Wednesday, November 30, 2011

Ham activating a Rest Area help Australian sailor adrift off the coast of Mexico.

11/24/2011 -- IHRAS Members assist Australian Sailor adrift near Mexico.
Jon - N5JLD

Well it went sort of like this. KF5FEI and I showed up at the rest stop just before 5 am CST. We got set up and the noise from the lights lighting up the rest stop was horrible. Way to much for SSB even with DSB, oh well so I waited for daylight. Bill was setup for PSK31 and not having much better luck with all the noise. As daylight arrived the band started to wake up with it. Bill made a handful of contacts and I could hear a lot on phone but no one heard me. I switched to Bill's antenna and spun the dial to 14.325 and called CQ. Well VK3LAA came back and answered my call. That's right VK. Problem was that he was not in Australia but off the coast of Mexico. In a boat, dead in the water and looking for help. Bill started looking on how to get a hold of the Coast Guard while I was talking to him getting to location and his current status. He was in a 35 foot sailboat but his motor was not working and he is adrift with no winds. Well Bill got a hold of the USCG in California and we were relaying information back and forth. The USCG was trying to raise the Mexican Coast Guard as VK3LAA was having no luck on Maritime VHF. Bill then called Scott McBain to see if we could find a club member with a base station and maybe a beam that might be better suited, remember we were portable at a rest stop south of Fort Worth. Robert AD5VJ signed on and took over the lead as he was able to get with the folks over on 14.300 with the Maritime Mobile Net. They in turn got in contact with all their support personnel and got him the help he needed. I signed off with VK3LAA as he was in very good hands. I spun the dial again and made contacts with CA and MO. We then called it a day, packed up and headed for Turkey time.

Just your average day and the rest stop...........


The above story was posted on the "Rest Areas On The Air" Yahoo group

Making a Spherical Audion Tube by Ron Soyland

Another great series of videos from Ron Soyland. In this video he recreates the classic Audion tube invented by Lee De Forest in 1906. The particular tube he creates in this video appears to be similar to the 1909 version of the Audion but substantially better made. The original Audion tubes were usually crudely constructed without the benefit of modern tooling or our current understanding of thermionic emission, they were expensive and had a short lifetime but paved the way for better tubes in the following years.

Tuesday, November 29, 2011

Making a Fleming Diode Tube - Ron Soyland

Its not often we get to see someone create a vacuum tube in their home workshop. Ron Soyland, a member of the Houston Vintage Radio Association, created these YouTube videos to show the process behind reproducing a Fleming diode tube. He carries out every task himself, from creating the glass envelope to final evacuation and testing.
Each video is approximately 10-15 minutes long and there are seven parts. Grab yourself a beverage and sit back to watch this fascinating process from raw glass to electronic component.

Essential information regarding 6146 tubes by K9STH

The 6146 family of tubes has been used in many home-brew commercial and transmitters over the years. The following information explains important points to look out for when replacing these tubes or home-brewing your own 6146 based transmitter. Normally I don't just copy and paste an entire article but this information should be included in every 6146 based rig's instruction manual, in bold type, at the start. KF5CZO

6146/6146A/6146B/6146W 8298/8298A/6293 
*6883/*6883A/*6883B *8032/*8032A/*8552 
Tubes Explained 
(*12 volt filament)

The 6146 and the 6146A differ in the type of heater (filament) and can be "mixed" in use (i.e. one 6146 and one 6146A in a DX-100). There are no other differences. The heater in the 6146A was developed by RCA and is called a "dark heater". The type 8298 is the same tube as the 6146A.

The 6146B is the same tube as the 8298A. The 6146B is a different tube from the 6146/6146A/8298. Sometimes they will work in place of the 6146/6146A, but often they will NOT. This is due to the different bias requirements of the 6146B, different inter-electrode capacitances, among other things. Often it is impossible to either neutralize the final in a rig designed for the 6146/6146A or the neutralization does not "hold" for very long (often less than an hour).

The 6146B/8298A have a very bad habit of producing VHF and UHF parasitic oscillations which can cause all sorts of problems including TVI as well as the tube literally "burning" itself up. This is when they are used in circuits that were designed for the 6146/6146A.

Collins Radio had to modify production of the later S-Line units to allow the military to use 6146B type tubes. This required a redesign of the neutralization circuit which is in place in the later 32S3, 32S3A, KWM-2, and KWM-2A units. The earlier versions of these models must use the 6146/6146A tubes. The later version can use all three types.

There is a "pulse" tube that is a very heavy duty version of the 6146 and can be substituted without any problems. This is the 6293. A 6293 will outlast a "plain" 6146 by at least 5 times the life (over 10 times is not that unusual!). We would "kill" back in the late 1950s and early 1960s to get our hands on a pair of 6293 tubes for our DX-100s, etc.

