Biggest surprises and Biggest disappointments - Rigs and Antennas

[w3jn]

My biggest disappointment was a Collins 75A-4.  Couldn't wait to get it home and play with it.  That lasted all of a half hour before the audio quality irritated me so much I shut it off.  I fiddled with it for a bit doing an alignment, etc., but sold it at the next hamfest.  My second biggest disappointment is my SX-88 - nice receiver, but certainly not of legendary quality.

My biggest surprise was how nice my converted HW-12 sounded after a quickie half-hour conversion to AM.  I've gotten several .wav files (TNX, Bill, Bill, and the rest of you!) and it sounds pretty good.  Still, it's a terrible piece of junk - but a nice sounding piece of junk.

[Jim, W5JO]

Disapppointments Huh?  In old radios there are few, but must agree Collins audio is one, alignment of National receivers is another (I hate their coil loop bending) and not having enough height or space I want for antennas, watching the resistors in parasitic suppressors fry in transmitters and the horrible sound of modern receivers in the AM mode.

Surprises, Leo Meyersons contributions despite his Pi Network design, stability of B&W 5100 & B model and the longivity of 50's era equipment.  Thus far I have been rewarded with nice people who contribute parts, support and help with this stuff.  I am really surprised at my new Globe Champion 300A, which is doing a great job, even though it is a bit audio restricted. 

[Steve - WB3HUZ]

I once worked South Africa using an old inner spring mattress as an antenna. I'd recommend this setup to anyone. You can sleep on it too, but only when not transmitting.

[Vortex Joe - N3IBX]

I once worked South Africa using an old inner spring mattress as an antenna. I'd recommend this setup to anyone. You can sleep on it too, but only when not transmitting.

Steve - That's what one would call "modulating the bedsprings" - hi!
Joe N3IBX

[wa2zdy]

I was at the Jersey shore this past weekend.  My buddy N2FVV has a summer home there on a salt water lagoon.

He has a 5BTV mounted on a pipe stuck in the mud at the bottom of the lagoon and the pipe is also secured to the dock.  He has several radials run inland from the water and radials buried in the mud at the bottom too.

I was on 20 and 40 over the weekend and trust me, that antenna gets out!   Salt water of course makes for a good ground.   So while it certainly isn't an ideal antenna, if it's all you can do and you're wiling to do the radials that are needed, it'll work pretty well.

[K3ZS]

A few years ago I finally put up a high 135 ft doublet in the trees, far from the house, fed with ladder line and counterweighted.  Had one contact with it.  I grounded it when not in use.  It was struck directly by lighting, vaporizing the wire, scared the daylights out of my wife who saw it happen and wiped out many electronic things in the house.  I put up a another one and now just disconnect it, but no grounding.

[AG4YO]

It's magic!!!!!

Live in a subdivision with a Nazi committee and the Fuhrer himself lives next door.  I have a Alpha DXCC in my attic (big high attic) and one of these Isotron 80's on a pole dead in the middle of the attic up clear in the attic air.  Isotron actually transmitts well but receives like a brick.  No, it ain't a wire at 50 feet, but I must admit it suprised me.  I am going to run 200+ feet of very small wire around the inside of my fence for a better RX antenna. I use the DXCC on my Kenwood 2000 and it works well on all bands. 

Miss my 4.5 acres in Pensacola where there were no restrictions...

[Steve - WB3HUZ]

YO: You might consider a loop in your attic. Run the wire around the perimeter of your attic and feed it with open-wire or ladder line. You can deploy a fair amount of wire this way. I used this arrangement years ago to make an 80 foot long loop. Worked real well on 40 meters and fair on 75 meters.

[Glenn NY4NC]

I have no doubt that would produce a bigger signal than the little Isotron.

YO: You might consider a loop in your attic. Run the wire around the perimeter of your attic and feed it with open-wire or ladder line. You can deploy a fair amount of wire this way. I used this arrangement years ago to make an 80 foot long loop. Worked real well on 40 meters and fair on 75 meters.

[K1JJ]

Someone had mentioned somewhere, that the way the coax shield terminated on the Isotron - it was effectively floating RF-wise.  They came to the conclusion that the antenna really works by making the coax part of the radiating element. The equivalent circuit would be something like a vertical wire fed against ground.  I'd have to see one in the flesh myself.

ie, If the coax shield terminates to that little frame surrounding the coil, you have an incredibly small groundplane/ element for the shield to work against - unless the WHOLE Isotron is the top section of the "vertical loaded whip"  includng the coax, and the surrounding  Earth is the groundplane... I dunno..

T

T

[KB2WIG]

I still think that the light bulb is an effective radiator for RF.......   wire up a pig tailed lamp socket with a hunk of wire shaped like that thar iso tron and feed it with coax... hang er up high so everyone can see u mod ulating.....  klc

[Glenn NY4NC]

When I was a novice, I used to try and make contacts with my light bulb dummy load, connected to my DX-40 with a length of zip cord!... Tried for the "Worked All Dummy Loads" award but never made it. 

I still think that the light bulb is an effective radiator for RF.......   wire up a pig tailed lamp socket with a hunk of wire shaped like that thar iso tron and feed it with coax... hang er up high so everyone can see u mod ulating.....  klc

[WB1AEX]

Biggest surprise:  Working Deano WA1KNX on 160 meters during a late night winter QSO using 100 mw with the Viking One variac power supply cranked to the minimum readable voltage.

Biggest disappointment:  Watching the plastic insulating material drip from between the turns of the big B&W inductor in the pi-network of my homebrew 4-400 rig as I keyed it up on 75 meters for the first time for a test run.  Oooops, you mean I can't leave the unused portion of the coil hanging off the end like that???

