The AM Forum
March 28, 2024, 07:32:31 PM *
Welcome, Guest. Please login or register.

Login with username, password and session length
 
   Home   Help Calendar Links Staff List Gallery Login Register  
Pages: 1 [2]   Go Down
  Print  
Author Topic: Johnson 500 Modulator  (Read 10879 times)
0 Members and 1 Guest are viewing this topic.
WA1HZK
Member

Offline Offline

Posts: 1104


WWW
« Reply #25 on: March 17, 2021, 07:11:32 PM »

Found some 10KV connectors. https://www.ebay.com/itm/4Pcs-10kV-Lantern-Type-Banana-Cross-High-Voltage-Connectors-Plugs-Sockets/313322898733?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
I can't believe what they are getting for HV wire these days. So I guess I'll try 8X. I have always used that in the past and been OK.
Anyway don't try those E-Bay advertised HV connectors that look like BNC's, not good at all. Advertised for RG-59 but might work with RG-6.
Trouble is, most of that Cable TV Coax is just junk. I have never had cable break down like that with a 2.2KV modulated signal.
So I'll wait for the next E-Bay delivery and try again. Back to making ammunition for the coming Civil War.
Keith WA1HZK
Logged

AM is Not A Hobby - It's a "Way of Life"!
Timmy, Sometime in 2007 on a Mountain Far Away..
www.criticalradio.com
www.criticalbattery.com
www.criticaltowers.com
www.criticalresponder.com
Official Registered "Old Buzzard"
WBear2GCR
Member

Offline Offline

Posts: 4135


Brrrr- it's cold in the shack! Fire up the BIG RIG


WWW
« Reply #26 on: March 17, 2021, 08:26:59 PM »

Hang on.

The HV BNC connectors fried or the coax inside fried??

The ones you show are NG, the chassis mount needs to be the one with the male plug
not the female!  You do not want HOT B+ exposed off the end of a cable!!

Can you post a link or example of the HV BNCs you had?

Regular BNCs should handle 2kv all day. Fwiw. As will RG-58 or 59.

                   _-_-bear

The coax should be of the solid poly, not foam.

IF you need HV wire I have some super high voltage rated wire, the OD is similar
to RG-8, but it is flexible. You can have a few feet to meet your build needs for
the cost of sheeping. Email me. BUT, coax with a shield is safer. FYI.

Again a problem is that the male should not be exposed with HV in any way that it could
come in contact with one's body - ever.
Logged

_-_- bear WB2GCR                   http://www.bearlabs.com
WA1HZK
Member

Offline Offline

Posts: 1104


WWW
« Reply #27 on: March 17, 2021, 11:02:53 PM »

This is the one that flashed over.
https://www.ebay.com/itm/5Pcs-RP-BNC-Female-high-voltage-power-RF-connector-SHV-5000V-RG6/201428261714?_trkparms=ispr%3D1&hash=item2ee60f5b52:g:AWUAAOSwFnFV9g95&amdata=enc%3AAQAFAAACgBaobrjLl8XobRIiIML1V4Imu%252Fn%252BzU5L90Z278x5ickkrmmq8hWevtuKE7%252F%252BLfVXto%252FVPbPR9YcnnRjCTIyH4Zg7OMogYHLskhOvU91VenaUhUwQlrFUL5CcSKpmCXVzpjI64NKA%252BI5kJ%252Bg6bUavabK1PGdyza%252Bh%252F2Ub63TNJvGxxS3hJrXqAB06yqNYUPvvVYlhAZ6jN4C3IKj9V4%252Fnh0GeaLeFl0H0y36%252FRZWj5EBZdKu3hGVNRjJq3cxLqazxAe6CuTC1gsSvK0EwA0knd7XF5TWJJdmbdZF%252FMkUezMgzMs2Ow%252FeJ024iLUi0wgB7fY2pFGqNb7%252FSrAANkvLGy1VJMXDyHPxIA1icEluMuIKu3NKZF%252Bxot3DTpal7Zyxn7hCLUfFZwL27whi40bjE7H6eIrbOyWb4DmQdVKTGxnjRMtZssJuKhgCXKlvLLzfKnZoZy0m46opyI2nNLEtRwmnRbF61sfG5AJzFzWjo%252BP2cirQvT9N%252BqBYHLH7xUJk%252F3%252B7tjqAaSKLi8mVHbcu7w15Fz%252FW%252B8VL%252FHY4o%252BBTMApdgT659jaVPDTfBs3OIsiH%252Bsu8v2KbUbG0Ks4POJP%252BoU1ORh60%252BEVp0dKUQuZfvA34f19a%252B2Bk5lmkrViBXDwOZ62%252FZnQHyJeIJ7L1emEjxeLuloERhIlgdRkhneJ3fkDLKwbkrc%252BXpi21Z8Z3%252FBd1zsq5uR1oeg1NZe1tVfNTJhD1vb0hzGl8%252BdewgSgcdD8y1JO13hXoDO66%252FdV1JLOfKF%252FmsWzJ%252B7%252FkXUmmoZA0oKjLiT%252F2LRz5tEmrXyazJLorHK%252BewYPINo5gEBCpSZ%252BM6oMa2n2275g25bxOqmM9EcxA%253D%7Ccksum%3A2014282617141588ac9589bb4342a2672b658e0987a4%7Campid%3APL_CLK%7Cclp%3A2334524

