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Old July 30th 03, 07:05 PM
Funnie Stuff continues watch for dragons
 
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: Frank Gilliland wrote:

:What started your rant was my mention of hot switching of the amplifier
:which was part of the original thread. You said it might have a
:sequenced, arc'd or what term you'd like to use... relay. I said it does
:not. In short, as shown the original (pride brand I belive) amplifier
:probably hot switches RF unless you can prove otherwise.

: Wrong. It does neither until someone proves otherwise. I really don't care if
: the amp uses a sequenced relay or not, since it is designed for illegal use in
: the US market anyway.

Funny you felt compelled to comment on my mention of hot switching
issues with the amplifier in the original thread.

: Pride amps suck. Period. They are probably the worst designed piece-of-**** amps
: ever pushed onto the ultra-gullible illegal CBer market. But most of them had
: one advantage that few CB amplifiers ever had (or ever will have): they used
: seperate relays for input and output. And yes, they ARE sequenced! Even the
: diminutive Pride 100 had seperate, sequenced relays. And the use of seperate
: relays was enough to give them a reputation for stability (never breaking into
: oscillation), regardless of the fact that they would splatter up and down the
: spectrum like a spark-gap transmitter.

Actually
I have one or two Pride amps that are actually pretty nice. The mobiles
are crap for various reasons, but they are not exclusive in the poop
department. The early Palomar tx-50, tx-75 and tx-100 mobiles were just as
bad. I believe a spark-gap transmitter would do much worse.

: Lame excuse, Skippy. You should pick up a copy of the ARRL handbook. I'm sure
: Scott can give you the card catalog number if you can't afford a copy at the
: local used book store.

I have most every Handbook frankie... The newer ones tend to be quite
different as the technology moves along. One of your last posts, includes
information from a 1978 edition... got one newer... say the last decade at
least..?

:If you stay with one example amplifier circuit, then it's much easier to
:get into specifics... I'm not even sure where you'r "pulling your load on
:the output tank until after it powers down" statement from. What do you
:consider "powers down" frankie..? Sequential RF relays are not an
:essential part of any tube or solid state power transmitter... your going
:to up the power level of the topic amplifier to some broadcast
:transmitter now..?

: Wrong. You ALWAYS apply plate voltage before screen voltage. It's a given. Just
: like using ground for the other end of any B+ supply. Or star-grounding each RF
: stage of an amplifier or receiver. When you read a schematic, some things don't
: need to be mentioned, and sequential keying is one of them. That's just ONE of
: the fundamentals you missed in your internet-based education.

I, nor anyone else ever claimed a tubes screen voltage should be applied
before the anode voltage. Why did you bother to mention it..?

I'm not sure where you're going with your "using ground for the other end
of any B+ Supply" statement.... I hate to rain on your parade, but there
are plenty of Amplifiers which do not use ground as the "other end" of the
B+ Supply. Some of the are amplifier brands you mentioned in one of your
most recient posts. Maybe you should better explain your statement..?

Sequential keying is not an issue in most of my amplifiers frankie, the
relays I use are much faster than the driving radio. That's current
technology frankie... how about you catching up. :-) You can read about
it at Rich's web page in the SB-220 QSK section. You might add a bit of
internet-based education to your current lineup of dated data.

: Quit whining and stay on topic -- why are sequential relays "bad news"?

Ahh... your moving around again... but what the heck. If the relays are
mechanical open frame type, they are slow and cause hot switching in the
typical amateur station.

You can avoid hot switching by switching to other options... like fast
reed relays (which you claimed don't handle RF), or vacuum relays which
switch much faster that most common amateur radios.

If you want to drag the thread back over to your beloved broadcast
transmitter, most all do not have T/R relays of any type switching the
rf pipe.
The original thread started over someone asking about a relative low power
level solid state HF mobile amplifier... a Pride was it not..? When you
jump back and forth from small solid state amps to large tube amps,
consider taking a moment to at least layout the example for the readers.

:If you jump to larger broadcast transmitters... they are often loaded with
:relays and permissive controls, but for the most part, there are no
:special sequenced TR relays switching RF in the output power section. Per
:the original thread that you took off dancing your tune... there is no
:hot switching of rf in a typical broadcast transmitter.

