Topics

Look at this on eBay, ubitx, budget test equipment.

Kelly Mabry
 

Guys, I hope you indulge me, but is this a good cheap signal generator?  It has come down in price, and now that i am building and starting up my new ham shack, I wanted some recommendations.  Sorry I could not find the other thread in my emails.

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F293068522725

73,
Kelly K5AID 




Sent from my Verizon, Samsung Galaxy smartphone

RICHARD
 

I have found over the years is you need one that has a good attenuator and no leakage.   That’s were the big bucks come in.

 

K6KWQ

 

Sent from Mail for Windows 10

 


From: BITX20@groups.io <BITX20@groups.io> on behalf of Kelly Mabry <kmabry2007@...>
Sent: Sunday, May 12, 2019 4:11:06 PM
To: BITX20@groups.io
Subject: [BITX20] Look at this on eBay, ubitx, budget test equipment.
 
Guys, I hope you indulge me, but is this a good cheap signal generator?  It has come down in price, and now that i am building and starting up my new ham shack, I wanted some recommendations.  Sorry I could not find the other thread in my emails.

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F293068522725

73,
Kelly K5AID 




Sent from my Verizon, Samsung Galaxy smartphone

Kelly Mabry
 

Yes, I understand.  But I dont have big bucks, and likely will not on a disabilty ssi check. However, I am endevoring to do something. I try to do my own research, however, I don't  have a nearby club that I can fall back on. I don't  want to pollute the thread with newbie questions outside of ubitx. Its been 40 years since I had test equipment. I am not looking for pity, but for knowledge and direction. That nudge that sends this old newbie stamping off in a good direction until he can run on his own again.

73,

Kelly K5AID 

Laurence Oberman
 

Kelly,
What s your budget.
I have heard mixed reviews about these units, mostly related to stability.
At the price however its a good deal.

Regards
Laurence

On Sun, May 12, 2019 at 7:11 PM Kelly Mabry <kmabry2007@...> wrote:

Guys, I hope you indulge me, but is this a good cheap signal generator? It has come down in price, and now that i am building and starting up my new ham shack, I wanted some recommendations. Sorry I could not find the other thread in my emails.

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F293068522725

73,
Kelly K5AID




Sent from my Verizon, Samsung Galaxy smartphone

Kelly Mabry
 

Hi Laurence, at the best case I can realistically squeeze about 50 bucks a month out of the budget starting June 2019.  That doent allow for much, I know. So for now I either must build or scrounge (I might can do area hamfests next year) (either Littlerock, AR or Memphis) thank God for my kia Soul! 

I was able to buy the ubitx due to the fact that mom wanted to hit the casinos in Mississippi,  just over the  state line. So I drove her, borrowed 20 bucks to keep from being bored and played slots...I hit for $205! Paid mom back, and ordered the ubitx the next day. As i had ordered the case from Sunil a few days before...and here I am...lol
Oh... yeah. $ 0.25/spin if you must know...Isle of Capri, Lula MS..hi hi.

73,

Kelly K5AID 

Curt
 

Kelly

I would slow down and consider what test equipment is needed for your work.  Signal generator?  I use signals on the air or noise from the atmosphere.  When I need a signal generator, I use a simple I transistor xtal oscillator that puts out 2 different rather low signal levels. 

A power meter?  A diode some resistors and a capacitor can do okay with a DVM. 

If you ever build your own VFOs then a frequency counter could be useful.  Even these can be inexpensive kits from qrpguys or others. 

Enjoy refining your ubitx and be patient OM. 

Curt

Tom, wb6b
 

Hi,

The price for the signal generator you linked, $54 is really good. I'm tempted to order one as a second signal generator (with two I don't have to worry about what leakage there might be between the channels). Even if imperfect compared to expensive signal generators they are sure handy and useful. I like the similar one I have. Just don't expect to calibrate your atomic clocks with it. 

I recently, by accident, drove the full 20 volt output into a short circuit and the signal generator seems to have survived with nary a puff of smoke emanating from the spaces around the buttons, while running a test to find the resonant frequency of a cheap piezoelectric transducer. Works well for many tasks at a very economical price. 

