency is about about 8ft tall will be reasonable about 33% as its pretty
close to 1/2 size.  Center fed is about the best.

For 40M its about 1/4 size and allowing for the fact that cars are a terrible counterpoise for
the antenna so efficiency under 10% are the norm.  IF you can tolerate a taller than 8ft
antenna that helps, center loaded is best.  Do not use an antenna tuner as you at the wrong
end of the cable.  Its best if the tuner is at the base of the antenna.

https://k0bg.com/
K0BG has a very complete site on how to get the best out of a mobile antenna.

I run 40M mobile QRP using KNQ7A or FT817 and the antenna is a cheap 40M 8ft
centerfed whip with mods.  The mods are a 9 turn 1-inch dia coil from the base to
ground to load the antenna.  Then the antenna itself has the longest whip section
possible at the top and is tuned by removing some of the plastic shrink and removing
turns to keep it as long as possible.  This is more efficient than shortening the whip
to tune it.  Its good for about 30khz either side of where tuned.    Using a tuner to
get more bandwidth results in a significant loss in efficiency as they antenna is then
untuned. I verified this with a field strength meter.  However those antennas are
cheap (about 20$) and I can carry two (one for 7163, and 7250) in the bed of the pickup.  

Ignition noise it a problem with the car/truck... fix it and then you hear the other near you.

Allison

Re: Homebrew li-ion battery pack into ubitx

Ted
 

Yes, and one can score some nice LiPo cells from a cordless drill battery pack and get a charging controller for the intended voltage (12v, 16v, etc) on eBay with separate leads to sense each 4v step of the battery pack for balanced charging.


Ted
K3RTA  

Re: Homebrew li-ion battery pack into ubitx

Ted
 

My end-of-the-world build has a kit type tuner similar to this bulit into the faceplate and it seems to work OK. I added two switches to switch the two variable caps in or out independently which seems to help in some cases to add or subtract in that way. I haven't logged contacts on that build as of yet though I haven't been out with it, either.

Re: Homebrew li-ion battery pack into ubitx

Jerry Gaffke
 

The transformer of an EFHW  matching network matches the 50 ohm transmitter
to an expected impedance into the wire of between 2500 and 3000 ohms.

Power is Volts*Amps, or Volts*(Volts/Ohms).
At 5 Watts of RF power,    5watts = Volts*Volts/3000ohms,   therefore  Volts = sqrt(3000*5) = 122 Volts RMS.
At 100 Watts, it's still around 548 Volts RMS, not yet kilovolts

The polyvaricons are rated for something around 100 Volts:
    https://www.mikeselectronicparts.com/product/variable-capacitor-335pf-20pf/

Generally, you can press a polyvaricon somewhat beyond 100 Volts.
A polyvaricon works at 5 Watts for an EFHW, though an air-variable cap would be a better choice.
If an air gap does arc over, it will self-repair once the ionized air circulates out.
And an air gap capacitor has a higher Q, and thus lower losses.

The qrpkits Sota Tuner successfully uses a polyvaricon:in an EFHW tuner:
    https://www.qrpkits.com/sota.html
They claim a max of 5 Watts CW, 10 Watts PEP.
On 10 Watt peaks, that would be  sqrt(3000*10) = 173 Volts RMS.
Perhaps they are more concerned about heating than they are about arcing?

Anything other than a resonant EFHW will be lower impedance,
and thus lower voltages across a tuning capacitor.

Jerry, KE7ER



On Mon, Apr 15, 2019 at 12:33 AM, Sandeep Lohia wrote:
End fed 1/2 wave is a voltage fed antenna Sarma ji, there might be more then kilo volts present even with QRP at end of coil...
Therefore thin PVC variable Gang Capacitor won't help...

Re: ubitx mobile in a car

Ted
 

Well, as asked (by someone months ago, forgot whom), here are some pix of my mobile-purposed uBitx -

 https://groups.io/g/BITX20/album?id=86462&p



Re: Relationship between IF-S, calibration, and BFO?

Wiley1
 

That is exactly what I was wondering Vic. I will give it a shot tonight. 

Thanks
Bill
KE8EYM

Re: Relationship between IF-S, calibration, and BFO?

