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Locked Transmit Loop?
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ED MONTAIGNE
To purchase or to make? Mr Ed? On Mon, Jan 10, 2022, 10:52 AM Grady Hawkins <gradyhawk1952@...> wrote: Are there any transmit rated loops out there that are worth their salt? |
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Hello Grady,
Monday, January 10, 2022 I have received some really strong signals on 160 meters from people using a small transmitting loop. I would imagine they are tuning with a BIG vacuum capacitor and the tuning will be fickle, but fair play to them, they are banging a hell of a signal out from what's a tiny aerial on top band. I would imagine these are home made loops and have some mega voltages on them, let the cat beware ;) Best regards, Chris mailto:chris@... GH> Are there any transmit rated loops out there that are worth their salt? GH> Thanks GH> Grady |
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I am afraid i cannot recommend any ( except maybe for the ciro nazzoni, but that¡¯s very very expensive)
All i have seen are over priced for what they are. Can you make one?? It if done well will out perorm commercial ones and be much cheaper.plus you have bragging rights you did it yourself. Plus not difficult for a low power one. Simon g0zen |
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They are extremely easy to build yourself.? However, be advised that any mag loop is extremely narrowbanded.? On 40-meters with my homebrew 1-Meter diameter 1/2-inch copper tubing loop, the 2:1 SWR points are about 5 to 8 kHz apart (extremely Hi-Q).? The lower frequencies are even narrower.? The hedge to that is to make the loop larger. ? Also, the tuning capacitor must be a high-voltage unit, preferably, a vacuum variable cap.? One day on the air, we were discussing a mag loop for 630-Meters.? It would have to be huge.? A small loop of 1 to 2-meters in diameter likely would be so narrow that voice communication would not be possible due to the extremely high Q.? Yes, narrower than 2.5 kHz! Dave - W?LEV ? On Sat, Jan 22, 2022 at 11:18 AM Simon <ohhellnotagain@...> wrote: I am afraid i cannot recommend any ( except maybe for the ciro nazzoni, but that¡¯s very very expensive) -- Dave - W?LEV Just Let Darwin Work |
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Mike Penkas
¿ªÔÆÌåÓýI have a pic of a 6 foot 3 1/2 in irrigation pipe helically ?wound with 44 feet of 3 inch copper sheet on QRZ? Used a gamma feed.? Q was extreme.? I only had 2khz bandwidth on 75 meters and the ss linear would go into swr shutdown on voice peaks. WA8EBM -------- Original message -------- From: W0LEV <davearea51a@...> Date: 1/22/22 14:32 (GMT-05:00) Subject: Re: [loopantennas] Transmit Loop? They are extremely easy to build yourself.? However, be advised that any mag loop is extremely narrowbanded.? On 40-meters with my homebrew 1-Meter diameter 1/2-inch copper tubing loop, the 2:1 SWR points are about 5 to 8 kHz apart (extremely Hi-Q).? The lower frequencies are even narrower.? The hedge to that is to make the loop larger. ? Also, the tuning capacitor must be a high-voltage unit, preferably, a vacuum variable cap.? One day on the air, we were discussing a mag loop for 630-Meters.? It would have to be huge.? A small loop of 1 to 2-meters in diameter likely would be so narrow that voice communication would not be possible due to the extremely high Q.? Yes, narrower than 2.5 kHz! Dave - W?LEV ? On Sat, Jan 22, 2022 at 11:18 AM Simon <ohhellnotagain@...> wrote: I am afraid i cannot recommend any ( except maybe for the ciro nazzoni, but that¡¯s very very expensive) -- Dave - W?LEV Just Let Darwin Work |
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I've attached a copy of my own transmitting loop antenna.? It does not use the expensive variable vacuum capacitor not the difficult delta loop.
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? Chris Trask N7ZWY / WDX3HLB Senior Member IEEE -----Original Message-----
From: Sent: Jan 22, 2022 4:18 AM To: Subject: Re: [loopantennas] Transmit Loop? ? I am afraid i cannot recommend any ( except maybe for the ciro nazzoni, but that¡¯s very very expensive) All i have seen are over priced for what they are. ? Can you make one?? It if done well will out perorm commercial ones and be much cheaper.plus you have bragging rights you did it yourself. Plus not difficult for a low power one. ? Simon g0zen |
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Dave
You can not tx voice on 630m.. not allowed Plus bandwidth would be more like 500hz if lucky. My BIG 160m loop has bandwidth of 2.5khz ( just.) that has a circumference of 20m.i can not use the ldmos amp on that as its swr trip comes in ( set at 2:1 ) .Had to make a valve ( tube) amp for it.( could set the swr trip higher with out worries about damage.) amps are full legal.. A 1m dia loop would not be possible on 160, or 80 let alone 630m. Thats if you want it to work with any efficiency. Simon g0zen |
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In my home brewing for 630-meters, the audio power BJTs work very well.? Three or five hundred watts is easy on 630-meters using those.? FETs are a bit more fragile. Dave - W?LEV? On Sat, Jan 22, 2022 at 10:49 PM Simon <ohhellnotagain@...> wrote: Dave -- Dave - W?LEV Just Let Darwin Work |
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As to the legality of phone (SSB) on 630-Meters, here it is off the ARRL page: Dave - W?LEV On Sat, Jan 22, 2022 at 11:43 PM David Eckhardt <davearea51a@...> wrote:
-- Dave - W?LEV Just Let Darwin Work |
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On Sat, Jan 22, 2022 at 10:00 PM, Chris Trask - N7ZWY/WDX3HLB wrote:
I've attached a copy of my own transmitting loop antenna.? It does not use the expensive variable vacuum capacitor not the difficult delta loop.Hi Chris, Can you put a copy in the files section, as the forum doesn't seem to like attachments ? incidentally, for some reason your website link doesn't seem to be working. Regards, Martin |
I've attached a copy of my own transmitting loop antenna.? It does not use the expensive variable vacuum capacitor not the difficult delta loop.Hi Chris, Can you put a copy in the files section, as the forum doesn't seem to like attachments ? ? I just put a copy into the group files section.? I was surprised that it wasn't there already.? There will be an announcement to the group shortly. ? Chris ? When the going gets weird, the weird turn pro - Hunter S. Thompson |
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On Sun, Jan 23, 2022 at 04:03 PM, Chris Trask - N7ZWY/WDX3HLB wrote:
I just put a copy into the group files section.?Hi Chris, Sorry I don't know what file type it is as the extension is weird, I've tried the obvious ones but still can't open it. I think I can see a reference to Pagemaker in the text but no other clues. Regards, Martin |
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