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Re: Ultra Battery
¿ªÔÆÌåÓýYeah, that's the same cell that Batteryhookup.com is selling for $0.99 each (like I said, the shipping is the killer, you can order more to stay within the shipping limits and you'd still be CHEAPER than that one on ebayism.) Mike C. On 2/28/2023 7:44 PM, Dewey wrote:
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Re: Ultra Battery
¿ªÔÆÌåÓýThe yellow wire can just be clipped,i.e. not used. 2nd thing is unsolder the the existing wires and use the plug from the 3000mahr cell and use it on the 4500mahr cell, simple, yes. Mike C. On 2/28/2023 10:26 PM, Clyde Lambert
wrote:
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Re: Ultra Battery
Look very close. There are 3 leads on the battery. Red, Black and in between, yellow. It is not the same as the one in the TinySA which is a two wire connector. Clyde KC7BJE? On Tue, Feb 28, 2023, 6:30 PM Mike C. <mg@...> wrote:
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Re: Ultra Battery
¿ªÔÆÌåÓýNope, here's the link:? Look carefully at the picture, it's there. They did give the dimensions but in English units. Mike C. Sand Mtn GA On 2/28/2023 6:18 PM, David Massey
wrote:
"755275" didn't yield any result in a search on their website.? Typo? |
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I haven't done the math on the dissipation of each resistor in the qrpkits attenuators, but I think John Gord is probably correct that they won't do 5 watts continuously, unless you pick which end is driven and which stages are engaged.? Note that a lot of the high power attenuators (even fixed attenuators) like the ones I suggested above and included a link to on ebay, and the much more expensive ones that the cheaper ebay attenuators look like are the same: one end will take high power, and one end absolutely will not.? One of the high power attenuators I bought on ebay was labeled as to which end was the high power end.? I assumed the other one was the same, and so far I haven't burned it up.? For critical applications, I would avoid the pushbutton attenuators like those Evan linked to.?? Note that the 30 dB attenuator can have as much as 3.5 dB insertion loss besides the selected attenuation, and I went to the website for the BECEN 60 dB attenuator, it can have as much as 3 dB insertion loss.? I would also be concerned with the life of the pushbutton switches.? Pushbutton and toggle switch attenuators certainly are convenient, though.? The MiniCircuits stuff Dave recommended is indeed more expensive than the stuff you buy on ebay, but it's top notch and less expensive than the other "high end" brands.? I recently needed a coaxial DC block to protect a spectrum analyzer that will tolerate zero DC at the input and the MiniCircuits unit I bought, while sold as an 18 GHz model, has been swept to 26.5 GHz, and it's fine all the way up and again, cheaper than the other "high end" brands.? I will absolutely agree with Evan's recommendation for fully shielded attenuators, in fact, just in general RF equipment should be well shielded.? I recently was called upon to find a transmitter with a stuck mic, and several hams that came to observe noted that the signal was full scale on their radios even with the antenna disconnected, and this problem is often seen during hidden transmitter "bunny hunts."? It doesn't matter how directional your antenna is or how much attenuation you have inline if the signal can leak directly into your radio, or past your attenuators.
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Ultra Battery
¿ªÔÆÌåÓýJust a heads up, but if you need a battery for
your ULTRA. Batteryhookup.com (no, I'm not affiliated) has a
4.5Ahr cell for $0.99 ea. Size is 755275 and yes it fits like a
glove. That'll give you 50% more power than the 3Ahr presently
installed. Buying the cell singularly will cost the same as 20,
so buy many. That's about the min to stay within the shipping
minimum w/UPS. Yes, they are new cells. I've bought many with no
problems. It'll work out to $1.61/cell (shipping included) Mike C. Sand Mtn GA |
Mike C.
Clyde Lambert
Larry McElhiney
Jim Allyn - N7JA
David Massey