lockdown boredom

[surefm]

Another picture of board.

[surefm]

Trying it in stereo, all seems ok so far, leave it running for a couple of days.

[Albert H]

Albert I'm thinking flower pot antenna, not not sure if I'm calculating right, 2 quarter wavelengths of 81.3cm and 13 turn choke on a 32mm pipe is 87.6?

That'll work! You'll need to tweak the lengths slightly, so cut them slightly too big and trim for best SWR.

[Santiago]

Albert, I'm going to try a roll up slim Jim with 450ohm ladder wire, it's cheaper and looks like it's the best for stealth. just got a nice small 35amp car battery that easy to carry just need to work out possible running time
does anyone have a ball park fig on how many amps the rdvv board uses?

[Bton-FM]

Can’t you connect your multimeter in series with the RDVV whilst it is running and measure the current draw?

[teckniqs]

Albert, I'm going to try a roll up slim Jim with 450ohm ladder wire, it's cheaper and looks like it's the best for stealth. just got a nice small 35amp car battery that easy to carry just need to work out possible running time
does anyone have a ball park fig on how many amps the rdvv board uses?

Usually about 1 to 1.5 amps depending on the power output. You should last all day long.

[tokingmenace]

Can’t you connect your multimeter in series with the RDVV whilst it is running and measure the current draw?

Yes you can. A good way to calculate battery time.

[Santiago]

I did not know that, i have a multimeter thank you will try

[tokingmenace]

Albert, I'm going to try a roll up slim Jim with 450ohm ladder wire, it's cheaper and looks like it's the best for stealth. just got a nice small 35amp car battery that easy to carry just need to work out possible running time
does anyone have a ball park fig on how many amps the rdvv board uses?

Personally I would use a leisure battery, better life cycle for recharging, when your kit drain's it down really low.
You can pick-up small 75Ah one's cheap online.

Your car battery will be fine though, and you should get 24hours of continuous use. All depends what else you are thinking of
draining from it? mp3 player / phone for audio linking.

Adding a 12volt on/off timer switch is a good way to save power, say you just want to come on for 12hours Saturday & Sundays.
That way you can do a weekend stint and only have to change your battery once a week.
You have to think, is it worth wasting battery life in the early hours of the morning, when the potential for listeners will be low?

[Santiago]

it's just a little experiment for the weekends, want to see how low power I can go to cover my area, if I can do it on 6 watts or less that would be a bonus.
going to play pre recorded for now, if works I'll try 4g linking

[Albert H]

The batteries I used for things like this were big lead / acid sealed jobs that had been removed from burglar alarms. There was a company near me in North London (way back when I lived there) that maintained burglar alarms. Their field engineers would return to base each week with a bootful of batteries that they'd replaced just because the contracts said that they had to. Most of these batteries had just sat there on float charge for about 2 years until they were replaced. The boss of the company was glad to have me dispose of them for him!

[teckniqs]

The batteries I used for things like this were big lead / acid sealed jobs that had been removed from burglar alarms. There was a company near me in North London (way back when I lived there) that maintained burglar alarms. Their field engineers would return to base each week with a bootful of batteries that they'd replaced just because the contracts said that they had to. Most of these batteries had just sat there on float charge for about 2 years until they were replaced. The boss of the company was glad to have me dispose of them for him!

Sounds like the usual pair of 12v @7Ah Yuasa types.

[Albert H]

They were bigger than that. They're rated at 15.5 AH per battery. They're sealed. Some are Yuasa and others are Varta, Chloride and "Sunshine"! I've still got a pallet full of them in my lock-up.

[Santiago]

tested the board on the car battery, no noise at all, tweaked the power up to 8 watts and ran some audio through.. all seems good. just going to box it up no frills, attach heatsink and I've got a old maplin project box to put it in.

[Electronically]

tested the board on the car battery, no noise at all, tweaked the power up to 8 watts and ran some audio through.. all seems good. just going to box it up no frills, attach heatsink and I've got a old maplin project box to put it in.

Maplins box your talking about. Is that the one with the black cover top?. If so there hard to find these days. I've Been hunting for one of them.

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[teckniqs]

[Bton-FM]

Craplin was so annoyingly useless! Whenever you went to get some components you were missing they only ever had 3! Not to mention how overpriced it was.

[Santiago]

yea with black top, its been in storage 10+ years

[Electronically]

yea with black top, its been in storage 10+ years

Christ, wonder how there was none in maplins, you've bought them all lol.

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[Bton-FM]

Out of interest where do people get the enclosures for the rig? They are so expensive on Ebay.