The 12 volt equivalent of the 6146 is the 6883. The 12 volt equivalent of the 6146A is the 6883A/8032 and the 12 volt equivalent of the 6146B is the 6883B/8032A/8552. The same thing is true of these tubes, do not replace the 6883/6883A with the 6883B series of tubes.

Back in the late 1970s Motorola tried to replace all of their 6883A/8032 tube stock with 6883B/8032A/8552 type tubes. A very large number of Motrac units used the 8032 and only the very "latest" versions used the 8552 tubes. At the time I owned the Motorola reconditioned equipment center for the south-central US and we used, on average, over 100 8032 tubes a week. Just as soon as Motorola replaced the 8032 with the 8552, we started having virtually all of the Motrac units that were shipped to the customer arrive with the tube envelopes "shattered" by "normal" shipping. We had never had this happen before.

The construction of the Motrac is such that the tubes cannot be seen when the unit is assembled. What was happening is that in the 2 to 5 minutes that the radio was being tuned and final QC'd, that they were oscillating at UHF (parasitics) and the tubes were getting so hot that the glass envelope was destroyed!

We told Motorola what the problem was. However, they refused to believe us until they had well over 1000 warranty complaints from their service stations. It cost them quite a lot of money in warranty repair bills before they again started placing 8032 tubes in the boxes marked 8032!

I have quite a number of "boat anchor" rigs that use the 6146/6146A type of tubes including Collins 32S1, 32S3; Heath SB-110A, SB-401, DX-100, DX-35, Apache. I have owned rigs like the Knight T-150 and T-150A and others that were designed for the older tube. Frankly, all of them are much "happier" with the 6146/6146A instead of the 6146B.

Now, for the 6146W: Unfortunately, some of these are "ruggedized" 6146A tubes and the later ones are 6146B equivalents. The only way to tell is by the manufacture date on tubes by a particular manufacturer. Unfortunately, to my knowledge, there is no master list giving this information. Each manufacturer changed from the 6146A to 6146B construction in their 6146W at different times.

I haven't seen a notice from Heath about using the 6146B tube. However, several manufacturers, including Collins Radio, originally said that it was fine to use the newer tubes. But, after a very short period of time they found out different!

Thus, I would be very careful about using the 6146B and the 6146W tubes in place of the 6146/6146A. You might "get away" with it. However, you might also do some damage to your final amplifier section. If you decide to try the 6146W, then be sure and neutralize the final and check it after operating for an hour or two. If the neutralization remains OK for several days, then you should be "home free". But, if the neutralization changes, then you need to replace the 6146W tubes with the 6146/6146A types.

Glen, K9STH

Sunday, November 27, 2011

New project - Heathkit SB-101

I've recently been presented with a Heathkit SB-101 transceiver, Heathkit SB-600 speaker and Heathkit HP-23A power supply courtesy of Philip KJ5OW of the Katy Amateur Radio Society.

The SB-101 is a hollow state rig, the only solid state components being a few diodes. It uses the well known, and fortunately fairly common, 6146 output tubes in the finals.

The manual is available here : Heathkit_SB101_Manual

Heathkit SB-101 Transceiver
There looks to be a little work required before this rig is put on the air, a few resistors have cracked for reasons unknown and the rubber belts need replacement in the load and tune controls. It is something worth taking time on as the SB-101 is a well regarded rig that is still a strong performer today. There have been some modifications made to support an external linear master oscillator (VFO) which will need to be looked at but are probably fine as they stand.

I pulled my Heathkit HD-1410 keyer out of storage and was pleased to find it was the same color and style, matching the SB-101.

Heathkit SB-101 transceiver, SB-600 speaker, HP-23A power supply and HD-1410 electronic keyer.

Year of Manufacture: 1967-70 (Improved SB-100[1965-7])
Bands: 80 - 10 (500kc) (2 Mhz on 28-30 mhz)
Modes: CW & SSB
Power: 180W PEP SSB & 170 input CW - 6146 Output Tubes
Frequency Control: LMO- Linear Master Oscillator (Like PTO)
Selectivity: 6 Pole filter 2.1kc @ 6db down (Accessory CW filter 400hz)
Contstruction: Aluminum Chassis & Cabinet-Printed circuit board wiring
Keying: PTT and VOX voice operation, VOX with sidetone for CW
Power Supplies: AC or DC power supplies availiable
Microphone: High Impeadance Desk or Mobile Microphones availiable.
Frequency Control: Local LMO/Xtal, Remote VFO/SB-640 w/Mod

Accessories: SB-200 Linear Amplifier, SB-500 2mtr Xvtr, SB-600 Speaker, SB-610 Monitor Scope, SB-620 Panadapter, SB-630 Station Console, SB-640 Remote VFO & SB-650 Digital Read-out.

Features: Easy to operate, TX & RX circuits track, RX RF Preamp, Easy to calibrate and read dial calibration, Two-Tone Green wrinkle paint, Switched Metering, Construction Manual very comprehensive.