Damn, that's a stupid link.
The next ones I try will be very similar to the orig. stuff but rated 10KV. I'll just hook it up the same way. Only need the plate and screed feeds.
The above connectors might have been OK but were definitely not RG-59 Crimps as advertised.  The crappy RG59 was foam, that flashed over. Lasted a couple days. that's it.
Lesson learned, don't trust Chinese ads.
Logged

AM is Not A Hobby - It's a "Way of Life"!
Timmy, Sometime in 2007 on a Mountain Far Away..
www.criticalradio.com
www.criticalbattery.com
www.criticaltowers.com
www.criticalresponder.com
Official Registered "Old Buzzard"
Opcom
Patrick J. / KD5OEI
Contributing
Member
*
Offline Offline

Posts: 8308



WWW
« Reply #28 on: March 18, 2021, 09:19:01 AM »

Outdoor luminous sign sign wire is rated 15KV and it's not that costly. Shield from RG-8 can be slipped over it.


https://www.amazon.com/dp/B000NUX4PK/ref=twister_dp_update?_encoding=UTF8&th=1&psc=1

Ancor GTO-15 is single conductor, stranded AWG14 copper wire. The GTO-15 indicates it is highly insulated (for up to 15,000 volts). The "marine grade" indicates that it is tinned copper wire.
Logged

Radio Candelstein - Flagship Station of the NRK Radio Network.
KD6VXI
Contributing
Member
*
Offline Offline

Posts: 2648


Making AM GREAT Again!


« Reply #29 on: March 19, 2021, 02:12:13 PM »

Well I bought a set of HV connectors on E-bay, supposed to work with 5KV. First one connector vaporized now the cable flashed over. The ad for the HV connectors said use with RG-59.
Just making a note to all.... Don't. That's in the trash now. My last possible option is silver teflon PL's. Searching for better HV connectors that use RG-8 or 8X cable. That stuff looks a lot better for volts. This single holer can swing to almost 5K volts.
One of those projects where everything seems to break. At let the short is not on the decks.
Keith
WA1HZK

I've been using those connectors for close to 3 years now, ever since a (not installed by me) Millen HV connector had abraded insulation on it and threw 6.2Kv into the back of my hand.  I've used those SHV connectors to 7kv without issue.

I DON'T use standard RG59 with them, however.  I use RG-59 RATED for the voltage, and not all is at the levels I play with.  At 2.2kv, you should have been fine.

Incidentally that 6Kv "reach out and touch me" landed me in the hospital for 2 nights.  Doc said that it could take up to a year for symptoms to appear, so be careful.

Sure enough, 13 months later I was in the ICU having heart surgery.

I suspect a bad install.  It's not hard to have ONE wire of the braid get screwy when you're installing those connectors.  I know this from experience.  I now ohm all of them out before applying voltage to them.  I've installed enough now that I have it down pat, but I did have to trash 2 in the beginning.

