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 1 
 on: Yesterday at 08:19:06 PM 
Started by K8DI - Last post by Detroit47
Epoxy

 2 
 on: Yesterday at 05:58:59 PM 
Started by K8DI - Last post by W1RKW
looking at the picture and considering the amount of crud on the outside of the blower, I'd suspect that the blower internals might be just as cruddy if not worse causing an imbalance of the internal fan/squirrel cage and causing vibration. I'd pull the blower out and make sure the blower internals are clean.  Might as well disassemble the motor and lube the motor too. The motor oil port looks like it has its share of crud on it too. 

 3 
 on: Yesterday at 05:38:05 PM 
Started by K8DI - Last post by K8DI
Working on getting an old linear amp going. Applied filament power today, finally, all seems good...except that also means the blower. Air noise is acceptable, motor hum tolerable...but that motor hum vibrates the tank coils which rattles noisily on its form. The coil is flat wire on some sort of grooved former. Any ideas on how to shut the thing up? Glue? Foam?

Ed

PS picture is as received...I HAVE cleaned it up some;-)

 4 
 on: Yesterday at 05:34:01 PM 
Started by k7mdo - Last post by k7mdo
Old knobs... all for $15 plus postage.  I think the postage would be $15.00 in addition so total will be $30.

73, Tom

 5 
 on: Yesterday at 01:38:01 PM 
Started by ka1tdq - Last post by KD6VXI
Thanks Shane for the choke idea. In Phoenix I was living in a very noisy RF environment but the software was able to filter everything out. My first sniff last night found that 75 meters is actually pretty quiet where I am. No noticeable noise on the higher bands.

I've paired the SDRplays with high power transmitters for some time now. Unlike hollow-state receivers, a little voltage spike would send this thing to the moon. In the past, I've used a double-relay on the receiver, but now put two 1N914's in reverse-parallel on the antenna jack and call it good.

I'll report back with some on air checks in a bit.

Jon


If you don't have one, a USB cable with a choke is a good idea as well.

I had birdies on my first run with SDR...  On a whim I changed the cable out for the one I use on my VNWA and magically the birdies disappeared!  Of course, the VNWA one has a ferrite choke on it Smiley


--Shane

 6 
 on: Yesterday at 12:48:27 PM 
Started by ka1tdq - Last post by KD1SH
Same here; SDR taps in upstream of the amp. Between my grounding relay and the overload protector, the SDR would probably be safe, but I can't see any reason to tap sensitive stuff into the raging torrent when tapping into the trickling brook accomplishes the same thing. My intent in designing my T/R box was not only to use the relatively inexpensive SDRplay, but also my much more expensive Yaesu/Icom rice boxes as auxiliary receivers, if I wish, so I try to make blitzing a receiver as unlikely as possible.


...and, truth be told, I'm tapping the feedline directly after the low power transmitter and before the Acom amp. The receiver only needs to take bleed over from 14 watts carrier.

I haven't tried the double 1N914's directly from high power transmitters. I'll probably be less daring when the time comes and I'll go back to what you just described.

Jon

 7 
 on: Yesterday at 12:29:34 PM 
Started by ka1tdq - Last post by ka1tdq
...and, truth be told, I'm tapping the feedline directly after the low power transmitter and before the Acom amp. The receiver only needs to take bleed over from 14 watts carrier.

I haven't tried the double 1N914's directly from high power transmitters. I'll probably be less daring when the time comes and I'll go back to what you just described.

Jon

 8 
 on: Yesterday at 12:21:30 PM 
Started by ka1tdq - Last post by KD1SH
I use a homebrew T/R switch that grounds the input to the SDR when I key the mic and won't let the transmitter key up until the relays are activated, and I also use one of Array Solutions' receive overload protectors. https://www.arraysolutions.com/surge-and-rf-protection/as-rxfep

Thanks Shane for the choke idea. In Phoenix I was living in a very noisy RF environment but the software was able to filter everything out. My first sniff last night found that 75 meters is actually pretty quiet where I am. No noticeable noise on the higher bands.

I've paired the SDRplays with high power transmitters for some time now. Unlike hollow-state receivers, a little voltage spike would send this thing to the moon. In the past, I've used a double-relay on the receiver, but now put two 1N914's in reverse-parallel on the antenna jack and call it good.

I'll report back with some on air checks in a bit.

Jon


 9 
 on: Yesterday at 12:04:40 PM 
Started by ka1tdq - Last post by ka1tdq
Thanks Shane for the choke idea. In Phoenix I was living in a very noisy RF environment but the software was able to filter everything out. My first sniff last night found that 75 meters is actually pretty quiet where I am. No noticeable noise on the higher bands.

I've paired the SDRplays with high power transmitters for some time now. Unlike hollow-state receivers, a little voltage spike would send this thing to the moon. In the past, I've used a double-relay on the receiver, but now put two 1N914's in reverse-parallel on the antenna jack and call it good.

I'll report back with some on air checks in a bit.

Jon

 10 
 on: Yesterday at 11:48:57 AM 
Started by ka1tdq - Last post by KD1SH
I have one and I love it. It's my first SDR of any sort, so admittedly I lack a baseline for comparison, but with this one small box I free up a whole lot of space on the operating bench, and with the click-and-drag passband edges, notch filters, and all, I can hang in there when the band gets nasty and full of slop-bucket intrusion. I must admit that, being a boat anchor guy, I feel sort of guilty about relegating my faithful old BA receivers to the closet, but this little SDR opens up a whole new world of operating capability. That said, though, I'm not nearly ready to go SDR all the way - still a hollow-state transmitter devotee.

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