: DUH!!! There is no switching AT ALL in a broadcast transmitter because it's not
: a transceiver! How dumb do you think CBers are? Oh, that's right, you equated
: their mentality to Forrest Gump: "Life is box of chocolatte."

Looks like you're running out of of plank frankie... over the side you
will soon be. To the sharks with ye'

:As stated before, I'd settle on the name of any current Amateur or
:Commercial Amplifier which uses Sequential relays to switch RF...? I'd
:even offer up that you could also provide the name of any broadcast or
:amateur transmitter which uses your special sequential relays to switch
:RF..?

: I'm not a ham, but you are, and you claim to have a ****load of amps. Why don't
: you mic a few contacts and post the results? But remember that I have a few
: myself, and so do many people on this newsgroup -- IOW, don't post
: bogus data!

Actually, I'm only a pastrami sandwich... but being a ham has little to do
with the facts, other than it might expose your lack of real world hands
on experience about the amplifier hot switching topic; which is the
statement I made that you felt compelled attack in that original thread.

I don't know if I've bothered to mic a relay contact in some decades. On
the relative scale, most relays are cheap to replace when compared to
reliability issues. Most of my amplifier relays are reed or vacuum type
frankie... I'd have to damage them to get them open. :-) Some of my legal
limit level amateur amplifiers even have diode tr switching. Never has the
diode switching circuit failed... and they are fast as heck.

:That was the original topic of your follow up post to my comments on
:the mentioned amplifier... Sequential relays for RF t/r switching.

: It's been around a lot longer than you have, and even exists in your example of
: the Micor from Motorola. You want gapped contacts? I offered you a box full of
: them, but for some reason you have refused.

Thanks for the offer, but...
I have boxes of similar relays that I will probably never use. It's not
worth the postage to get them shipped down.

: and yes, I've had and still have a few Pride amplifiers
:in my collection. For the most part, they use generic relays. Some of
:their amplifier circuits are pretty nice, most of their mobile amplifiers
:are crap. Every amplifier they've produced had/has shortfalls in the
:designs... but so has most every brand of amplifier made. If you want to
:use one, you buy it and improve it as best possible and practical.

: What's your point? That you can't afford anything but Pride amps? Hey, I'll
: believe THAT! What I WON'T believe is that you designed and/or built any big
: amps (tube or ss) that worked! I think you have a few cheap amps that you value
: ONLY because you can't afford anything else!

The point was that I've have actual experience with the topic amplifiers,
something you seem to lack. You have me confused with someone who cares
that you believe I've designed or built amplifiers that worked. What you
think about hot switching TR relays has so far proven to be dated or wrong.

I'm slightly amused by your assumptions of my financial status frankie.
I'll be fine without your help, thank you. Back to the personal attacks
again... indicates you're about out of plank and ready to go over the
side. Watch out for the sharks...

:Your talking an old Motrac era tube radio, originally designed from the
:60's. You are not talking about any amateur or commercial amplifier
:produced on a large scale. ... or for the most part, even a relative small
:scale production for the consumer.

: Your lack of experience is showing yet again. Those old radios used the circuits
: most hacked by amateurs for both homebrew AND manufactured amps. Are you so
: stupid to think that the big companies used circuits designed by amateurs? No,
: not even close, Skippy, they used circuits designed by PROFESSIONALS, and the
: amateurs copied them!

Frank, the only thing I take out of a Motrac Radio are the receiver front
end... the rest is almost not worth pulling out of the radio. (actually I
do take a few more parts out of them for salvage).

What part of a Motrac era radio or circuit is going into my current
amplifier project frankie...?

Just as a trivia note... many of the engineers and technicians working at
Motorola and GE (and other radio companies) are/were hams.

You just want to focus around your vintage experience with a 60's era
radio to make your arc'd relay contacts comment(s) valid, even though the
radio hasn't been produced in some decades. No one is using that stuff
anymore frankie...

:The replacement for your mentioned 60's designed radio is/was a radio with
:delay A+ and A- controls and a reed relay switching 100 watts plus of RF.
:Commonly called a Micor... or the Mocom 70 depend on your pocket book and
:how deep you let Motorola into it.

