Hi. Here in North Florida just about sunset, bands like 20M and above take a serious dump.

Here's a simple tip...Program all the WWV frequencies into your radio and even CHU, if you want.
You will probably hear the 15 MHz WWV signal really loud until local 'grey line', then nothing. I noticed this while listening to the 'gents' on 14.275. One minute they are there and then......zip.
Ole Sol hasn't started making 'spots' like expected.
Still, after dark, look to the lower frequencies like 40 M and down to still be active. This may be the bands the other chaps are talking about.
I have a 706g and it it has a great receiver.
73
ron
N4UE

Hi, I have restored a few dozen Lafayette receivers. These radios had a drop of white paint on the coil screws. I usually apply a drop of Laquer Thinner to the paint and before it dries, turn the screw both ways a bit. Sometimes the paint will reharden. In this case, I sometimes will add a SMALL amount of Synthetic oil. That way the paint won't set up.

Some radios use wax, and a good hair dryer works for that, although there are chemicals to remove wax from clothing and carpets. I have no experience with these.

Gud Luk

ron

N4UE

Thanks Jim.
Sorry about the multiple posts. I asked my 'Elmers' question from the main page. I previewed it, and when I hit 'post', I got an error message (3X) HA HA
When I went to 'forums', then I saw the 3 postings. Strange.
Anyway, I must have one of the satelites, I went back today to get the sub-woofer, which was MUCH larger and VERY heavy, and it was gone. The place I buy my speakers is a Sherrif's Youth Ranch 'outlet', kinda like an indoor flea market. LOTS of the stuff is ex-evidence, put up for sale to benefit the Boy's Ranch. Kind of a win-win.....
The circuit board is very dense and loaded with SMT devices. I was hoping that there was a way to turn on the amp and speaker by sending a control signal (VDC, ground, whatever) via that small 'control' connector. I really don't want to toss the amp and just use the speaker and enclosure........

tnx

ron

N4UE

I recently acquired a Boston Digital Model BA735 Speaker. It is in mint condition. Power supply included. My question has to do with the 'control' connector, which resembles an "S" video connector.
The speaker is 7.5" H X 6" wide. It has an amp inside that I would like to use. Sending audio into the RCA connector, lights up the 'activity' LED. No output due to the fact it needs to be 'controlled' somehow. Can anyone tell me how it's controlled? I haven't started tearing it apart yet, YET... ha ha

tnx
73
N4UE

I recently acquired a Boston Digital Model BA735 Speaker. It is in mint condition. Power supply included. My question has to do with the 'control' connector, which resembles an "S" video connector.
The speaker is 7.5" H X 6" wide. It has an amp inside that I would like to use. Sending audio into the RCA connector, lights up the 'activity' LED. No output due to the fact it needs to be 'controlled' somehow. Can anyone tell me how it's controlled? I haven't started tearing it apart yet, YET... ha ha

tnx
73
N4UE

I recently acquired a Boston Digital Model BA735 Speaker. It is in mint condition. Power supply included. My question has to do with the 'control' connector, which resembles an "S" video connector.
The speaker is 7.5" H X 6" wide. It has an amp inside that I would like to use. Sending audio into the RCA connector, lights up the 'activity' LED. No output due to the fact it needs to be 'controlled' somehow. Can anyone tell me how it's controlled? I haven't started tearing it apart yet, YET... ha ha

tnx
73
N4UE

KG7LR, thank you! I didn't know where to start, although GOOGLE would have been my next choice.

tnx agn
73
ron
N4UE

Hi gang. I need 'assistance' from someone that owns a Datong FL1.
I need info concerning a resistor in mine that is burned in half.
If one of you nice owners could simply remove the cover (as if you were going to replace the battery), I would be VERY grateful. 4 screws on the bottom.
NO DISASSEMBLY REQUIRED!! Just cover removal.

On the main (lower) board, directly in back of the 'phone' jack, there are some resistors and diodes. These run side-to-side.
Starting from the front, (behind the 'phone' jack)
there is a 2200 Ohm resistor, then a 8200 Ohm, then a pair of diodes. Lastly, before the battery holder, there is one last resistor. This resistor is in 2 pieces and I cannot read it's value.
I suspect the previous owner had battery/ps poroblems.
Mine will only work on battery power. It is supposed to switch to the external supply autoimatically. Mine doesn't work from external at all.
This is a simple circut and rather than let the smoke out of something else, I'd like to know the correct value.
Yes, I have the owners Manual, but there is NO schematic...

thanks in advance!

ron
N4UE

My recent experience has been nothing short of FANTASTIC!
I bought a damaged MFJ-784 DSP Audio Filter (non-B) off of eBay. The seller stated the damage:
one broken knob
one broken pot
front panel dented (aluminum)

I called MFJ and spoke to a very friendly chap by the name of Jimmy. I was concerned about the cost of the above components, especially a new front panel.

Well, to make a long story short, the total for:
two knobs (one had a scratch)
new 10K pot
new front panel (now made of steel!)

Including shipping was $11.05! When I explained to Jimmy, I do NOT use a Credit Card, he said " no problem, I'll mail today, just send a check".....