Here is a link to a discussion about these inexpensive signal generators. Check the comments before and after this message, too.

https://groups.io/g/BITX20/message/67908

Tom, wb6b

Kelly Mabry
 

Thank you Curt.
After a great week of listening. I came into the shack to practice  my cw sending on the dummy load. Im at 17 wpm comfortably reading in my head... I turned my ubitx on and no sound. Moved the pot. No sound.. except for a scatchy sound and low signals. So i plugged in head phones. Same. I replaced the pot. Same. Took the headphone out. Same result. The agc was working fine when i turned it off last session about five days ago. I verified the audio plugs to the main board were connected properly. I rechecked to see if the mod for the cw paddle had anything to do with it. No ground outs, shorts found.
Thinking that I will remove the AGC and restore the traces in my V5, and hope for the best. I do know that it was connected  to  my windom antenna, we did have light rain, but i have lightning arrestors on my antennas. Thanks for listening...
73, 
Kelly K5AID 

Robert D. Bowers
 

Kelly, I would suggest this as a pattern of equipment purchases:

1: a good DVM.  There are good ones which won't break your wallet - and you would want as good as you can find.  I've seen them with all sorts of abilities, such as a (rather low bandwidth) frequency counter, transistor tester, and cap meter.  I've heard some horror stories about Chinese products, but I've used some of their stuff and have had no problems with it.  I use a fancy Radio Shack meter which has been adequate, accurate, and precise enough - and rugged.

(Equally important to a good meter - a good soldering iron.)

2: Look for a used scope, minimum 30mhz bandwidth.  Unless you have a lot of experience with them, stick to a used (but working) analog scope.  I've seen some pretty good deals at hamfests... working condition, for under $100.  The more you know, the more useful it can be!

3: Somewhere near the top, antenna testing gear is a necessity.  If you have soldering experience, I would suggest "rolling your own".  I could point out some inexpensive pieces that can be combined together as a very effective tool.  The Handbook has some good stuff in it, the Experimental Methods in RF design book is much better.  (I combine ideas from that with arduino, and have some really useful circuits, like a wide bandwidth and very sensitive dBm meter that reports signal strength to software or spreadsheet - more than a thousand times a second.)

4: Something that receives across the bands - a general coverage receiver of some sort is (IMO) almost a necessity on a decent bench - something with at least moderate shielding and can receive WWV and so on.  Along these lines, if you work with VHF or UHF, a decent SDR dongle is cheap and can be used for all sorts of things - like checking the deviation (and spurs) on a 2m rig.  I paid less than $30 for mine (NESDR Smart)... and there are some which are better and that can go down well into the HF range (mine stops around 27mhz). 

THEN I would recommend a signal generator.  (It could be combined with #3 to do some impressive work.)  I built my own unit by combining a DDS kit with a good attenuator salvaged from a burned signal generator.  You combine them together in a single case, and shield and ground everything, you can keep leakage to a minimum and have something really useful.  For instance... have a impedance bridge with an unknown ferrite toroid on one leg (with a single loop of wire through it)... drive the thing with the signal generator (programmed, using a computer to step it through a frequency range), and watch the output with the digitizing dBm meter.  Presto - you can with a little reading and math, figure out the characteristics of the toroid!  (Especially if you have a couple of known-value caps you can throw in the circuit...)

With those, you can get really creative.

Bob

N4FBZ

On 5/12/19 8:12 PM, Kelly Mabry wrote:
Hi Laurence, at the best case I can realistically squeeze about 50 bucks a month out of the budget starting June 2019.  That doent allow for much, I know. So for now I either must build or scrounge (I might can do area hamfests next year) (either Littlerock, AR or Memphis) thank God for my kia Soul! 

I was able to buy the ubitx due to the fact that mom wanted to hit the casinos in Mississippi,  just over the  state line. So I drove her, borrowed 20 bucks to keep from being bored and played slots...I hit for $205! Paid mom back, and ordered the ubitx the next day. As i had ordered the case from Sunil a few days before...and here I am...lol
Oh... yeah. $ 0.25/spin if you must know...Isle of Capri, Lula MS..hi hi.

73,

Kelly K5AID 

Tom, wb6b
 

On Sun, May 12, 2019 at 08:38 PM, Robert D. Bowers wrote:
3: Somewhere near the top, antenna testing gear is a necessity.
The previous suggestions look like good suggestions.

On the antenna testing front, one low cost possibility is to use a noise generator with a cheap SDR dongle (that can do HF frequencies) and a directional coupler to let the antenna mismatch from 50 ohms display as increased signal on the SDR.