: All Motorola radios used sequential switching. Check your Micor manual and look
: for the "P-T-T sequencing diagram" in the "Control Board" section. There you
: will find a diagram similar to the schematic I posted. And whether the
: sequencing is done with reed relays (a la Micor), seperate relays (a la Pride),
: or gapped relay contacts (a la Motorola, GE, Henry, Uniden, Kenwood, Henry,

Cute, but that still doesn't qualify your arc'd contacts relay statement,
of which you started out with... I hate to rain on your parade, but the
Micor base stations I have here, use only one reed relay (which you stated
doesn't handle rf). The typical delayed and Keyed A+ and A- lines in
those radios are clearly done to prevent hot switching, it's even
mentioned in a few places in their service manual. There's not an arc'd
relay contact in the place... went out with the Motrac it did... :-) your
first example radio.

Again frankie...
How about a mention of any current product amplifier product using
your special arc'd relays to switch "tr" the rf..? You can pick any of
the brands you mention above... I've got access to manuals for most
anything they've ever made.
How about the brand and part number for a current production (typical)
open frame relay made with special arc'd contacts for RF switching..?

: Collins...etc, etc), it all amounts to the same effect. The PROBLEM is that you
: can't accept that there is, and has been for some time, another method of
: sequential switching other than what you have learned from the internet! Get
: over your ego trip, learn from your mistakes, and move on!

I've yet to see any valid brand/model example made within the last few
decades that sequential switches RF using your arc'd relay contacts
method. You try like heck to skew your original arc'd contacts statements
over to a sequential switching topic... but homey ain't gonna' let you get
away with it. Care to address the original topic with the proper
answer..? We haven't seen the correct reply yet... we're waiting.

:Jeez frankie, in case you hadn't noticed... much of current amateur
:amplifier technology uses fast relays and electronic bias which don't
:require sequenced t/r relays. A typical reed or vacuum relay is faster
:than the typical driving radio/exciter. I can't believe you don't know
:this stuff... :-)

: So why do the same radios use delay lines for their sequential switching? And
: before you whine about going off-topic, don't forget that YOU were the one who
: first mentioned delay lines!

The original hot switching topic has to do with RF from the driving radio
(exciter/transmitter) arriving at the amplifier before the amplifiers
internal relay switching is completed. I wont bother calling you on the
off topic issue here, but I will say that the delay line question would
probably be specific to model of radio. I have radios which have them, I
have radios which don't have delay lines. It's brand/model/application
specific.

:[snipage of frankies previous dance and sing, topic avoidance...)
: What did you snip? I checked the previous post and it looks like you didn't snip
: anything....?

Then don't spazz about it... simple enough.

:: That didn't answer the question -- why are they "bad news"? Because they aren't
:: "popular"? Maybe you should take a closer look at some of these un-"popular"
:: amps from makers like Collins, Henry, Kenwood.... or hey, you could even check
:: your copy of the ARRL handbook! I have the 1978 edition and it shows a couple
:: examples of sequenced relays.
:
:Notice the Decade... 1978 We've come a long way from 1978. Let me
:repeat the question; are there any current Amplifier mfgrs using
:Sequential Relays to switch RF..?

: Almost all of them, including your referenced Micor. But that didn't answer the
: question -- why are they "bad news"?

The Micor never hot switched because the payed attention to details...
even without a reed relay in place, hot switching would have been minimal
because they delay the RF to allow the relay time to complete movement.
The manuals clearly state said... Now, on to the current generation...

The "bad news" answer was addressed earlier in this follow up post.

I believe if you check the current Amateur product line, many or
most of the serious amplifier mfgrs are using vacuum and reed relay
switching and even pin diode (type circuit) switched. Those that include
the just mentioned do not have a problem with hot switching rf. There are
and will always be some lower priced amplifiers which use the classic
frame type relay switching. To addres the hot switching issue, many have
tried to include relay switching speed-up circuits in the TR controls.

:As a sidebar notation: The collins 30-L1, 30-S1, Henry Series and the ill
:fated Kenwood TL-series of hf amplifiers did not use sequential relays for
:RF switching. Many or most of the above hot switch rf, which is not good
:news. That's where this all started...

: Aside from the fact that triodes don't have screen grids, keep going.....

What would having screen grids matter in the subject of hot switching
frankie..? Hows does it relate..? A tetrode equiped Collins 30-S1 hot
switches just as bad as some of the 3-500z amplifiers by those other
mfgrs.

:No, I think that material writen in 1978 was probably pretty good in
:1978, not always the best in 2003... some 25 years later. Things
:change... big time.