I called MFJ Tue afternoon and the parts were in the Post Office Thursday morning!!!

I cannot see how they could possibly provide service ANY better than that!

I also feel that I am a 'lucky' ham. I have 3 tuners, a 259B, a Voice Keyer, and about a dozen smaller items.
I have NEVER, EVER had one problem. Lucky?

ron
N4UE

OK, I know I can't (!!) be the only one having this problem. I have dozens of MALE 'N' connectors. ALL of them have the smaller ID center pin that fits RG-213, etc.
I just purchased 100' of 9913F7. It has the same center diameter as regular (old) 9913 with the solid center.
In the past, this was an easy fix. A few minutes with a file on the old 9913 and the center conductor went right into the 'N' center pin.
Obviously, I can't do this with the stranded center conductor of the 9913F7.

PLEASE tell me that I can purchase JUST some larger diameter center pins!!! Where? Man, I don't want to waste all these nice 'N' connectors for want of a pin....

tnx
ron
N4UE

Good 'ole Radiomart subscribes to this policy, BIG TIME.

He DOES have nice equipment for sale from time to time. Although I am not allowed to bid on his "LOOK, FROM MY PERSONAL COLLECTION" etc, I have been to his house, once.
All I can say is the way to tell if he's lying, is to watch his lips. If they move, he's lying.

I understand that everyone wants max $ for their sale items. I have NO problem with that...
What bugs me is seing him sell a MINT (really!!) Drake SPR-4 and have ALL the crystals, Noise Blanker, etc, listed seperately.
If a buyer is not well versed in a particular item, they may indeed get that "MINT" radio, but not be able to enjoy it due to lack of coverage....

my $.02

Asbestos suit nearby......

ron

N4UE

Robert, these are pretty good receivers. I have a lot (!!) of Trio-Kenwood receivers. They are very easy to restore.

I would sugest you:

1, locate a friend with a Transconductance type tube tester (or buy one off of ePay, er, eBay)
2, replace the coupling and bypass caps under the chassis. Although some guys don't agree, I have ALWAYS replaced caps in these locations. I just recently compleded (another) Lafayette HA-350. Another Trio-Kenwood radio. All the coupling / bypass caps were nfg. Just like my Collins and Hallicrafter radios, puting modern caps in, makes a huge difference. Every radio or piece of test equipment that comes through here, gets ALL the caps tested and replaced if necessary.
In fact, I came into the shack about 1 hour ago. I turned the HA-350 on cold. I immediatly tuned it to 15 MHz WWV. I only had to verrrry slightly touch the tuning knob (just once) and it's still there. Yes, it is AM, but listening to the 'people' on 14.275 USB also indicates a remarkable lack of drift. Of cource I'm using a small muffin fan to cool the old girl.....
3, don't just wholesale change the tubes! I have tested many hundreds (maybe thousands) of these original Japanese tubes and I don't remember only one or two being bad. Usually gassy.
4. Some (not all) of these old radios will benefit from changing the 6BA6 (RF amp) to a 6BZ6. Some really like it, others don't. Your radio will tell you if it like it!
5. Perform a good alignment. My experience with old receivers is a mixed bag. Some adjustments, will be dead on, and others will be waaaay off.

If you do not wish to spend the $ to acquire the needed test equipment, send ne an e-mail....

n4ue@arrl.net

or

bonddaleena@aol.com

gud luck and HAVE FUN....2012 is coming....

ron
N4UE

G3RPZ and VR2AX, thank you for your reply.

I'll try to answer your questions, but 'big bertha' has been in storage for a couple of years....

First, the PS... This thing is strictly (!!) 240VAC.

The Plate Transformer is set to run on 6 KV, 3 KV center tapped. That's why the input Variacs are there, to regulate the B+. These Variacs are VERY large, and I have them set pretty low. With these transformer mid taps, and slightly advancing the Variacs, I can easily achieve 1500 W out, as verified by a Bird Digital Wattmeter, I borrowed from work....
The PS is a basic L input. The capacitor bank is shunted with some strange looking devices. They look like small florescent lamps! If memory serves me correctly, I measured about 100K ohms.
These 'tubes' are hard to describe.... Because of the size of the PS and their placement in the PS, these tubes are virtually impossible to get to.
I would be more than glad to send digital photos of the inside of both the PS and the RF deck.

As far as the rectification goes... The original builder built a beautiful (large) assembly of about 200 (!!!) of the older 'top hat' style silicon rectifiers. The old design and my 'update' are full wave. Each diode was inserted in it's own heat sink and nicely bypassed with an equalizing resistor and ceramic cap. This entire assembly was painted with red Glyptol.
A couple of years ago, I replaced all these diodes with 4 of K2AW's BIG rectifier modules mounted on a nice, big aluminum heat sink with it's own muffin fan to provide any necessary cooling. Although the change to the more modern rectifier stack made me feel better, it made NO difference in the resulting voltage sag during key down.

Again, I can get enough B+ by simply cranking up the Variacs, that I could MELT the 500Zgs. This PS could probably power a TV station.

