RF Burns

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@Timothy_Osman 8 сағат бұрын

I don't know why antique electronics isnt a thing if that shop existed I'd be shopping

@rfburns3472 3 сағат бұрын

Lots of antique stuff on eBay my friend.

@Timothy_Osman 3 сағат бұрын

Sure I pick up alot of cheap factory rejects there that have been educational. But thanks I never thought to search it there!

@Timothy_Osman 3 сағат бұрын

The one that really blows my mind looking at is the original voltaic pile. Like just the sheer enormity of innovation that came from there it's surreal just looking at it 😂

@javiermac381 10 сағат бұрын

Can I download your cheat sheet?

@cha1rtech 20 сағат бұрын

I remember reading somewhere that a quartz crystal oscillator's output frequency would vary in the low single digit parts per billion depending on the orientation of the crystal, would like to see that demonstrated if possible

@rfburns3472 4 сағат бұрын

Here you go! kzbin.info/www/bejne/sHqvqJqHnc92lbM

@steveb3885 22 сағат бұрын

those vna sweeps are useless, the nanovna only has 110 points across the range. you would miss so many resonant spikes trying to scan that wide of a frequency IF you lose the heatpipe heatsink, it will cool better. heatpipes are not capable of moving that much heat.

@rfburns3472 22 сағат бұрын

Your absolutely correct Steve about the 110 data points across such a wine band of frequencies. Although not shown in the video, I have done narrow band scans and found no issues with "spikes" at all. Good comment. Also, not much I can say about the heat pipes as I have never removed them to see if cooling is better.

@steveb3885 21 сағат бұрын

@rfburns3472 it won't change. Heat pipes rely in vapor state change to move heat, which the do well, just not at that wattage if heat. A cooper cored solid sink would move more heat at a faster rate. I use a copper cored with a 250w resistor, and 200w cw, never exceeds 120F with a 80mm fan. HS is from an early 2000s Dell desktop (they used huge sinks in their older towers)

@curtchase3730 23 сағат бұрын

Ahh, Is that battery one of those real 9v output types, or the traditional 7.2v types? Many of those Lithium batteries have a smps in them that could generate EMI. Take a AM transistor radio and hold it's antenna up to the battery with your amp off. Tune the dial and listen for noise/squealing sounds. Anyway, that little board is wild. Amazing the bandwidth! Crazy. I see the switch there will do a proper bypass of the signal when amp is off, otherwise I'd expect a super weak signal, if any, leaking though the circuit when it is off. Nice.

@rfburns3472 22 сағат бұрын

Great observation Curt! The battery puts out a solid 9.1 volts and shuts down immediately when exhausted. I like that. The amp doesn't lose gain when the battery loses its supply capacity. I have heard others say they can cause EMI, especially the musical instrument folks. Is it possible their is some kind of chemical action going on in these lithium ion batteries? I will try the transistor radio test you suggested.

@cheesedoodlefeeder Күн бұрын

I use a similar LNA for a loop on the ground antenna (kk5jy design) and the LNA makes a hugh improvement. Note that the LOG antenna has a very low noise floor.

@rfburns3472 22 сағат бұрын

I appreciate your comment!

@Stewart-HA5RV Күн бұрын

This looks perfect for a Loop on the ground receive antenna!

@rfburns3472 22 сағат бұрын

Yes, and perhaps worth the the effort to try. 73's

@bdg77 Күн бұрын

Very useful little gadget!

@rfburns3472 Күн бұрын

Yes indeed!

@TomSherwood-z5l Күн бұрын

I got a small HP counter but it came without the higher tolerance osc. option. Although the internal one is adjustable and pretty good. I bought an old oven osc. on ebay out of some HP microwave instrument. Had to assemble it as a unit with a power supply and indicators and a buffer in the output in a chassis but now I have a better reference for the counter and my sig. generator that also lacks the high stab. option. I calibrate it from time to time with a Rubidium standard that was made for for portable cellular system use.