: How? Does the current ARRL handbook say something different? Does it assume that
: we are all using 1n4007's that were made within the past couple years (you know,
: the years when they are manufactured to such tight tolerances that they all
: switch off at EXACTLY the same time?)? Or does it realize the possibility that
: some of us don't have a retail account with Perfection Rectifier, INC?

Some of the current handbooks mention special diode or rectifier banks
made for amplifier applications. The common units are the "Silicon Alley"
k2au type high voltage rectifiers which are actually just series strings
of diodes in potted material.... and get this... they have not parallel
caps or resistors inside, nor do the recomend them.

The last bank of Continental Broadcast transmitter rectifiers I had to
replace were pretty much the same type of unit. Larger rectifier units
made up of potted series diode strings. Same with the last Elcom, Bauer,
Sparta, CCA and similar broadcast transmitter rectifier units I've had to
replace. It's a common layout, I'm happy to say they do not often fail.

I buy my common 1Nxxxx series diodes from Digikey or Newark.

You would have to consult a specific hand book project for me to provide
some feedback about said... Rich, many others and myself don't always
take the handbook information as 100% That's why the amps list server is
so popular, these topics are mentioned and gone over.

:My original statement was about hot switching rf through the example
:amplifier, your attempts to divert to some other dual relay example are
:bogus.

: There is no diversion, Skippy. Hot switching RF is easily avoided by sequential
: switching; i.e, sequential relays.

Tell me/us how a typical exciter/radio/transmitter providing a very
optomistic... slightly delayed rf signal and external amplifier TR
relay contact closure could possibly transfer the coaxial paths ("tr
switch") using your original arc'd contact relays..?

Unless the relay are very fast... using reed relays you stated would
not handle rf... or vacuum type or a pin diode type switching is used, hot
switching will probably happen.

When you use some of the above mentioned... sequential relay switching
requrements in the common current generation rf amplifier go out the
window. Simple enough and you learned it on the internet... from me even.

:Special sequential RF or your magic modified arc'd open frame type relays
:are old technology and not used in modern equipment. By nature, they are
:expensive and unreliable when compared to electronic switching (pin
:diode) reed or vacuum relays used in most current Amateur Amplifiers.
:Simple enough...

: But the amplifier in question didn't use PIN diodes, or indicate the use of reed
: or vacuum relays. Now what's your problem, Skippy?

Not a problem on my part, was on your part when I mentioned the original
topic amplifier hot switched (used a typical open frame relay).

Any amplifier which senses rf to signal and change it's T/R relay, hot
switches big time bad.

:I'm sure we'll be waiting some time for your example of special
:model sequential tr (for switching rf) relays used in any modern radio
:equipment. Those mechnical relays your standing behind are long gone from
:the big picture.
:The clock ticks louder and louder...

: You seem to have an answer for everything else (except why sequential relays are
: "bad news"), so why do some manufacturers still use open-contact relays?

Cost mostly... most all of the better stuff has moved to diode switching
circuits, vacuum and reed relays to increase their T/R speeds... which
prevent hot switching.

:"Your trap" seems to be shut on any current example..? what's up with
:that frankie..?

: Why are sequential relays "bad news", Skippy?

See my answer toward the first part of this text frankie... you've tried
to rehash that question 3 or 4 times now. When refering to your original
mentioned arc'd contact type relays... they hot switch.

:Onward...
:The number of relays required to complete the TR function is another
:whole topic.

: Don't pull that off-topic crap -- why are sequential relays "bad news"? Address
: the issue, Skippy!

If you review you past post... those darn motrac era arc'd relays are
waiting for you to come home for your crow sandwich.

: I do not care to bring in your latest off topic
:number of relay diversion as it was never part of the original thread.
:Stay on track frankie.

: Gladly. Why are sequential relays "bad news"?

You gotta love it...

:The original amplifier circuit which started all this, is still hot
:switching RF.

: Possible, yet unproven. Regardless, why are sequential relays "bad news"?

If it was the original open frame type relay, there is almost no other end
result. Notice how I wrote "almost"... there are ways to prevent
hot switching of vintage amplifiers... a whole different thread, maybe
another time. Is your bad news diatribe all you're holding onto now
frankie... the plank is getting even shorter... the sharks are hungry.

: Your original followup to my mention of said suggested the
:amplifier might have had a sequential relay (or similar function) TR
:switching RF. I claim is does not and I stand by it until you prove
:otherwise.