Also, I've received connectors that have an insulation bushing/washer that goes on the center pin and also received ones that didn't.  You install the center pin on the coax and then a flat teflon washer goes over it.  Then insert the pin into the connector and slide the ferrule up.  flare the braid back and crimp.

Sorry you had problems with your connector, but you're a lot better off safe than sorry.  I'm now taking meds to try to keep me from having to go back for another surgery.  Surgery sucks, but dying was the other option.

--Shane
KD6VXI
Logged
AG5CK
Member

Offline Offline

Posts: 36


« Reply #30 on: March 19, 2021, 08:19:22 PM »

Well I bought a set of HV connectors on E-bay, supposed to work with 5KV. First one connector vaporized now the cable flashed over. The ad for the HV connectors said use with RG-59.
Just making a note to all.... Don't. That's in the trash now. My last possible option is silver teflon PL's. Searching for better HV connectors that use RG-8 or 8X cable. That stuff looks a lot better for volts. This single holer can swing to almost 5K volts.
One of those projects where everything seems to break. At let the short is not on the decks.
Keith
WA1HZK

I've been using those connectors for close to 3 years now, ever since a (not installed by me) Millen HV connector had abraded insulation on it and threw 6.2Kv into the back of my hand.  I've used those SHV connectors to 7kv without issue.

I DON'T use standard RG59 with them, however.  I use RG-59 RATED for the voltage, and not all is at the levels I play with.  At 2.2kv, you should have been fine.

Incidentally that 6Kv "reach out and touch me" landed me in the hospital for 2 nights.  Doc said that it could take up to a year for symptoms to appear, so be careful.

Sure enough, 13 months later I was in the ICU having heart surgery.

I suspect a bad install.  It's not hard to have ONE wire of the braid get screwy when you're installing those connectors.  I know this from experience.  I now ohm all of them out before applying voltage to them.  I've installed enough now that I have it down pat, but I did have to trash 2 in the beginning.

Also, I've received connectors that have an insulation bushing/washer that goes on the center pin and also received ones that didn't.  You install the center pin on the coax and then a flat teflon washer goes over it.  Then insert the pin into the connector and slide the ferrule up.  flare the braid back and crimp.

Sorry you had problems with your connector, but you're a lot better off safe than sorry.  I'm now taking meds to try to keep me from having to go back for another surgery.  Surgery sucks, but dying was the other option.

--Shane
KD6VXI

Your story made me change my mind about using quick connectors. Glad you're still kicking and I wish you the best.This is what I did with rg213 to bring 5kv to my rf deck.



* 20201102_113044.jpg (1986.23 KB, 4032x1960 - viewed 291 times.)

* 20201118_160011.jpg (2081.15 KB, 4032x1960 - viewed 292 times.)
Logged
KD6VXI
Contributing
Member
*
Offline Offline

Posts: 2648


Making AM GREAT Again!


« Reply #31 on: March 19, 2021, 10:49:27 PM »

I used CGB before.  They are available at depot, etc.  The tighter you screw them down the more they compress the rubber bushing in them.  It's what we have to use in the electric world.  They work pretty good.

I pulled a ton of RG8 sized neon sign cord out of a Target store I did the electric on for a remodel.  It's just like RG8 but the dielectric is something more akin to rubber.  It's great for tying chassis ground together and brining b+ to the RF deck.  Unfortunately the source wasn't infinite and I'm low.....  And haven't found a new source:  Hence my finding that rg59 and SHV connector.

Glad you made it safe.  Sucks the SHV didn't work out though.

--Shane
KD6VXI
Logged
WA1HZK
Member

Offline Offline

Posts: 1104


WWW
« Reply #32 on: April 13, 2021, 11:03:41 PM »

The 10KV parts are too big. Save them for homebrew chassis. I bought another set of the HV 5KV connectors and the proper RG-6 Crimper. I'll try this again. If the High voltage stays in the RG6 where it belongs, I can start testing again. If it looks clean, I'll set things up for 25 feet away and see what happens. I took a month to reorder the connectors from China so that threw a wrench into the project.
Keith
WA1HZK
Logged

AM is Not A Hobby - It's a "Way of Life"!
Timmy, Sometime in 2007 on a Mountain Far Away..
www.criticalradio.com
www.criticalbattery.com
www.criticaltowers.com
www.criticalresponder.com
Official Registered "Old Buzzard"
w6wuh
Member

Offline Offline

Posts: 7


« Reply #33 on: April 16, 2021, 05:42:09 PM »

"I have removed some mods, and now it seems to modulate ok"

This sentence should be chiseled into stone somewhere !