@rfburns3472 Күн бұрын

Very cool Tom! My next standard is going to be Rubidium.

@sirmister4411 Күн бұрын

Nice for a deaf old man like myself

@rfburns3472 Күн бұрын

It’s a nice little device.

@John151283 Күн бұрын

Thanks for the Information., Interesting ✌️👍👍👍

@rfburns3472 Күн бұрын

Your welcome John!

@pyrlik6968 Күн бұрын

Obwohl mein Englisch schlecht ist, sehr interessant, Daumen hoch 👍

@rfburns3472 Күн бұрын

Glad you liked the video!

@jertres2887 Күн бұрын

If you put it between a band pass filter and the receiver it might help more with the signal to noise, if… it’s a single band receiver.

@rfburns3472 Күн бұрын

Good comment…I agree.

@Subgunman Күн бұрын

A source for this board assembly?

@rfburns3472 Күн бұрын

www.aliexpress.us/item/3256803352141378.html?spm=a2g0o.order_list.order_list_main.79.6d4a1802DstVqb&gatewayAdapt=glo2usa

@Subgunman 6 сағат бұрын

@@rfburns3472thanks!

@KF0NNQ Күн бұрын

Thank you. You kept your build at a good mix between NASA engineer and novice techie. Hmm, will this video convince my XYL that I need an oscilloscope? Probably not. Have a Merry Christmas and 73, Bill.

@rfburns3472 Күн бұрын

Thanks Bill and 73's

@countryside8122 2 күн бұрын

Is WWV still at 2.5,10,15,20 and 25MHZ??

@rfburns3472 2 күн бұрын

"The station radiates 10 000 W on 5 MHz, 10 MHz, and 15 MHz; and 2500 W on 2.5 MHz and 20 MHz." - NIST

@Tobys-Dad Күн бұрын

And 25 mhz as well.

@G6MDX-Dai Күн бұрын

⁠@@Tobys-DadNot 25 MHz. It’s easy to check on the WWV/NIST website.

@johnwest7993 2 күн бұрын

Thank you. I'm watching videos like your to get ideas for my ow project. I have a consumer grade freq counter, a small, light, bench counter that looks very much like yours. I did add a jack for a nominal 12 volts to make it more portable, and I figure on adding 1 of the several $3 crystal oven pulls I got from eBay or some Chinese website. I just need to put it on a small bd to put in the counter box, add some good supply regulation, calibrate it against my GPS freq reference, and it should make the cheap old counter worthy of having among the higher end gear. Those inexpensive, (dirt cheap,) Xtal ovens can really upgrade a lot of cheap gear to almost lab grade for hobbyists, from my freq counters, to sig gens and function gens, to my old tube and early transistor ham gear they are practically a miracle upgrade for my or any hobbyist's electronics bench. I bought 16 of them at just under than $3 each, with 1 defective one. The rest will slowly go into my bench gear and experiments as the winter snows dictate. Again, thanks for the video.

@rfburns3472 2 күн бұрын

Glad your getting some use out of these inexpensive XO's John. Sounds like your having fun with it all. I am just begining to use them. For this project, I really wanted to find a 1 MHz OCXO. I could not find them anywhere for less than $100. Ouch!

@gordselectronicshobby3853 2 күн бұрын

It amplifies noise as well.

@rfburns3472 2 күн бұрын

Correct....About 3.1 dB. On my radio it added 1 S-Unit of noise.

@willthecat3861 Күн бұрын

@@rfburns3472 Not sure how you are getting that? What is the noise figure?

@alainblazit9504 Күн бұрын

It amplifies the noise from the antenna, but not the one of the input stage of the receiver.

@barrymayson2492 Күн бұрын

The noise figures are in the specs for the RF device used . They use different devices on these boards so hard to define. The way I use one is with an attenuation and I can tune it for the least amount I need but can hear the signal and use the signal enhancement etc to get a good clean signal. I just had a thought are you asking about noise generated in the device ? Or the amplified band noise?