Bill Orr asured me that the amp was OK. "The power HAS to be going somewhere", Bill said. Yeah, but I don't want to waste the RF by low efficiency turning all the watts into heat! ha ha

thanks again,

ron

N4UE

Looooong post, sorry!

A while back, I posted asking for a dialog concerning a 6 Meter amp. I had a couple of replies, but not what I had hoped. WB2WIK responded that he had built several and wanted to know if I needed his help. Thanks, Steve, but you and I have already corresponded on that subject. ha ha

Before I get 'flamed' for bragging, please understand, I am JUST trying to make #1, the best it can be.

Here's what I have:

1. I am in the process of 'reworking', the "Mother of all 6 Meter amps". I bought this linear from a chap in Pa. back in the mid-80s. He was a retired machinist and the quality of workmanship on this thing is a true thing of beauty. I do NOT want to cut it up or otherwise destroy what he achieved. As Steve told me some time ago, he may have been an excellent craftsman, but a poor Engineer. OK, that could be true.
He built this amp using an OLD article by Bill Orr in CQ Mag. In fact, I corresponded with Bill (before he became a SK), concerning the amps efficiency.
The RF Deck alone, is 22" W, 16" D, 14" H.
Thre aluminum plate he used, has almost invisable joint lines. I have a complete machine shop here with high tech 2008 equipment and couldn't duplicate the fit/finish. He must have done it all by hand!

The P/S is 26" W, 20" D, 36" H.
WITHOUT the HV xformers and chokes, it weighs about 130 lbs. It's on casters, thank goodness!

OK, now comes my questions no one has been able to help me with........

The PS uses an xformer that weighs about 150 lbs! (pole pig?) It has mutiple taps, for HV out (220 VAC in). Right now, (for the last 20 years), I have been running it with the HV tap set at 50%. It is a choke input PS which goes against the current trend of cap input. It has two chokes. One is the size of a socker ball and the other is about the size of a smallish football. Yes, they are VERY heavy!!
What am I looking for? More efficiency from this OLD design. My HV drop is large (almost 50%, key down).
At WIK's recommendation, I tried removing the chokes, it made no difference. The capacitor 'bank' for this monster is a bunch (!!) of series/paralled oil filled VERY large HV cans (probably full of PCB!!!). Anyway, recently, I measured the capacity of the filter 'stack'. My NIST calibrated bridge indicated 18 MFD.
Input to the PS is provided by ganged 220 VAC Variacs. Using the medium xformer tap and about 50% of the variacs, I can get 1500W OUT, using a new pair of 3-500Zgs.

I have updated the plate chokes fron original, plus used silver plated copper tubing for the plate coil. The RF deck has a nice big vacuum variable in the pi network. I get a nice smooth peak and dip with the existing circuit. It has never arced over or gone into self oscillation.
It's the HV drop that I am concerned about.

The input to the rf deck will also be covered after item #2.

#2. I have another 6 Meter amp project. It is an Amp Supply amp. It has a Peter Dahl xformer. A large external cap bank (built by the previous owner). Yep, more big oil filled caps.
I am going to convert it to a dedicated 50 MHz amp, using a pair of 3-400Zs.

I have all the parts necessary. I hope! ha ha

My question for this amp as well as 'big bertha' above is a common one. I am looking for the best input matching circuit for both.
When I bought the 'big' amp, I redesigned the input circuit. The builder had a SB-110A. Most of my 50 MHz radios are SS, so they are a little more pickey. The design I used was a pi-network, with a compression mica cap on the input and output. It worked OK, but due to the physical layout of the RF Deck, was impossible to adjust with the tubes hot and the air plenum sealed. In this iteration, I want to run one (or at last resort, two) shafts out the front of the amp to ensure the 756PRO sees a low SWR and doesn't start cutting back it's output.

I have a whole 3 ring binder of amp design, including converting an SB-220 to 50 MHz, etc, etc.
None of the input designs has yet struck my fancy.

So, ANY ideas about good input circuits and reducing the voltage drop on 'big bertha'? I REALLY don't like running 4KV + during standby!!!

Thanks a lot in advance.

ron

N4UE

I have had Powerline Noise for a long time here in North Florida. I live in a unpopulated area, which is VERY old.
Florida Power and Light has been outstanding about finding and eliminating the noise. There is another Ham about 1/2 mile from me, that has the occasional noises as well.
Recently, I started hearing a noise which sounded like the typical 'loose hardware' buzz. Strange, it was most prevelant from 20 MHz upward.
Today, I turned on the 756PRO to listen on 50.125 MHz. There the noise was. It was intermittant. It shows up like the spikes of a comb (facing upward). It would come and go.

Just playing around, I disconnected the Optical Mouse (3D it says in the bottom). The noise went away!!
Plugging the Mouse in and out, confirmed it indeed was the source of the problem.
It is a USB Optical Mouse plugged into the shack's Acer TravelMate 2430
I went out to my well stocked junk box and grabbed a couple of torroids that the USB connector would pass through. The noise disappeared.
Since I am PC 'dumb', it appeared the noise would appear when the PC was 'looking for the mouse'?

Anyone else had this problem???

Guess I'll look for a USB NON-Optical Mouse next...


ron

N4UE