Date
1 - 9 of 9
Shack in a box with 4SQRP kits?
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Ross Tucker (NS7F)
Hi all-
I'm investigating what it'd take to build a shack-in-a-box out of mostly 4SQRP kits. I don't want to integrate the components TOO tightly- I want to be able to reuse them for other projects later. The major components would be: * Bayou Jumper (w/ Souper Upper and a KD1JV Simple Keyer Chip to allow me to plug in paddles) * Bioenno LiFePO4 battery * QRP-Labs "50W" amplifier * 4SQRP Tuner One immediate problem I'm facing is that the tuner is only rated at 10 W. The amp puts out 25 W (when fed with 12 V). What needs to be beefed up in the tuner to make it safe at this power level? Also, where can I buy little BNC jumpers? I need them to connect the radio to the amp and the amp to the tuner- so maybe 6"?ty Thanks for your time! Ross, NS7F
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Curt
Ross
You could be in hot water for the mostly part, but I may join you a bit since 4state doesn't make a competitor. I suggest using the nice amp as an add on at home. Oh with good prop we do qso at fewer watts in these parts. While I enjoy my fun regen transceiver I would not build a mini station around it. Most do the regen for adventure, and I have even done ragchews on 80m. To grow a tuner to 25 watts need higher voltage capacitors, larger toroid and slightly thicker wire. Only the knows and connectors are common. Well most of us get our bnc jumpers from junk piles at hamfests or from friends that have surplus. Often nice to have one with pl259 on the other end also. If you need something fast check Amazon or low cost ham distributors. Cheap ham and someone else out there. Acquire good stuff from 4state as it's offered but maybe you can't get everything at once. Appreciate the folk who design and kit this stuff, oh I can't mention competition but they are ham Brethren from qrp community. Curt
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For greater power handling (25w rather than 10W...), I'd suggest going up a size on the torroid and maybe a size up on the wire for it. Try to find a varicap with Teflon insulators, too.
Ted K3RTA
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John Lonigro
It seems to me that, if you need to replace the varicaps with ones
that can handle higher voltages, and you need to replace the toroid
with a bigger one, then you will have replaced the entire tuner,
other than the LED circuit, which might also need tweaking to handle
the higher voltages. I suggest it would be easier to build one
from scratch than to try to retrofit the existing one to a higher
power. And, since 25 Watts is only a few dB higher than 10 Watts,
you should ask yourself if it's even worth it.
toggle quoted messageShow quoted text
On the other hand, if you really want to run 25 Watts into this tuner, it would be an interesting experiment to see if it could handle the power unmodified. If the capacitors don't arc, then toroid heating might be the only concern. At a low transmit duty cycle, that may not be a serious issue. And if the experiment results in the tuner self-destructing, you'd have to replace the capacitors and toroid anyway. At that point, you could try to stuff the case with components that can handle 25 Watts (after extinguishing the flames and letting the case cool-hi). 72, John, AA0VE On 11/17/22 07:07, Ted via groups.io
wrote:
For greater power handling (25w rather than 10W...), I'd suggest going up a size on the torroid and maybe a size up on the wire for it. Try to find a varicap with Teflon insulators, too.
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Steve MIller
Instead of speculating or suffering a possible meltdown, wouldn't it be best to speak to the designer who can answer your questions???? Steve N0SM
On Thursday, November 17, 2022 at 08:07:47 AM CST, John Lonigro <jonigro@...> wrote:
It seems to me that, if you need to replace the varicaps with ones
that can handle higher voltages, and you need to replace the toroid
with a bigger one, then you will have replaced the entire tuner,
other than the LED circuit, which might also need tweaking to handle
the higher voltages. I suggest it would be easier to build one
from scratch than to try to retrofit the existing one to a higher
power. And, since 25 Watts is only a few dB higher than 10 Watts,
you should ask yourself if it's even worth it. On the other hand, if you really want to run 25 Watts into this tuner, it would be an interesting experiment to see if it could handle the power unmodified. If the capacitors don't arc, then toroid heating might be the only concern. At a low transmit duty cycle, that may not be a serious issue. And if the experiment results in the tuner self-destructing, you'd have to replace the capacitors and toroid anyway. At that point, you could try to stuff the case with components that can handle 25 Watts (after extinguishing the flames and letting the case cool-hi). 72, John, AA0VE On 11/17/22 07:07, Ted via groups.io
wrote:
For greater power handling (25w rather than 10W...), I'd suggest going up a size on the torroid and maybe a size up on the wire for it. Try to find a varicap with Teflon insulators, too.
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nm0s_qrp
The power limitation on the 4SQRP tuner is actually the voltage rating on the 1N4148 diodes. As long as the power is kept to 10W or so when the tuner is switched 'in', it will be safe, and then power can be raised to 30 to 50 W (depending on VSWR) when the tuner is switched 'out'.
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John Lonigro
I prefer speculating about flaming tuners (hi).
toggle quoted messageShow quoted text
But Steve is obviously correct and I’m glad NM0S chimed in with the definitive answer. Thanks, Dave. John, AA0VE
On Nov 17, 2022, at 8:31 AM, Steve MIller via groups.io <steven0sm@...> wrote:
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William Franklin
A comment about John's, AA0VE, reply and suggestions. I totally agree that it would be best to design a tuner to fit the power requirement. Besides the strain on the capacitors and toroid. the resistors in the bridge might survive a high power a few times.
However, it's just a matter of when, not if, that someone, whether by ignorance or error, will exceed the ability of the bridge resistors power handling capability. The bridge resistors play a more important part in protecting the solid state amplifiers.
So, the bridge method of matching adjustment is much preferred over tuning the solid state amp with a conventional tuner into a high swr load until the proper matched is achieved. Questions, answers, observations, and curiosity like this is what makes amateur
radio so much fun. Hang in there, and don't forget, what one gains from failure is experience. Learned a lot of my stuff that way. Good luck.
73, Bill, K5WB
From: main@4SQRP.groups.io <main@4SQRP.groups.io> on behalf of John Lonigro <jonigro@...>
Sent: Thursday, November 17, 2022 11:13 AM To: main@4sqrp.groups.io <main@4sqrp.groups.io> Subject: Re: [4SQRP] Shack in a box with 4SQRP kits? I prefer speculating about flaming tuners (hi).
But Steve is obviously correct and I’m glad NM0S chimed in with the definitive answer. Thanks, Dave.
John, AA0VE
On Nov 17, 2022, at 8:31 AM, Steve MIller via groups.io <steven0sm@...> wrote:
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Gerald Sherman
An antenna analyzer might be a good idea for getting an unknown or variable antenna into the ballpark. They don't care about SWR with regard to getting the system into tune. I use an Antuino from HFSignals in Hyderabad (India). There are others. Gerry Sherman Sent from the Linux Thunderbird On 2022-11-17 20:02, William Franklin
wrote:
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