Air Variable Tuning Capacitors
I am planning to build the No Excuses QRP transceiver and am not sure where to locate the correct air variable capacitors for tuning. As a complete novice (except for a couple of smaller projects) I am not sure if any tuning capacitor is appropriate. Ocean State Electronics had the parts that I needed, but because of service related issues with the company (or rather a complete lack of service) I need to find a different supplier. I need two capacitors - 4-50 pF(OSE part number AVC50), and 6- 150 pF (AVC150). I am giving the OSE part numbers to give you a clearer idea of what I want. (BTW, I need the second capacitor for a different project).
I did check several companies fromm ARRL site but was still not sure if the few I found were suitable.
What a shame - I had ordered everything for the radio through OSE to the tune of over $150.00 and they completely blew me off. I thought I had the perfect project because all of the part numbers were right there and I didn't have to question whether the parts I was purchasing were the correct parts.
Originally Posted by KD0DQL
A good source for air variable caps (which I'm sure you discovered are becoming quite rare) is Midnight Science. www.midnightscience.com
"The more you know, the less you don't know."
A trip to the local "junque" store netted two "all american 5" am radios for $5. The lady even cautioned me "You know, it says on the tag that they don't work".
The air variables, tubes, sockets, (audio) transformers are a goldmine of parts. If only I could find a really old TV, unfortunately, those were sent to the dump decades ago, the newer ones aren't worth parting out.
What cap values do you need? If not too high, I may have some.
TOM K8ERV Montrose Colo
RF Parts has a good selection.
They're not cheap, since many are not being made anymore. They're a very labor-intensive device. I know -- I used to work for Hammarlund.
Your best bet will be at hamfests. You'll often find boxes of used ones at reasonable prices. Hint: the real treasures are often found in those ratty old boxes under the tables.
"Where the people fear the government you have tyranny. Where the government fears the people you have liberty."
John Basil Barnhill
"To learn who rules over you, simply find out who you are not allowed to criticize."
I just bought several of these, and I am very happy with the construction and the price was $9 each.
Try Dans Small Parts and Kits, or heck, call Fair Radio, they usually have stuff not even in the catalog... Get to the hamfests!
Cap Ranges needed
[QUOTE][What cap values do you need? If not too high, I may have some.
TOM K8ERV Montrose Colo ]
For the no excuses radio, they recommend 5-50 pF. The other project recommends 6-150 but it can go to 200 pF. They need shafts for the knobs. The 5-50 pF capacitor for which the OSE catalog was given in the article for the No Excuses radio has the following description (being new I don't know whats important or not so I'll give you everything) - single hole panel mount with Grade L4 ceramic. End shaft is insulated. Shaft is 1/4" dia X 1/2" long. Air gaps on plates are 0.16" and rated to 640 V.
I don't have any with insulated shafts, and the air gaps are much smaller, sorry.
TOM K8ERV Montrose Colo
Air variable tuning capacitors
One of the biggest mistakes a newbie makes is to trying to duplicate needed parts EXACTLY. For good info on building small transmitters and receivers....get a copy of Lindsay Publishing Company catalog (on line). He has books very resonable. Much good info on homebrewing and parts selection. Simple (and yes, he is a Ham.) 73 Joe W4CBJ