See

http://www.eham.net/forums/CompanyReviews/2925
http://www.eham.net/forums/CompanyReviews/2686

HA6SST

Would anyone be willing to email me part of the Yaesu Quadra schematic? I don't need all of it, just the schematic of one of the four amplifier boards based around the MRF150.

Email address is edwardalmos@gmail.com

Tnx

HA6SST

1) 22 foot mast constructed of 1.5 inch aluminum tubing, all joints fitted with bonding straps.

2) Icom automatic ATU fitted at the base, housed in a waterproof box.

3) Lots and lots of wire down there to act as a groundplane. This was done a week or so before the roofer placed the final layer of tar on the roof so I suspect the wires will last forever.

4) 50 ohm feeder running three floors down the side of the building to my apartment shack.

HA6SST

I don't think the pacemaker will be a problem.

1) Pacemakers are manufactured with a metal shell which completely encloses the device. This provides a shield from RF interference.

2) The pacemaker is inside the body, this may provide even more shielding at some frequencies.

3) The lead from the pacemaker to the heart is short and (in my case anyway) shielded. It would be about a quarter-wave at 222MHz but nowhere near a resonant length at any other ham frequency.

4) The lead from the pacemaker is an output, not an input, and of fairly low impedance.

5) Manufacturers of pacemakers have been aware of RF interference issues for some time and they do design around them. The liability issues in this area are frightening so manufacturers normally adopt a 'belt and braces' approach.

6) The inverse square law is your (or your daughters) friend. An antenna way up in the air will have no effect on your daughters health unless you are radiating many kilowatts.

And finally........

7) I was fitted with a pacemaker in 2001 and since then I have operated from 160m to 70cm using up to 2Kw of power.. I'm still here.

Please wish your daughter good luck from me and tell her to get well soon.

HA6SST

Nice people to do business with. I have never dealt with the main office in the USA but their European office is staffed with friendly people who know their products. Shipping as charged at a flat rate of $10 and all parts go out by registered mail.

The website at http://www.minicircuits.com contains full details of all their products including datasheets and performance graphs.

Best of all, their technical support staff know what they are talking about and are honest enough to recommend a cheaper product if it will do the job.

HA6SST

In theory you could check for harmonics using an absorption wavemeter. You would probably have to build this and calibrate it as I haven't seen one for years.

HA6SST

Glad to see I wasn't the only one to encounter poor customer service from LDG. They make great autotuners but their customer service technique could do with some improvement.

Emails to them were not answered and when they finally decided to answer one of my messages they didn't answer the question.

HA6SST

Thanks.

After an hour going crazy on Google the link http://www.uoguelph.ca/~antoon/gadgets/mostest.htm
 was just what I needed.

HA6SST

Testing power transistors is easy, just use the diode function on a multimeter. How do I test power MOSFETs such as the MRF150 and what results should I see?

HA6SST

Parts arrived two weeks after placing the order (shipped from Thailand) and funds have been taken from my credit card.

No problems.

HA6SST

Maybe this will help:

1pf
10pf
100pf = 0.1nf  = 0n1
1000pf = 1nf = 1n0

1nf
10nf = 0.01uf
100nf = 0.1uf
1000nf = 1uf

Capacitors just shown as 0.1 will almost certainly be 0.1uf or 100nf

The terms uf and mfd are interchangable, so a 1uf and a 1 mfd capacitor are the same part.

HA6SST

Am I the only one that is frightened by the thought of CB enthusiasts using Kilowatt amplifiers? I thought that your FCC was against these devices.

HA6SST

OK, I will have an attempt at explaining this as I asked a similar question some time ago and did some research into the subject.

Imagine if you have an HF receiver with two IF stages, the first stage is at 10.7MHz and the second stage is at 455KHz. Your first mixer is connected to a VFO, this converts your wanted frequency to 10.7MHz. Your second mixer is driven by an oscillator running at 10.245MHz, this converts 10.7MHz to 455KHz.

Normally the 10.245MHz oscillator is fixed but if you vary its frequency by (say) +/- 1.5KHz you have an IF Shift control. With the oscillator at 10.245MHz you will hear the full audio range. As you raise and lower this frequency you are tuning your 455KHz 'receiver' across the width of the 10.7MHz I.F.

With the oscillator at one end of the range you will only hear the low frequencies in a signal. At the other end of the range you only hear the high frequencies.

HA6SST

See:

http://members.aol.com/k3uoc/saudi.htm

http://forum.virtualtourist.com/2/discussion-328322-1-1-Travel-0-3009-Saudi_Arabia-discussion.html?wosid=Bsw4c04yHlcHq4GXRQKgoM

The short answer, no chance.

HA6SST

"They can have my lead alloy solder when they pry it from my dead, cold hands."

Amen to that. Taking advantage of the move to lead-free solder I now have four reels of PbSn solder in various sizes of diameter sitting in my cupboard. These were obtained at a bargain price and will be enough to last me for a long time. I have been using PbSn solder for thirty years and had no ill effects.

HA6SST