Heathkit Transceiver Resources:

Sunday, November 20, 2011

Latest restoration project - Espey R-366/TRR-5 Radio Receiver

The Espey R-366/TRR-5 is a general purpose receiving set designed for use as an entertainment unit or auxiliary communications receiver. The receiver is a manually tuned, 16 tube superheterodyne. It has a tuning range of 540 to 30,000 kc in five tuning bands and receives either CW or voice signals.

It is similar to the Scott receiver AN/SRR-3 of the same period and produced under Contract NObsr-43229 dated 15 March 1949.

A user manual is available here : ANTRR5_INSTRUCTION_BOOK

The front panel as it originally looked.
The front panel once it had been cleaned.

First page in NAVSHIPS describing AN/TRR-5 and performance specifications.
Detailed shipping information for AN/TRR-5 receiver.
From the Antique Radio Forums :
Most of them were purged via DRMO in 1968-1973 and I only saw small numbers of them trickling through the system so I am guessing they were made in only a small quantity. None of the ones I have run across have had cabinets and all were in pretty atrocious condition. I vaguely recall the processing papers showing the equipment had come back from Vietnam, Guam, S. Korea and Japan.
Geoff Fors - WB6NVH

If you have any information regarding these receivers please leave a comment. If you have a R-366 of your own please let me know the serial number in the comments!

R-366/TRR-5 serial number registry:
  1. #623 : KF5CZO - Owen Morgan
  2. #050 : AE5VB - Hugh Coleman
  3. #132 : W5AMI - Brian Sherrod
  4. #591 : KC9KUH - Brian Love : (Compliance plate missing)
  5. #290 : KC5IIE - Chris Krug (Update 01/11/2012 : Sold to W5XTL - Jeramy Ross)
  6. #653 (Sold on Ebay, spotted by Brian KC9KUH)
  7. #251 (Sold on Ebay, spotted by Brian KC9KUH)
  8. #340 (Sold on Ebay, spotted by Brian KC9KUH)
  9. #468 Jeff Wewers
  10. #140 Gilbert Mendez
Using the formula N=m(1 + k − 1) − 1  from the german tank problem where m is the largest serial number observed and k is the count of serial numbers we see that the current estimated number of R-366/TRR-5 receivers produced is N=653(1+10 − 1) − 1 or approximately 717.

After bringing this receiver up on a variac to reform the filter capacitors I monitored the power usage and found it to be in line with the users manual @ approx 125W.
Audio is great due to the push-pull output stage and either a 6 ohm or a 600 ohm speaker can be used, both impedances are available on the rear connectors.
Readout seems accurate and the VFO is stable after just a few minutes warmup. Tuning the HAM bands is fairly touchy but this is really an AM rig by design.

Serial number 623 of how many? This seems to be a rare radio but I have heard of at least 4 other people with the R-366.

The bandchange is accomplished by rotating the circular turret. Each of the five bands has a complete set of discrete components in its sector of the drums.

Military amphenol right angled connectors. The three pin connector is 110V power in and the four pin is the 6/600 ohm speaker connector.
I was fortunate enough to be given period style military connectors for these sockets. Both neutral and active lines are fused on the power input circuit however I made sure to wire the active line to the power switch side for safety.

The receiver chassis slides out on roller slides for servicing and inspection. The full circuit diagram is also on the band change turret cover ... a thoughtful addition!

The only modification I can find is the antenna connector. Its been replaced with a SO-239 bulkhead connector for convenience. Personally not something I would have done myself but it makes life easier so I'm not complaining.

An unmodified antenna connection from another Espey R-366

Monday, November 14, 2011

Why not thorium?

A thought provoking documentary on nuclear energy using thorium, a safer and abundant source of reactor fuel.

Thursday, November 3, 2011

A murmuration of starlings

A chance encounter and shared moment with one of natures greatest and most fleeting phenomena.

Tuesday, November 1, 2011

2M Tape-Measure Yagi Antenna

A great antenna for 2M that can be built from parts obtained from HomeDepot or Lowes is the 2M tape-measure yagi antenna.

The link to the plans and instructions is here.

Two meter antenna built using PVC pipe and an inexpensive steel tape measure.

Sick radio on the bench

Should have been an easy fix but I suspect, after running a few searches through Google, that it is suffering from the dreaded silver mica disease. This would require taking the IF coil cans apart and replacing the integral silver mica capacitors with external units, not a project for the feint of heart!

Another day perhaps ... there are other projects to complete first.

Zenith 6J05 chassis and IF cans, looks simple enough doesn't it?

Front view of the Zenith chassis, the dial light also requires replacement.

Tubes! ... Some will be used in a homebrew transmitter.
The EICO signal tracer (behind the box of tubes) is working fine now but the EICO RF signal generator requires work.

An old tube AF power amp, low pass filter, coils, chokes and my meter collection ... there is even an RF ammeter in there somewhere.