: Then it shall remain unproven. Still, why are sequential relays "bad news"?

How many of your reading this think frankie's fallen overboard..? :-)

:By the way Mr Technology... since you're paying attention of course..
:
:A typical "properly designed" amateur amplifier with reed relay switching
:probably doesn't have to have a sequential relay circuit, the reed relay
:is often faster than any typical Amateur Radio driving said amplifier.

: The primary purpose of sequential relays is to provide the proper sequence
: between RX RF, audio input, final drive, final load and final power input (and
: screen bias for pentode/tetrode finals). Screw up the sequence and you can screw
: up the tranceiver. Now, why are sequential relays "bad news", Skippy?

Twas an amplifier frankie, not a radio...
The original amplifier didn't have your magic list of additional functions
listed above. It had one or more open frame relays that hot switched,
regardless of any special arc'd contact you may claim it has/had, that is
all...

::I guess all the keyed A+ and A- used by companies like Motorola (for
::decades) prefer the harder route. Come on now frankie...
:
:: No. After the old tube monsters went extinct, Motorola took a different path and
:: built some radios that put the relay sequencing into the mic switch, which
:: wasn't too popular because the mics weren't interchangeable between radios. But
:: many shops tried anyway, resulting in a lot of bad radios, which is one reason
:: why their radios sucked for a long time. The Mocom line used a single sequenced
:: relay, which was made just before they began using sequenced reed relays (using
:: circuits similar to what I provided in the schematic).
:
:Motorola produced high powered tube amplifiers through the 80's and into
:the 90's.

: So?

When addressing the original topic of amplifiers, motorola used fast reed
relays for tube amp circuits well into the 90's. The were fast and they
did not hot switch. Your Motrac generation arc'd relays were long gone
from the scene.

:These magic radios you claim Motorola produced with sequential TR - RF
:switching... how about a model name...? In the commercial world, they
:were not long term reliable, they were expensive and they fell by the
:wayside when the technology moved on... some 25 or more years ago..?

: All of them, or haven't you been paying attention?

Your lifted web picture shows two relays... which Motorola product used
two sequenced relays..? Were they arc'd contact type like you first
started out with... or were they reed relays which you claimed were bad
for RF..?

:: But you should know all this already because you are a radio tech, right?
:
:Yeah, just by luck I worked for a Motorola Service Station for "a few
:years", it also happens to be one of the largest in the Nation... still.

: Then why haven't you learned anything about sequential relays? What did you do
: there -- mop the floors in the heads?

Maybe it won't matter if you walk the plank... the sharks may not eat you
for fear of too much gas.

:So after you abandon your Sequential relay statements and try to merge
:your current foot in mouth position into some type of sequential reed
:relay circuit... how about you get back on track. As in current
:amplifier or radio technology... some 20 to 25 year later.

: You keep whining about "dated" technology, yet you don't even know what
: was used in the past OR the present.

You're pretty much out of steam now frankie... it's a beatiful day outside
and I'm going to start putting in arc'd relays into my pride amplifiers,
so hopefully you've got something valid in the next few statements... or
I'm pretty much done with you.

::I believe the original subject was an Amplifier... was it not..? The
::last radio with a t/r relay was made ...? .... years ago..? ... decades
::ago..?
:
:: T/R relays are still used today -- did you forget about that amplifier we were
:: talking about?
:
:Was a pride right..? if it was made as shown in the original diagram, it
:still hot switches RF as I first mentioned. You claim it doesn't and you
:are wrong. Nothing has changed...

: Wrong. Most of Pride's amps used seperate relays in a mode where one relay
: controlled the other -- sequenced relays.

And they hot switched rf like a mo-fo... I haven't seen a pride amp that
didn't hot switch rf.

::: Reed relays don't carry RF very well. And they certainly don't carry
::: power because it tends to vaporize the Hg and destroy the relay. They
::: are usually only used for low-voltage DC and audio switching. But you
::: knew that, didn't you Skippy?
::
::I'm laughing at you big time here frankie.. I guess decades of Motorola,
::GE, EF Johnson, Aerotron rf amplifier and radio switching with reed relays
::doesn't prove anything.
:
:: By "power" I meant kilowatts, but I'll let you gloat for a while anyway because
:: I should have stated myself more clearly.
:
:The original amplifier was not at the kilowatt level.... but just for the
:sake of others reading this. The typical multi kilowatt level amateur
:amplifier uses reed relay switching on the input and vacuum relay
:switching on the output. In some cases, vacuum relays are used on both the
:input and the output. They handle the RF well and they are very fast...
:fast enough that the driving radio is most often not subject to rf hot
:switching.

