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HIGH SWR / HIGH REFLECTED POWER SHUT DOWN CIRCUIT !!
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pentalab
--- In ham_amplifiers@..., "Peter Voelpel" <df3kv@...>
wrote: full drive. They should have no problem when the antenna gets lost...### Peter, et all ### I had an engineer buddy of mine cook up a high reflected power shut down circuit for me. My buddy got a hold of a ton of Bird single line sections. He joined two of em together with some brass rod and soldered the outside flanges... to fabricate a "double line section". ### He made two such assemblies. We installed one on the input of the amp... and the 2nd one on the output. [4 x slugs installed] ### Since the big amp is remoted 30' away from the shack..... we had to be able to read all 4 x line sections in BOTH locations. My engineer buddy designed a peak reading board that would work with all 4 x line sections.... and continuously monitor the PEP reflected power from the ant [line section # 4 ] ### Only one bird 30 ua meter is used in each location.... and either end can be switched independently to any of the 4 x line sections. He used line drivers at the amp end.. to drive the box in the shack. ### The high PEP reflected power threshold is fully adjustable... and in this case was set to 1 kw. When the threshold is exceeded.... a minature dpdt relay operates [ in <2 msecs] and one set of contacts applies -10 vdc to the ALC jack of the Yaesu MK-V.... shutting it down asap !! ### The 2nd set of conatcts activates a 2nd, identical relay [also in < 2 msecs] ### This 2nd DPDT relay opens up the key line to both the IPA [ intermediate pwr amp] and also the 12 kw amp. The circuit latches.... and lights a red led. A spring loaded push button resets the circuit . [AFTER you find out why the high swr condition occured] ### Since the 2 x minature relay's are sequenced.... the ALC shut down on the xcvr occurs 1st.... followed by kicking BOTH amps off line ! NO Hot switching! ### To key both amps.... I used a PAIR of P+B opto isolators.... they run on +13.8 vdc @ 10 ma each. The "electronic TX ground" from pin 2 of the MK-V's band data jack supplies the grnd to both opto's on TX. ### The output side of each opto is rated at 200 Vdc @ 1 A CCS. They also have 4 kv isolation between input and output... and operate in under 100 microseconds. Cheap too. ### We used +120 vdc to operate all 4 x vac relays in the big amp. [speed up circuit, with a pair of dropping resistors] ### The high swr circuit could have been configured to open off the INPUT to both opto's instead.. of the Opto outputs. Moot point. ## I had my engineer buddy also include a short 12-14 msec delay... used in conjunction with the yaesu "TX inhibit lead" [used on both the 1000-D... plane MP.... MK-V /field. ## BOTH amps are keyed NOW.... after 10-14 msecs... TX inhibit is removed... allowing full power from the Yaesu MK-V. ### This delay ensures the vac relays won't hotswitch on TX... even though all 4 x are sped up.... we are using RJ1A's on the input side [one for drive RF... the 2nd RJ1A shorts out the 100k resistor to remove the cutoff bias. We paralled a pair of larger, slower vac relays on the output 10 kw side. ### We didn't want a situation where input relays operated 1st... drive applied to cathode... and no ant connected ...yet !! ### This delay circuit is for SSB / FM /AM ### In the MK-V menu.... on CW only.,... you can delay the RF by 0-30 msecs [ digital delay... NOTHING gets truncated either] ... and still key the amps in real time... NOW. It needs to be set between 10-30 msecs. ## The above T/R scheme is super fast vox cw/ ssb /fm /am. Due to the 'slower' larger vac relays on the 12 kw output side....qsk is not recomended. ### If anybody is interested.... the high swr circuit will be made available down the road... along with the rest of the schematics. It's saved everyones bacon a few times so far... works slick... and works on any bird line section / slug size. Later......... Jim VE7RF |
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PA3DUV
¿ªÔÆÌåÓýGreat info Jim!
NOW we're talking amplifiers ;-)
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Thuis yahoo group has the possibility of posting
pictures, files?and the like. Some pics of your "QRP" amps?
(They also make the usual? 10 kw??
5 kw.. 2.5 kw?? qrp? slugs.) would be very much
appreciated.
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Thanks again for the very interesting
contributions!
