On Mar 6, 2024, at 8:05?AM, Wes Winkler via groups.io <wewinkler@...> wrote:

?I got a couple of Drake SL-2300 2.3-5645kHz Filters at a swap meet and am contemplating testing them with a NanoVNA.? I have three concerns.

1) Can I directly connect the filter to the Nano VNA? I am mainly concerned about damaging the filter due to the signal input signal level.
2) I reviewed the TR-7 manual but it not immediately obvious which is the input, and which is the output of the filter.
3) An idea of what the input/output impedance termination should be?? I may need matching transformers for the Nano VNA test.?
--
Regards,
Wes
W4JYK

I thought I posted this but will try again.
My T4X-B just stopped transmitting on 75 and 160. Not sure if 160 worked before since I never tried it, but losing 75 meters is hard since that is my major band of choice for the twins.
It will try and get resonant but the RF Tune knob is clear over past the 40M mark, and still virtually no output. I tried cycling the band switch a few times but that didn't change anything.

Can I get a little help on what to look for?

Thanks!
Greg "Gus" Anderson

On Mar 5, 2024, at 10:01 AM, Steve Wedge, W1ES/4 via <w1es@...> wrote:

Tim, the sole reason for the CW position, at the time of manufacture, was to keep within the power regulations that were in place, in the USA, at the time. ?The limitation was 1000 watts input power, which was obtained on CW by multiplying the plate voltage by the plate current. It was acceptable then to estimate the power input for SSB, since there was no easy way to measure PEP.

Having said all of that, I do consider the CW position to be useful for digital modes, as it limits the power out to a safe level for the amp. When I use the amp (rarely) for digital modes, I keep my output at around 500 - 600W. ?On CW, I use the amp on the “SSB” position to get max power out, which is around 1200W if you keep the grid current within the tube ratings.

Steve Wedge, W1ES/4

Time flies like an arrow. Fruit flies like a banana.

Sent from for iOS

On Mar 5, 2024, at 9:41?PM, Stan Gammons via groups.io <buttercup11421@...> wrote:

On 3/5/24 21:32, Gary Follett wrote:

Nice work on the replacement pot!

AxMan Surplus in Saint Paul likely has exact replacements but not too likely they would take the trouble to look for them when the selling price is likely around $0.99 plus shipping.

Gary

W0DVN

PS: What is the value? Next time I am over there I may have a look to see if they have the correct value.

Thanks.? I found some 201 series pots on Epay, but the price for 2 is what I gave for a 10 piece of the horizontal mount 201 series pot.? The R-4B receiver sensitivity and S meter sensitivity pots are both 1K.

73

Stan
KM4HQE

On Mar 5, 2024, at 8:13?PM, Stan Gammons via groups.io <buttercup11421@...> wrote:

On 3/3/24 15:13, Jim Shorney wrote:

Yeah, just looking at the relatively soft material they are crimped to makes me nervous. Once they start to loosen up the end is near. I don't like to mess with the legs at all.

True.? While not the ideal thing to do; here's what I did since I've been unable to find any of the original CTS 201 series pots of the correct value which mount vertically.? CTS still has this document on their website even though it looks like they discontinued the 201 series.?

Replacing the pots helped matters a lot.? I'm able to get -1.35 volts on TP2, but the S meter sensitivity is fully clockwise to get 40 DB S meter reading. So, maybe some of the resistors in the circuit have changed value. With a 1 uV signal on 7 Mhz from my HP8656B signal generator, the S meter reads about S3.

73

Stan
KM4HQE

<pot2.JPG>

I use it for DXCC points and chasing various special events. I don't get the mass of stateside stations happily working each other every day. That's not fun to me. There is a specific skill set that is unique to getting the most out of FT/JT modes. I have had to work hard for some of the DX contacts I have made. It is not a lot different than trying to cut through a CW or SSB pile up.

73

-Jim
NU0C

On Tue, 5 Mar 2024 21:52:42 +0000 (UTC)
"amfone via groups.io" amfone20000@... wrote:

Thats what I have found out as well Jim about FT8, but I do not use it now, once I got the software working and found out what was going on it was just not for me, I like keyboard to keyboard modes. But FT8 is there all the time, lots of activity.
73 Tim
WB8UHZ

On Tuesday, March 5, 2024 at 04:13:26 PM EST, Jim Shorney jimnu0c@... wrote:

Yeah, 110 watts is my TR7 barefoot. :) It handles it without breaking a sweat. I use higher power when chasing a rare DX that I need. To quote Joe Taylor, FT/JT mode "is not a low power mode, it is a weak signal mode".