: Nobody said they weren't fast. I said they are lossy; and they are when compared
: to a good open-contact relay designed for power RF. Reed relays are cheaper and
: smaller. If given a choice, I'll spend a couple extra bucks for a -good- relay.

So again... who's go those open contact relays that don't hot switch rf in
the typical amateur amplifier..? Why are most of the current amplifier
mfgrs using them..?

:Actually...
:I was hoping you'd comment on your statement that "reed relays don't carry
:RF well..." but you avoided it big time.

: They don't. They are used because they are cheap and small.

.... and fast... and they work well... and they don't hot switch rf in a
typical amateur amplifier (properly designed of course), like the open
contact/frame relays do in typical layouts.

: quit professing your ignorance by trying to top someone with five years of
: college and over 25 years experience in the field! Hey, I don't know everything,

Only 5 years frankie..? down here, College is a 2 year visit.

Any topic related paperwork (certificates or diplomas) down the
educational isle for you...?

:Simple enough...
:Compared to the alternatives like pin diode, reed and vacuum relay, it's
:very unreliable.

: Wrong. The reliability of the electro-mechanical relay is a tough act to beat.
: While the vacuum relay reduces arcing of the contacts, that only extends the
: life of the contacts. The reed relay is based on the same principle, but it's
: advantages are only it's small size and low cost. The PIN diode has severe power
: limitations, and is highly vulnerable to transient peaks and surges. And when
: you consider that an open-contact relay is easily maintained just by cleaning
: the contacts, and replaced with the simplicity of a vacuuum tube, there are FEW
: devices that can be considered to be as reliable.

That's why most of the current amateur amplifier mfgrs are not using
them..?

: It's also more expensive than some of the circuits which
:replaced it.

: You get what you pay for.

Hey, we agree on one thing...

:Now your turn frankie.... who's bending relay contacts these days and
:where can we find it done..?

: Beats me. But if you want to know who is using sequential relays, pick just
: about anybody in the list. How they implement them is strictly a matter for

Aaaaahhhhh.... again we see you try and merge your original arc'd relay
contacts into a now revised sequential relay bail out topic...

Nope, you made the arc'd relay statements and you get to stay with them
frankie. No cigar on the bail out.

: their engineers. For the amateur building an amp using open-contact relays, I
: would recommend gapping the contacts on one relay as one method of sequencing
: the switching, and I know that some do it that way. For manufacturing, I don't
: know why anyone would use an open-contact relay except for RF power switching.

My how the story changes....

: Frankly, I'm suprised how many use reed relays and not open-contact relays for
: RF power switching. But that's their problem because I don't use those radios or
: recommend them to any of my customers. If you saw the specs for yourself, you
: wouldn't either.

You might ask most of the major amp mfgrs and post your question on amps.
You could get unbiased answers from people in the industry. I might be
one of them... :-)

: So? People still use low-tech devices like wheel-barrows, matches, .... heck,
: even alcohol has been around for thousands of years and still works just the
: same! Do you barbecue with charcoal or propane (yuk!)? Is the fabric in the
: clothing you wear not made on a loom? And I think that even down there in
: granola-land that boats float based on the principle of Archimedes law of
: displacement. Just because technology is "dated" doesn't mean it's "bad news".

It is when it hot switches RF...

:It's been fun for the most part.
:
:"73's and good luck in the contest"
:skipp

: Read a book.

Do almost every day frankie... OK, I'm pretty much done with you for
this thread... you can continue to walk the arc'd relay plank if you want.

Maybe next time you won't try to jump around off topic so much... better
than previous times... but still pretty much a poor attempt at a smoke
screen on your part.

Sum it up frankie... open frame "arc'd" relays in typical amateur
amplifier rf switching "TR" circuits hot switch. In most typical cases,
they do not complete their movement before the rf arrives. In short, they
are not fast enough for many modern radios. Hot Switching is bad news.

that is all... I'm out of here.

skipp
http://sonic.ucdavis.edu

rip: Bob Hope, a great man...