I want to build a matching network for a 53-foot vertical for 80/75 and 40. I should be able to cover 80/75 with three LC pairs and 40 with a single pair. So a set of fixed inductors and capacitors w
<I want to build a matching network for a 53-foot vertical for 80/75 and 40. I should be able to cover 80/75 with three LC pairs and 40 with a single pair. So a set of fixed inductors and capacitors
The design calls for capacitor values in the range 100pF to 300pF. Assuming an unloaded Q of 1000, TLW says at legal limit the capacitor will see worst-case peak voltage around 1500V and RMS current
Thanks Jim. The CDE 942 series starts at .01uF so not suitable. But I'll look at other PP dielectric types. -- Art Greenberg art@artg.tv _______________________________________________ ______________
I have a Jennings UCS-500. I'd rather use it for something else, but I agree its suitable. Coil inductances range from about 3uH to 6uH. Air wound is appropriate as dissipation in the coil will be ar
I match my top loaded 160m T with switched series capacitors and PCB relays. I run QRO (SSB QSO's with ZL's yesterday, - yea for conditions). My match covers most all the band in four steps, no induc
Russian vacuum and ceramic caps are often found on ebay. Made for combat conditions. N0UU _______________________________________________ _______________________________________________ TowerTalk mai
Yeah, you probably need pF. Tesla coilers need nF, so they string 10 of the 2kV 0.15 uF units together to get a 20kV 15nf unit. _______________________________________________ ______________________
Grant, A very interesting setup on that vertical! I'm extending an existing 43-foot vertical to get a marginally better and easier to feed antenna for 80/75 while still being suitable for 40m, which
Thanks for the pointer. -- Art Greenberg WA2LLN art@artg.tv _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting
Oops. Parallel. Series won't do it ... -- Art Greenberg WA2LLN art@artg.tv _______________________________________________ _______________________________________________ TowerTalk mailing list Tower
My solution (http://www.w7kf.com/Articles/Projects/LNetworkCoupler.html) was to use air variable capacitors, one for each circuit. Adjust them once and then consider them as fixed values. It seemed e
Nice work, Doug. Yep, it would be nice to be able to fine tune. I don't have air variables in my junk box. I'll see what I can find. Thanks! -- Art Greenberg WA2LLN art@artg.tv ______________________
<I match my top loaded 160m T with switched series capacitors and PCB relays. I run QRO (SSB QSO's with ZL's yesterday, - yea for conditions). My match covers most all the band in four steps, no indu
Alex UR4LL is where you'll find them; http://www.ur4ll.net/ 73, Maximo Russian vacuum and ceramic caps are often found on ebay. Made for combat conditions. N0UU ______________________________________
Best deal in HV high-current RF doorknob capacitors is the Russian surplus market. On ebay, search for "K15Y capacitor". They ship out of Eastern EU and arrive in about 10 days. Ive had really good l
If you top load a 43 ft vertical to make it resonant on 80 meters, it will be a voltage fed vertical on 40 meters. That means the impedance will be around 1000 ohms. Now you can put that vacuum varia
Interesting design problem. In addition to voltage breakdown, an important issue with capacitors for this application is ESR. The cheap stuff you found don't satisfy that. I did something like this o
Glad you rang in, Jim. I haven't looked at anything other than lumped LC at this point. I should look at the alternatives. I'd probably learn something. In the meantime, thanks to other responses I l