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R: Re: [BITX20] BITX40 Sensitivity
Giovanni Caracuta
sensitivity or not sensitivity.............. How many don't have see that? https://www.youtube.com/watch?v=q2v4Q69bs8g ?73 de Giovanni (i7iwn)
----Messaggio originale---- |
Re: - W8TEE board
Adrian, I use extra strong glasses and lots of light. On Tue, Jul 11, 2017, 9:38 AM Jack Purdum via Groups.Io <econjack=[email protected]> wrote:
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Re: Exposing Fake IRF510's, and a cheap antenna pole alternative
¿ªÔÆÌåÓýI looked too at the fishing poles. I would bet they are all of the same "crappyness". I doubt if any are much better than others?? Maybe all made by the same Manf? I may find the Jack pole you mentioned? Mike, WA6ISP On 7/11/2017 6:03 AM, Michael Davis
wrote:
Unfortunately the 7.2 meter is sold out. The next shorter one is 6.3 meters. There are others on eBay in the 7.2 meter length for $10-$12. Not sure of the quality though. I have the 31 foot Jackite pole. Pricey ($70) but nice. Sent from Mike's iPad WA1MAD -- Mike Hagen, WA6ISP 10917 Bryant Street Yucaipa, Ca. 92399 (909) 918-0058 PayPal ID "MotDog@..." Mike@... |
Re: BITX40 Sensitivity
¿ªÔÆÌåÓýIf you got real 50 Ohms, the Attenuator is usually 50 Ohms in dB (Power).? You can calculated it.? But you have to know what is coming out of the generator.? You can convert between power and uV with P = E squared/R(that is 50 ohms).? There are also nice charts you can search for, or make your own in Excel. Measure your output of the generator into the
Attenuator with X10 probe and highest freq scope you can get.? But a bigger signal ahead of the Attenuator are a lot easy to measure.? I use my attenuator all the time, maybe 80 dB cranked in? I can't recommend the K5BCQ more, it is cheap and works great.? You can make you own real easy.? 1W mox resistors from Mouser work fine. Make some 20 dB, 6 and 3 stages? Mike, WA6ISP On 7/11/2017 4:25 AM, C¨¦sar EA3IAV
wrote:
But... If I use an attenuator that is "analog"... How am I going to know the amount of microvolts that I am iinjecting into the BITX? -- Mike Hagen, WA6ISP 10917 Bryant Street Yucaipa, Ca. 92399 (909) 918-0058 PayPal ID "MotDog@..." Mike@... |
Re: Exposing Fake IRF510's, and a cheap antenna pole alternative
Michael Davis
Unfortunately the 7.2 meter is sold out. The next shorter one is 6.3 meters. There are others on eBay in the 7.2 meter length for $10-$12. Not sure of the quality though. I have the 31 foot Jackite pole. Pricey ($70) but nice.
Sent from Mike's iPad WA1MAD |
Re: Exposing Fake IRF510's, and a cheap antenna pole alternative
Jack Purdum
Ryan: Thanks for the post. Also, at the bottom of the antenna pole article is a link to BITX40: Is It A Good?Beginners HF?Radio. I also found it interesting as it shows what can be done with a little work and a $10 case from Banggood. It also mentions Peter Parker's ebook: Minimum QRP, which I have read. Most of us here are familiar with Peter's work and the book is definitely worth a read, especially for someone just getting started in QRP. Jack, W8TEE From: Ryan Flowers <geocrasher@...> To: [email protected] Sent: Tuesday, July 11, 2017 2:39 AM Subject: [BITX20] Exposing Fake IRF510's, and a cheap antenna pole alternative Hello all! I thought I'd share links to a couple of things I've posted lately that are relevant to the group. The first is about how easy it is to get cheap but fake IRF510's (and how to avoid them) ?and the second about how to get cheap (but real actual working) 23 foot (7.2m) telescopic poles for portable antennas etc. I hope you enjoy them :) 73! -- Ryan Flowers W7RLF ?
