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#1
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My old Cushcraft A3 is more than likely due for a take down and
refurbish. Ive not really touched it in a long time and have never opened the traps. 15m is suffering so I may have a bad trap. So, I did a net search and not too many have posted how its done. SOOOO, with that I come hat in hand for hints/tips etc from those that have went there. Scotty N7HJ |
#2
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"Rick Scott" wrote in message
ps.com... My old Cushcraft A3 is more than likely due for a take down and refurbish. Ive not really touched it in a long time and have never opened the traps. 15m is suffering so I may have a bad trap. So, I did a net search and not too many have posted how its done. SOOOO, with that I come hat in hand for hints/tips etc from those that have went there. Scotty N7HJ Scotty - The first step I would take is get replacement stainless steel hardware - IF this was version before that usage. These web pages may be helpful http://www.iol.ie/~bravo/Troubleshooting%20Traps.htm If you try to disassemble the driven element traps on the Cushcraft A3 - the proper way to remove the trap covers is to slip the black trap caps off. If the traps have been up in the weather for a while, it may be difficult to remove them without breaking them. You can order replacement caps from Cushcraft. they were around $1.30 apiece in 2001. There are 24 caps on an A3S. When your A3 was new, the traps had a paper sticker indicating which was which. Why the traps weren't engraved or marked with a permanent sticker is a mystery that only CC can answer. Taking them apart though is not one of them though! Inside - the traps look the same. 1) Attach them using very short leads to a HP network analyzer and punch up the Smith chart. Start around 18 Mhz , and crank the frequency up until the readout on the display switches from inductance to capacitance. Note that frequency. You will find 2 whose frequency is about 150Kz higher than the other 4. 2) Use a grid dip meter placed end to end on a non-conductive table to determine which 2 resonate higher that the other 4. The network analyzer is a better approach. Cushcraft directions (via email on towertalk / contesting.com) for trap disassembly: The traps of the A3 and A3S can only be separated one way. First of all, the 10 meter traps are the same and you can use them in any position. Be sure the end with the contact screw for the body to element junction is nearest the boom. The 15 meter traps can be identified by the fact that they are "swagged" to a smaller tubing size on the outboard side. There are 2 different types of 15 meter traps. 4 of the traps are used in the reflector and driver elements. There are two 15 meter traps that are used in the director and they have a higher frequency of resonance. That is the only way to tell the difference. Check the traps with a dip meter and that should tell you which are which." Cushcraft used to perform this service often for a nominal fee, but it looks like that level of support has stopped. |
#3
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gb wrote:
Outstanding information. Exactly what I needed. Thanks a ton Scotty N7HJ |
#4
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I dunno for sure but, this might work ...
has anyone out there tried putting traps into a food dehydrator for a few days to dry out ? then of course, you would seal it up with something like scotchkote or urethane. "Rick Scott" wrote in message ps.com... My old Cushcraft A3 is more than likely due for a take down and refurbish. Ive not really touched it in a long time and have never opened the traps. 15m is suffering so I may have a bad trap. So, I did a net search and not too many have posted how its done. SOOOO, with that I come hat in hand for hints/tips etc from those that have went there. Scotty N7HJ |
#5
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Hal Rosser wrote:
I dunno for sure but, this might work ... has anyone out there tried putting traps into a food dehydrator for a few days to dry out ? Nitrogen flushing always worked for me, at least for awhile. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
#6
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![]() "Cecil Moore" wrote in message ... Hal Rosser wrote: I dunno for sure but, this might work ... has anyone out there tried putting traps into a food dehydrator for a few days to dry out ? Nitrogen flushing always worked for me, at least for awhile. -- 73, Cecil http://www.qsl.net/w5dxp I guess the word is "Kool!" our Wal-Mart ran out of nitrogen toilets, so nitrogen flushing may be a second alternative. |
#7
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Rick Scott wrote:
My old Cushcraft A3 is more than likely due for a take down and refurbish. Ive not really touched it in a long time and have never opened the traps. 15m is suffering so I may have a bad trap. So, I did a net search and not too many have posted how its done. SOOOO, with that I come hat in hand for hints/tips etc from those that have went there. Scotty N7HJ And one other easy thing that definately helps on VHF/UHF, is cleaning the aluminum elements. I use scotchbrite pads with aluminum cleaner. As I remember Brasso maight be a substitute. Someone correct me if I'm wrong there. If the cleaners aren't available, just the pads plus light detergent followed by a good rinse will do a lot to clean up the skin of the element. Tom K0TAR |
#8
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Tom Ring wrote:
Rick Scott wrote: My old Cushcraft A3 is more than likely due for a take down and refurbish. Ive not really touched it in a long time and have never opened the traps. 15m is suffering so I may have a bad trap. So, I did a net search and not too many have posted how its done. SOOOO, with that I come hat in hand for hints/tips etc from those that have went there. Scotty N7HJ And one other easy thing that definately helps on VHF/UHF, is cleaning the aluminum elements. I use scotchbrite pads with aluminum cleaner. As I remember Brasso maight be a substitute. Someone correct me if I'm wrong there. If the cleaners aren't available, just the pads plus light detergent followed by a good rinse will do a lot to clean up the skin of the element. Tom K0TAR What do you do to protect them afterwords ? Scotty N7HJ |
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