@HughTVDX Күн бұрын

Is the led adding noise? For a quick check just disconnect it.. If it is just put a small value cap across it. Are those wires going to the switch from the in/out connections causing stray noise? The preamp may be oscillating way up around 1GHz with the wires like that and the gain involved, just a thought.

@Cassius609 2 күн бұрын

That tube radio is huge! A proper boat anchor.

@rfburns3472 2 күн бұрын

Yes indeed! My first ham radio receiver my father gave me 60 years ago.

@KF0NNQ 2 күн бұрын

Dang cheap and awesome gain. I appreciate how you tested and explained each step. It runs off a 9V rechargeable? Incredible. I need one of these rigs. Thanks and 73, Bill.

@rfburns3472 2 күн бұрын

Well, it surprised me Bill! The lithium-ion battery is best since it will hold out at 9 volts till it’s time for a recharge. This is better than a 9-volt alkaline battery that losses voltage with time which makes the gain of the amp go down slowly. Also, if I use 12 volts, I get about one more S-unit out of it!

@cthoadmin7458 14 күн бұрын

Excellent, subscribed immediately. Excellent content sir! 73 de vk4qp

@rfburns3472 14 күн бұрын

Thank you kindly and welcome to my channel! More to come! 73's

@tomleddy7620 15 күн бұрын

Mines good to go! Thanks for the info.

@rfburns3472 14 күн бұрын

Your welcome Tom!

@tomleddy7620 15 күн бұрын

Great video. I just got a Nanovna H4 and I’m learning. Or trying at least.

@rfburns3472 14 күн бұрын

For less than $70 theres a lot to learn about this little gem! Thanks for watching.

@davestelling 24 күн бұрын

P.S. What a cool radio, your military surplus! Now, this loop external antenna is only for the AM band? It wouldn't do any good for the shortwave, or FM reception? "Radio" itself is still magical to me, I sure get alot of enjoyment just fiddling with my new little Tecsun... it's the PL - 330...take care...

@rfburns3472 20 күн бұрын

The loop antenna is only capable of tuning roughly 500 to 1700 KHz which is the AM broadcast band. So it would not help with SW or FM reception.

@davestelling 24 күн бұрын

Evening... A friend recently sent me the Tecsun PL-330 radio, and one of these reel-up wire external antennas. I haven't been able to get a thing on the shortwave and not too much on the AM, or "Medium" band. Wondering if this external antenna might be worth the investment for me? (It's $31.00 on the Amazon. A decent amount for me, right now.) This little radio brings back some really good memories of when I was a kid scanning around the AM band during the night when I was supposed to be asleep! Appreciate your making this video, thanks...

@rfburns3472 20 күн бұрын

Hello Dave and thanks for tuning in to my channel. Your lack of resonable recpetion from the Tecsun seems a bit odd especially with AM standard boardcast stations. The loop antenna may help unless you are hurdreds of miles away from some stations. Also, shortwave reception can vary quite a bit form daytime to nighttime hours.

@chasingskywaves-Hz Ай бұрын

Would oil immersion take more heat away?

@rfburns3472 Ай бұрын

Take more heat away from this design? I would think it would.

@komputatek Ай бұрын

What cable / test lead are you using for shorting the Nano-vna? I made one with RG58 but I get 90d full inductance. I even shorted one of the pig tails that came with my Nano but it too goes full inductance

@rfburns3472 Ай бұрын

The cable/test leads are the ones in the video. Sorry, but I am not clear on how you explained your test setup.

@mandytuning Ай бұрын

Humm,you give me an idea,Im gonna try this with my picoscope and ignition coil pick up sensor.

@rfburns3472 Ай бұрын

Good to hear that! Hope it works out for you.

@MuzzleMike Ай бұрын

Thank you ! I will check my diy 49-1 and gives my nanoVNA some other uses .