?<-- Learn how to go digital on the BITX40
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Re: - W8TEE board
Jack Purdum
Adrian: SMD's aren't as bad as you might think. Try this: On one leg of U2's PCB pad, place the thinnest touch of solder you can ("tinning" the pad). Using bent-tip tweezers (I bought one like this--ebay #131672888160), orient the SMD into place and touch the tinned lead with the iron while pressing down on U2. Don't actually try to hold it with the tweezer tips, just a downward pressure on the chip. (I've learned that trying to hold an SMD with tweezers causes they to reach terminal velocity, placing them in an undetectable orbit.) That should solder that leg enough to allow you to lightly solder the rest of the legs in place. You may need to touch up the first leg after the others are done. Jack, W8TEE From: Adrian <a.futrill@...> To: [email protected] Sent: Tuesday, July 11, 2017 2:41 AM Subject: Re: [BITX20] - W8TEE board I finally received all of the components for the assembly of the W8TEE VFO today. Question how on earth do you fit U2 on the board? My hands shake at the best of times.? Adrian VK4KL |
Re: Enclosures again...
chris gress
That looks very good you have done a first class job? On 11 Jul 2017 13:00, "Vince Vielhaber" <vev@...> wrote:
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Re: Enclosures again...
Vince Vielhaber
Do you remember what model that one is? 1120 perhaps?
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Thanks! Vince. It is perfectly possible. I have an mdt on a Peli Case and it is very --
Michigan VHF Corp. |
Re: Additional BPF's for other Bands
chris gress
Hi the links you posted are not working I would like to see one for 60m and 80 I am sorted for lpf for 80m / 60m? On 11 Jul 2017 12:41, "KF5GLB John" <KF5GLB@...> wrote:
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Re: BITX40 Sensitivity
Vince Vielhaber
Use a step or a bunch of fixed attenuators. 2mv is -41dbm. Raj and I
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were still hearing our generators at -130 (which is 0.07uv). See if you can find 3 30db fixed attenuators and you'll be good. Then for the measurement, use a chart (or do the math). Here's a chart that covers 0dbm to -140dbm in 1db steps. Vince. But... If I use an attenuator that is "analog"... How am I going to know --
Michigan VHF Corp. |
Re: Additional BPF's for other Bands
¿ªÔÆÌåÓýThank you for the info. Keep up the good work? I'll build one for mine 73 John Sent from my iPhone On Feb 4, 2017, at 7:40 PM, Ken <chase8043@...> wrote:
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Re: BITX40 Sensitivity
Vince Vielhaber
That one is still going to require attenuation. The lowest it puts out is
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2mv and you're going to need .1uv or less for sensitivity measurements. Vince. Really cool one! I have just ordered the 30mhz vesion. --
Michigan VHF Corp. |
Re: Exposing Fake IRF510's, and a cheap antenna pole alternative
chris gress
I hope mine are not fakes I have had the parts over 2 years? On 11 Jul 2017 08:37, "Mvs Sarma" <mvssarma@...> wrote:
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Re: Exposing Fake IRF510's, and a cheap antenna pole alternative
Ryan, ?IRF510 like? devices as we get from International rectifiers are fine.On Tue, Jul 11, 2017 at 12:09 PM, Ryan Flowers <geocrasher@...> wrote: Hello all! --
Regards
Sarma ? |
Exposing Fake IRF510's, and a cheap antenna pole alternative
Hello all!
I thought I'd share links to a couple of things I've posted lately that are relevant to the group. The first is about how easy it is to get cheap but fake IRF510's (and how to avoid them) ?and the second about how to get cheap (but real actual working) 23 foot (7.2m) telescopic poles for portable antennas etc. I hope you enjoy them :) 73! -- Ryan Flowers W7RLF ? ?<-- Learn how to go digital on the BITX40 |