Long Long ago, there was a company named Palomar Engineers. Their most famous product , a noise bridge, was inexpensive and had a lot of uses. Palomar Engineers repackaged a portion of the noise bridge circuitry into a product designed specifically to allow you to tune your antenna tuner without putting a signal on the air. That product was the PT-340 Tuner Tuner.
I strive to be a polite ham and due as little on-the-air tuning as possible. A couple of weeks ago this PT-340 popped up in the QTH.com classifieds and I bought it, and I’m really impressed with it.
It certainly lets me tune my antenna tuner off-the-air. The thing that really impresses me however is that I can tune my Drake MN-2000 Antenna Tuner much faster and more accurately than by conventional means.
With the the radio set to receive on the desired frequency, I turn on the PT-340. It injects a white noise signal. Then I tune my MN-2000 tuner to null out the white noise. That’s it. (Then I turn off the PT-340, of course).
I’m surprised that modern antenna tuners don’t have this function built in.
Once again, a new hame asked about HF antennas and coax on Facebook. And once again, someone said “Get RG-213 because it is lower loss.” Let’s Look at the specs (These specs come from the DX Engineering catalog):
|Diameter||.240 in||.405 in|
|Min Bend Radius||2.4 in||5 in|
As you can see:
- RG-213’s loss per hundred feet is only .4 dB less than RG8X.
- RG213 is considerably more expensive than RG8X
- RG213 is twice the diameter with a solid polyethylene dielectric, making it heavier and much less flexible.
- Both are Direct-Bury
I run 100ft of RG8X from my Drake TR-4C to my Hy-Gain AV-640 vertical. The difference in loss is unnoticeable.
There ARE circumstances where RG8X is not the best choice:
- Your coax run is several hundred feet
- You are running high power
- You are operating an higher frequencies
In both these cases however, I would probably choose LMR-400 instead.
Over the weekend I repaired my Hy-Gain AV-640 vertical and replaced the coax. Everything is working nicely again. I talked to N3EON Steve in Baltimore this afternoon and he gave me a nice 59 report.
However, as I was tuning up, Sweet Lady Wife walked into the ham shack and said “You are turning my radio on and off”. Her radio is a Bose WaveRadio, and it sits almost exactly opposite the RCS-4 antenna switchbox. The RCS-4 box is mounted outside the house, and the Bose is right inside, up against that same wall, just 10 inches from the RCS-4. And the RCS-4 switchbox has a plastic cover instead of metal. I took the RCS-4 out of the equation, did another tune up, and the Bose was quite happy. So much for the RCS-4.
I tried breaking thru a pileup to reach a PJ4 (Bonaire) station that was booming in, but my little pistol was no match for the big guns. He said he wil be on every night this week so I’ll keep trying. When the income tax refund arrives, I’ll get an electrician in here to run a dedicated line for the Ten-Tec Centaur amplifier. Then perhaps I’ll have more success.
The replacement coax should arrive tomorrow that will hopefully fix my 6db loss.
In the meantime, I dug out my Ameritron RCS-4 Remote Antenna Switch. I packed it away when I moved, and it occurred to me that I’ll probably be adding additional antennas in the future, so I should go ahead and install it. I’ll mount the outside box (the upper one in the photo) on the wall adjacent to the antenna mast.
I’m getting antsy to get back on the air.
My first HF rig was a Heathkit HW-100
I bought it use. I think I paid $125 for in around 1979. It was old and tired when I bought it. As a result, I probably spend as much time with the covers off, fixing it as I did operating. I discovered first-hand what the term ‘gassy finals’ meant.
By then, Heathkit had already brought out its slightly improved successor, the HW_101. The 101 had a switchable CW filter so you could switch between SSB and CW filters. It also had several technical improvements. I bought the HW-101 manual and spent a lot of time with the 100 and 101 manuals and schematics side by side. I eventually incorporated most of the 101’s improvements into my 100.
I woke up a couple of days ago after a windstorm to discover that the SWR on my Hy-Gain AV-640 on 40m was way out of whack (7:1). 30m was also bad. 20m was ok.(1.3:1). I walked outside and saw that one of the 40m capacity hat spokes was bent down and hooked on a 30m spoke. That explains that.
My MFJ-269 Antenna Analyzer also was displaying about 6db of coax loss. I’ve inspected the coax, expecting to find that a little animal had been chewing on it but I see no signs of damage. I suspect the heavy rains (9 inches in October) may be the culprit.
I’ve ordered replacement coax from HRO, and as soon as the ground dries out a bit more I’ll tilt the AV-640 down, fix the 40m spoke problem, and give the whole thing a good inspection. And replace the coax at the same time.
I was not planning to buy an amplifier. I’ve operated barefoot all my life and had no compelling reason to change that. Then a fellow ham about 45 minutes away from me decided to sell his 600W Ten-Tec Centaur for a price too good to pass up.
Unfortunately, Ill need to have an additional electrical circuit installed in order to use it. It draws just 12A at 110V, but with everything else here in the shack on a single circuit I’m sure I would pop the breaker when I key the Centaur up. It will run on 220VAC. If I’m going to have an extra electrical circuit put in, I might as well make it 220V 20A circuit in case sometime in the future I move to a bigger amplifier.