God save us all from ill advised "mods".

else where I read... " I have no audio coupling cap and almost no modulation"
do tell...

Mods
dirty & old parts
misadjusted transmitters

will account for almost all modulator failures

although the goofy cables in the viking 500 design  probably figure in a few disasters.
Logged
WA1HZK
Member

Offline Offline

Posts: 1104


WWW
« Reply #34 on: April 16, 2021, 07:51:29 PM »

It works. I ran it this afternoon and set up the audio with Brent, W1IA. Reports were good. Brent says I sound like me. Life is good.
The only issue is lack of good positive peaks on the signal. After dicking with the feedback and switching the phase of the audio the opinion was that I probably have weak tubes in the modulator.
Having ruined so many this winter I was down to my last used pair. Hey, if that's all I need, no sweat. Now to finish the 25 foot cables and if the radio doesn't puke about that, I'll finally get this installed the way I want it and write this up with some pictures.
Glass FETS, gotta love them.
KC
Logged

AM is Not A Hobby - It's a "Way of Life"!
Timmy, Sometime in 2007 on a Mountain Far Away..
www.criticalradio.com
www.criticalbattery.com
www.criticaltowers.com
www.criticalresponder.com
Official Registered "Old Buzzard"
WBear2GCR
Member

Offline Offline

Posts: 4135


Brrrr- it's cold in the shack! Fire up the BIG RIG


WWW
« Reply #35 on: April 17, 2021, 12:26:51 AM »

For coax used for HV, the polyfoam I am told is NG.
What is good is the solid poly.

I'd never use crimp connectors myself.
Never have.

Hope you get the positive peaks working.
I'd swap the modulator tubes first, as you were going negative just fine.

Also double check the bias and resting and peak current in the modulator!
See what the manual calls for with full snot modulation as far as current.
IF ur making that, there might be a bad winding in the mod iron. But that may
show up in a resistance check.

I was seeing momentary very high peaks in the positive, intermittently
and only with certain vocal sounds. Hard to say what that is.

In addition, if you are coming out of a line level signal path, and depending on
what that is, IF ur using two of three pins on an XLR out, swap to the "other"
pin phase and see if the problem goes away or the positive peaks change.

                _-_-bear
Logged

_-_- bear WB2GCR                   http://www.bearlabs.com
WD5JKO
Member

Offline Offline

Posts: 1996


WD5JKO


« Reply #36 on: April 17, 2021, 10:32:42 AM »



Remember the 1K grid resistors were added to solve parasitic oscillations. With Class B grid drive, the driving impedance needs to be as low as possible. Adding 1K to each side is huge. This will limit upward modulation. Back earlier in this same thread, I suggested removing the resistors and keep the 2.5mh chokes that were added at the same time as the 1K grid resistors.
If the parasitic was at RF, a neon bulb could be temporarily attached to each plate with one lead, and the other lead sticking up in the air. If the bulbs ever light up, then you have a parasitic. The glow will be orange at HF and purple at VHF.

Jim
Wd5JKO

Logged
WA1HZK
Member

Offline Offline

Posts: 1104


WWW
« Reply #37 on: April 17, 2021, 10:46:19 AM »

Good point.
I'll wind some suppressors for the plates and install them. That won't hurt anything and jump over the resistors and see what that does to the positive peaks.
A new set of 572b's is on order.
Logged

AM is Not A Hobby - It's a "Way of Life"!
Timmy, Sometime in 2007 on a Mountain Far Away..
www.criticalradio.com
www.criticalbattery.com
www.criticaltowers.com
www.criticalresponder.com
Official Registered "Old Buzzard"
Pages: 1 [2]   Go Up
  Print  
 
Jump to:  

AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
 AMfone © 2001-2015
Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Page created in 0.093 seconds with 19 queries.