@rfburns3472 Ай бұрын

Please do that Mike and let us know what you find out! 73's

@WECB640 2 ай бұрын

I'm wondering if the internal pot has its 3rd leg open from ground. That would then present whatever ohmic resistance the pot is rated for in series, but not allow for any shunt of the signal. Looks like either a design flaw or a quality control issue IMO. 73 OM

@rfburns3472 2 ай бұрын

I agree if the common leg is open. I am guessing its by design. The manual has a contact for tech support. I just may give them a call and report back. Thanks for the comment!

@WECB640 2 ай бұрын

@@rfburns3472 Did you open the box and confirm with a VOM?

@Terrar-fr1bk 2 ай бұрын

Why did you cut the legs on one of the SMA connectors? Wouldn't you then change the characteristic impedance of the connector, since they are designed for 50 Ohm? In this line of thought, isn't it better to just put the pins of the two SMA connectors against each other and solder where they touch? On the other hand, the legs don't provide sufficient shielding as the brass jacket and the dielectric do, therefore keeping the legs short might be better. What do you think?

@rfburns3472 2 ай бұрын

You have a very good question. Look at the video starting at 4:00. Here you can see the device impedance is flat from 1 MHz to 30 Mhz. It's 49 Ohms and with basically no significant reactance indicated on the VNA. So, shortening the length of the connectors does not affect the test results in any negative way. What does improve shortening the distance is a better response from 30 MHz to 650 Mhz. After 650 MHz the return loss goes off the rails as shown below. The terminator is good to 650 Mhz. These measurements were the worst case at 650 Mhz. Return Loss: -20.6 dB SWR: 1.206 Z = 44.6 ohms -j7.1 S21 Insertion Loss: -3.93 dB

@joes6718 2 ай бұрын

What type of clamp on ferrite core did you use for the sensors? Informative video THANKS

@rfburns3472 2 ай бұрын

Hi Joe. Got them from DigiKey. www.digikey.com/en/products/detail/fair-rite-products-corp/0444164181/8594097?_gl=1*lkn6ue*_up*MQ..&gclid=EAIaIQobChMI2feL75D_iAMVMjYIBR0fsAFTEAAYAiAAEgJvxPD_BwE

@joes6718 2 ай бұрын

@@rfburns3472 Thanks for your novel approach with this project and expedient response. Joe

@rfburns3472 2 ай бұрын

@@joes6718 Your welcome Joe. I am working on a tester with a amplifier for folks who have very low common mode currents.

@patrickwall8517 2 ай бұрын

Yes, loop antennas do tend to be less noisy than wire antennas.

@rfburns3472 2 ай бұрын

Agreed

@patrickwall8517 2 ай бұрын

That antenna works pretty well. I like the name you chose for your channel.

@rfburns3472 2 ай бұрын

Thanks Patrick! I been burned plently of times by RF.

@ke4tmt91 3 ай бұрын

Anyone try using a multimeter to skip construction of the meter circuit and box?

@vetinger 3 ай бұрын

How if needed to be adjust? Thanks!!!

@peteleoni9665 3 ай бұрын

Where can I find that surplus aviation radio? Thanks.

@rfburns3472 3 ай бұрын

I purchased mine on eBay. The AM broadcast band radios are a bit rare, but they come up every now and then for auction.

@MobiusHorizons 3 ай бұрын

Is there some way that you could power the fan from the incoming RF energy? it seems like that would be very cool.

@rfburns3472 3 ай бұрын

That's a very good question. The problem is connecting anything to the resistor termination leads would cause a massive disturbance in the desired impedance. You might have a better chance using a thermoelectric system to transfer heat into electricity. The fan I used with a 9.1 volt battery draws .240 amps. That's 2.2 watts of power.

@andrewbarnett84 3 ай бұрын

Interesting battery.

@rfburns3472 3 ай бұрын

Agreed. They are new to me so I need some time to prove their reliability.

@KF0NNQ 3 ай бұрын

Never considered building my own attenuators. Another worthwhile project. Oh for the time and money, not to mention soldering skills. Thanks and 73, KF0NNQ.

@rfburns3472 3 ай бұрын

Your welomce Bill and thanks for your comment.