Vic WA4THR
 

IF-S is basically controlling the BFO on receive. If you adjust the BFO (shown as USB Calibration in Memory Manager) by the amount you have been adjusting your IF-S then you will correct that error and not have to use IF-S and your transmit will be corrected as well.

=Vic=

Re: Relationship between IF-S, calibration, and BFO?

EI4GNB
 

If You have set up correctly, then comfortable listening will likely require some IF-S to shift the bandpass downwards, adding more lower end, but all the way to the right sounds like You are way off.. I'm about 20% for nice even audio on the waterfall in JTDX, and less scratchy audio for phone. (V4 board)

Re: Homebrew li-ion battery pack into ubitx

MVS Sarma
 

I learnt another point today. Thanks Saneep jee


On Mon, 15 Apr 2019, 1:03 pm Sandeep Lohia <sandeeplohia12@... wrote:
End fed 1/2 wave is a voltage fed antenna Sarma ji, there might be more then kilo volts present even with QRP at end of coil...
Therefore thin PVC variable Gang Capacitor won't help...

On Mon 15 Apr, 2019, 12:35 PM Dave Dixon, <wylyeguy2@...> wrote:
Sarma,
               Look up G0POT for his efhw aerial and vk3 ye for his atu..Regards Dave.

On Mon, 15 Apr 2019 at 07:53, MVS Sarma <mvssarma@...> wrote:
Dear Pratap jee,
Your power inside is really welcome .
 One could take out the rig to field, with some end fed or a fold-able vertical antenna and used for an hour. 

Other mods are curiously awaited. Being a QRP, perhaps you can use PVC gang caps. 

Regards
sarma
vu3zmv

Re: Homebrew li-ion battery pack into ubitx

Sandeep Lohia
 

End fed 1/2 wave is a voltage fed antenna Sarma ji, there might be more then kilo volts present even with QRP at end of coil...
Therefore thin PVC variable Gang Capacitor won't help...

On Mon 15 Apr, 2019, 12:35 PM Dave Dixon, <wylyeguy2@...> wrote:
Sarma,
               Look up G0POT for his efhw aerial and vk3 ye for his atu..Regards Dave.

On Mon, 15 Apr 2019 at 07:53, MVS Sarma <mvssarma@...> wrote:
Dear Pratap jee,
Your power inside is really welcome .
 One could take out the rig to field, with some end fed or a fold-able vertical antenna and used for an hour. 

Other mods are curiously awaited. Being a QRP, perhaps you can use PVC gang caps. 

Regards
sarma
vu3zmv

Re: Homebrew li-ion battery pack into ubitx

Dave Dixon
 

Sarma,
               Look up G0POT for his efhw aerial and vk3 ye for his atu..Regards Dave.


On Mon, 15 Apr 2019 at 07:53, MVS Sarma <mvssarma@...> wrote:
Dear Pratap jee,
Your power inside is really welcome .
 One could take out the rig to field, with some end fed or a fold-able vertical antenna and used for an hour. 

Other mods are curiously awaited. Being a QRP, perhaps you can use PVC gang caps. 

Regards
sarma
vu3zmv

Re: Homebrew li-ion battery pack into ubitx

MVS Sarma
 

Dear Pratap jee,
Your power inside is really welcome .
 One could take out the rig to field, with some end fed or a fold-able vertical antenna and used for an hour. 

Other mods are curiously awaited. Being a QRP, perhaps you can use PVC gang caps. 

Regards
sarma
vu3zmv

Re: error Receive Length = 0/1027

MVS Sarma
 

Hi Cristian,
Please upload a screen shot of your error.
 secondly, please check whether you have set the port and Port has recognised  the CH340G  usb interface.
Finally define the chip as atmega328, and if possible as old bootloader.
the Arduino Nano is also to be selected.

all the best
regards
sarma
vu3zmv
 

Homebrew li-ion battery pack into ubitx

Prathap Naidu
 

Hi guys
Yesterday I Installed a homebrew 3S2P li-ion battery pack into my ubitx cabinet
Had planned my cabinet for the right space & fit
Now I can carry my ubitx for outdoor  action
Next I am building a small SOTA atu
Happy home brewing
Best 73
Pop
VU2POP