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Cheers, Dick
PA3DUV
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pentalab
--- In ham_amplifiers@..., PA3DUV <pa3duv@...> wrote:
the like. Some pics of your "QRP" amps (They also make the usual 10 kw 5 kw.. 2.5 kw qrp slugs.) would be very much appreciated. ### Tnx Dick..... As soon as I can figure out this pix posting deal... We will try and get some pix up. ### Just to set the record straight. I design this QRO stuff [including everything downstream like baluns, LC networks for stacked arrays, etc, for ... "clients" [who will remain nameless for obvious reasons] ### IMO.... I could care less how one gets their ERP. 1500w into stacked yagi's is... "OK".... but 5 kw into a dipole is a "no-no" ..gimme a break ! ### These 1500-2000w amps just bore me to tears. IMO... it's just as easy to build a big one as a small one. To me, it's an engineering challenge.... since you will never read any... "how to build a 5-15 kw linear" in any ARRL hand book / QST article. ### When AES / RF Parts / Coaxial Dynamics tell me they sell 10 kw slugs like popcorn.... it's blatantly obvious this QRO scenario is, and always has been.. alive and well. ### Eimac tells me their is this... "secret world wide underground network of QRO amp bulders ".... so secret.. they don't even know each other !! ### For a laff... check out JA6TAY's site. He doesn't mess about. ### Well, the cat's out of the bag now ! I fully intend to post as much of these "trade secrets" as I can. None of it is rocket science really. It starts off as an engineering problem... reverts to a... "sizing issue" then back to an engineering issue. ### All as it amounts to is ... either using bigger components.... or doing stuff like paralleling 8 x 200pf @ 15 kv HEC ceramic doorknobs to make a plate block cap assy. ### heck.... rolls of 3/8" and 1/2" copper tubing is dirt cheap at home depot or any other hardware store. Buy it by the foot... or buy the entire roll. ### My buddy saw hundreds of these brand new 135 A 3 phase contactor's on e-bay... dirt cheap. We paralled all 3 poles together.. to make one big 400 A SPST-DM contactor.... and stuck one such assy in each leg of the 240 V [single phase] line. A 3rd such contactor assy was used for the step start. ### BTW... the coils on those contactor's were rated at 220 V. My electrician buddy told me to run em on 240 V... without any drop resistor ! They rate em at 220 V... simply cuz it's a mid point between 208 V... and 240 V... and will work on all 3 x voltages nicely. They even came with 4 x complete sets of AUX contacts. ### a buddy of mine in Ohio has access to dozens of pole pigs... in various KVA sizes.... with or without the oil. ### 7-16 DIN chassis connector's are starting to show up dirt cheap on the surplus market. Best and most practical QRO connector ever made.... originally designed by the german Military in the mid 60's.... now all the cell ph co's use em. ### There are TWO connector's you can always get for any coax... type N and 7-16 DIN. You just can't blow up the huge 7mm center conductor on a DIN [.284" ! ] They are only 1.25" square to boot... not much bigger than a SO-239 / Type N. Later.... Jim VE7RF |
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On Sep 23, 2006, at 1:35 AM, pentalab wrote:
--- In ham_amplifiers@..., PA3DUV <pa3duv@...> wrote:Lifting an 85lb transformer is not easy for this old fart.the like. Some pics of your "QRP" amps (They also make the usual 10 To me, it's anIndeed. ... since you will never read any... "how toThe laugher is that W1AW had an Alpha 2, 8877 amplifier until the ARRL sold it to because it had a habit of zapping 8877s. The purchaser of the amplifier, QST Editor Mark Wilson, installed a low VHF-Q parasitic suppressors and apparently put the amplifier to good use. Amen to that. It starts off as an engineeringWith one or two thousand ohms of of RL, 1600pF is not necessary for the DC blocker cap at MF/HF. ... cheers, Jim R L MEASURES, AG6K. 805-386-3734 r@... |
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pentalab
--- In ham_amplifiers@..., R L Measures <r@...> wrote:
it's just as easy to build a big one as a small one. ##### Use a cum-a-long hooked to a basement beam... or one of those small devices used to lift small engines. Me... after tearing the crate apart.... I slid the 253 lb Dahl straight across from the pallet it came on, to the new RE-enforced cabinet. I re-enforced it with a sheet of 1/4" aluminium on top... and unistrut below...used 4.25" dolley wheels. ### Rich.... get some help....from ur helper babe... or ask Riley H to give u a hand, the next time he stops by... for tea. .low VHF-Q parasitic suppressors and apparently put the amplifier... since you will never read any... "how toThe laugher is that W1AW had an Alpha 2, 8877 amplifier until the to good use. ### Kilobuck 8877's are about the least cost effective.. throw away tube one can buy these days. You can buy a 3CX-3000A7 brand new... with a 3 yr - 12,000 warranty for a paltry $50.00 more... and have it rebuilt over and over and over. Instant on too... and does an easy 5300 watts out... with 200 w of drive.... or for you legal limit types.... 50 w of drive will produce 1500 w out. ### Ted Henry agreed with me... said the 8877 for HF... was a dumb way to go...... unless available as MRI pulls.. or u got deep pockets. Can you imagine spending 2 grand to re-tube a 2 x 8877 Alpha 77-SX ??? ### Alpha's newest amp is gonna use a single 8877... no vac tune cap... and no pin diodes ! They just don't ..'get it' ### You can buy 2 x brand new YC-243's for a tiny bit more.. [socketless version of a 6000A7 GG triode] For $2200.00 you can get a brand new Svetlana 3CX-10K 15 kv HEC ceramic doorknobs to make a plate block cap assy. for the DC blocker cap at MF/HF. ### I have heard everything from way more [9000 pf] to slightly less. I can't find any two engineering books that are evenly remotely close. ### I figured for 1.8 mhz... 1600pf would do the trick. For the high bands, the caps current rating goes way up.... thank god... cuz the current through those caps on the high bands is just bizzare. #### How much do you think is needed... for say a 1500 ohm RL @ 1.8 mhz ???? Later...... Jim VE7RF ... |
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PA3DUV
¿ªÔÆÌåÓý> Lifting an 85lb transformer is not easy for
this old fart.