73

-Jim
NU0C

On Tue, 5 Mar 2024 20:57:04 +0000 (UTC)
"amfone via groups.io" amfone20000@... wrote:

Right Jim you have to run the tubes hot enough so the getter works, I can tell with the L7 that that is occurring when the thermostatically controlled fan turns to high speed on the L4B its east to see the tubes.
OK on running the amp in SSB mode for CW operation, I have not done that. On digital modes, I just do it for fun so my "big" power is about 110 watts or so. I wish we had more RTTY ops than just on contest weekends.
73 Tim
WB8UHZ

On Tuesday, March 5, 2024 at 03:24:25 PM EST, Bill Leonard N0CU billincolo73@... wrote:

I have read that the power switches on the R4 seriestransmitters and receivers are also hard to find and/or expensive. If so, isthere any benefit to installing some type of surge current reduction on theseunits to extend their life, or is the failure mechanism mostly a mechanicalissue?

Bill N0CU

On Tue, Mar 5, 2024 at 11:58?AM Rick W4XA myr748@... wrote:

On Tue, Mar 5, 2024 at 03:50 AM, Jim Altman wrote:

I was seeing a little arcing from the power switch contacts and installed the SSR with perfect results. I could tell there was a little arc because the lightning detector on my weather station, only a few feet from the amp, would give me a false positive everytime i turned on the amp. Given the difficulty of finding replacement switches and rebuild kits for the switch, its a nice solution,
73 Jim, W4UCK

Yeah, you only see that "arc" if the switch is closed (or opened) while the voltage is at a peak (sine wave peak)

If you have ever plugged (or unplugged) in any device that's "ON" when you plug it in and have noticed a little spark, flipped a light switch on or off and heard the faint "snap" it likely happened at or near the sine wave peak (positive or negative) and of course, you do not see that spark or hear it every time.

The trick is to "flip" the switch when the voltage is crossing at or near zero.

Now maybe there are people that can "see" the sine wave in their heads and are fast enough to flip the switch at the right time, and won't need a little additional help getting the timing right.

For the rest of us, an SSR does it nicely.

W8ZR suggested using only one but you can use 2 when powering with 240AC. (have a look at the power supply schematic for the Commander 2500) page 16

You also do not have to use the DC controlled model either. (Commander 2500 uses AC SSR's) I am going to use the AC controlled model eliminating the need for a separate (always powered) small DC power supply Either way, the control "side" of the SSR draws so little current as to be insignificant.

I'll be operating my Loudenboomer (powered by the L-4B plate transformer) on 120AC and always in the "high-voltage" mode. (240 is really not required for a 1kw input amp) so I'll use one OPTO22 Model 120A25 in the"hot" side.

For a 240 VAC powered amp, I would use two 240A45 (AC controlled) or 240D45 (DC controlled) units.

See the link below for specs:

OPTO22 (opens a PDF viewer)

The key with these is that they "turn-on" at zero crossing (zero voltage) and give a slight measure of ramp-up in voltage.
I seem to remember that Tom, W8JI said the only reason "step-start" is needed, is to protect the ON/OFF switch. with an SSR, the voltage on the PS circuits doesn't "slam" on it ramps up at a "sine-wave rate". The actual current in the SSR control circuit is on the order of mA.
See page 2 of the above publication for the features.

I'm also using a CRYDOM MPDCD3 DC SSR for a keying interface to use with my IC-705 (similar to the OPTO22 DC60MP) with a double 3v lithium battery holder for complete isolation to protect the IC-705 keying circuit driving any amplifier.

All the SSR's I have bought so far I have gotten from eBay. All used. If you buy them new, they're crazy expensive but there's nothing wrong with used ones. They either work or they don't.

BE VERY Careful buying the cheap knock-off SSR's. They frequently have triacs inside that are not rated for the claimed current on the outside of the device. And if you're going to run them at or near max current ratings, ABSOLUTELY MIND THE HEAT DISSIPATION!!

I'm using a 120V 25A device on my Loudenboomer and will use two 240v 45A devices in my L-4B (The L-4B even at Key-DOWN 1200 W output doesn't pop a 15A breaker. Mounting to the chassis will likely be more than enough heat sink in the L-4B

Even after many hours the one I mounted in my AC-4 gets only slightly warm using the chassis as a heat sink (I used a little heat grease too)

I do have a small heat sink that I'll probably use in the Loudenboomer.

--

73

-Jim
NU0C

Yeah, 110 watts is my TR7 barefoot. :) It handles it without breaking a sweat. I use higher power when chasing a rare DX that I need. To quote Joe Taylor, FT/JT mode "is not a low power mode, it is a weak signal mode".

