24 January 2012

Price List for Low VHF-Q/Low VHF-Rp Parasitic Suppressor Retrofit-Kits and Other Items

Parasitic-Suppressor Retrofit-Kits include nickel-chromium-iron alloy wire; 430'F / 221'C tin-silver solder and nichrome soldering flux, glitch protection and RF-NFB resistors; capacitors; 200a-peak glitch protection diodes; instructions; diagrams and an easier-to-understand, condensed version of the Oct 1988 QST article.

Retrofit-kits are available for the majority of contemporary grounded-grid amplifiers. If you need a special kit, telephone me and we can probably arrive at a solution. Amplifiers up to 100kW PEP have been retrofitted with low VHF Q parasitic suppressors.

For more information on intermittent VHF parasitic oscillation and some photographs of parasitic-damaged amplifier parts, see QST magazine, Parasitics Revisited, Part-1: September 1990, page 15 and Part-2: October 1990, page 32.

Suppressor Retrofit-Kit for:	Price	per additional amplifier add
(1) 3CX1200A7/3-1000Z	$ 16.50	$5.50
(1) 3-500Z, 3-400Z	15.00	4.50
(1) 8873 [SB-230]	15.50	4.50
(1) 8877	17.00	5.50
(2) 3-500Zs, 3-400Zs	16.50	5.50
(2) 572Bs or 811As	14.50	4.50
(2) 3CX800A7s	18.50	5.50
(2) 3CX800A7s - Titan 425	18.50	5.50
(2) 8873s, 8874s	17.00	5.50
MLA-2500	18.50	6.50
(3) 8874s	17.50	6.00
(4) 572Bs or 811As	18.50	6.00
4-1000A {up to 2-tubes}	19.50	10.00

.

SHIPPING

UNITED STATES: Actual cost of First-Class postage. .

INTERNATIONAL: Actual cost of postage. to airmail your order to your country. Example, 8-ounces to Australia: $7.00.

CA residents add 8.25% Sales-Tax.. Shipping charges are not taxable.

All prices are subject to change without written notice. If our costs increase, we increase prices. If our costs decrease, we decrease prices.

Guarantee --- Our VHF parasitic suppressor retrofit kits are guaranteed to make your amplifier more stable. If you feel your amplifier was not made more stable by our retrofit kit, you owe us nothing for the kit - or, a refund will be made if you already paid.

Most of the parasitic-suppressor retrofit kits are designed to make their respective amplifier-tubes safe to use with C. 100W of drive power. This is accomplished by adding RF negative-feedback [RF-NFB] resistors (Rc) n series with a G-G amplifier's cathode-input circuitry. This will prevent sensitive tubes like the 8874 and 3CX800A7 from being over-driven by a 100W transceiver. RF--NFB works better than amplifier to transceiver ALC. RF--NFB also increases amplifier linearity and stability. If you own a transceiver that can not deliver approx. 100w, you can choose to leave out, or reduce the value of, the RF-NFB resistors during the modification procedure.

If you know how to solder and you can read/comprehend English, you can probably install a suppressor retrofit kit. Anyone who can build a Heathkit® can do it. If you have a problem or question, you can call me on the telephone. When I am not available, my answering service takes messages. I return all calls on my dime.

There are people who install suppressor retrofit kit, however, amplifiers that are shipped via UPS--Surface are virtually certain to be subjected to severe G-forces [dropped/thrown]. UPS--2nd Day handles packages somewhat less roughly. Glass amplifier tubes should be shipped in separate, large, boxes. Put packing pellets in partly-filled sealed plastic shopping bags to avoid settling during shipping. /// UPS is pronounced "OOPS".

Other Items

Resistors:

R	P	TOL.+/-%	MAX-V	PART #	PRICE	TYPE
0.82-ohms	2W	5%		79	$ 0.26	MF
1.0-ohms	0.5W	5%		80.5	$ 0.05	MF
1.0-ohms	3W	5%		80	$ 0.28	MF
10-ohms	3w	5%		81	$ 0.28	MOF
15-ohms	10W, 120J	5%		81.3	$ 1.77	WW surge-R
100-ohms	3W	5%		83	$ 0.28	MOF
200-ohms	2W	5%		84	$ 0.26	MOF
510-ohms	3W	5%		84.5	$ 0.64	MOF
100k-ohms	3W	5% (<1% typical )	500V	86	$ 0.28	MOF
100k-ohms, Bag of 100	3W	5% (<1% typical )	500V	86.2	$ 22.00	MOF
30-ohms	0.25W	5%		88	$ 0.05	C
470-ohms	0.5W	5%		88.4	$ 0.05	C
51-ohms	0.5W	5%		88.5	$ 0.05	C

