6al5's Anyone?

[Edward B Richards]

Dave;
Some thoughts:
1. In my 50 years of repairing radios I don't think I have found 3 bad
6AL5 tubes. They are a dual diode and very long life. I suggest you pass
this one by and should you ever need one you can get it for less than the
$10 you mention,
2, On the Collins antenna impedance, if you use a 4:1 balun you will have
a 75 ohm input which, using 75 ohm coax, is a perfect match for a dipole
antenna (theoretically, in free space).
Regards and Happy Y2K-1.  Ed Richards


On Thu, 7 Jan 1999 07:26:26 -0600 "James D. Mayfield"
<kb9bnr at REVEALED.NET> writes:
>I am not trying to get in to the tube business. I had a call yesterday
>from
>a guy I know and he offered me some 6al5's NOS mil spec tubes. I have
>to
>buy them in lots of 100. I would not mind having ten for myself but I
>don't
>need 100. If I could find 7 or 8 of you guys that would commit to
>buying 10
>each for $10.00 shipped to you, I will get these for us. Do I have any
>takers? I will buy more if the demand is there.
>
>By the way I got my first Collins, this week. It's a 75A1, and it's in
>very
>nice shape. The alignment was a bit out of wack, but a few minutes on
>the
>bench and it was working just fine.
>
>Also here is a good question for you Collins guys. The gent I bought
>it
>from told me that since it was designed for use with a 300 ohm
>antenna, it
>would be a little deaf it feed with 50 ohm coax. That is certainly the
>case. I found that if I feed the input signal directly to pin one of
>v1
>(6ak5) then the radio really comes to life! but this seems wrong to
>me. I
>was told and I agree that it should be feed thru a cap to pin one, but
>I
>have no idea what value. Looking at the handbook last night, I saw
>several
>circuits that used a 100 or up to 250 pf cap to the input. What do you
>think.....
>
>73 Dave
>
>*********************************************
>Dave Mayfield KB9BNR
>Personal Web Page
>http://home.revealed.net/qste/bnr/kb9bnr.html
>
>--- --- --- --- --- --- --- --- --- --- --- --- --- --
>To subscribe: listserv at listserv.tempe.gov
>and in body: subscribe HEATH yourfirstname yourlastname
>To unsubscribe:  listserv at listserv.tempe.gov
>and in body: signoff HEATH
>Archives for HEATH: http://www.tempe.gov/archives
>--- --- --- --- --- --- --- --- --- --- --- --- --- --
>

--- --- --- --- --- --- --- --- --- --- --- --- --- --
To subscribe: listserv at listserv.tempe.gov
and in body: subscribe HEATH yourfirstname yourlastname
To unsubscribe:  listserv at listserv.tempe.gov
and in body: signoff HEATH
Archives for HEATH: http://www.tempe.gov/archives
--- --- --- --- --- --- --- --- --- --- --- --- --- --