73

-Jim
NU0C

On Tue, 5 Mar 2024 20:57:04 +0000 (UTC)
"amfone via groups.io" <amfone20000@...> wrote:

> Right Jim you have to run the tubes hot enough so the getter works, I can tell with the L7 that that is occurring when the thermostatically controlled fan turns to high speed on the L4B its east to see the tubes.
> OK on running the amp in SSB mode for CW operation, I have not done that. On digital modes, I just do it for fun so my "big" power is about 110 watts or so. I wish we had more RTTY ops than just on contest weekends.
> 73 Tim
> WB8UHZ
>
> On Tuesday, March 5, 2024 at 03:24:25 PM EST, Bill Leonard N0CU <billincolo73@...> wrote:
>
>
> I have read that the power switches on the R4 seriestransmitters and receivers are also hard to find and/or expensive. If so, isthere any benefit to installing some type of surge current reduction on theseunits to extend their life, or is the failure mechanism mostly a mechanicalissue?
>
> Bill N0CU
>
> On Tue, Mar 5, 2024 at 11:58?AM Rick W4XA <myr748@...> wrote:
>
> On Tue, Mar 5, 2024 at 03:50 AM, Jim Altman wrote:
>
> I was seeing a little arcing from the power switch contacts and installed the SSR with perfect results. I could tell there was a little arc because the lightning detector on my weather station, only a few feet from the amp, would give me a false positive everytime i turned on the amp. Given the difficulty of finding replacement switches and rebuild kits for the switch, its a nice solution,
> 73 Jim, W4UCK
>
>
> Yeah, you only see that "arc" if the switch is closed (or opened) while the voltage is at a peak (sine wave peak)
>
> If you have ever plugged (or unplugged) in any device that's "ON" when you plug it in and have noticed a little spark, flipped a light switch on or off and heard the faint "snap" it likely happened at or near the sine wave peak (positive or negative) and of course, you do not see that spark or hear it every time.
>
> The trick is to "flip" the switch when the voltage is crossing at or near zero.
>
> Now maybe there are people that can "see" the sine wave in their heads and are fast enough to flip the switch at the right time, and won't need a little additional help getting the timing right.
>
> For the rest of us, an SSR does it nicely.
>
> W8ZR suggested using only one but you can use 2 when powering with 240AC. (have a look at the power supply schematic for the Commander 2500) page 16
>
> You also do not have to use the DC controlled model either. (Commander 2500 uses AC SSR's) I am going to use the AC controlled model eliminating the need for a separate (always powered) small DC power supply Either way, the control "side" of the SSR draws so little current as to be insignificant.
>
> I'll be operating my Loudenboomer (powered by the L-4B plate transformer) on 120AC and always in the "high-voltage" mode. (240 is really not required for a 1kw input amp) so I'll use one OPTO22 Model 120A25 in the"hot" side.
>
> For a 240 VAC powered amp, I would use two 240A45 (AC controlled) or 240D45 (DC controlled) units.
>
> See the link below for specs:
>
> OPTO22 (opens a PDF viewer)
>
> The key with these is that they "turn-on" at zero crossing (zero voltage) and give a slight measure of ramp-up in voltage.
> I seem to remember that Tom, W8JI said the only reason "step-start" is needed, is to protect the ON/OFF switch. with an SSR, the voltage on the PS circuits doesn't "slam" on it ramps up at a "sine-wave rate". The actual current in the SSR control circuit is on the order of mA.
> See page 2 of the above publication for the features.
>
> I'm also using a CRYDOM MPDCD3 DC SSR for a keying interface to use with my IC-705 (similar to the OPTO22 DC60MP) with a double 3v lithium battery holder for complete isolation to protect the IC-705 keying circuit driving any amplifier.
>
>
> All the SSR's I have bought so far I have gotten from eBay. All used. If you buy them new, they're crazy expensive but there's nothing wrong with used ones. They either work or they don't.
>
> BE VERY Careful buying the cheap knock-off SSR's. They frequently have triacs inside that are not rated for the claimed current on the outside of the device. And if you're going to run them at or near max current ratings, ABSOLUTELY MIND THE HEAT DISSIPATION!! https://www.youtube.com/watch?v=FV9t1GFVbhU
>
> I'm using a 120V 25A device on my Loudenboomer and will use two 240v 45A devices in my L-4B (The L-4B even at Key-DOWN 1200 W output doesn't pop a 15A breaker. Mounting to the chassis will likely be more than enough heat sink in the L-4B
>
> Even after many hours the one I mounted in my AC-4 gets only slightly warm using the chassis as a heat sink (I used a little heat grease too)
>
> I do have a small heat sink that I'll probably use in the Loudenboomer.
>
>



--

73

-Jim
NU0C