@pietleroux5169 3 ай бұрын

Thanks! this is great practical way of testing them!

@rfburns3472 3 ай бұрын

Glad you liked the tester! Stay tuned to the channel as I will be adding an RF amplifier to increase the sensitivity for use with low power transmitters.

@JDS11ify 3 ай бұрын

Just found your channel. Great presentation. Question: I only have 1 watt resistors to make 450 ohms. Will they handle any power? I presume they will but am still curious.

@rfburns3472 3 ай бұрын

Welcome to the channel! As demonstrated in the video, the two resistors can be whatever wattage you have on hand as long as they are noninductive. But, let's say instead of using the NanoVNA as the source, and you use your transmitter, you may easily burn up those resistors that only have a 1 watt rating. This would depend on how much power you apply to the UNUN's 50 ohm connection point.

@Arnold7221 3 ай бұрын

Impressive good going would love to see the diagram

@rfburns3472 3 ай бұрын

Thank you kindly Arnold! The best way to get the diagram would be to contact Charles Smith, KV4JT. His email is good in ORZ.com. Charles says, "I have manuals...... The cost is minimal. If you want a manual please contact me at my email address and I will arrange to send you one. I only mail manuals. I do not post them anywhere else.

@petercharleslaurent 4 ай бұрын

Only for test ... then if you wana test its at your own risk

@deanberglund2332 4 ай бұрын

I played your previous 2 videos on Zoom to some ham radio club members and one of the guys commented on exactly what you are referring to on the shield part of the dummy load. He suggested wiring it straight up from the heat sink to the SO-239, which I then did when I built mine. I haven't tested it yet on a NanoVNA but there should be an improvement because it doesn't have to travel through the stand offs. I think I'll be happy with my build. I also won't be using it for higher power than maybe 50 watts on UHF either. I am thinking of suggesting this dummy load build for a future Build a Thon project.

@rfburns3472 3 ай бұрын

Hi Dean. Let me know how your tests work out. I extended the 4 screws on the SO-239 to make a pressure fit on the flange resistors just below. I was somewhat disapointed to find thre was no improvment noted on the NanoVNA. It's possible the copper clad bridge connecting the 4 spacers to the heat sink was still having an affect on the measurement's even with a more direct connection. 73's

@andrewbarnett84 4 ай бұрын

Very good exactly what I had in mind. I have an Anaren 450 Watt 50 Ohm termination like yours. Just looking for suitable heatsinks now. 73 Andrew ZL2ALW

@rfburns3472 3 ай бұрын

Thank you Andrew! Take a look at some of the CPU coolers that could be used for a heat sink. Just be careful when mounting the flange resistor to not drill into the "heat pipes" that run through the sink's mounting plate. I like this one for dissipating lots of heat. Might be overkill however. www.amazon.com/Thermalright-Peerless-SE-Aluminium-Technology/dp/B09LGY38L4?source=ps-sl-shoppingads-lpcontext&ref_=fplfs&smid=A1BCKG4OE2CKC4&th=1 The problem with this one is you cannot drill into the plate due to the 6 heat pipes running through it. Some other means of pressure mounting must be used. Let me know how your project works out. 73's

@rfburns3472 4 ай бұрын

Sorry folks for the abrupt ending. I set the camera down and must have hit the stop recording button!

@rfburns3472 4 ай бұрын

Hello All, I am working on upgrading the tester with an active RF amplifier for those who run low transmitter power. Please subscribe and you will be notified when this occurs. 73's!

@clems6989 4 ай бұрын

Very good catch !!

@rfburns3472 4 ай бұрын

Thank you Clems. Wish I would have figured that one out before I did the video! Live and learn. LOL

@rfburns3472 4 ай бұрын

Hi friends. This design proved to have poor results above 60 Mhz. So, I redesigned it for excellent performance from 1 Mhz to 650 Mhz. Worst case SWR is at 1.4 GHz 1.4:1 Please see video Part 3 soon to be released this weekend. Thanks for watching!

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