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I just put an M24 2 metric tonne lifting eye on
a?1ft studbolt through the steel reinforced concrete ceiling of my garage
to get the 30 kVA 1500 rpm diesel genset and HT
power supply on and off the trailer. Using a
chain come along even a physically challenged person like the undersigned can do
the job ;-)
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Cheers, Dick
PA3DUV
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craxd
Dick,
You can buy a 1-2 ton chain fall hoist from harbor Freight for about $40.00. One can mount this in the ceiling stationary by the hook, and pull a pick up truck under it allowing the lift (if the ceiling is high enough). It takes about the same amount of room as a come-a-long, but is way easier to use. One can build some dollys to set the equipment on and move it around the shop where ever you want. Actually, One could mount the hoist outside to get it higher in the air for a larger truck if you have a hard top or corcrete drive way to roll the dolly on. They also make a set of wheels that riggers use to move heavy machinery the same way. You can sometimes find them on ebay at a cheap price. If I was to use a hoist of any kind, I'd strongly recommend obtaining a small I beam about 8 inches high at least, and set it atop two walls to carry the load. Then mount the hoist to it. You can run these between ceiling joists and set the ends on top of the sill plate. A lot of the time, you can buy one cut new pretty cheap. A scrap yard is another place to look. You only need one about the size that some place over double-car garage doors in place of a header when they use brick. A luxury is to get is a small fork lift if you have a garage. Here, they come in at the local two scrap yards all the time. To be honest, there's not much wrong with some. A buddy of mine who owns a small machine shop bought one from one of the yards that was electric and they threw in a charger. I rebuilt the drive board and got it going. I think he got it for $0.08 a pound which was $0.02 over what they paid. I think it was one by Yale, however it was white in color. They are very nice if your going to be doing a lot of heavy lifting. You can mount a boom on the forks and you have a built in crane. I ran my welding/repair portion of my machine shop with two lift trucks this way. Best, Will --- In ham_amplifiers@..., PA3DUV <pa3duv@...> wrote: through the steel reinforced concrete ceiling of my garage to get theLifting an 85lb transformer is not easy for this old fart.I just put an M24 2 metric tonne lifting eye on a 1ft studbolt 30 kVA 1500 rpm diesel genset and HT power supply on and off the trailer. Using a chain come along even a physically challenged person like the undersigned can do the job ;-) SHUT DOWN CIRCUIT !! and > the like. Some pics of your "QRP" amps (They also make the usual10 > kw 5 kw.. 2.5 kw qrp slugs.) would be very much appreciated.low VHF-Q parasitic suppressors and apparently put the amplifier togood use.about. >for the DC blocker cap at MF/HF. |
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Tony King - W4ZT
R L Measures wrote:
<snip> Lifting an 85lb transformer is not easy for this old fart.A small fold up Engine Lift can solve that and many other heavy lifting jobs. One of these helped me lift my mill and lathe when I brought them home and I have a 164 lb Peter Dahl to move too ;) 73, Tony W4ZT |
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On Sep 23, 2006, at 3:31 PM, Tony King - W4ZT wrote:
R L Measures wrote:I used a sledge hammer handle, a strap, a hook, helper-girl on one end of the handle, and me on the other end to lift it in place. R L MEASURES, AG6K. 805-386-3734 r@... |