Diodes:

TYPE	AMPS	PIV	PEAK	RECOVERY TIME	PART #	PRICE
1N5408	3A	1,000V	200a		7.1	$ 0.22
SF-25B	2A	300V		35nSec	7.2	$0.90
1.5KE47CARL	31.9-peak	47V	1500w		44.4	$1.20

• 1N5408: general purpose Si rectifier.
• The SF25B is an ultra-fast diode that is used in series with a suitable R for adding positive half-cycle loading to the cathode of a g-g amplifier that lacks a tuned-input circuit to improve input SWR.
• . The 1.5CE47CARL: is a1500w-peak ,47v, bi-directioonal, V-transient suppressor.that we use to suppress v-transients across Q1 in the high-speed switching circuit in Figure 7B.

Capacitors

C	MFG RATING	TEST V @25ºC	+/- % TOL	PART #	PRICE	TYPE / USE
560uF	450WV. 105ºC	540V	20	95	$11.00	HV electrolytic filters
150uF	200WV, 105ºC		20	95.1	$1.97	electrolytic filter
2700pF	3000WV	9000V	10	96	$1.38	cer bypass
10,000pF	500V		20	94	$0.15	cer bypass
470pF	3000V		10	91	$0.25	cer
33pF	1000V		10	92	$0.10	cer

Orders of 2 or more 450WV filter caps, are matched. .

The150µF, 200V cap., P/N 95.1. is used for the PS for the high-speed switching circuit in Figure 7B.

HSS Parts: - - NEC PS2505-1 optoisolator; 80V >300% I-gain; 6µS, 80mA max. input; $1.00 [pn--44.3]. HV switching transistor; NPN, 300V, 0.5A, $0.35 each [pn--44] -- includes 2, 1k-ohm base-bias resistors; 10A 100V NPN flat-pak transistor for electronic cathode bias switch (Q1 in ECBS) [pn-44.1, $2.30 each; transient V suppressor for ECBS (D1), 1.5CE47A - 1500W peak,Vz= 47v [pn-44.4] $1.20. - - - Parts kit - including the resistors ,capacitors, and the solid-state parts. for the high-speed switching mod: $10 [pn-47]. The high speed vacuum relay, RF input relay and the perfboard are not included.

Parts for +150V PS for HSS mod when no built in +110V to +150V PS is built in the amplifier (Drake L4-B, Henry 3KA, et cetera):--- Capacitor, Matsushita,105ºC, 150uF, 200V, pn 95.1, $1.83; rectifier, 3A/1kV pn 7.1, $0.22; current-limiting R, 10-ohms, 3w, MOF, pn 81, $0.48.

The 430ºF/221ºC, eutectic, silver solder we supply in the retrofit-kits is: corrosion resistant, approx. 3.5-times stronger than 60/40 tin-lead electronics solder, flows well on difficult to solder materials, and contains no toxic hazards. It is FDA-approved for use on food utensils. It surpasses Mil-Spec purity standards. 1/8" / 3.17mm diameter silver solder: $0.16 per inch /25mm, pn--41.2}. This material works well with liquid rosin flux for soldering copper, silver, tin, brass, pins on 3-500Zs, and printed circuit boards. It is excellent for use on antennas and ground systems. It also works well for soldering aluminum by using J. W. Harris® aluminum soldering flux {available at welding supply shops}.

Low VHF-Q/Low VHF-Rp conductor material: Ni-Cr #22 [0.8mm] wire,: 4ft coils, pn--45, $1.00 each -. DC R = c. 1.0 ohms per foot. Nichrome ribbon, 0.25 inch by 4-mil, $3.00 per foot, 0.8-ohm/foot.

Ordering Information

Each suppressor retrofit kit order should include the amplifier model and the quantity of such amplifiers that you are modifying. We would also like to have a telephone number where you can be reached in the evenings or on weekends--just in case there's a question. If you have a question, please feel free to telephone me up to 8pm CA time.

Payment: Personal cheque, cash in either U. S. dollars or Euros wrapped in newspaper comics, or PayPal. If you use PayPal, please add 3.9% to cover PayPal's take.

Your cheque is not deposited until after your order is mailed. Unless otherwise requested, small refunds are normally made in extra silver solder or cash. Larger refunds are made by cheque payable in U.S.$. Make cheques payable to R. L, Measures.

--Address--

Richard L. Measures, AG6K

6455 La Cumbre Road

Somis, CA, 93066 -- 805 386 3734, r@somis.org

Overseas orders: Please tell us what to write on the package to help your retrofit-kit pass smoothly through your country's customs or import-duty department.