Here are a couple of examples. The advantage of this particular "Reflection Bridge" is you can choose the impedance you want to be the proper match. For 50 ohms, just put a 50 ohm resistor on the reference port.

https://www.ebay.com/itm/ORIGINAL-RF-SWR-Reflection-Bridge-0-1-3000-MHZ-Antenna-Analyzer-VHF-UHF-VSWR/292083525131

https://www.ebay.com/itm/2018-new-version-noise-source-Simple-spectrum-external-tracking-source/111392810099

Tom, wb6b

_Dave_ AD0B
 

Kelly
I am going off track but I think the reason that you are looking for test equipment is just as interesting as a discussion about it.

Have to ask. You did disconnect your antenna before the storm.

The other day had the antennas off before a storm rolled in The leads were sitting on a grounded plate. Later could hear a ticking so I went in the shack and the antenna lead was sending half inch long sparks to ground.

The sparks were not from lightning per say but voltages were well above what I would expect most hf receivers would handle. They were not the million ampere discharge.

I don't believe that any "lightning arrestor" is worth much. Just a step above deer whistles.
Lightning is going to do what it is going to do.

Richard Seguin
 

I have a signal generator like the one that you posted. It's working
well for me so far. I suggest building a 6dB attenuator and hooking
the sig gen to that when you want to measure RF signals though.

Richard (VE1X0R)

Curt
 

Kelly

first, best to unplug rig from antennas even when you have lightning arrrestors.  or be blessed by a switch that grounds antennas not in use. 

second, I am still thinking storm may not have taken out your ubitx.  yes try soldering something across that RF attenuator to effectively move it out of the circuit - let's hope it is this simple!  If this AGC is installed similar to the VK3YE - there are no ubitx connections changed - so I am doubting it is in the act.  I really think it may be something simple that has opened up. 

17 wpm - I would not fret your CW capability - this is nearly top end for straight key use.  plenty of QSOs can happen at that speed. 

73 Curt

iz oos
 

Hi, do you know the chip inside? AD9851 maybe? How many dbm is it rated?


Il 13/mag/2019 14:11, "Richard Seguin" <richard.seguin@...> ha scritto:
I have a signal generator like the one that you posted.  It's working
well for me so far.  I suggest building a 6dB attenuator and hooking
the sig gen to that when you want to measure RF signals though.

Richard (VE1X0R)



Kelly Mabry
 

Hi guys, thanks for all the recommendations and ideas. 
All of these ideas are not just food for thought, It is a meal worth savoring... thank you everyone. I am going to remove the AGC for now, restore the severed rf path and evaluate. 

73, and thank you everyone!
Kelly K5AID 

KM4TRT
 

I also have a cheap (50) signal generator(feeltech 3200s dual channel).0-30 MHz  It does most everything I want for HF and was able to trace the signal on several bit x's with my scope.  The only thing Is that dual channel does not output two different frequencies, so you can do dual tone.
I'm certainly no expert, but I bought a scope for $50 at a ham fest and found it somewhat difficult to use.
I bought a digital new (Hantek) for 200 and love it .  I can run dual traces and it goes to 200 MHz.  Actually tested with an arduino generator and it was over 200 MHz before the signal detererated.

Andy kKM4TRT

Kelly Mabry
 

And no I did not unplug the antenna. I usually do unplug as a habit, however this time i did not.
73,

Kelly K5AID 

iz oos
 

My HF antennas are DC short circuited but I always unplug them when not in use. You probably can add a bleed resistor across or eventually an inductor big enough and with a high inductance, but in any case unplug it, always.


Il 13/mag/2019 18:04, "Kelly Mabry" <kmabry2007@...> ha scritto:
And no I did not unplug the antenna. I usually do unplug as a habit, however this time i did not.
73,

Kelly K5AID 

Jerry Gaffke
 

It's very tough, to protect a radio installation from a direct lightning strike 
But it's well worth protecting your gear from high voltage electric fields.

Just the wind blowing on an antenna wire can build up a large static charge,
enough to blow out a radio front end.  
During an electrical storm, even though you may not get a direct hit to the antenna,
there will be high static charges floating around that can draw quite large sparks.

Here's an old thread describing some of the measures you can take.
    https://groups.io/g/BITX20/topic/18853788

Jerry, KE7ER


On Mon, May 13, 2019 at 05:02 AM, d balfour wrote:
I don't believe that any "lightning arrestor" is worth much. Just a step above deer whistles.
Lightning is going to do what it is going to do.

Kelly Mabry
 

Richard, thanks for reminding me abiut the attenuator. You sure thats enough? I was figuring 10dB. According to the Resistor tables for a Pi it seems easier. Just my own opinion...

73, 
Kelly K5AID