:O)

Rob WB1AEX

[AG4YO]

YO: You might consider a loop in your attic. Run the wire around the perimeter of your attic and feed it with open-wire or ladder line. You can deploy a fair amount of wire this way. I used this arrangement years ago to make an 80 foot long loop. Worked real well on 40 meters and fair on 75 meters.

Have the full sized multiband dipole up there now.  But your idea is a good one, worth a try.  I keep hoping I will get a brain storm and get a good stealth design for outside that the Gestapo won't see....      

[K1JJ]

Biggest disappointment:  Watching the plastic insulating material drip from between the turns of the big B&W inductor in the pi-network of my homebrew 4-400 rig as I keyed it up on 75 meters for the first time for a test run.  Oooops, you mean I can't leave the unused portion of the coil hanging off the end like that???

:O)
Rob WB1AEX

Hola Rob!

Sounds yaellowy.

You got me curious - why do ya think the coil melted with the extra turns hanging like that?  I know there is a Tesla effect creating coronas and stuff off the end, but I wonder why the form melted? What was the configuration?

I usually leave the 50 ohm end of a tank coil floating and then tap down the coil with the loading cap. Better Q that way w/o shorting the coil.  I've seen a shorted coil secton heat up, even though it was supposedly out of the RF circuit. With the free tapping technique, assuming there is no corona, there is no heat on the unused side.

Corona can occur with free tapping on the higher bands when much of the coil is hanging out, unused. But no problem usually on 160-40M. A lot depends on the bandswitch spacing, etc.

T

[WB1AEX]

Hola Rob!

Sounds yaellowy.

You got me curious - why do ya think the coil melted with the extra turns hanging like that?  I know there is a Tesla effect creating coronas and stuff off the end, but I wonder why the form melted? What was the configuration?

Hi Tom,

Several people offered their theories about why this happened. All of them seemed plausible. The configuration was a simple pi-network and what I did was put a strap that ran from across the end of the coil back to the point I was tapping to tune the network. Seemed like a good idea, but keep in mind that the coil was actually about a foot long, so there was quite a bit of coil hanging off there. The theory that sounded most likely to me was that a fair amount of RF was being coupled into that section of the coil because it still offered a  lot of inductance to the circuit in spite of my feeble effort to short the turns. As I recall, the melting points were evenly spaced across the surplus windings, about every 3rd turn the plastic evacuated the coil. Probably a harmonic or parasitic several multiples above 75 meters. Remember... cough cough... this was definitely a FB example of JS design, and my first attempt at a high power amp. It all worked fine when I cut off the extra (melted) coil, and as I recall it only took a total length of about 4 inches to make it resonate on 160 meters. Live and learn, eh?

Hey nice working you on 6m the other day. I ended up putting a 3 element beam up there and it's been great fun.

73,

Rob WB1AEX

[K1JJ]

OK, Rob -


Yes, the config you described is what I meant by shorting the coil across itself and producing heat. That makes sense.  Though, most finals these days do that. I see it all the time, especially in low power <100 watt commercial rigs.

To avoid that situation, as I described, I tap the floating coil from the loading cap side and hardwire the plate tuning cap to the other end.  I was told the Q is better as well as more efficient due to that shorted area not wasting power for whatever reason.

Yes, it was a surprise to hear you break in on 6M.

I just got in from a two hour tower climb tonight. Put up the second 5el 10M Yagi at 92'. It went up FB. The second one is up at 62' and I still need to finish up the third at 32'. I really enjoy seeing the end result sitting up there from the ground...

Good going on your 6M beam you got up. It makes all the difference in the whirl after guys put them up.

73,
T

[w1guh]

Biggest disappointment...Mohawk...'nuff said.

Biggest surprise...Scratchy...well built & rugged.

Or....


Biggest disappoint AND biggest surprise...

GPR-90 with the GSB-1 SB adapter.

The rx was only so-so as a performer.  The GSB's gotta be one of the sweetest ways to listen to slop-bucket.

Re: Hustler 4BTV and Hygain 14AVS.  Had both, and they got out FB.  The trouble came on receive.  Guys I could barely hear under the QRM came through FB when a guy with a beam could block out the QRM.

[WA1GFZ]

biggest surprise gotham vertical 500 feet from the beach on 20 meters TR4.

[WD8BIL]

.

[Vortex Joe - N3IBX]

My biggest disappointment was a Collins 75A-4.  Couldn't wait to get it home and play with it.  That lasted all of a half hour before the audio quality irritated me so much I shut it off.  I fiddled with it for a bit doing an alignment, etc., but sold it at the next hamfest.  My second biggest disappointment is my SX-88 - nice receiver, but certainly not of legendary quality.

My biggest surprise was how nice my converted HW-12 sounded after a quickie half-hour conversion to AM.  I've gotten several .wav files (TNX, Bill, Bill, and the rest of you!) and it sounds pretty good.  Still, it's a terrible piece of junk - but a nice sounding piece of junk.

John,
      Let me second how good your little Griefkit sounds on the air. It can't be told from a "whatever" class B plate modulated rig with all sorts of audio mods. I remember asking you what you were using one night, whilst in QSO with you, and was astounded to hear how good it sounds on the air. It's the best rig I've heard you on!

Regarding the 75A's, Frank aka: Slab-a-Dabba-Doo, KB3AHE, has my old A3 he got from a swap we had. He told me he's going to do an audio mod on it to liven it up a little. I can't wait to hear what it sounds like!

Best Regards,
                  Joe N3IBX

[WA1GFZ]

My biggest surprise is the front to side ratio of my 12 element LPDA.
and shack pba